Abstract

High-resolution spectroscopy not only can identify atoms and molecules but also can provide detailed information on their chemical and physical environment and relative motion. In the terahertz frequency region of the electromagnetic spectrum, where many molecules have fundamental vibrational modes, there is a lack of powerful sources with narrow linewidths that can be used for absorption measurements or as local oscillators in heterodyne detectors. The most promising solid-state source is the THz frequency quantum cascade laser (QCL), however, the linewidth of this compact semiconductor laser is typically too broad for many applications, and its frequency is not directly referenced to primary frequency standards. In this work, we injection lock a QCL operating at 2 THz to a compact fiber-based telecommunications wavelength frequency comb, where the comb line spacing is referenced to a microwave frequency reference. This results in the QCL frequency locking to an integer harmonic of the microwave reference, and the QCL linewidth reducing to the multiplied linewidth of the microwave reference, <100  Hz. Furthermore, we perform phase-resolved detection of the locked QCL and measure the phase noise of the locked system to be 75  dBc/Hz at 10 kHz offset from the 2 THz carrier.

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References

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  1. A. E. Siegman, Lasers (University Science Books, 1989).
  2. S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
    [Crossref]
  3. L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
    [Crossref]
  4. J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
    [Crossref]
  5. E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
    [Crossref]
  6. E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
    [Crossref]
  7. P. Jansen, H. L. Bethlem, and W. Ubachs, “Perspective: tipping the scales: search for drifting constants from molecular spectra,” J. Chem. Phys. 140, 010901 (2014).
    [Crossref]
  8. J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
    [Crossref]
  9. O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
    [Crossref]
  10. H. W. Hubers, “Terahertz heterodyne receivers,” IEEE J. Sel. Top. Quantum Electron. 14, 378–391 (2008).
    [Crossref]
  11. O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
    [Crossref]
  12. J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
    [Crossref]
  13. S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
    [Crossref]
  14. R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
    [Crossref]
  15. L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
    [Crossref]
  16. A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
    [Crossref]
  17. M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
    [Crossref]
  18. R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
    [Crossref]
  19. Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
    [Crossref]
  20. S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
    [Crossref]
  21. A. Barkan, F. K. Tittel, D. M. Mittleman, R. Dengler, P. H. Siegel, G. Scalari, L. Ajili, J. Faist, H. E. Beere, E. H. Linfield, A. G. Davies, and D. A. Ritchie, “Linewidth and tuning characteristics of terahertz quantum cascade lasers,” Opt. Lett. 29, 575–577 (2004).
    [Crossref]
  22. H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
    [Crossref]
  23. P. Khosropanah, A. Baryshev, W. Zhang, W. Jellema, J. N. Hovenier, J. R. Gao, T. M. Klapwijk, D. G. Paveliev, B. S. Williams, S. Kumar, Q. Hu, J. L. Reno, B. Klein, and J. L. Hesler, “Phase locking of a 2.7  THz quantum cascade laser to a microwave reference,” Opt. Lett. 34, 2958–2960 (2009).
    [Crossref]
  24. D. Rabanus, U. U. Graf, M. Philipp, O. Ricken, J. Stutzki, B. Vowinkel, M. C. Wiedner, C. Walther, M. Fischer, and J. Faist, “Phase locking of a 1.5 terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver,” Opt. Express 17, 1159–1168 (2009).
    [Crossref]
  25. L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
    [Crossref]
  26. B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
    [Crossref]
  27. S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
    [Crossref]
  28. K.-E. Peiponen, A. Zeitler, and M. Kuwata-Gonokami, Terahertz Spectroscopy: Theory and Applications (Springer, 2012).
  29. S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
    [Crossref]
  30. Y.-S. Lee, Principles of Terahertz Science and Technology (Springer, 2009).
  31. J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
    [Crossref]
  32. B. S. Williams, “Terahertz quantum-cascade lasers,” Nat. Photonics 1, 517–525 (2007).
    [Crossref]
  33. G. Liu, X. Jin, and S. L. Chuang, “Measurement of linewidth enhancement factor of semiconductor lasers using an injection-locking technique,” IEEE Photon. Technol. Lett. 13, 430–432 (2001).
    [Crossref]
  34. K. Balakier, M. J. Fice, L. Ponnampalam, A. J. Seeds, and C. C. Renaud, “Monolithically integrated optical phase lock loop for microwave photonics,” J. Lightwave Technol. 32, 3893–3900 (2014).
    [Crossref]
  35. C. Walton, A. C. Bordonalli, and A. J. Seeds, “High-performance heterodyne optical injection phase-lock loop using wide linewidth semiconductor lasers,” IEEE Photon. Technol. Lett. 10, 427–429 (1998).
    [Crossref]
  36. C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
    [Crossref]
  37. “University of Leeds data repository,” https://doi.org/10.5518/224 .

2016 (2)

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

2015 (4)

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

2014 (5)

K. Balakier, M. J. Fice, L. Ponnampalam, A. J. Seeds, and C. C. Renaud, “Monolithically integrated optical phase lock loop for microwave photonics,” J. Lightwave Technol. 32, 3893–3900 (2014).
[Crossref]

P. Jansen, H. L. Bethlem, and W. Ubachs, “Perspective: tipping the scales: search for drifting constants from molecular spectra,” J. Chem. Phys. 140, 010901 (2014).
[Crossref]

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

2012 (4)

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref]

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
[Crossref]

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

2011 (2)

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

2010 (2)

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

2009 (2)

2008 (4)

J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
[Crossref]

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

H. W. Hubers, “Terahertz heterodyne receivers,” IEEE J. Sel. Top. Quantum Electron. 14, 378–391 (2008).
[Crossref]

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

2007 (2)

B. S. Williams, “Terahertz quantum-cascade lasers,” Nat. Photonics 1, 517–525 (2007).
[Crossref]

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

2006 (1)

E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
[Crossref]

2004 (1)

2002 (1)

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

2001 (1)

G. Liu, X. Jin, and S. L. Chuang, “Measurement of linewidth enhancement factor of semiconductor lasers using an injection-locking technique,” IEEE Photon. Technol. Lett. 13, 430–432 (2001).
[Crossref]

1999 (1)

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

1998 (1)

C. Walton, A. C. Bordonalli, and A. J. Seeds, “High-performance heterodyne optical injection phase-lock loop using wide linewidth semiconductor lasers,” IEEE Photon. Technol. Lett. 10, 427–429 (1998).
[Crossref]

Abgrall, M.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Ajili, L.

Amy-Klein, A.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Argence, B.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Asvany, O.

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Balakier, K.

Barbieri, S.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Barkan, A.

Baron, J.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Barry, J. F.

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

Bartalini, S.

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Bartolini, P.

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Baryshev, A.

Beere, H.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Beere, H. E.

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
[Crossref]

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

A. Barkan, F. K. Tittel, D. M. Mittleman, R. Dengler, P. H. Siegel, G. Scalari, L. Ajili, J. Faist, H. E. Beere, E. H. Linfield, A. G. Davies, and D. A. Ritchie, “Linewidth and tuning characteristics of terahertz quantum cascade lasers,” Opt. Lett. 29, 575–577 (2004).
[Crossref]

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Beltram, F.

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Bennett, S.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

Bethlem, H. L.

P. Jansen, H. L. Bethlem, and W. Ubachs, “Perspective: tipping the scales: search for drifting constants from molecular spectra,” J. Chem. Phys. 140, 010901 (2014).
[Crossref]

Blaser, S.

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref]

Bordonalli, A. C.

C. Walton, A. C. Bordonalli, and A. J. Seeds, “High-performance heterodyne optical injection phase-lock loop using wide linewidth semiconductor lasers,” IEEE Photon. Technol. Lett. 10, 427–429 (1998).
[Crossref]

Borodin, A.

J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
[Crossref]

Brünken, S.

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

Burr, E.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

Cai, B.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

Campbell, W. C.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Cancio, P.

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Cannard, P.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Chanteau, B.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Chardonnet, C.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Chen, L.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Chuang, S. L.

G. Liu, X. Jin, and S. L. Chuang, “Measurement of linewidth enhancement factor of semiconductor lasers using an injection-locking technique,” IEEE Photon. Technol. Lett. 13, 430–432 (2001).
[Crossref]

Cole, S.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Colombelli, R.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Consolino, L.

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Darquié, B.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Daussy, C.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Davies, A. G.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

A. Barkan, F. K. Tittel, D. M. Mittleman, R. Dengler, P. H. Siegel, G. Scalari, L. Ajili, J. Faist, H. E. Beere, E. H. Linfield, A. G. Davies, and D. A. Ritchie, “Linewidth and tuning characteristics of terahertz quantum cascade lasers,” Opt. Lett. 29, 575–577 (2004).
[Crossref]

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

De Natale, P.

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Dean, P.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

DeMille, D.

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Dengler, R.

Ding, L.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Döhler, G. H.

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

Doyle, J. M.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Endres, E. S.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Faist, J.

Fice, M. J.

Fischer, M.

Freeman, J.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Freeman, J. R.

J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
[Crossref]

Gabrielse, G.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Gao, J. R.

Geistlinger, K.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Gellie, P.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Gerin, M.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Giesen, T. F.

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Giles Davies, A.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Giuliani, G.

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

Gossard, A. C.

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

Gough, O.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

Graf, U. U.

Green, R. P.

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

Gregoire, S.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Gurevich, Y. V.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Gusdorf, A.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Güsten, R.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Gwilliam, R.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Hansen, M.

J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
[Crossref]

Harrison, P.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Hartogh, P.

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Hauser, D.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Hbers, H.-W.

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Hesler, J. L.

Hess, P. W.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Honingh, N.

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Hovenier, J. N.

Hu, Q.

Hubers, H. W.

H. W. Hubers, “Terahertz heterodyne receivers,” IEEE J. Sel. Top. Quantum Electron. 14, 378–391 (2008).
[Crossref]

Hübers, H. W.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Hübers, H.-W.

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

Hudson, E. R.

E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
[Crossref]

Hugi, A.

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref]

Hutzler, N. R.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Ikonic, Z.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Indjin, D.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Inguscio, M.

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

Iotti, R. C.

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Jacobs, K.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Jansen, P.

P. Jansen, H. L. Bethlem, and W. Ubachs, “Perspective: tipping the scales: search for drifting constants from molecular spectra,” J. Chem. Phys. 140, 010901 (2014).
[Crossref]

Jarchow, C.

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Jellema, W.

Jin, X.

G. Liu, X. Jin, and S. L. Chuang, “Measurement of linewidth enhancement factor of semiconductor lasers using an injection-locking technique,” IEEE Photon. Technol. Lett. 13, 430–432 (2001).
[Crossref]

Khanna, S. P.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Khosropanah, P.

Kirilov, E.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Klapwijk, T. M.

Klein, B.

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

P. Khosropanah, A. Baryshev, W. Zhang, W. Jellema, J. N. Hovenier, J. R. Gao, T. M. Klapwijk, D. G. Paveliev, B. S. Williams, S. Kumar, Q. Hu, J. L. Reno, B. Klein, and J. L. Hesler, “Phase locking of a 2.7  THz quantum cascade laser to a microwave reference,” Opt. Lett. 34, 2958–2960 (2009).
[Crossref]

Kliese, R.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Köhler, R.

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Kozyryev, I.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Kumar, S.

Kumar, S. S.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Kuwata-Gonokami, M.

K.-E. Peiponen, A. Zeitler, and M. Kuwata-Gonokami, Terahertz Spectroscopy: Theory and Applications (Springer, 2012).

Lachab, M.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Lakhmanskaya, O.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Le Coq, Y.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Lealman, I.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Lee, S.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Lee, Y.-S.

Y.-S. Lee, Principles of Terahertz Science and Technology (Springer, 2009).

Leng Lim, Y.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Leurini, S.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Levrier, F.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Lewandowski, H. J.

E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
[Crossref]

Li, L.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Linfield, E. H.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

A. Barkan, F. K. Tittel, D. M. Mittleman, R. Dengler, P. H. Siegel, G. Scalari, L. Ajili, J. Faist, H. E. Beere, E. H. Linfield, A. G. Davies, and D. A. Ritchie, “Linewidth and tuning characteristics of terahertz quantum cascade lasers,” Opt. Lett. 29, 575–577 (2004).
[Crossref]

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Liu, G.

G. Liu, X. Jin, and S. L. Chuang, “Measurement of linewidth enhancement factor of semiconductor lasers using an injection-locking technique,” IEEE Photon. Technol. Lett. 13, 430–432 (2001).
[Crossref]

Liu, H. C.

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref]

Lopez, O.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Mahler, L.

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

Maineult, W.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Malzer, S.

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

Marshall, O. P.

J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
[Crossref]

McCarron, D. J.

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

Menten, K. M.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Mittleman, D. M.

Moore, R.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Müller, H. S. P.

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Nicolodi, D.

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

Nikolic, M.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Norrgard, E. B.

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

O’Leary, B. R.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Panda, C. D.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Pantouvaki, M.

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Parsons, M. F.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Paveliev, D. G.

Pavlov, S. G.

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

Peiponen, K.-E.

K.-E. Peiponen, A. Zeitler, and M. Kuwata-Gonokami, Terahertz Spectroscopy: Theory and Applications (Springer, 2012).

Petrik, E. S.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Philipp, M.

Ponnampalam, L.

Potapov, A.

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

Preu, S.

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

Rabanus, D.

Rakic, A. D.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Renaud, C. C.

K. Balakier, M. J. Fice, L. Ponnampalam, A. J. Seeds, and C. C. Renaud, “Monolithically integrated optical phase lock loop for microwave photonics,” J. Lightwave Technol. 32, 3893–3900 (2014).
[Crossref]

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

Reno, J. L.

Rezac, L.

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Richter, H.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

Ricken, O.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

D. Rabanus, U. U. Graf, M. Philipp, O. Ricken, J. Stutzki, B. Vowinkel, M. C. Wiedner, C. Walther, M. Fischer, and J. Faist, “Phase locking of a 1.5 terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver,” Opt. Express 17, 1159–1168 (2009).
[Crossref]

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Ritchie, D.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Ritchie, D. A.

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
[Crossref]

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

A. Barkan, F. K. Tittel, D. M. Mittleman, R. Dengler, P. H. Siegel, G. Scalari, L. Ajili, J. Faist, H. E. Beere, E. H. Linfield, A. G. Davies, and D. A. Ritchie, “Linewidth and tuning characteristics of terahertz quantum cascade lasers,” Opt. Lett. 29, 575–577 (2004).
[Crossref]

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Rossi, F.

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Santarelli, G.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Sawyer, B. C.

E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
[Crossref]

Scalari, G.

Schiller, S.

J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
[Crossref]

Schlemmer, S.

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Seeds, A. J.

K. Balakier, M. J. Fice, L. Ponnampalam, A. J. Seeds, and C. C. Renaud, “Monolithically integrated optical phase lock loop for microwave photonics,” J. Lightwave Technol. 32, 3893–3900 (2014).
[Crossref]

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

C. Walton, A. C. Bordonalli, and A. J. Seeds, “High-performance heterodyne optical injection phase-lock loop using wide linewidth semiconductor lasers,” IEEE Photon. Technol. Lett. 10, 427–429 (1998).
[Crossref]

Semenov, A. D.

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

Shen, J.

J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
[Crossref]

Siegel, P. H.

Siegman, A. E.

A. E. Siegman, Lasers (University Science Books, 1989).

Sirtori, C.

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Spaun, B.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Spieler, S.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Steinecker, M. H.

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

Stutzki, J.

Tarbutt, M. R.

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

Taschin, A.

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Tittel, F. K.

Torre, R.

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Tredicucci, A.

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

Ubachs, W.

P. Jansen, H. L. Bethlem, and W. Ubachs, “Perspective: tipping the scales: search for drifting constants from molecular spectra,” J. Chem. Phys. 140, 010901 (2014).
[Crossref]

Valavanis, A.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Villares, G.

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref]

Vitiello, M. S.

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Vowinkel, B.

Vutha, A. C.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Walther, C.

Walton, C.

C. Walton, A. C. Bordonalli, and A. J. Seeds, “High-performance heterodyne optical injection phase-lock loop using wide linewidth semiconductor lasers,” IEEE Photon. Technol. Lett. 10, 427–429 (1998).
[Crossref]

Wang, L. J.

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

West, A. D.

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

Wester, R.

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Wiedner, M. C.

D. Rabanus, U. U. Graf, M. Philipp, O. Ricken, J. Stutzki, B. Vowinkel, M. C. Wiedner, C. Walther, M. Fischer, and J. Faist, “Phase locking of a 1.5 terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver,” Opt. Express 17, 1159–1168 (2009).
[Crossref]

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Wiesemeyer, H.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Williams, B. S.

Wilson, S. J.

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

Wyrowski, F.

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

Xu, J.-H.

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

Yamada, K. M. T.

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

Ye, J.

E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
[Crossref]

Zeitler, A.

K.-E. Peiponen, A. Zeitler, and M. Kuwata-Gonokami, Terahertz Spectroscopy: Theory and Applications (Springer, 2012).

Zhang, W.

Zhu, J.

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

Appl. Phys. Lett. (4)

R. P. Green, J.-H. Xu, L. Mahler, A. Tredicucci, F. Beltram, G. Giuliani, H. E. Beere, and D. A. Ritchie, “Linewidth enhancement factor of terahertz quantum cascade lasers,” Appl. Phys. Lett. 92, 071106 (2008).
[Crossref]

Y. Leng Lim, P. Dean, M. Nikolić, R. Kliese, S. P. Khanna, M. Lachab, A. Valavanis, D. Indjin, Z. Ikonić, P. Harrison, E. H. Linfield, A. Giles Davies, S. J. Wilson, and A. D. Rakić, “Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers,” Appl. Phys. Lett. 99, 081108 (2011).
[Crossref]

H. Richter, S. G. Pavlov, A. D. Semenov, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and H.-W. Hübers, “Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line,” Appl. Phys. Lett. 96, 071112 (2010).
[Crossref]

J. R. Freeman, O. P. Marshall, H. E. Beere, and D. A. Ritchie, “Improved wall-plug efficiency of a 1.9  THz quantum cascade laser by an automated design approach,” Appl. Phys. Lett. 93, 191119 (2008).
[Crossref]

Astron. Astrophys. (2)

S. Leurini, F. Wyrowski, H. Wiesemeyer, A. Gusdorf, R. Güsten, K. M. Menten, M. Gerin, F. Levrier, H. W. Hübers, K. Jacobs, O. Ricken, and H. Richter, “Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39,” Astron. Astrophys. 584, A70 (2015).
[Crossref]

L. Rezac, P. Hartogh, R. Güsten, H. Wiesemeyer, H.-W. Hbers, C. Jarchow, H. Richter, B. Klein, and N. Honingh, “First detection of the 63 μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA⋆,” Astron. Astrophys. 580, L10 (2015).
[Crossref]

Electron. Lett. (1)

L. Li, L. Chen, J. Zhu, J. Freeman, P. Dean, A. Valavanis, A. G. Davies, and E. H. Linfield, “Terahertz quantum cascade lasers with >1  W output powers,” Electron. Lett. 50, 309–311 (2014).
[Crossref]

IEEE J. Quantum Electron. (1)

C. C. Renaud, M. Pantouvaki, S. Gregoire, I. Lealman, P. Cannard, S. Cole, R. Moore, R. Gwilliam, and A. J. Seeds, “A monolithic MQW InP-InGaAsP-based optical comb generator,” IEEE J. Quantum Electron. 43, 998–1005 (2007).
[Crossref]

IEEE J. Sel. Top. Quantum Electron. (1)

H. W. Hubers, “Terahertz heterodyne receivers,” IEEE J. Sel. Top. Quantum Electron. 14, 378–391 (2008).
[Crossref]

IEEE Photon. Technol. Lett. (3)

G. Liu, X. Jin, and S. L. Chuang, “Measurement of linewidth enhancement factor of semiconductor lasers using an injection-locking technique,” IEEE Photon. Technol. Lett. 13, 430–432 (2001).
[Crossref]

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett. 11, 551–553 (1999).
[Crossref]

C. Walton, A. C. Bordonalli, and A. J. Seeds, “High-performance heterodyne optical injection phase-lock loop using wide linewidth semiconductor lasers,” IEEE Photon. Technol. Lett. 10, 427–429 (1998).
[Crossref]

J. Appl. Phys. (1)

S. Preu, G. H. Döhler, S. Malzer, L. J. Wang, and A. C. Gossard, “Tunable, continuous-wave terahertz photomixer sources and applications,” J. Appl. Phys. 109, 061301 (2011).
[Crossref]

J. Chem. Phys. (1)

P. Jansen, H. L. Bethlem, and W. Ubachs, “Perspective: tipping the scales: search for drifting constants from molecular spectra,” J. Chem. Phys. 140, 010901 (2014).
[Crossref]

J. Lightwave Technol. (1)

Nat. Commun. (1)

L. Consolino, A. Taschin, P. Bartolini, S. Bartalini, P. Cancio, A. Tredicucci, H. E. Beere, D. A. Ritchie, R. Torre, M. S. Vitiello, and P. De Natale, “Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers,” Nat. Commun. 3, 1040 (2012).
[Crossref]

Nat. Photonics (4)

B. Argence, B. Chanteau, O. Lopez, D. Nicolodi, M. Abgrall, C. Chardonnet, C. Daussy, B. Darquié, Y. Le Coq, and A. Amy-Klein, “Quantum cascade laser frequency stabilization at the sub-Hz level,” Nat. Photonics 9, 456–460 (2015).
[Crossref]

M. S. Vitiello, L. Consolino, S. Bartalini, A. Taschin, A. Tredicucci, M. Inguscio, and P. De Natale, “Quantum-limited frequency fluctuations in a terahertz laser,” Nat. Photonics 6, 525–528 (2012).
[Crossref]

B. S. Williams, “Terahertz quantum-cascade lasers,” Nat. Photonics 1, 517–525 (2007).
[Crossref]

S. Barbieri, P. Gellie, G. Santarelli, L. Ding, W. Maineult, C. Sirtori, R. Colombelli, H. Beere, and D. Ritchie, “Phase-locking of a 2.7, THz quantum cascade laser to a mode-locked erbium-doped fibre laser,” Nat. Photonics 4, 636–640 (2010).
[Crossref]

Nature (3)

R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, “Terahertz semiconductor heterostructure laser,” Nature 417, 156–159 (2002).
[Crossref]

J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker, and D. DeMille, “Magneto-optical trapping of a diatomic molecule,” Nature 512, 286–289 (2014).
[Crossref]

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref]

Opt. Express (1)

Opt. Lett. (2)

Phys. Rev. A (2)

J. Shen, A. Borodin, M. Hansen, and S. Schiller, “Observation of a rotational transition of trapped and sympathetically cooled molecular ions,” Phys. Rev. A 85, 032519 (2012).
[Crossref]

S. Lee, D. Hauser, O. Lakhmanskaya, S. Spieler, E. S. Endres, K. Geistlinger, S. S. Kumar, and R. Wester, “Terahertz-visible two-photon rotational spectroscopy of cold OD−,” Phys. Rev. A 93, 032513 (2016).
[Crossref]

Phys. Rev. Lett. (3)

E. B. Norrgard, D. J. McCarron, M. H. Steinecker, M. R. Tarbutt, and D. DeMille, “Submillikelvin dipolar molecules in a radio-frequency magneto-optical trap,” Phys. Rev. Lett. 116, 063004 (2016).
[Crossref]

E. R. Hudson, H. J. Lewandowski, B. C. Sawyer, and J. Ye, “Cold molecule spectroscopy for constraining the evolution of the fine structure constant,” Phys. Rev. Lett. 96, 143004 (2006).
[Crossref]

O. Asvany, O. Ricken, H. S. P. Müller, M. C. Wiedner, T. F. Giesen, and S. Schlemmer, “High-resolution rotational spectroscopy in a cold ion trap: H2D+ and D2H+,” Phys. Rev. Lett. 100, 233004 (2008).
[Crossref]

Science (2)

J. Baron, W. C. Campbell, D. DeMille, J. M. Doyle, G. Gabrielse, Y. V. Gurevich, P. W. Hess, N. R. Hutzler, E. Kirilov, I. Kozyryev, B. R. O’Leary, C. D. Panda, M. F. Parsons, E. S. Petrik, B. Spaun, A. C. Vutha, and A. D. West, “Order of magnitude smaller limit on the electric dipole moment of the electron,” Science 343, 269–272 (2014).
[Crossref]

O. Asvany, K. M. T. Yamada, S. Brünken, A. Potapov, and S. Schlemmer, “Experimental ground-state combination differences of CH5,” Science 347, 1346–1349 (2015).
[Crossref]

Other (4)

A. E. Siegman, Lasers (University Science Books, 1989).

Y.-S. Lee, Principles of Terahertz Science and Technology (Springer, 2009).

K.-E. Peiponen, A. Zeitler, and M. Kuwata-Gonokami, Terahertz Spectroscopy: Theory and Applications (Springer, 2012).

“University of Leeds data repository,” https://doi.org/10.5518/224 .

Supplementary Material (1)

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» Supplement 1       Supplementary text and figures

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Figures (6)

Fig. 1.
Fig. 1.

Experimental arrangement used for injection locking the THz QCL. Electronic connections are shown in black, fiber connections and near-IR are in red, and free-space THz radiation is in green. Also shown, from the top left, are the RF signal generator (RF Gen); the wideband comb source (COMB); tunable bandpass filters; tunable DBR lasers, laser 1 and laser 2; polarization controllers (PC); an erbium-doped fiber amplifier (EDFA); the continuous-wave THz transmitter (Tx); a function generator (FG); the quantum cascade laser (QCL); a free-space optical delay line for phase adjustment (Δψ); the continuous-wave THz receiver (Rx); a transimpedance amplifier (TIA); and an oscilloscope (SCOPE) for data acquisition.

Fig. 2.
Fig. 2.

I–V characteristics and THz output of the QCL. The device is operated in continuous wave with a heat sink temperature of 14 K. The blue dot marks the operating current used in this work (775 mA). The spectrum acquired at this operating point, when the QCL is free-running, is shown in the inset. The resolution for this spectrum is 250 MHz and shows a single lasing mode.

Fig. 3.
Fig. 3.

Beat signal between the reference signal derived from the comb source and the QCL for the THz transmitter is off (black) and on (red). The QCL current is adjusted to tune the QCL frequency. The QCL current is adjusted over a range of 1.5 mA to tune the QCL emission frequency over the 9 MHz range shown in the figure.

Fig. 4.
Fig. 4.

(a) Integrated noise (0–10 MHz) as a function of the heterodyne beat signal position. The shaded region indicates the heterodyne frequencies for where the QCL becomes locked. (b) The observed locking range as a function of Tx power, showing a least-squares fitting to Adler’s equation.

Fig. 5.
Fig. 5.

Amplitude and phase of the locked signal measured using a lock-in amplifier. The frequency of the QCL is adjusted via its drive current and converted to frequency using the measured dependence of 6.5  MHz/mA. For each current (frequency) value, the detection phase is scanned and the sinusoidal waveform from the receiver recorded on the lock-in amplifier (shown in the insets). The amplitude and phase of this signal are shown for two injection powers. Because the detection is coherent, only QCL signals phase-locked to the comb will lead to a measurable signal.

Fig. 6.
Fig. 6.

Measured noise for the locked and unlocked QCL. For the locked QCL, two traces are shown, acquired using two different gain (bandwidth) settings for the transimpedance amplifier to cover both low and high frequencies. The noise floor is also indicated, measured by tuning the QCL frequency away from the reference frequency so that the heterodyne beat lies outside the detection bandwidth. The inset shows the heterodyne beat between the locked QCL and the THz reference frequency.

Equations (2)

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IRxGp(ω,t)EQCL(ω,t),
Δυlock2υ0QeP1P0,