Abstract

We report the design and construction of a cavity enhanced absorption spectrometer using broadband Brewster’s angle prism retroreflectors and a spatially coherent 500 nm to > 1.75 µm supercontinuum excitation source. Using prisms made from fused silica an effective cavity reflectivity of > 99.99% at 1.064 µm was achieved. A proof of principle experiment was performed by recording the cavity enhanced absorption spectrum of the weak b-X (1←0) transition of molecular oxygen at 14529 cm-1 and the fifth overtone of the acetylene C-H stretch at 18430 cm-1. CCD frames were integrated for 150 sec and 30 sec, with 3 frames (each 100 cm-1 wide) and 1 frame (266 cm-1 wide) required to observe the O2 and C2H2 spectra, respectively. A rms noise equivalent absorption (αmin) of 7.21 × 10-8 cm-1 Hz-1/2 and 1.28 × 10-7 cm-1 Hz-1/2 with full width half maximum line widths of 0.18 cm-1 and 0.44 cm-1 were achieved for the molecular oxygen band and the acetylene overtone, respectively.

© 2008 Optical Society of America

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  1. A. O'Keefe and D. A. G. Deacon, "Cavity ring-down optical spectrometer for absorption-measurements using pulsed laser sources," Rev. Sci. Instrum. 59, 2544-2551 (1988).
    [CrossRef]
  2. R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).
  3. A. O'Keefe, "Integrated cavity output analysis of ultra-weak absorption," Chem. Phys. Lett. 293, 331-336 (1998).
    [CrossRef]
  4. J. Ye, L. S. Ma, and J. L. Hall, "Sub-doppler optical frequency reference at 1.064 ?m by means of ultrasensitive cavity-enhanced frequency modulation spectroscopy of a C2HD overtone transition," Opt. Lett. 21, 1000-1002 (1996).
    [CrossRef] [PubMed]
  5. G. Rempe, R. J. Thompson, H. J. Kimble, and R. Lalezari, "Measurement of ultralow losses in an optical interferometer," Opt. Lett. 17, 363-365 (1992).
    [CrossRef] [PubMed]
  6. M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye, "Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection," Science 311, 1595-1599 (2006).
    [CrossRef] [PubMed]
  7. M. J. Thorpe, D. D. Hudson, K. D. Moll, J. Lasri, and J. Ye, "Cavity-ringdown molecular spectroscopy based on an optical frequency comb at 1.45-1.65 ?m," Opt. Lett. 32, 307-309 (2007).
    [CrossRef] [PubMed]
  8. M. J. Thorpe, D. Balslev-Clausen, M. S. Kirchner, and J. Ye, "Cavity-enhanced optical frequency comb spectroscopy: application to human breath analysis," Opt. Express 16, 2387-2397 (2008).
    [CrossRef] [PubMed]
  9. K. K. Lehmann, "Recent advances in cavity ring-down spectroscopy & related methods," in Cavity Ring-Down User Meeting (University of Cork, Cork Ireland 2006), http://laser-spectroscopy.ucc.ie/CRDS_UserMeeting_2006/Home.htm
  10. K. K. Lehmann and P. Rabinowitz, "High-finesse optical resonator for cavity ring-down spectroscopy based upon Brewster's angle prism retroreflectors," U.S. Patent 5973864 (1999).
  11. G. Engel, W. B. Yan, J. B. Dudek, K. K. Lehmann, and P. Rabinowitz, "Ring-down spectroscopy with a Brewster's angle prism resonator," in Laser Spectroscopy XIV International Conference, R. Blatt, J. Eschner, D. Leibfried, and F. Schmidt-Kaler, eds. (World Scientific, Singapore, 1999), pp. 314-315.
  12. A. C. R. Pipino, J. W. Hudgens, and R. E. Huie, "Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity," Rev. Sci. Instrum. 68, 2978-2989 (1997).
    [CrossRef]
  13. W. J. Wadsworth, N. Joly, J. C. Knight, T. A. Birks, F. Biancalana, and P. S. J. Russell, "Supercontinuum and four-wave mixing with Q-switched pulses in endlessly single-mode photonic crystal fibres," Opt. Express 12, 299-309 (2004).
    [CrossRef] [PubMed]
  14. J. M. Langridge, T. Laurila, R. S. Watt, R. L. Jones, C. F. Kaminski, and J. Hult, "Cavity enhanced absorption spectroscopy of multiple trace gas species using a supercontinuum radiation source," Opt. Express 16, 10178-10188 (2008).
    [CrossRef] [PubMed]
  15. S. E. Fiedler, A. Hese, and A. A. Ruth, "Incoherent broad-band cavity-enhanced absorption spectroscopy," Chem. Phys. Lett. 371, 284-294 (2003).
    [CrossRef]
  16. S. M. Ball, I. M. Povey, E. G. Norton, and R. L. Jones, "Broadband cavity ringdown spectroscopy of the NO3 radical," Chem. Phys. Lett. 342, 113-120 (2001).
    [CrossRef]
  17. K. K. Lehmann, Department of Chemistry, University of Virginia, Charlottesville, VA 22904, P. S. Johnston and P. Rabinowitz are preparing a manuscript to be called "Design and analysis of Brewster's angle prism retroreflectors for cavity enhanced spectroscopy."
  18. M. Bass, ed., Handbook of Optics Volume II - Devices, Measurements, and Properties, 2nd ed. (McGraw-Hill), Vol. 2.
  19. C. Xiong and W. J. Wadsworth, "Polarized supercontinuum in birefringent photonic crystal fibre pumped at 1064 nm and application to tuneable visible/UV generation," Opt. Express 16, 2438-2445 (2008).
    [CrossRef] [PubMed]
  20. W. Becker, Advanced time-correlated single photon counting techniques (Springer, New York, 2005).
    [CrossRef]
  21. S. Schroder, M. Kamprath, A. Duparre, A. Tunnermann, B. Kuhn, and U. Klett, "Bulk scattering properties of synthetic fused silica at 193 nm," Opt. Express 14, 10537-10549 (2006).
    [CrossRef] [PubMed]
  22. G. J. Scherer, K. K. Lehmann, and W. Klemperer, "The high-resolution visible overtone spectrum of acetylene," J. Chem. Phys. 78, 2817-2832 (1983).
    [CrossRef]
  23. L. S. Rothman,  et al., "The HITRAN 2004 molecular spectroscopic database," J. Quant. Spectrosc. Radiat. Transfer 96, 139-204 (2005).
    [CrossRef]
  24. J. S. Wong, "Pressure Broadening of single vibrational-rotational transitions of acetylene at ?=5," J. Mol. Spectrosc. 82, 449-451 (1980).
    [CrossRef]
  25. H. Chen and W. B. Yan, "Prism-based cavity ringdown spectroscopy: broadband and ultrahigh reflectivity," in 62nd International Symposium on Molecular Spectroscopy (The Ohio State University Columbus, OH, 2007), http://hdl.handle.net/1811/31394.
  26. T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
    [CrossRef]
  27. E. Hamers, D. Schram, and R. Engeln, "Fourier transform phase shift cavity ring down spectroscopy," Chem. Phys. Lett. 365, 237-243 (2002).
    [CrossRef]
  28. A. A. Ruth, J. Orphal, and S. E. Fiedler, "Fourier-transform cavity-enhanced absorption spectroscopy using an incoherent broadband light source," Appl. Opt. 46, 3611-3616 (2007).
    [CrossRef] [PubMed]

2008

2007

2006

S. Schroder, M. Kamprath, A. Duparre, A. Tunnermann, B. Kuhn, and U. Klett, "Bulk scattering properties of synthetic fused silica at 193 nm," Opt. Express 14, 10537-10549 (2006).
[CrossRef] [PubMed]

M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye, "Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection," Science 311, 1595-1599 (2006).
[CrossRef] [PubMed]

2005

L. S. Rothman,  et al., "The HITRAN 2004 molecular spectroscopic database," J. Quant. Spectrosc. Radiat. Transfer 96, 139-204 (2005).
[CrossRef]

2004

2003

S. E. Fiedler, A. Hese, and A. A. Ruth, "Incoherent broad-band cavity-enhanced absorption spectroscopy," Chem. Phys. Lett. 371, 284-294 (2003).
[CrossRef]

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

2002

E. Hamers, D. Schram, and R. Engeln, "Fourier transform phase shift cavity ring down spectroscopy," Chem. Phys. Lett. 365, 237-243 (2002).
[CrossRef]

2001

S. M. Ball, I. M. Povey, E. G. Norton, and R. L. Jones, "Broadband cavity ringdown spectroscopy of the NO3 radical," Chem. Phys. Lett. 342, 113-120 (2001).
[CrossRef]

1998

R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).

A. O'Keefe, "Integrated cavity output analysis of ultra-weak absorption," Chem. Phys. Lett. 293, 331-336 (1998).
[CrossRef]

1997

A. C. R. Pipino, J. W. Hudgens, and R. E. Huie, "Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity," Rev. Sci. Instrum. 68, 2978-2989 (1997).
[CrossRef]

1996

1992

1988

A. O'Keefe and D. A. G. Deacon, "Cavity ring-down optical spectrometer for absorption-measurements using pulsed laser sources," Rev. Sci. Instrum. 59, 2544-2551 (1988).
[CrossRef]

1983

G. J. Scherer, K. K. Lehmann, and W. Klemperer, "The high-resolution visible overtone spectrum of acetylene," J. Chem. Phys. 78, 2817-2832 (1983).
[CrossRef]

1980

J. S. Wong, "Pressure Broadening of single vibrational-rotational transitions of acetylene at ?=5," J. Mol. Spectrosc. 82, 449-451 (1980).
[CrossRef]

Ball, S. M.

S. M. Ball, I. M. Povey, E. G. Norton, and R. L. Jones, "Broadband cavity ringdown spectroscopy of the NO3 radical," Chem. Phys. Lett. 342, 113-120 (2001).
[CrossRef]

Balslev-Clausen, D.

Berden, G.

R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).

Biancalana, F.

Birks, T. A.

Deacon, D. A. G.

A. O'Keefe and D. A. G. Deacon, "Cavity ring-down optical spectrometer for absorption-measurements using pulsed laser sources," Rev. Sci. Instrum. 59, 2544-2551 (1988).
[CrossRef]

Duparre, A.

Engeln, R.

E. Hamers, D. Schram, and R. Engeln, "Fourier transform phase shift cavity ring down spectroscopy," Chem. Phys. Lett. 365, 237-243 (2002).
[CrossRef]

R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).

Fiedler, S. E.

A. A. Ruth, J. Orphal, and S. E. Fiedler, "Fourier-transform cavity-enhanced absorption spectroscopy using an incoherent broadband light source," Appl. Opt. 46, 3611-3616 (2007).
[CrossRef] [PubMed]

S. E. Fiedler, A. Hese, and A. A. Ruth, "Incoherent broad-band cavity-enhanced absorption spectroscopy," Chem. Phys. Lett. 371, 284-294 (2003).
[CrossRef]

Hall, J. L.

Hamers, E.

E. Hamers, D. Schram, and R. Engeln, "Fourier transform phase shift cavity ring down spectroscopy," Chem. Phys. Lett. 365, 237-243 (2002).
[CrossRef]

Hansen, K. P.

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

Hese, A.

S. E. Fiedler, A. Hese, and A. A. Ruth, "Incoherent broad-band cavity-enhanced absorption spectroscopy," Chem. Phys. Lett. 371, 284-294 (2003).
[CrossRef]

Hudgens, J. W.

A. C. R. Pipino, J. W. Hudgens, and R. E. Huie, "Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity," Rev. Sci. Instrum. 68, 2978-2989 (1997).
[CrossRef]

Hudson, D. D.

Huie, R. E.

A. C. R. Pipino, J. W. Hudgens, and R. E. Huie, "Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity," Rev. Sci. Instrum. 68, 2978-2989 (1997).
[CrossRef]

Hult, J.

Joly, N.

Jones, R. J.

M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye, "Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection," Science 311, 1595-1599 (2006).
[CrossRef] [PubMed]

Jones, R. L.

Kaminski, C. F.

Kamprath, M.

Kimble, H. J.

Kirchner, M. S.

Klemperer, W.

G. J. Scherer, K. K. Lehmann, and W. Klemperer, "The high-resolution visible overtone spectrum of acetylene," J. Chem. Phys. 78, 2817-2832 (1983).
[CrossRef]

Klett, U.

Knight, J. C.

Kuhn, B.

Lalezari, R.

Langridge, J. M.

Lasri, J.

Laurila, T.

Lehmann, K. K.

G. J. Scherer, K. K. Lehmann, and W. Klemperer, "The high-resolution visible overtone spectrum of acetylene," J. Chem. Phys. 78, 2817-2832 (1983).
[CrossRef]

Limpert, J.

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

Ma, L. S.

Meijer, G.

R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).

Moll, K. D.

M. J. Thorpe, D. D. Hudson, K. D. Moll, J. Lasri, and J. Ye, "Cavity-ringdown molecular spectroscopy based on an optical frequency comb at 1.45-1.65 ?m," Opt. Lett. 32, 307-309 (2007).
[CrossRef] [PubMed]

M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye, "Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection," Science 311, 1595-1599 (2006).
[CrossRef] [PubMed]

Norton, E. G.

S. M. Ball, I. M. Povey, E. G. Norton, and R. L. Jones, "Broadband cavity ringdown spectroscopy of the NO3 radical," Chem. Phys. Lett. 342, 113-120 (2001).
[CrossRef]

O'Keefe, A.

A. O'Keefe, "Integrated cavity output analysis of ultra-weak absorption," Chem. Phys. Lett. 293, 331-336 (1998).
[CrossRef]

A. O'Keefe and D. A. G. Deacon, "Cavity ring-down optical spectrometer for absorption-measurements using pulsed laser sources," Rev. Sci. Instrum. 59, 2544-2551 (1988).
[CrossRef]

Orphal, J.

Peeters, R.

R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).

Pipino, A. C. R.

A. C. R. Pipino, J. W. Hudgens, and R. E. Huie, "Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity," Rev. Sci. Instrum. 68, 2978-2989 (1997).
[CrossRef]

Povey, I. M.

S. M. Ball, I. M. Povey, E. G. Norton, and R. L. Jones, "Broadband cavity ringdown spectroscopy of the NO3 radical," Chem. Phys. Lett. 342, 113-120 (2001).
[CrossRef]

Rempe, G.

Rothman, L. S.

L. S. Rothman,  et al., "The HITRAN 2004 molecular spectroscopic database," J. Quant. Spectrosc. Radiat. Transfer 96, 139-204 (2005).
[CrossRef]

Russell, P. S. J.

Ruth, A. A.

A. A. Ruth, J. Orphal, and S. E. Fiedler, "Fourier-transform cavity-enhanced absorption spectroscopy using an incoherent broadband light source," Appl. Opt. 46, 3611-3616 (2007).
[CrossRef] [PubMed]

S. E. Fiedler, A. Hese, and A. A. Ruth, "Incoherent broad-band cavity-enhanced absorption spectroscopy," Chem. Phys. Lett. 371, 284-294 (2003).
[CrossRef]

Safdi, B.

M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye, "Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection," Science 311, 1595-1599 (2006).
[CrossRef] [PubMed]

Scherer, G. J.

G. J. Scherer, K. K. Lehmann, and W. Klemperer, "The high-resolution visible overtone spectrum of acetylene," J. Chem. Phys. 78, 2817-2832 (1983).
[CrossRef]

Schram, D.

E. Hamers, D. Schram, and R. Engeln, "Fourier transform phase shift cavity ring down spectroscopy," Chem. Phys. Lett. 365, 237-243 (2002).
[CrossRef]

Schreiber, T.

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

Schroder, S.

Thompson, R. J.

Thorpe, M. J.

Tunnermann, A.

S. Schroder, M. Kamprath, A. Duparre, A. Tunnermann, B. Kuhn, and U. Klett, "Bulk scattering properties of synthetic fused silica at 193 nm," Opt. Express 14, 10537-10549 (2006).
[CrossRef] [PubMed]

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

Wadsworth, W. J.

Watt, R. S.

Wong, J. S.

J. S. Wong, "Pressure Broadening of single vibrational-rotational transitions of acetylene at ?=5," J. Mol. Spectrosc. 82, 449-451 (1980).
[CrossRef]

Xiong, C.

Ye, J.

Zellmer, H.

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

Appl. Opt.

Chem. Phys. Lett.

E. Hamers, D. Schram, and R. Engeln, "Fourier transform phase shift cavity ring down spectroscopy," Chem. Phys. Lett. 365, 237-243 (2002).
[CrossRef]

A. O'Keefe, "Integrated cavity output analysis of ultra-weak absorption," Chem. Phys. Lett. 293, 331-336 (1998).
[CrossRef]

S. E. Fiedler, A. Hese, and A. A. Ruth, "Incoherent broad-band cavity-enhanced absorption spectroscopy," Chem. Phys. Lett. 371, 284-294 (2003).
[CrossRef]

S. M. Ball, I. M. Povey, E. G. Norton, and R. L. Jones, "Broadband cavity ringdown spectroscopy of the NO3 radical," Chem. Phys. Lett. 342, 113-120 (2001).
[CrossRef]

J. Chem. Phys.

G. J. Scherer, K. K. Lehmann, and W. Klemperer, "The high-resolution visible overtone spectrum of acetylene," J. Chem. Phys. 78, 2817-2832 (1983).
[CrossRef]

J. Mol. Spectrosc.

J. S. Wong, "Pressure Broadening of single vibrational-rotational transitions of acetylene at ?=5," J. Mol. Spectrosc. 82, 449-451 (1980).
[CrossRef]

J. Quant. Spectrosc. Radiat. Transfer

L. S. Rothman,  et al., "The HITRAN 2004 molecular spectroscopic database," J. Quant. Spectrosc. Radiat. Transfer 96, 139-204 (2005).
[CrossRef]

Opt. Commun.

T. Schreiber, J. Limpert, H. Zellmer, A. Tunnermann, and K. P. Hansen, "High average power supercontinuum generation in photonic crystal fibers," Opt. Commun. 228, 71-78 (2003).
[CrossRef]

Opt. Express

Opt. Lett.

Rev. Sci. Instrum.

A. C. R. Pipino, J. W. Hudgens, and R. E. Huie, "Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity," Rev. Sci. Instrum. 68, 2978-2989 (1997).
[CrossRef]

A. O'Keefe and D. A. G. Deacon, "Cavity ring-down optical spectrometer for absorption-measurements using pulsed laser sources," Rev. Sci. Instrum. 59, 2544-2551 (1988).
[CrossRef]

R. Engeln, G. Berden, R. Peeters, and G. Meijer, "Cavity enhanced absorption and cavity enhanced magnetic rotation spectroscopy," Rev. Sci. Instrum. 69, 3763-3769 (1998).

Science

M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye, "Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection," Science 311, 1595-1599 (2006).
[CrossRef] [PubMed]

Other

K. K. Lehmann, "Recent advances in cavity ring-down spectroscopy & related methods," in Cavity Ring-Down User Meeting (University of Cork, Cork Ireland 2006), http://laser-spectroscopy.ucc.ie/CRDS_UserMeeting_2006/Home.htm

K. K. Lehmann and P. Rabinowitz, "High-finesse optical resonator for cavity ring-down spectroscopy based upon Brewster's angle prism retroreflectors," U.S. Patent 5973864 (1999).

G. Engel, W. B. Yan, J. B. Dudek, K. K. Lehmann, and P. Rabinowitz, "Ring-down spectroscopy with a Brewster's angle prism resonator," in Laser Spectroscopy XIV International Conference, R. Blatt, J. Eschner, D. Leibfried, and F. Schmidt-Kaler, eds. (World Scientific, Singapore, 1999), pp. 314-315.

K. K. Lehmann, Department of Chemistry, University of Virginia, Charlottesville, VA 22904, P. S. Johnston and P. Rabinowitz are preparing a manuscript to be called "Design and analysis of Brewster's angle prism retroreflectors for cavity enhanced spectroscopy."

M. Bass, ed., Handbook of Optics Volume II - Devices, Measurements, and Properties, 2nd ed. (McGraw-Hill), Vol. 2.

W. Becker, Advanced time-correlated single photon counting techniques (Springer, New York, 2005).
[CrossRef]

H. Chen and W. B. Yan, "Prism-based cavity ringdown spectroscopy: broadband and ultrahigh reflectivity," in 62nd International Symposium on Molecular Spectroscopy (The Ohio State University Columbus, OH, 2007), http://hdl.handle.net/1811/31394.

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Figures (8)

Fig. 1.
Fig. 1.

Schematic of the cavity enhanced absorption spectrometer showing the major components of the spectrometer: the supercontinuum source, the broadband Brewster’s angle retroreflector prism cavity, and the dispersive grating spectrograph.

Fig. 2.
Fig. 2.

A schematic of the Brewster angle retroreflector based ring cavity showing the optical beam path. Light is coupled into the cavity at Ro and decoupled at R5. All surfaces are flat except EF which has a 6 m convex curve. Labels are referred to in the text along with prism dimensions and angles. The effective reflectivity of the cavity is controlled by tuning the input prism around Brewster’s angle.

Fig. 3.
Fig. 3.

Schematic of the vacuum chamber showing the external opto-mechanical stages and flexible bellow connections. The chamber on the left has been cut away to show the mounting of the prism.

Fig. 4.
Fig. 4.

The calculated Fresnel loss per prism across the visible and near-IR for a fixed prism alignment at Brewster’s angle for 1064 nm.

Fig. 5.
Fig. 5.

Spectrum of the supercontinuum generated by pumping 13.5 m of the SC-5.0-1040 fiber with 10 ns, 34 µJ pulses from a Q-switched Nd:YAG laser. The spectrum was observed using an optical spectrum analyzer. The molecular spectra reported elsewhere in this paper were recorded using 20 m of fiber, however the fiber broke before we were able to record the supercontinuum spectrum.

Fig. 6.
Fig. 6.

Fit of the observed round trip cavity loss with Eq. 3, as determined from the ring-down time, as a function of wavelength. The 2σ error bars from the ring-down fits are indicated. Also shown are the individual loss contributions from the dominant loss mechanisms: Rayleigh scattering and Fresnel loss. The resulting fit parameters are given in the text.

Fig. 7.
Fig. 7.

The experimental cavity enhanced absorption spectrum of the b1∑+g-X3- g(v = 1←0) transition of molecular oxygen in air referenced to dry nitrogen gas, along with the HITRAN predicted spectrum [23].

Fig. 8.
Fig. 8.

Cavity enhanced absorption spectrum of the fifth overtone of the acetylene C-H stretch. The complete spectrum was recorded at a single grating position at a partial pressure of C2H2 of 1 atm and referenced to 1 atm of dry nitrogen gas.

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

α ( ν ) = ( c τ ( ν ) ) 1 ( 1 + n ( ν ) L p L g ) ( I o ( ν ) I ( ν ) 1 )
R ( λ ) = ( n ( λ ) 4 1 ) 2 4 n ( λ ) 6 δ θ ( λ ) 2
L ( λ ) = 4 ( 2 π σ λ n ( λ ) 2 1 n ( λ ) 2 + 1 ) 2 + ( 16 π n ( λ ) cos ( θ ) σ λ ) 2 + A λ 4 + ( n ( λ ) 4 1 ) 2 2 n ( λ ) 6 ( δ θ 1 ( λ ) 2 + δ θ 2 ( λ ) 2 )

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