Abstract

We present a non-contact optical technique for the measurement of laser-induced temperature changes in solids. Two-band differential luminescence thermometry (TBDLT) achieves a sensitivity of 7  mK and enables a precise measurement of the net quantum efficiency of optical refrigerator materials. The TBDLT detects internal temperature changes by decoupling surface and bulk heating effects via time-resolved luminescence spectroscopy. Several Yb3+-doped fluorozirconate (ZrF4BaF2LaF3AlF3NaFInF3, ZBLANI) glasses fabricated from precursors of varying purity and by different processes are analyzed in detail. A net quantum efficiency of (97.39±0.01)% at 238 K (at a pump wavelength of 1020.5 nm) is found for a ZBLANI:1% Yb3+ laser-cooling sample produced from metal fluoride precursors that were purified by chelate-assisted solvent extraction and dried in hydrofluoric gas. In comparison, a ZBLANI:1% Yb3+ sample produced from commercial-grade metal fluoride precursors showed pronounced laser-induced heating that is indicative of a substantially higher impurity concentration. The TBDLT enables rapid and sensitive benchmarking of laser-cooling materials and provides critical feedback to the development and optimization of high-performance optical cryocooler materials.

© 2010 Optical Society of America

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References

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  1. R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
    [CrossRef]
  2. M. P. Hehlen, in Optical Refrigeration: Science and Applications of Laser Cooling of Solids, R.I.Epstein and M.Sheik-Bahae, eds. (Wiley, 2009), pp. 33-68.
  3. W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).
  4. D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
    [CrossRef]
  5. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.
  6. R. Frey, F. Micheron, and J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489-4498 (2000).
    [CrossRef]
  7. G. Mills and A. Mord, “Performance modeling of optical refrigeration,” Cryogenics 46, 176-182 (2006).
    [CrossRef]
  8. G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
    [CrossRef]
  9. V. K. Rai, “Temperature sensors and optical sensors,” Appl. Phys. B 88, 297-303 (2007).
    [CrossRef]
  10. B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).
  11. D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
    [CrossRef]
  12. W. M. Patterson, M. Sheik-Bahae, R. I. Epstein, and M. P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators,” J. Appl. Phys. (to be published).
  13. M. Sheik-Bahae and R. I. Epstein, “Optical refrigeration,” Nat. Photonics 1, 693-699 (2007).
    [CrossRef]
  14. M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75, 144302 (2007).
    [CrossRef]

2009

D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
[CrossRef]

2008

W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

2007

M. Sheik-Bahae and R. I. Epstein, “Optical refrigeration,” Nat. Photonics 1, 693-699 (2007).
[CrossRef]

M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75, 144302 (2007).
[CrossRef]

V. K. Rai, “Temperature sensors and optical sensors,” Appl. Phys. B 88, 297-303 (2007).
[CrossRef]

2006

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

G. Mills and A. Mord, “Performance modeling of optical refrigeration,” Cryogenics 46, 176-182 (2006).
[CrossRef]

2000

R. Frey, F. Micheron, and J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489-4498 (2000).
[CrossRef]

1998

G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
[CrossRef]

1995

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

Bender, D. A.

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

Bigotta, S.

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

Buchwald, M. I.

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

Di Lieto, A.

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

Edwards, B. C.

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

Epstein, R. I.

D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
[CrossRef]

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).

M. Sheik-Bahae and R. I. Epstein, “Optical refrigeration,” Nat. Photonics 1, 693-699 (2007).
[CrossRef]

M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75, 144302 (2007).
[CrossRef]

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

W. M. Patterson, M. Sheik-Bahae, R. I. Epstein, and M. P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators,” J. Appl. Phys. (to be published).

Frey, R.

R. Frey, F. Micheron, and J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489-4498 (2000).
[CrossRef]

Gosnell, T. R.

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

Grousson, R.

G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
[CrossRef]

Hasselbeck, M. P.

D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
[CrossRef]

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

Hehlen, M. P.

W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).

M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75, 144302 (2007).
[CrossRef]

W. M. Patterson, M. Sheik-Bahae, R. I. Epstein, and M. P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators,” J. Appl. Phys. (to be published).

M. P. Hehlen, in Optical Refrigeration: Science and Applications of Laser Cooling of Solids, R.I.Epstein and M.Sheik-Bahae, eds. (Wiley, 2009), pp. 33-68.

Imangholi, B.

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

Inoue, H.

M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75, 144302 (2007).
[CrossRef]

Kurtz, S.

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

Lamouche, G.

G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
[CrossRef]

Lavallard, P.

G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
[CrossRef]

Melgaard, S. D.

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

Micheron, F.

R. Frey, F. Micheron, and J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489-4498 (2000).
[CrossRef]

Mills, G.

G. Mills and A. Mord, “Performance modeling of optical refrigeration,” Cryogenics 46, 176-182 (2006).
[CrossRef]

Mord, A.

G. Mills and A. Mord, “Performance modeling of optical refrigeration,” Cryogenics 46, 176-182 (2006).
[CrossRef]

Mungan, C. E.

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

Patterson, W. M.

W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).

W. M. Patterson, M. Sheik-Bahae, R. I. Epstein, and M. P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators,” J. Appl. Phys. (to be published).

Pocholle, J. P.

R. Frey, F. Micheron, and J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489-4498 (2000).
[CrossRef]

Rai, V. K.

V. K. Rai, “Temperature sensors and optical sensors,” Appl. Phys. B 88, 297-303 (2007).
[CrossRef]

Seletskiy, D.

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

Seletskiy, D. V.

D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
[CrossRef]

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

Sheik-Bahae, M.

D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
[CrossRef]

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).

M. Sheik-Bahae and R. I. Epstein, “Optical refrigeration,” Nat. Photonics 1, 693-699 (2007).
[CrossRef]

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

W. M. Patterson, M. Sheik-Bahae, R. I. Epstein, and M. P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators,” J. Appl. Phys. (to be published).

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

Suris, R.

G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
[CrossRef]

Tonelli, M.

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

Wang, C.

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

Appl. Phys. B

V. K. Rai, “Temperature sensors and optical sensors,” Appl. Phys. B 88, 297-303 (2007).
[CrossRef]

Cryogenics

G. Mills and A. Mord, “Performance modeling of optical refrigeration,” Cryogenics 46, 176-182 (2006).
[CrossRef]

J. Appl. Phys.

G. Lamouche, P. Lavallard, R. Suris, and R. Grousson, “Low temperature laser cooling with a rare earth doped glass,” J. Appl. Phys. 84, 509-516 (1998).
[CrossRef]

R. Frey, F. Micheron, and J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489-4498 (2000).
[CrossRef]

Nat. Photonics

M. Sheik-Bahae and R. I. Epstein, “Optical refrigeration,” Nat. Photonics 1, 693-699 (2007).
[CrossRef]

Nature

R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, and C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature 377, 500-503 (1995).
[CrossRef]

Phys. Rev. B

M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75, 144302 (2007).
[CrossRef]

Proc. SPIE

W. M. Patterson, M. P. Hehlen, R. I. Epstein, and M. Sheik-Bahae, “Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration,” Proc. SPIE 7228, 72280C (2008).

D. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Bigotta, and M. Tonelli, “Cooling of Yb:YLF using cavity enhanced resonant absorption,” Proc. SPIE 6907, 69070B (2008).
[CrossRef]

B. Imangholi, M. P. Hasselbeck, D. A. Bender, C. Wang, M. Sheik-Bahae, R. I. Epstein, and S. Kurtz, “Differential luminescence thermometry in semiconductor laser cooling,” Proc. SPIE 6115, 215-220 (2006).

D. V. Seletskiy, M. P. Hasselbeck, M. Sheik-Bahae, and R. I. Epstein, “Fast differential luminescence thermometry,” Proc. SPIE 7228, 72280K (2009).
[CrossRef]

Other

W. M. Patterson, M. Sheik-Bahae, R. I. Epstein, and M. P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators,” J. Appl. Phys. (to be published).

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. Di Lieto, M. Tonelli, R. I. Epstein, and M. Sheik-Bahae, “Demonstration of an optical cryocooler,” in Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper IPDA9.

M. P. Hehlen, in Optical Refrigeration: Science and Applications of Laser Cooling of Solids, R.I.Epstein and M.Sheik-Bahae, eds. (Wiley, 2009), pp. 33-68.

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Figures (8)

Fig. 1
Fig. 1

Area normalized luminescence spectra at different temperatures for Sample 4 (see Table 1). As the temperature is increased, the luminescence intensity of regions A and C increases while the luminescence intensity of regions B and D decreases. Note that the full spectrum, which extends to > 1030   nm , is not shown for clarity.

Fig. 2
Fig. 2

Area normalized luminescence spectra at different temperatures for Sample 4 (left axis) and transmission spectra of the commercial bandpass filters (right axis) used in the TBDLT experiment. Filters A and D are chosen such as to select and integrate a sizable portion of the luminescence spectrum regions + A and −D (see Fig. 1), respectively.

Fig. 3
Fig. 3

Calculation of the normalized laser-induced temperature change as a function of wavelength illustrating the two points for a given sample temperature where Δ T (and thus η cool ) goes to zero. The long-wavelength zero crossing arises due to α b > 0 . A widely tunable pump source would clearly be required to predict T ZCT for this long-wavelength zero crossing. However, near this zero crossing, a large Δ T is observed, allowing greater sensitivity. The short-wavelength zero crossing occurs when λ p = λ ¯ f . Here, α r is large and α b can be neglected, allowing for a measurement of η ext . The values of η ext , η abs , and α b used for this example calculation are also shown.

Fig. 4
Fig. 4

Schematic of the TBDLT experimental setup described in detail in Subsection 3B. The transmission spectra of the filters used to define bands A and D are shown in Fig. 2.

Fig. 5
Fig. 5

Transient TBDLT signal corresponding to the laser-induced temperature change at different ambient sample temperatures for Samples 4 (left) and 7 (right). Negative slopes indicate laser-induced cooling while positive slopes indicate laser-induced heating. The solid lines are fits of the power law [Eq. (3)] to the experimental data.

Fig. 6
Fig. 6

TBDLT parameter as a function of ambient temperature for Samples 4 (circles) and 7 (squares). Open symbols indicate ϑ calculated from a theoretical model [12], while closed symbols indicate experimental data. Points below the horizontal line ( ϑ < 0 ) indicate laser-induced cooling while points above the line ( ϑ > 0 ) indicate heating. From this data, the T ZCT ) can be deduced as 238 K for Sample 4 and 158 K for Sample 7.

Fig. 7
Fig. 7

Mean luminescence wavelength λ ¯ f ( T ) as a function of temperature for Samples 4 (open circles) and 7 (filled squares). The cubic polynomial fits (solid lines) were used to interpolate λ ¯ f ( T ) at temperatures of interest. The mean luminescence wavelength is defined as λ ¯ f ( T ) = λ I ( λ , T ) d λ / I ( λ , T ) d λ which is calculated from luminescence spectra I ( λ , T ) .

Fig. 8
Fig. 8

TBDLT parameter ϑ [measured in vacuum at room temperature ( T = 296   K ) and with λ p = 1020.5   nm ] for a qualitative comparison of several ZBLANI : Yb 3 + samples fabricated in our laboratory (Samples 1–6) and one sample commercially procured (IPG, Sample 7). A positive ϑ corresponds to heating, while a negative ϑ corresponds to local laser-induced cooling. Here we show a steady improvement in our purified materials over those produced with commercially available starting materials.

Tables (2)

Tables Icon

Table 1 Yb 3 + -Doped Fluorozirconate Glass Samples Used in This Study. The ZBLANI Composition is Given in Mole Percent of the Respective ZBLANI Metal Fluoride Constituents. A Detailed Description of Solvent-Extraction and Hydrogen Fluoride Gas Drying Processes is Given in [2]

Tables Icon

Table 2 Summary of Parameters Critical for Assessment and Comparison of Samples 4 and 7. T ZCT and η were Measured as Described in Detail in this Article. η ext was Measured Using a Thermal Camera and a Ti:Sapphire Pump Source in a Fractional Heating Experiment as Described Elsewhere [14]. η abs was Derived from the Measurements of η and η ext . α b was Calculated Given η abs and α r . Sample 7 has lower T ZCT , η abs , α b , and higher η and η ext , Indicating That It Contained Fewer Impurities as Compared to Sample 4. The Values for η abs , α b , and α r are Reported at T ZCT and λ p = 1020.6   nm

Equations (6)

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

Ξ ( T , t ) = I A ( T , t ) I D ( T , t ) I A ( T , t ) + I D ( T , t ) .
I A ( T , t ) = I ( λ , T , t ) θ A ( λ ) d λ ,
I D ( T , t ) = I ( λ , T , t ) θ D ( λ ) d λ ,
Ξ ( T , t ) t ϑ .
η cool = ( η λ p λ ¯ f ) / λ ¯ f ,
η ( λ p , T ) = η abs η ext ,

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