Abstract

A 250-µm-diameter fiber of ytterbium-doped ZBLAN (fluorine combined with Zr, Ba, La, Al, and Na) has been cooled from room temperature. We coupled 1.0 W of laser light from a 1013-nm diode laser into the fiber. We measured the temperature of the fiber by using both fluorescence techniques and a microthermocouple. These microthermocouple measurements show that the cooled fiber can be used to refrigerate materials brought into contact with it. This, in conjunction with the use of a diode laser as the light source, demonstrates that practical solid-state laser coolers can be realized.

© 2001 Optical Society of America

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References

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  1. P. Pringsheim, “Zwei Bemerkungen über den Unterscheid von Lumineszenz-und Termperaturstreahlung,” Z. Phys. 57, 739–746 (1929).
    [CrossRef]
  2. L. Landau, “On the thermodynamics of photoluminescence,” J. Phys. (Moscow) 10, 503–506 (1946).
  3. S. R. Bowman, “Lasers without internal heat generation,” IEEE J. Quantum Electron. 3, 115–122 (1999).
    [CrossRef]
  4. R. Frey, F. Micheron, J. P. Pocholle, “Comparison of Peltier and anti-Stokes optical coolings,” J. Appl. Phys. 87, 4489–4498 (2000).
    [CrossRef]
  5. A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).
  6. H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
    [CrossRef]
  7. E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
    [CrossRef]
  8. J. L. Clark, G. Rumbles, “Laser cooling in the condensed phase by frequency up-conversion,” Phys. Rev. Lett. 76, 2037–2040 (1996).
    [CrossRef] [PubMed]
  9. R. I. Epstein, M. I. Buchwald, B. C. Edwards, T. R. Gosnell, C. E. Mungan, “Observation of laser-induced fluorescent cooling of a solid,” Nature (London) 377, 500–503 (1995).
    [CrossRef]
  10. T. R. Gosnell, “Laser cooling of a solid by 65 K starting from room temperature,” Opt. Lett. 24, 1041–1043 (1999).
    [CrossRef]
  11. C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
    [CrossRef]
  12. B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
    [CrossRef]
  13. C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
    [CrossRef] [PubMed]
  14. J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
    [CrossRef]

2001 (1)

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

2000 (3)

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

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

1999 (4)

T. R. Gosnell, “Laser cooling of a solid by 65 K starting from room temperature,” Opt. Lett. 24, 1041–1043 (1999).
[CrossRef]

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

S. R. Bowman, “Lasers without internal heat generation,” IEEE J. Quantum Electron. 3, 115–122 (1999).
[CrossRef]

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

1997 (2)

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

1996 (1)

J. L. Clark, G. Rumbles, “Laser cooling in the condensed phase by frequency up-conversion,” Phys. Rev. Lett. 76, 2037–2040 (1996).
[CrossRef] [PubMed]

1995 (1)

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

1946 (1)

L. Landau, “On the thermodynamics of photoluminescence,” J. Phys. (Moscow) 10, 503–506 (1946).

1929 (1)

P. Pringsheim, “Zwei Bemerkungen über den Unterscheid von Lumineszenz-und Termperaturstreahlung,” Z. Phys. 57, 739–746 (1929).
[CrossRef]

Adam, J. L.

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

Anderson, J. E.

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

Balda, R.

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

Bertness, K. A.

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

Bowman, S. R.

S. R. Bowman, “Lasers without internal heat generation,” IEEE J. Quantum Electron. 3, 115–122 (1999).
[CrossRef]

Buchwald, M. I.

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

Buchwald, M. J.

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

Clark, J. L.

J. L. Clark, G. Rumbles, “Laser cooling in the condensed phase by frequency up-conversion,” Phys. Rev. Lett. 76, 2037–2040 (1996).
[CrossRef] [PubMed]

Cornell, E. A.

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

Edwards, B. C.

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

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

Epstein, R. I.

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

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

Fernández, J.

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

Finkeissen, E.

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

Frey, R.

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

Friese, M. E. J.

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

García, A. J.

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

Gauck, H.

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

Gfoerer, T. H.

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

Gosnell, T. R.

T. R. Gosnell, “Laser cooling of a solid by 65 K starting from room temperature,” Opt. Lett. 24, 1041–1043 (1999).
[CrossRef]

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

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

Heckenberg, N. R.

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

Hoyt, C. W.

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

Landau, L.

L. Landau, “On the thermodynamics of photoluminescence,” J. Phys. (Moscow) 10, 503–506 (1946).

Mendioroz, A.

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

Micheron, F.

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

Mills, G. L.

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

Mord, A. J.

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

Mungan, C. E.

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

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

Pocholle, J. P.

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

Potemski, M.

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

Pringsheim, P.

P. Pringsheim, “Zwei Bemerkungen über den Unterscheid von Lumineszenz-und Termperaturstreahlung,” Z. Phys. 57, 739–746 (1929).
[CrossRef]

Rayner, A.

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

Renn, M. J.

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

Rubinsztein-Dunlop, H.

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

Rumbles, G.

J. L. Clark, G. Rumbles, “Laser cooling in the condensed phase by frequency up-conversion,” Phys. Rev. Lett. 76, 2037–2040 (1996).
[CrossRef] [PubMed]

Sheik-Bahae, M.

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

Truscott, A. G.

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

Viña, L.

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

Weimann, G.

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

Wyder, P.

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

Appl. Phys. A (1)

H. Gauck, T. H. Gfoerer, M. J. Renn, E. A. Cornell, K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys. A 64, 143–147 (1997).
[CrossRef]

Appl. Phys. Lett. (1)

E. Finkeissen, M. Potemski, P. Wyder, L. Viña, G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75, 1258–1260 (1999).
[CrossRef]

IEEE J. Quantum Electron. (1)

S. R. Bowman, “Lasers without internal heat generation,” IEEE J. Quantum Electron. 3, 115–122 (1999).
[CrossRef]

J. Appl. Phys. (2)

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

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, A. J. Mord, “Demonstration of a solid-state optical cooler: an approach to cryogenic refrigeration,” J. Appl. Phys. 86, 6489–6493 (1999).
[CrossRef]

J. Mod. Opt. (1)

A. Rayner, M. E. J. Friese, A. G. Truscott, N. R. Heckenberg, H. Rubinsztein-Dunlop, “Laser cooling of a solid from ambient temperature,” J. Mod. Opt. 48, 103–114 (2001).

J. Phys. (Moscow) (1)

L. Landau, “On the thermodynamics of photoluminescence,” J. Phys. (Moscow) 10, 503–506 (1946).

Nature (London) (1)

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

Opt. Lett. (1)

Phys. Rev. B (1)

J. Fernández, A. Mendioroz, A. J. García, R. Balda, J. L. Adam, “Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses,” Phys. Rev. B 62, 3213–3217 (2000).
[CrossRef]

Phys. Rev. Lett. (3)

C. W. Hoyt, M. Sheik-Bahae, R. I. Epstein, B. C. Edwards, J. E. Anderson, “Observation of anti-Stokes fluorescence cooling in thulium-doped glass,” Phys. Rev. Lett. 85, 3600–3603 (2000).
[CrossRef] [PubMed]

C. E. Mungan, M. J. Buchwald, B. C. Edwards, R. I. Epstein, T. R. Gosnell, “Laser cooling of a solid by 16 K starting from room temperature,” Phys. Rev. Lett. 78, 1030–1033 (1997).
[CrossRef]

J. L. Clark, G. Rumbles, “Laser cooling in the condensed phase by frequency up-conversion,” Phys. Rev. Lett. 76, 2037–2040 (1996).
[CrossRef] [PubMed]

Z. Phys. (1)

P. Pringsheim, “Zwei Bemerkungen über den Unterscheid von Lumineszenz-und Termperaturstreahlung,” Z. Phys. 57, 739–746 (1929).
[CrossRef]

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Figures (7)

Fig. 1
Fig. 1

Schematic of the experimental apparatus. Light from the diode laser is coupled into the fiber to be cooled. The fiber is mounted on two pairs of crossed silica fibers to reduce the heat load on the fiber to be essentially radiative. A microthermocouple is mounted on a rotating shaft, controlled by a stepper motor, so that it can be brought into contact with the fiber as required. A shutter attached to the shaft prevents laser radiation from striking the microthermocouple.

Fig. 2
Fig. 2

Calibration of fluorescence intensity at 950 nm as a function of temperature with the pump laser operating at 1015 nm. The intensity is essentially linear over the calibration range. The solid line is a fit to the data points (circles).

Fig. 3
Fig. 3

Calibration of an E-type microthermocouple. The temperature of the thermocouple was varied by a Peltier device and compared with the temperature of a calibrated thermistor. The graph indicates a 0.04-mV K-1 sensitivity of the microthermocouple.

Fig. 4
Fig. 4

Fluorescence temperature measurement of laser cooling. The fluorescence intensity at 950 nm is observed over time after the laser light is switched on at time zero. The intensity at time zero is normalized to one so temperature changes can be read from the calibration. The signal is given for incident laser powers of 1.0, 0.50, and 0.25 W. The lower solid curve is the best-fit exponential to the data with 1-W incident power. The other two curves are scaled by their incident power. The temperature changes indicated by these data are 3.7, 1.7, and 0.8 K, respectively, for decreasing power.

Fig. 5
Fig. 5

Microthermocouple measurement of laser cooling. At time zero, the thermocouple is brought into contact with the cooled fiber, with the shutter simultaneously blocking all incoming laser light. The thermal EMF is then observed as the fiber and the thermocouple reequilibrate with their surroundings. The three curves in order of decreasing inital EMF are for incident laser powers of 1.0, 0.5, and 0.25 W, corresponding to temperature changes of 1.0, 0.5, and 0.25 K.

Fig. 6
Fig. 6

Microthermocouple measurement of laser cooling at a number of laser wavelengths compared with earlier photothermal deflection results. The latter are scaled to give cooling by 13 K at 1015 nm with 0.85-W input power as observed in our earlier experiment. Both sets of data are normalized to show the temperature change per watt of incident power. The curves of fit represent the expected temperature change with only radiative loss, with an offset to account for parasitic heating.

Fig. 7
Fig. 7

Results of modeling to determine the effects of impurity absorption and coupling efficiency on cooling power. Incident power is assumed to be 1 W. Cooling power is seen to decrease with an increase in background absorption and also as the coupling efficiency decreases.

Equations (3)

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ΔT=P1-exp-αlQλin/λav-14σεAT3,
Pcool=PabsorbedQλin/λav-1.
Px=P exp-α+βx,

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