OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 17 — Aug. 16, 2010
  • pp: 18061–18066
« Show journal navigation

Laser cooling of a semiconductor load to 165 K

Denis V. Seletskiy, Seth D. Melgaard, Alberto Di Lieto, Mauro Tonelli, and Mansoor Sheik-Bahae  »View Author Affiliations


Optics Express, Vol. 18, Issue 17, pp. 18061-18066 (2010)
http://dx.doi.org/10.1364/OE.18.018061


View Full Text Article

Acrobat PDF (8511 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Abstract: We demonstrate cooling of a 2 micron thick GaAs/InGaP double-heterostructure to 165 K from ambient using an all-solid-state optical refrigerator. Cooler is comprised of Yb3+-doped YLF crystal, utilizing 3.5 Watts of absorbed power near the E4-E5 Stark manifold transition.

© 2010 OSA

1. Introduction

Laser cooling of solids or optical refrigeration is based on anti-Stokes fluorescence [1

1. P. Pringsheim, “Zwei bemerkungen uËber den unterschied von lumineszenz- und Temperaturstrahlung,” Z. Phys. 57(11-12), 739–746 (1929). [CrossRef]

]. With laser light tuned to the wavelengths just above mean emission wavelength (λf) of the transition, the subsequent fluorescence upconversion requires phonon absorption in order to establish quasi equilibrium. The efficient escape of the fluorescence then carries heat and entropy away from the material resulting in net cooling [2

2. M. Sheik-Bahae and R. I. Epstein, “Optical Refrigeration: Advancing toward an all-solid-state cryocooler,” Nat. Photonics 1(12), 693–699 (2007). [CrossRef]

,3

3. M. Sheik-Bahae and R. I. Epstein, “Laser Cooling of Solids,” Laser Photonics Rev. 3(1-2), 67–84 (2009). [CrossRef]

]. The essential conditions for achieving this cooling in solids are availability of high quantum efficiency transition and extremely high purity materials. The former requirement can be satisfied for rare-earth ions in hosts with low phonon energy such as fluoride or chloride glasses and crystals.

Net optical refrigeration was first demonstrated in a Yb-doped glass by Epstein et al. in 1995 [4

4. R. I. Epstein, M. Buchwald, B. Edwards, T. Gosnell, and C. Mungan, “Observation of laser induced fluorescent cooling of a solid,” Nature 377(6549), 500–503 (1995). [CrossRef]

]. Since then, much progress has been made in cooling a variety of glass and crystal hosts, doped with rare-earth ions of Yb, Tm and Er [2,3 and references within]. Despite tremendous theoretical [5

5. A. N. Oraevsky, “Cooling of semiconductors by laser radiation,” J. Russ. Laser Res. 17(5), 471–479 (1996). [CrossRef]

9

9. J. B. Khurgin, “Band gap engineering for laser cooling of semiconductors,” J. Appl. Phys. 100(11), 113116 (2006). [CrossRef]

] and experimental [10

10. E. Finkeißen, M. Potemski, P. Wyder, L. Vina, and G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75(9), 1258–1260 (1999). [CrossRef]

13

13. C. Wang, M. P. Hasselbeck, C.-Y. Li, and M. Sheik-Bahae, “Characterization of external quantum efficiency and absorption efficiency in GaAs/ InGaP double heterostructures for laser cooling applications,” Proc. SPIE 7614, 76140B (2010). [CrossRef]

] progress, no direct net cooling has been observed in semiconductors in large due to the stringent high purity requirement.

Since the first observation of optical refrigeration, its implication for achieving an all-solid-state cryocooler, that surpasses the performance of thermoelectric (TE) coolers, was discussed. Currently, standard TE or Peltier coolers can marginally reach 170K with diminishing efficiency. Only mechanical coolers and/or using cryogens can deliver lower temperatures. In the recent work on cooling Yb-doped YLF crystal to 155K [14

14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

] the temperature barrier set by TE coolers has been surpassed thus materializing one of the essential goals of optical refrigeration. Here we report another milestone by demonstrating Yb:YLF optical refrigerator to cool a payload to 165 K. This work serves as a proof-of-principle demonstration of the feasibility of optical refrigeration to be a viable vibration-free cooling technology that is also immune to electromagnetic interference. While current results already improve over TE cooler performance, temperatures near liquid nitrogen are predicted with modest improvements in material quality [14

14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

].

The cooling efficiency, defined as the ratio of the cooling power (Pc) to the absorbed laser power, has been given as [2

2. M. Sheik-Bahae and R. I. Epstein, “Optical Refrigeration: Advancing toward an all-solid-state cryocooler,” Nat. Photonics 1(12), 693–699 (2007). [CrossRef]

]
ηc(λ,T)=ηext[11+αbα(λ,T)]λλf(T)1,
(1)
where ηext is the external quantum efficiency (EQE) defined as the fraction of excited ions that lead to a fluorescence photon exiting the host material. The absorption coefficients α(λ,T) and αb are associated with the cooling transition of the active ion (e.g. Yb3+), and the background parasitic absorption. Rare-earth ions in low phonon energy hosts (such as fluorides) have provided high ηext (> 99%), making them ideal candidates for laser cooling. However, what ultimately limits the minimum achievable temperature is that only a fraction of absorbed photons lead to an excitation of cooling transition. This quantity, also known as the absorption efficiency ηabs, is indicated by the bracketed term in Eq. (1), which depends on the ratio αb/α(λ,T). As the temperature is lowered, the cooling efficiency decreases due to primarily two factors: decreasing of the resonant absorption and red-shifting of λf(T), as a consequence of Boltzmann distribution of excitations in the ground- and excited states respectively. The background absorption originates from unwanted contamination such as transition metals, and is taken to be temperature independent and broadband within the spectral region of cooling transition [15

15. M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75(14), 144302 (2007). [CrossRef]

].

Enhancement of the absorption efficiency is possible either by decrease of background absorption or by enhancement of the resonant absorption. Such enhancement is available in hosts with long range order – i.e. crystals, due to homogeneous broadening associated with the Stark manifold states, hence preserving the oscillator strength of the transitions. Figure 1
Fig. 1 (a) Stark manifold and the cooling E4-E5 transition in Yb; (b) Spectra of cooling efficiency (Eq. (1) of the Yb:YLF for different temperatures in degree Kelvin with measured values of ηext = 0.995 and αb = 4.2*10−4 cm−1 [14]. Spectra for which cooling is possible are shown in blue; cooling ceases for temperatures below minimum achievable temperature (red). Cooling efficiency is enhanced near the E4-E5 transition (1020 nm), yielding minimum achievable temperature of ~115 K.
shows cooling efficiency spectra (Eq. (1)) at different temperatures for an optical 2F7/22F5/2 transition in Yb3+-doped YLF crystalline host (5% doped, excitation is polarized along the c-axis). As is evident from the figure, cooling efficiency is enhanced at 1020 nm, corresponding to E4-E5 Stark manifold transition. In a recent set of experiments, by exciting Yb:YLF sample near the E4-E5 transition (1023 nm) with 9 Watts of incident power we demonstrated cooling to 155K [14

14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

]. This sample is grown by Czochralski method resulting in high-purity (low background absorption) material [16

16. N. Coluccelli, G. Galzerano, L. Bonelli, A. Di Lieto, M. Tonelli, and P. Laporta, “Diode-pumped passively mode-locked Yb:YLF laser,” Opt. Express 16(5), 2922–2927 (2008). [CrossRef] [PubMed]

].

2. Experiment and results

In this work, we exploit Yb:YLF optical refrigerator to cool a load comprised of a GaAs semiconductor passivated by GaInP cladding in a double heterostructure geometry with high external quantum efficiency. The payload material is chosen such that the mean luminescence wavelength of the Yb emission is above the band-edge absorption of the semiconductor even at room temperature, making the payload optically transparent to the fluorescence. This allows for direct thermal contact of the heterostructure with the crystal surface by means of a thin and nominally transparent high conductivity adhesive layer. Load thickness is 2 μm with the diameter of 0.8 mm corresponding to a weight of ~5 micrograms.

Temperature of an optical refrigerator and load is deduced by simultaneously monitoring the fluorescence spectrum of Yb:YLF and GaAs band-edge emission. Figure 2
Fig. 2 (a) Schematic of experimental setup; (b) Temperature of the crystal (Yb:YLF) and GaAs load as a function of time. High power laser is incident at t = 0 min, following by turn-off at t ~55min, when steady state was achieved, time is re-zeroed after the laser is turned off. Both Yb:YLF and GaAs temperatures are deduced by non-contact techniques. The cooling and warming dynamics are fitted with single exponential curves. Inset shows GaAs/InGaP spectra at two corresponding points (a: T = 265K, b: T = 165K).
outlines experimental setup [17

17. D. V. 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]

,18

18. D. V. Seletskiy, M. P. Hasselbeck, and M. Sheik-Bahae, “Cavity-enhanced absorption for optical refrigeration,” Appl. Phys. Lett. 96(18), 181106 (2010). [CrossRef]

] where a continuous wave Yb:YAG thin-disk laser, delivering 9W at 1023 nm, excites the Yb:YLF crystal in a non-resonant cavity geometry. Blackbody thermal load is minimized by housing the cryocooler assembly in a tightly fit clamshell inside of which is coated with a low thermal emissivity coating that is highly absorbing for the near IR and visible radiation [19

19. B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, and A. J. Mord, “Demonstration of a Solid-State Optical Cooler: An Approach to Cryogenic Refrigeration,” J. Appl. Phys. 86(11), 6489–6493 (1999). [CrossRef]

,20

20. J. Thiede, J. Distel, S. R. Greenfield, and R. I. Epstein, “Cooling to 208 K by optical refrigeration,” Appl. Phys. Lett. 86(15), 154107 (2005). [CrossRef]

].

A y-split optical fiber is fed-through the vacuum chamber in order to collect fluorescence of the Yb:YLF crystal excited by the pump laser and GaAs luminescence, excited by the weak laser diode that is coupled at one of the fiber ports on the ambient side. Second port is used to spectrally resolve both emission signals in a spectrometer in real time (Fig. 2(a)). Temperature of the Yb:YLF is determined by differential luminescence thermometry (DLT) technique [21

21. 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, 61151C (2006). [CrossRef]

], where raw signal is obtained by integrating spectral difference of the two luminescence signals: at known (reference) and unknown temperatures. The scalar integral value is converted to temperature by means of a separate calibration experiment performed in the optical cryostat with experimental accuracy of ± 1 degree [14

14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

]. GaAs temperature is deduced from the well-known temperature dependence of the band-gap [22

22. Y. Varshni, “Temperature dependence of the energy gap in semiconductors,” Physica 34(1), 149–154 (1967). [CrossRef]

]. In this method temperature accuracy is limited by the wavelength resolution of the spectrometer and is less than ± 2 degrees at low temperatures.

Cooling of Yb:YLF with GaAs load is shown in Fig. 2(b). After nearly 30 minutes of laser irradiation, a steady-state temperature of 165 K is reached by both the cryocooler and the payload. The fact that both cooler and load are at nearly the same temperature proves that no substantial thermal gradient exists between them. The cool-down and warm-up (rise) times are fitted with single exponential curves via least-squares algorithm. As is shown below, these fits provide a straightforward way of estimating the cooling and parasitic load powers in the Yb:YLF cryocooler.

It should be noted that an earlier attempt at cooling a thermal load using optical refrigeration in Yb-doped ZBLAN glass had resulted in a temperature drop of 12 degrees below ambient [23

23. G. L. Mills and A. J. Mord, “Performance modeling of optical refrigerators,” Cryogenics 46(2-3), 176–182 (2006). [CrossRef]

]. The achieved here temperature of 165 K is colder than the benchmark of standard thermoelectric coolers. Without the load, the bare YLF crystal has cooled to 155 K in a separate experiment [14

14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

]. As discussed below, this small discrepancy is attributed to increased parasitic absorption due to the adhesive as well as GaAs double heterostructure itself.

3. Analysis of the Temperature Dynamics

The temperature dependence of the cooling power (driving term) is also determined directly from the fits. At room temperature a cooling power of 150 mW is available for the given pumping conditions. The cooling power diminishes as temperature is decreased, reaching a balance with the parasitic load (steady-state) at T = 165 K, with the cooling power of 20 mW (Fig. 3(b)). It should be noted that the temperature dependence of the cooling power can also be estimated from the known cooling efficiency (Eq. (1)) and the absorbed power [14

14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

]. At ambient we obtain Pcool = 140 mW, in good agreement with the fitting results. At low temperature however we obtain agreement with the temperature dynamics only if we increase the background absorption by factor of 4 (Eq. (1)). We attribute such increase due to the parasitic absorption in the material of the load as well as the adhesive used for attachment. Finally, we note that GaAs absorption spectrally overlaps with the upconverted emission due to other rare-earth species in the Yb:YLF crystal which can also be responsible for the deduced increase in the background absorption.

4. Summary

We have cooled a semiconductor load by means of an optical refrigerator to a temperature of 165K, utilizing E4-E5 Stark manifold transition. This is a first demonstration of cooling a payload with an optical refrigerator, surpassing the performance of a standard thermoelectric cooler. Analysis of the temperature evolution points to the fact that radiative load needs to be decreased in order to achieve lower temperatures.

Acknowledgements

We thank Richard I. Epstein and Stefano Bigotta for helpful dialog. Chengao Wang is appreciated for GaAs sample preparation and Michael Hasselbeck for his assistance with LabView software. This work was supported by an AFOSR Multi-University Research Initiative Grant No. FA9550-04-1-0356 entitled Consortium for Laser Cooling in Solids.

References and links

1.

P. Pringsheim, “Zwei bemerkungen uËber den unterschied von lumineszenz- und Temperaturstrahlung,” Z. Phys. 57(11-12), 739–746 (1929). [CrossRef]

2.

M. Sheik-Bahae and R. I. Epstein, “Optical Refrigeration: Advancing toward an all-solid-state cryocooler,” Nat. Photonics 1(12), 693–699 (2007). [CrossRef]

3.

M. Sheik-Bahae and R. I. Epstein, “Laser Cooling of Solids,” Laser Photonics Rev. 3(1-2), 67–84 (2009). [CrossRef]

4.

R. I. Epstein, M. Buchwald, B. Edwards, T. Gosnell, and C. Mungan, “Observation of laser induced fluorescent cooling of a solid,” Nature 377(6549), 500–503 (1995). [CrossRef]

5.

A. N. Oraevsky, “Cooling of semiconductors by laser radiation,” J. Russ. Laser Res. 17(5), 471–479 (1996). [CrossRef]

6.

L. A. Rivlin and A. A. Zadernovsky, “Laser cooling of semiconductors,” Opt. Commun. 139(4-6), 219–222 (1997). [CrossRef]

7.

M. Sheik-Bahae and R. I. Epstein, “Can laser light cool semiconductors?” Phys. Rev. Lett. 92(24), 247403 (2004). [CrossRef] [PubMed]

8.

G. Rupper, N. H. Kwong, and R. Binder, “Large excitonic enhancement of optical refrigeration in semiconductors,” Phys. Rev. Lett. 97(11), 117401 (2006). [CrossRef] [PubMed]

9.

J. B. Khurgin, “Band gap engineering for laser cooling of semiconductors,” J. Appl. Phys. 100(11), 113116 (2006). [CrossRef]

10.

E. Finkeißen, M. Potemski, P. Wyder, L. Vina, and G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75(9), 1258–1260 (1999). [CrossRef]

11.

H. Gauck, T. H. Gfroerer, M. J. Renn, E. A. Cornell, and K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys., A Mater. Sci. Process. 64(2), 143–147 (1997). [CrossRef]

12.

M. Sheik-Bahae, B. Imangholi, M. P. Hasselbeck, R. I. Epstein, and S. Kurtz, “Advances in Laser Cooling of Semiconductors,” Proc. SPIE 6115, 611518 (2006). [CrossRef]

13.

C. Wang, M. P. Hasselbeck, C.-Y. Li, and M. Sheik-Bahae, “Characterization of external quantum efficiency and absorption efficiency in GaAs/ InGaP double heterostructures for laser cooling applications,” Proc. SPIE 7614, 76140B (2010). [CrossRef]

14.

D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]

15.

M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75(14), 144302 (2007). [CrossRef]

16.

N. Coluccelli, G. Galzerano, L. Bonelli, A. Di Lieto, M. Tonelli, and P. Laporta, “Diode-pumped passively mode-locked Yb:YLF laser,” Opt. Express 16(5), 2922–2927 (2008). [CrossRef] [PubMed]

17.

D. V. 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]

18.

D. V. Seletskiy, M. P. Hasselbeck, and M. Sheik-Bahae, “Cavity-enhanced absorption for optical refrigeration,” Appl. Phys. Lett. 96(18), 181106 (2010). [CrossRef]

19.

B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, and A. J. Mord, “Demonstration of a Solid-State Optical Cooler: An Approach to Cryogenic Refrigeration,” J. Appl. Phys. 86(11), 6489–6493 (1999). [CrossRef]

20.

J. Thiede, J. Distel, S. R. Greenfield, and R. I. Epstein, “Cooling to 208 K by optical refrigeration,” Appl. Phys. Lett. 86(15), 154107 (2005). [CrossRef]

21.

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, 61151C (2006). [CrossRef]

22.

Y. Varshni, “Temperature dependence of the energy gap in semiconductors,” Physica 34(1), 149–154 (1967). [CrossRef]

23.

G. L. Mills and A. J. Mord, “Performance modeling of optical refrigerators,” Cryogenics 46(2-3), 176–182 (2006). [CrossRef]

24.

C. W. Hoyt, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Greenfield, J. Thiede, J. Distel, and J. Valencia, “Advances in laser cooling of thulium-doped glass,” J. Opt. Soc. Am. B 20(5), 1066–1074 (2003). [CrossRef]

25.

R. L. Aggarwal, D. J. Ripin, J. R. Ochoa, and T. Y. Fan, “Measurement of thermo-optic properties of Y3Al5O12, Lu3Al5O12, YAIO3, LiYF4, LiLuF4, BaY2F8, KGd(WO4)2, and KY(WO4)2 laser crystals in the 80–300 K temperature range,” J. Appl. Phys. 98, 103514 (2005). [CrossRef]

OCIS Codes
(140.3320) Lasers and laser optics : Laser cooling
(160.5690) Materials : Rare-earth-doped materials

ToC Category:
Atomic and Molecular Physics

History
Original Manuscript: June 28, 2010
Revised Manuscript: August 2, 2010
Manuscript Accepted: August 2, 2010
Published: August 6, 2010

Citation
Denis V. Seletskiy, Seth D. Melgaard, Alberto Di Lieto, Mauro Tonelli, and Mansoor Sheik-Bahae, "Laser cooling of a semiconductor load to 165 K," Opt. Express 18, 18061-18066 (2010)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-18-17-18061


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. P. Pringsheim, “Zwei bemerkungen uËber den unterschied von lumineszenz- und Temperaturstrahlung,” Z. Phys. 57(11-12), 739–746 (1929). [CrossRef]
  2. M. Sheik-Bahae and R. I. Epstein, “Optical Refrigeration: Advancing toward an all-solid-state cryocooler,” Nat. Photonics 1(12), 693–699 (2007). [CrossRef]
  3. M. Sheik-Bahae and R. I. Epstein, “Laser Cooling of Solids,” Laser Photonics Rev. 3(1-2), 67–84 (2009). [CrossRef]
  4. R. I. Epstein, M. Buchwald, B. Edwards, T. Gosnell, and C. Mungan, “Observation of laser induced fluorescent cooling of a solid,” Nature 377(6549), 500–503 (1995). [CrossRef]
  5. A. N. Oraevsky, “Cooling of semiconductors by laser radiation,” J. Russ. Laser Res. 17(5), 471–479 (1996). [CrossRef]
  6. L. A. Rivlin and A. A. Zadernovsky, “Laser cooling of semiconductors,” Opt. Commun. 139(4-6), 219–222 (1997). [CrossRef]
  7. M. Sheik-Bahae and R. I. Epstein, “Can laser light cool semiconductors?” Phys. Rev. Lett. 92(24), 247403 (2004). [CrossRef] [PubMed]
  8. G. Rupper, N. H. Kwong, and R. Binder, “Large excitonic enhancement of optical refrigeration in semiconductors,” Phys. Rev. Lett. 97(11), 117401 (2006). [CrossRef] [PubMed]
  9. J. B. Khurgin, “Band gap engineering for laser cooling of semiconductors,” J. Appl. Phys. 100(11), 113116 (2006). [CrossRef]
  10. E. Finkeißen, M. Potemski, P. Wyder, L. Vina, and G. Weimann, “Cooling of a semiconductor by luminescence up-conversion,” Appl. Phys. Lett. 75(9), 1258–1260 (1999). [CrossRef]
  11. H. Gauck, T. H. Gfroerer, M. J. Renn, E. A. Cornell, and K. A. Bertness, “External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure,” Appl. Phys., A Mater. Sci. Process. 64(2), 143–147 (1997). [CrossRef]
  12. M. Sheik-Bahae, B. Imangholi, M. P. Hasselbeck, R. I. Epstein, and S. Kurtz, “Advances in Laser Cooling of Semiconductors,” Proc. SPIE 6115, 611518 (2006). [CrossRef]
  13. C. Wang, M. P. Hasselbeck, C.-Y. Li, and M. Sheik-Bahae, “Characterization of external quantum efficiency and absorption efficiency in GaAs/ InGaP double heterostructures for laser cooling applications,” Proc. SPIE 7614, 76140B (2010). [CrossRef]
  14. D. V. Seletskiy, S. D. Melgaard, S. Bigotta, A. D. Lieto, M. Tonelli, and M. Sheik-Bahae, “Laser cooling of solids to cryogenic temperatures,” Nat. Photonics 4(3), 161–164 (2010). [CrossRef]
  15. M. P. Hehlen, R. I. Epstein, and H. Inoue, “Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN,” Phys. Rev. B 75(14), 144302 (2007). [CrossRef]
  16. N. Coluccelli, G. Galzerano, L. Bonelli, A. Di Lieto, M. Tonelli, and P. Laporta, “Diode-pumped passively mode-locked Yb:YLF laser,” Opt. Express 16(5), 2922–2927 (2008). [CrossRef] [PubMed]
  17. D. V. 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]
  18. D. V. Seletskiy, M. P. Hasselbeck, and M. Sheik-Bahae, “Cavity-enhanced absorption for optical refrigeration,” Appl. Phys. Lett. 96(18), 181106 (2010). [CrossRef]
  19. B. C. Edwards, J. E. Anderson, R. I. Epstein, G. L. Mills, and A. J. Mord, “Demonstration of a Solid-State Optical Cooler: An Approach to Cryogenic Refrigeration,” J. Appl. Phys. 86(11), 6489–6493 (1999). [CrossRef]
  20. J. Thiede, J. Distel, S. R. Greenfield, and R. I. Epstein, “Cooling to 208 K by optical refrigeration,” Appl. Phys. Lett. 86(15), 154107 (2005). [CrossRef]
  21. 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, 61151C (2006). [CrossRef]
  22. Y. Varshni, “Temperature dependence of the energy gap in semiconductors,” Physica 34(1), 149–154 (1967). [CrossRef]
  23. G. L. Mills and A. J. Mord, “Performance modeling of optical refrigerators,” Cryogenics 46(2-3), 176–182 (2006). [CrossRef]
  24. C. W. Hoyt, M. P. Hasselbeck, M. Sheik-Bahae, R. I. Epstein, S. Greenfield, J. Thiede, J. Distel, and J. Valencia, “Advances in laser cooling of thulium-doped glass,” J. Opt. Soc. Am. B 20(5), 1066–1074 (2003). [CrossRef]
  25. R. L. Aggarwal, D. J. Ripin, J. R. Ochoa, and T. Y. Fan, “Measurement of thermo-optic properties of Y3Al5O12, Lu3Al5O12, YAIO3, LiYF4, LiLuF4, BaY2F8, KGd(WO4)2, and KY(WO4)2 laser crystals in the 80–300 K temperature range,” J. Appl. Phys. 98, 103514 (2005). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 2 Fig. 3
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited