Differential luminescence thermometry in semiconductor laser cooling

Imangholi, Babak; Hasselbeck, Michael P.; Bender, Daniel A.; Wang, Chengao; Sheik‐Bahae, Mansoor; Epstein, Richard I.; Kurtz, Sarah

doi:10.1117/12.646346

Cited by 28 publications

(22 citation statements)

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“…Temperature of the sample is measured in a non-contact way, utilizing differential luminescence thermometry (DLT) technique . 9 Cooling results are displayed in Figure 2. Initially, pump laser is tuned to 1027nm, but after steady-state is reached, pump laser is blue-shifted in sequence allowing sample to reach thermal equilibrium at each point.…”

Section: Experimental Setup and Resultsmentioning

confidence: 99%

Recent progress in laser cooling via resonant cavity

Seletskiy

Melgaard

Hasselbeck

et al. 2009

Laser Refrigeration of Solids II

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We discuss recent progress in the laser cooling experiments via resonant cavity. Following analysis of the cooling efficiency, we highlight importance of wavelength dependence of the minimum achievable temperature for a given cryocooler. Following the analysis, we utilize pump detuning along with reduction of thermal load on the sample to achieve absolute temperature of nearly 200K, a 98.5 degree drop, starting from room temperature. Wavelength dependent analysis suggests that further improvement is possible.

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Section: Experimental Setup and Resultsmentioning

confidence: 99%

Recent progress in laser cooling via resonant cavity

Seletskiy

Melgaard

Hasselbeck

et al. 2009

Laser Refrigeration of Solids II

Self Cite

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“…[1][2][3] Recently an EQE of 99% at 100K has been reported by our group. 2,8 While this satisfies the criteria for laser cooling, the presence of parasitic background absorption has remained as the key challenge in achieving this goal .…”

Section: Introductionmentioning

confidence: 99%

Heterostructure design optimization for laser cooling of GaAs

Imangholi¹,

Wang²,

Soto³

et al. 2007

SPIE Proceedings

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Doping of the clad layers in thin GaAs/GaInP heterostructures, displaces the band energy discontinuity, modifies the carrier concentration in the active GaAs region and changes the quality of the hetero-interfaces. As a result, internal and consequently external quantum efficiencies in the double heterostructure are affected. In this paper, the interfacial quality of GaAs/GaInP heterostructure is systematically investigated by adjusting the doping level and type (n or p) of the cladding layer. An optimum structure for laser cooling applications is proposed.Keywords: semiconductor laser cooling, external quantum efficiency, internal quantum efficiency, bandgap discontinuity, double heterostructure design, GaAs/GaInp, GaAs/AlGaAs.

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“…Most laser cooling demonstrations require the measurement of temperature using fine thermo-couples 17 , thermal cameras 1 , refractive index monitoring 5,18 , the measurement of the emitted fluorescence spectra of the sample 19 , or of a fluorescent probe 20,21 . Difficulties in temperature measurement due to the transparency of the material at the detected wavelength 17 , competing optical effects 18 , complex optical alignment, or pump modulation 20 can make the calibration cumbersome.…”

Section: Introductionmentioning

confidence: 99%

Direct measurement of laser cooling of Yb:YAG crystal at atmospheric pressure using a fiber Bragg grating

et al. 2014

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Although Yb:YAG has been cooled in a vacuum environment 1 , we report for the first time an experimental demonstration of optical cooling at atmospheric pressure. A Yb:YAG crystal is supported on thin silica fibers, inside a matt-black chamber with air at atmospheric pressure, and pumped at 1029 nm in the pulsed and CW regimes. Direct measurement of the crystal surface temperature during pumping was made possible by using a low thermal-mass, transparent fiber Bragg grating (FBG) sensor. The FBG interrogation system has sufficient sensitivity to measure the background absorption of the sample to below 10 -4 cm -1 , and bulk cooling at a pump power as low as 17 mW. The dynamical measurement of the temperature allows the determination of the overall heat transfer coefficient of the sample in the air, of 22 W.m -2 K -1 . A temperature drop of 8.8 K from the chamber temperature is observed in the Yb:YAG crystal in air when pumped with 4.2 W at 1029 nm, close to 8.9 K observed in vacuum 1 . A background absorption α b = 2.9×10 -4 cm -1 is estimated with a pump wavelength at 1550 nm. Simulations predict further cooling when the sample's cross sectional area and the pump power are optimized, including absorption saturation effects. The choice of an efficient geometry, the use of a readily available temperature sensor in less controlled environments should simplify implementation of laser cooling systems and the development of commercial devices.

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Differential luminescence thermometry in semiconductor laser cooling

Cited by 28 publications

References 0 publications

Recent progress in laser cooling via resonant cavity

Recent progress in laser cooling via resonant cavity

Heterostructure design optimization for laser cooling of GaAs

Direct measurement of laser cooling of Yb:YAG crystal at atmospheric pressure using a fiber Bragg grating

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