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Loss processes on crystal cooling efficiency

Francesco Caminati, Giovanni Cittadino, Eugenio Damiano +2 more

In the perspective of building a solid state cryocooler based on optical refrigeration, it is strategic to develop high purity crystals and to have a full understanding of the mechanisms that can reduce cooling efficiency. In this paper we highlight two loss mechanisms that can hinder the optical refrigeration performance of a Yb:YLF monocrystal: the presence of impurities and fluorescence reabsorption. We show how the presence of impurities can be inferred by measuring the mean lifetime of the Yb optical transition. We measure how a few ppms of other rare earth ions can be detrimental for optical refrigeration by exciting a cooling Yb:YLF sample with two laser sources. We also report the first practical demonstration of the negative effect of fluorescence reabsorption on the cooling performance.In the perspective of building a solid state cryocooler based on optical refrigeration, it is strategic to develop high purity crystals and to have a full understanding of the mechanisms that can reduce cooling efficiency. In this paper we highlight two loss mechanisms that can hinder the optical refrigeration performance of a Yb:YLF monocrystal: the presence of impurities and fluorescence reabsorption. We show how the presence of impurities can be inferred by measuring the mean lifetime of the Yb optical transition. We measure how a few ppms of other rare earth ions can be detrimental for optical refrigeration by exciting a cooling Yb:YLF sample with two laser sources. We also report the first practical demonstration of the negative effect of fluorescence reabsorption on the cooling performance.

Optics ExpressOct 7, 20216 citations

Superconducting Detectors

George H. Rieke

Cambridge University Press eBooksApr 30, 20211 citation

Otto refrigerator based on a superconducting qubit: Classical and quantum performance

Bayan Karimi, Jukka P Pekola

Experimental demonstration of a truly quantum mechanical solid-state heat engine or refrigerator remains elusive up to now. Here, a four-stroke quantum refrigerator that can be realized using a superconducting qubit coupled alternately to two resonators with embedded reservoirs is analyzed theoretically. Besides being a practically feasible thermal machine, this concept presents a number of fundamentally interesting features. At high frequencies, the system exhibits nearly coherent dynamics, leading to quantum oscillations in cooling power versus operation frequency. At intermediate frequencies, an ideal Otto cycle can be realized. In the nearly adiabatic regime, the cooling power is quadratic in frequency and can be separated to classical and quantum contributions. Interestingly, it is shown here that quantum coherence leads always to performance that is inferior as compared to that arising from purely classical dynamics. Furthermore, in the nearly adiabatic regime the efficiency of the refrigerator exceeds clearly that of the standard Otto cycle.Experimental demonstration of a truly quantum mechanical solid-state heat engine or refrigerator remains elusive up to now. Here, a four-stroke quantum refrigerator that can be realized using a superconducting qubit coupled alternately to two resonators with embedded reservoirs is analyzed theoretically. Besides being a practically feasible thermal machine, this concept presents a number of fundamentally interesting features. At high frequencies, the system exhibits nearly coherent dynamics, leading to quantum oscillations in cooling power versus operation frequency. At intermediate frequencies, an ideal Otto cycle can be realized. In the nearly adiabatic regime, the cooling power is quadratic in frequency and can be separated to classical and quantum contributions. Interestingly, it is shown here that quantum coherence leads always to performance that is inferior as compared to that arising from purely classical dynamics. Furthermore, in the nearly adiabatic regime the efficiency of the refrigerator exceeds clearly that of the standard Otto cycle.

arXiv:1610.02776Physical review. B./Physical review. BNov 9, 2016150 citations

Superconducting X-ray detectors

Can Hui Yang, Mengting Si, Lixing You

Science China Information SciencesJul 15, 202012 citations

Sub-50-mK Electronic Cooling with Large-Area Superconducting Tunnel Junctions

Hung Q. Nguyen, M. Meschke, H. Courtois +1 more

Experiments conducted below 0.1 K require expensive, complicated cryogenic apparatus. What if an integrated solid-state device could be used instead? The authors present just such an on-chip refrigerator, based on a superconductor/normal-metal junction, that chills down to 30 mK with remarkable cooling power. This provides a means to reduce thermal noise in e.g. qubits, SQUIPT magnetometers, or the sensitive detectors required for astronomy experiments.

Physical Review AppliedNov 4, 201475 citations

Detectors Based on Superconductors

Karl K. Berggren, Eric A. Dauler, Andrew J. Kerman +2 more

Experimental methods in the physical sciencesJan 1, 20136 citations

First demonstration of a superconducting detector cooled by solid-state refrigerators.

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First demonstration of a superconducting detector cooled by solid-state refrigerators.

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