Entropy and efficiency in laser cooling of solids

X. L. Ruan, S. C. Rand, and M. Kaviany

Phys. Rev. B 75, 214304 – Published 18 June 2007

Abstract

The thermodynamics of laser cooling of solids is analyzed. Using the general theory of radiation entropy, the important roles of the optical frequency and the photon distribution function in determining the radiation entropy are identified. The usefulness of a narrow-band approximation is established for a wide range of radiant sources. This approximation is then applied to compare the entropies of different light sources, including blackbody radiation, lasers, fluorescence, and the emerging class of random lasers. Based on these results, the Carnot efficiency for laser cooling of solids is determined for emission fields with various entropy characteristics. It is shown that fluorescent emission is the most efficient form of the radiated field for laser cooling of solids, and cooling schemes based on any stimulated emission process (including random laser action) are inherently less efficient. The influence of luminescence quantum yield on cooling is also considered.

5 More

Received 19 April 2006

DOI:https://doi.org/10.1103/PhysRevB.75.214304

Authors & Affiliations

X. L. Ruan^1,*, S. C. Rand², and M. Kaviany^1,†

¹Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48105, USA
²Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48105, USA

^*Present address: School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907.
^†Author to whom all correspondence should be addressed. Electronic address: kaviany@umich.edu

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 75, Iss. 21 — 1 June 2007

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Physical Review B

covering condensed matter and materials physics