Can Laser Light Cool Semiconductors?
Abstract
The concept of laser cooling (optical refrigeration) by luminescence up-conversion in solids dates back to 1929 [1]. Pringsheim recognized that thermal vibrational energy can be removed by anti-Stokes fluorescence if a material is excited with photons having energy below the mean fluorescence energy (see Fig. 1). Material purity problems prevented observation of this type of laser cooling until 1995, when it was first demonstrated in ytterbium-doped glass [2]. This was followed soon after by reports of cooling in dye solutions [3] and thulium-doped glass [4]. Attaining net cooling in semiconductors, however, has remained elusive. A key problem has been the inability of luminescence to efficiently escape from a semiconductor due to total internal reflection [5,6]. Although the theory of semiconductor cooling has been tackled previously [7,8], the critical issues of luminescence trapping and redshifting have not been taken into account. These processes have the potential to frustrate attempts to achieve semiconductor net cooling. Here, we resolve this problem and show that laser cooling of semiconductors is feasible.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 18, 2004
- Accession Number
- ADA597297
Entities
People
- Mansoor Sheik-bahae
- Richard I. Epstein
Organizations
- Los Alamos National Laboratory