Surface Plasmon-Assisted Laser Cooling of Solids

Laser refrigeration of a semiconductor placed in the proximity of a metal surface is analyzed. It is shown that both the threshold and the efficiency of laser cooling can be significantly improved due to rapid energy transfer from the semiconductor to the metal via excitation of surface plasmon polaritons and their subsequent decay in the metal. Even further improvement of cooling efficiency is expected when the metal surface is periodically structured.

Figure 1

Principle of laser cooling of a semiconductor and methods for its enhancement using a photonic band gap with energy $E_{g,\mathrm{PC}}$ or an SPP with energy $E_{\mathrm{SPP}}$.

Figure 2

SPP-assisted cooling diagram.

Figure 3

(a) SPP dispersion. (b) Purcell enhancement factor in the structure in Fig. 2.

Figure 4

Cooling efficiency with (solid curves) and without (dashed curves) SPPs vs a nonradiative lifetime (a) at two different temperatures and (b) at 300 K in the presence of an SPP band gap for different band gap energies $E_{g,\mathrm{SPP}}$.