Abstract:

A record cooling to <125 K of an all-solid-state optical cryocooler by the anti-Stokes fluorescence cooling of a 10% Yb:YLF crystal. The record cooling achievable by the employment of a novel textured-MgF2 thermal link which improves thermal transport and fluorescence escape. Spectrally selective coatings on the multi-pass pump circulator mirrors tuned to be highly reflective for the pump wavelengths yet transmit longer wavelengths in the Stokes regime. The loss introduced prevents sufficient gain from building up leading to amplified spontaneous emission and lasing. The roles of other potential nonlinearities, such as pump saturation, are investigated.

Authors: Jackson L. Kock, Alexander R. Albrecht, Duncan McGraw, Richard I. Epstein, and Mansoor Sheik-Bahae