Advances in the optical refrigeration of silica: cooling by 18 K from room temperature

Abstract

Record laser cooling of Yb-doped silica by 18.4 K and 6.3 K was observed in vacuum and atmospheric pressure conditions, respectively. We present a detailed investigation into the optical refrigeration of ytterbium doped silica glass for both in-air and in-vacuum conditions using various pump powers. Temperature measurements were made relative to the room temperature using thermal camera imaging and differential luminescence thermometry. Through analysis of the temporal behavior of the temperature differential at the start of the in-vacuum experiments, we find the cooling efficiency of the studied silicates to be 0.66 ± 0.07%.