Anti-stokes fluorescence cooling of lanthanum aluminosilicate glasses

This study reports on the fabrication of ytterbium-doped lanthanum-aluminosilicate (LAS) glasses using the modified chemical vapor deposition (MCVD) process combined with solution doping. The fabricated samples exhibit near-unity quantum efficiencies and background absorptions below 10 dB·km⁻¹, enabling the observation of anti-Stokes fluorescence cooling (ASFC) under excitation wavelengths ranging from 1030 to 1080 nm. Measurements conducted in ambient conditions demonstrated net cooling of up to −8.2 K from room temperature in small bulk samples and −7.9 K in long rods of the material.