Laser cooling of ytterbium-doped silica glass
Esmaeil Mobini, Saeid Rostami, Mostafa Peysokhan, Alexander R. Albrecht, Stefan Kühn, Sigrun Hein, Christian Hupel, Johannes Nold, Nicoletta Haarlammert, Thomas Schreiber, Ramona Eberhardt, Andreas Tünnermann, Mansoor Sheik‐Bahae, Arash Mafi
Abstract
Abstract Laser cooling of a solid is achieved when a coherent laser illuminates the material in the red tail of its absorption spectrum, and the heat is carried out by anti-Stokes fluorescence of the blue-shifted photons. Solid-state laser cooling has been successfully demonstrated in several materials, including rare-earth-doped crystals and glasses. Here we show the net cooling of high-purity Yb-doped silica glass samples that are fabricated with low impurities to reduce their parasitic background loss for fiber laser applications. The non-radiative decay rate of the excited state in Yb ions is very small in these glasses due to the low level of impurities, resulting in near-unity quantum efficiency. We report the measurement of the cooling efficiency as a function of the laser wavelength, from which the quantum efficiency of the Yb-doped silica is calculated.