[22p-A402-1~13] 3.4 Laser system and materials (formerly 3.5)

[22p-A402-12] Laser cooling of ytterbium-doped fluoride crystals

〇Hiroki Tanaka¹, Stefan Pueschel¹, Christian Kraenkel¹ (1.Leibniz-Inst. Kristallzuechtung)

Keywords:laser cooling, crystal growth, anti-Stokes fluorescence

Optically active solids can be refrigerated by anti-Stokes fluorescence driven by laser excitation. Ytterbium-doped fluoride crystals exhibit their great potential as laser cooling media for all-solid-state optical cryocoolers. In this work, we grew different fluoride crystals doped with ytterbium ions by the Czochralski method, and experimentally examined their laser cooling characteristics. We further estimated the minimum achievable temperatures of each crystal using temperature-dependent absorption and fluorescence spectral data.