Temperature-dependent spectroscopy of Yb:YLF and prospects for laser cooling

Ytterbium-doped materials are promising for high power solid-state lasers as well as laser cooling [1] . Cooling of Yb-doped fluoride crystals, particularly LiYF 4 (YLF), has been very successful, achieving cooling of high purity Yb:YLF crystals to below 100 K [2] . Here, we revisit the detailed temperature-dependent spectroscopy of Yb:YLF in order to fully reveal its potential as a laser cooling medium and to address requirements to achieve the liquid nitrogen temperature at 77 K.