On the origin of anti-Stokes laser-induced cooling of Yb3+-doped glass

Abstract Anti-Stokes cooling between room temperature and 77 K in a new fluorochloride glass (CNBZn) doped with 1 mol% of YbF 3 has been demonstrated by using collinear photothermal deflection and conventional laser excitation spectroscopies under high photon irradiances. The cooling efficiency of CNBZn glass which is ∼2.0% relative to the absorbed laser power at 1010 nm and 300 K falls by about 20% at 77 K. A model accounting for the photon–ion–phonon interaction is in good agreement with the observed temperature dependence of the cooling process and shows its relation with the vibrational properties of the material.