High thermal conductivity and low quantum defect in Yb:CaGdAlO_4, a new infrared laser material for high power applications

摘要

2%Yb:CaGdAlO_4 (called CALGO) presents favorable thermo-mechanical properties with quite high measured thermal conductivity (Κ_(//c) = 6.3 and Κ_(⊥c) = 6.9 W.m~(-1).K~(-1)). Laser oscillations (from 1050 to 994 nm pumping at 979 nm) are demonstrated for the first time to our knowledge. This implies a very small quantum defect (down to 1.4%). A simple new figure of merit taking into account thermo-mechanical properties and quantum defect is proposed here in order to compare material resistance under high power laser pumping. Consequently, Yb:CALGO appears similar to garnets and sesquioxides with regard to laser power resistance.