Temperature resolved measurements of absorption and emission cross sections for various Yb³⁺-doped gain media from 100K to room temperature

摘要

It has been shown, that cryogenic cooling of Yb³⁺-doped media is increasing laser performance significantly[1,2]. The reason for this is the thermal depopulation of the lower laser levels turning the quasi three level extraction scheme into a real four level scheme. By now most of these cryogenic cooled amplifiers aim on liquid nitrogen temperature. For future systems it has to be estimated what is an optimum operation temperature as compromise between laser performance and effort for cooling. This is needed as well from an energetic point of view as from an financial point of view. For this it is necessary to know the basic absorption and emission cross sections in dependence of temperature.