Key Laboratary of Excited State Processes Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China;
Graduate School of the Chinese Academy of Sciences Beijing 100049 China;
Key Laboratary of Excited State Processes Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China;
thin disk laser; heat effect; PL spectrum; active region; heat removal; gain; barrier; spectral shift;