Q-switched 2-µm lasers by use of a Cr^2+:ZnSe saturable absorber

Abstract

Flash-lamp-pumped Ho:YAG (2090-nm) and Tm:YAG (2017-nm) lasers were, for the first time to our knowledge, passively Q switched by use of a Cr2+:ZnSe saturable absorber. A Q-switched Ho laser with 1.3-mJ pulse energy and approximately 90-ns pulse duration and a Q-switched Tm laser with approximately 3.2-mJ pulse energy and 90-ns pulse duration were demonstrated. Compared with the free-running output energies at the Q-switching threshold pump levels, the Q-switching efficiencies were approximately 5% for the Ho:YAG laser and 16% for the Tm:YAG laser.