Laser action in bulk Cr:ZnSe crystals

Abstract

Cr:ZnSe laser active material is one of the favourite possibility how to generate broadly tunable mid-infrared laser radiation at room-temperature. The aim of this study was to demonstrate and analyze pulsed as well as continuous-wave laser action in bulk Cr:ZnSe crystals grown by the floating-zone method or by the Bridgman method. The absorption spectra of Cr:ZnSe were measured to be from 1500 to 2000 nm, therefore various lasers were utilized for coherent longitudinal pumping of Cr:ZnSe laser, namely flashlamp-pumped Er:YAP laser (generated wavelength 1658 nm), diode-pumped Tm:YLF laser (generated wavelength 1912 nm), and diodepumped Tm:YAP laser (generated wavelength 1980 nm). In the first case, the Cr:ZnSe crystal grown by the Bridgman method was investigated. In the second case, the Cr:ZnSe crystal grown by the floating zone method was studied. In both cases, the homogeneity of the active Cr:ZnSe crystals was found reasonable good. The emission spectrum was from 2000 up to 2800 nm. The Cr:ZnSe laser generated radiation was broadly continuously tunable in the range from 2050 nm up to 2750 nm. The generated radiation beam spatial structure was close to TEM 00 .