1W continuous-wave laser generation and excited state absorption measurements in Cr2+:ZnSe

Cr2+-doped chalcogenide crystals were shown recently to be promising materials for highly efficient and broadly tunable mid-IR (2-3 μm) lasers [1]. Possible applications of these lasers include medicine, remote sensing and trace gas analysis. Pulsed [2], continuous wave (cw) [3, 4], gain-switched [5] and diode-side-pumped laser operation [6] has been demonstrated with Cr2+:ZnSe, which exhibit slope efficiency as high as 63% and tunability between 2138 nm and 2760 nm. However, one of the problems encountered with this kind of materials is their relatively high level of passive losses at the laser wavelength. Thus both detailed spectroscopic studies including ESA measurements and synthesis of materials by using various crystal-growth techniques are necessary to estimate the amount of intrinsic optical losses and reduce as much as possible what is due to extrinsic reasons such as unwanted impurities and lattice defects. In this paper we report for the first time to our knowledge on the results of ESA measurements in Cr2+:ZnSe as well as on the realization of 1W efficient cw laser with Cr2+:ZnSe crystals.