The atmospheric transmission windows of 2-5 and 8-12 µm, coupled with organic and other chemical absorption lines occurring throughout this middle-infrared (mid-IR) wavelength region give rise to a wide variety of medical, scientific, commercial and military applications. Communications, remote sensing, IR countermeasures, laser surgery and non-invasive imaging are just a few of the drivers of high-power solid-state mid-IR laser development. These laser sources must be versatile enough to operate in a variety of temporal modes from continuous wave (CW) all the way to ultrashort pulse while still being widely tunable for wavelength agility. All of this is required at ever increasing power output levels while conforming to size, weight and power consumption limitations under harsh operating environmental conditions.
Chromium-doped zinc selenide (Cr2+:ZnSe) lasers operating in the 2-3 µm region are excellent candidates to help fill these vital roles. As a transition-metal doped II-VI chalcogenide, Cr2+:ZnSe has a number of positive advantages over existing laser sources. Development and power scaling of these lasers however, has been hampered by thermal issues which have so far limited the ability of these lasers to be applied to systems-level development.
This work presents research into the nature and mitigation of these critical thermal issues in development of versatile Cr2+:ZnSe laser sources. Advanced models for thermal and laser performance are developed and used to design optimally configured laser systems. Among other advances for this material, >10 W CW output from a Cr2+:ZnSe oscillator and master-oscillator / power amplifier systems producing multi-watt, widely tunable power levels are demonstrated.