Power scaling feasibility of chromium-doped II-VI laser sources and the demonstration of a chromium-doped zinc selenide face-cooled disk laser

Tunable lasers in the 2–4 μm wavelength range are needed for Air Force sensor applications. Chromium-doped II-VI materials are a promising class of laser material for tunable operation in this wavelength range, but until recently had not produced enough output power to meet application requirements. This dissertation investigates Cr2+:II-VI material properties and potential laser designs, then experimentally demonstrates and analyzes the performance of a Cr2+:ZnSe disk laser design that can produce sufficient output power. Cr2+:II-VI laser materials are found to be susceptible to overheating and thermal lensing, but are otherwise satisfactory laser materials. The most feasible laser design given a 15 W pump power limit was a face-cooled disk laser design using Cr2+:ZnSe The experimental implementation of the laser design produced 4.3 W. However, the experimental laser worked well only under a restricted set of conditions, due to thermal lensing caused by a radially non-uniform absorbed power distribution in the laser disk. Design modifications are discussed which should reduce thermal lensing to acceptable levels. The conclusion is that Cr2+:II-VI laser sources can produce enough power for Air Force sensor applications, if enough effort is spent on ensuring adequate thermal management in the laser material.