Damage resistant optical components for 2-5-μm laser systems

In recent years, alkaline-earth fluoride materials have been developed for use as high performance optical components in lasers operating in the spectral range from 2 μm to 5 μm (for example, HF and DF lasers). However, as in the cases of high power Nd glass and CO2 lasers, damage to optical components due to extremely high optical fluxes has proved a severe system limitation. Suitable 2–5-μm optical materials for damage resistant optics have not yet been evaluated systematically using a well-controlled laser source in this spectral region. In this paper we will discuss the properties of candidate optical materials for high-power 2–5-μm laser systems and present experimental data on damage resistance for the best obtainable samples. This information describing the laser–light-material interaction will provide electrooptical system engineers with data essential to the design of reliable high-power 2–5-μm lasers.