Gradient infrared optical material prepared by a chemical vapor deposition process

An axial gradient, infrared optical material, ZnSxSe1−x, has been developed by codepositing ZnS and ZnSe in a controlled manner via a chemical vapor deposition process. This material has been characterized by measuring the compositional and refractive-index profiles, visible, and IR transmission, microstructure, and hardness. Axial index gradients produced thus far range from 0.024 to 0.066 mm−1 over a thickness of ~4 mm. An analytical model of the deposition process has been developed and successfully used to derive a deposition algorithm to produce specific index gradients.