Abstract

We have observed that the dominant loss mechanism in thermally deposited ZnS films is internal scattering at grain boundaries within the film. To reduce crystalline effects, we deposited ZnS onto liquid nitrogen cooled substrates. X-ray diffraction indicates that these films are amorphous and they exhibit significantly lower losses (<1 dB/cm) than films deposited at ambient temperatures (≃ 10 dB/cm). The cooling process may also reduce film density, which results in a lower refractive index and tensile stress within the ZnS films. Preliminary results on nonlinear properties of the cooled films are presented.

© 1988 Optical Society of America