Abstract

Boron nitride is a hard coating material and is highly transparent in the mid infrared wavelengths. The index of refraction of boron nitride in this wavelength region is dispersive and can be described by a sixth order Pelletier formula. A single layer boron nitride protective/antireflective coating was designed to maximize spectral transmittance over a wide range of angles of incidence using a merit function consisting of a transmission expression averaged over the spectral and angular ranges. The optimized boron nitride protective/antireflective coating on zinc selenide substrates was fabricated using ion beam sputter deposition. The spectral and angle of incidence response of the boron nitride coating was measured and compared with the theoretical calculations employing dispersive index of refraction.

© 1990 Optical Society of America