A new vacuum-etched high-transmittance (antireflection) film

Abstract

Films of high optical transmittance have been formed by the reactive sputter etching of quartz slides. With a globular metal masking layer, conical structures are formed in the quartz which form a gradient‐index film. To date films have been produced which have less than half the loss of an uncoated quartz surface over a 2:1 wavelength range. Film scattering limits the short‐wavelength performance and is shown to depend on the film structure’s average period.