Reflectance, transmittance, and loss spectra of multilayer Si/SiO(2) thin film mirrors and antireflection coatings for 1.5 microm.

A method is described for measuring transmittance, reflectance, and loss spectra in thin optical films. The method is applied to measure the properties of multilayer coatings of Si and SiO(2) used to make mirrors and antireflection coating in the 1.0-1. 7-microm wavelength region. Mirrors with reflectance up to 99.5% with nine quarter-wavelength layers and two-layer antireflection coatings with reflectance of <0.2% have been made.