Abstract

Research to identify methods for increasing the laser damage threshold probability of high reflection interference coatings dates to the early 1970's. Particular emphasis has been placed on the wavelength(s) coinciding with the laser line(s) being reflected by these coatings. This work typically addressed multi-layer stack coatings. Our work has examined a sine-wave refractive index profile, commonly called a rugate filter (Ref ¹). A single sine-wave refractive index profile having numerous identical cycles produces one well defined reflection band. This reflection band can be spectrally tailored and positioned anywhere within the passband of the filter with no associated higher order reflection bands present. The spectral location of this reflection band is twice the optical thickness of one of the cycles comprising the sine-wave refractive index profile.

© 1992 Optical Society of America