Abstract

Normal incidence measurements of single-layer gradient refractive-index antireflection films, produced by a chemical etch-leach process on glass sensitized by a phase-separating heat treatment, indicate very low reflection over a broad wavelength regime, 0.35–2.5 μm. First-surface measurements of the reflectance of the gradient index films have now been made, in the visible regime, at off-normal incidence (to 70°) using polarized light. These measurements show that significant reflection reduction is obtained even at high angles of incidence—5.7% reflectance from the filmed glass at 70° compared to 16.4% for the unfilmed glass. Furthermore, although the films exhibit a weak wavelength dependence at high angles, they continue to be effective over a broad spectral region. The optical properties observed are in good agreement with computations based on a gradient refractive-index film with a step at the air-film interface. The optical properties of the film offer considerable advantage over conventional interference films in many applications.

© 1977 Optical Society of America

Single-layer, gradient refractive index antireflection films effective from 0.35 to 2.5 μ

Michael Jay Minot
J. Opt. Soc. Am. 66(6) 515-519 (1976)

Optical characterization of thin films*

W. J. Anderson and W. N. Hansen
J. Opt. Soc. Am. 67(8) 1051-1058 (1977)

Design of single element gradient-index collimator

Duncan T. Moore
J. Opt. Soc. Am. 67(9) 1137-1143 (1977)

Polarimetric Methods for the Determination of the Refractive Index and the Thickness of Thin Films on Glass

Antonin Vašiček
J. Opt. Soc. Am. 37(3) 145-153 (1947)

Principal angle, principal azimuth, and principal-angle ellipsometry of film-substrate systems

R. M. A. Azzam and A.-R. M. Zaghloul
J. Opt. Soc. Am. 67(8) 1058-1065 (1977)