Abstract

An interpretation model for low reflectivity in ultrahigh spatial-frequency holographic relief gratings is proposed. The model is based on the concept that the grating effective index, caused by grating ultrahigh spatial frequency, is graded in the depth direction and forms an antireflective constitution similar to the multilayer coating. Numerical results show that a sinusoidal grating is antireflective over wide groove depth, wavelength and incident angle ranges, and a grating with nearly triangular section, having a circle arc index distribution, has a very low reflectivity, <10⁻⁴%. Reflectivity vs groove depth, obtained experimentally for a holographically recorded photoresist grating, agrees fairly well with the numerical results.

© 1987 Optical Society of America

Zero-reflectivity homogeneous layers and high spatial-frequency surface-relief gratings on lossy materials

Thomas K. Gaylord, E. N. Glytsis, and M. G. Moharam
Appl. Opt. 26(15) 3123-3135 (1987)

Antireflection surface structure: dielectric layer(s) over a high spatial-frequency surface-relief grating on a lossy substrate

Elias N. Glytsis and Thomas K. Gaylord
Appl. Opt. 27(20) 4288-4304 (1988)

Zero-reflectivity high spatial-frequency rectangular-groove dielectric surface-relief gratings

Thomas K. Gaylord, W. E. Baird, and M. G. Moharam
Appl. Opt. 25(24) 4562-4567 (1986)

Antireflection quarter-wave-thick, high-spatial-frequency, surface-relief gratings at oblique incidence

E. Cojocaru
Appl. Opt. 35(31) 6231-6235 (1996)

Antireflection gold surface-relief gratings: experimental characteristics

Nile F. Hartman and Thomas K. Gaylord
Appl. Opt. 27(17) 3738-3743 (1988)