Optical device using laterally-shiftable diffraction gratings

摘要

A double-sided grating divider acts as a light switch where the upper and lower grating dividers are arranged to accommodate a relative lateral shift therebetween of about one-fourth of the period of the diffraction grating elements and where the critical refraction angles of the grating dividers are more than about 43.6°. Lateral shift may be achieved by various devices including MEMS and metal couplers having a known/calibrated thermal coefficient of expansion over a temperature range of interest.

主权项

1. An optical device responsive to incident light having a component of wavelength, λ, the optical device comprising:
first and second substantially identical diffraction grating dividers each having a distributed plurality of grating elements having a predetermined, regular geometry and being formed of a first material contacting a medium and disposed at a surface of a substrate; said first and second diffraction grating dividers being arranged in mutually inverted but spaced apart and substantially aligned relationship; and means for varying lateral alignment of the first and second diffraction grating dividers relative to one another to vary a degree to which incident light is transmitted therethrough, wherein the first material has a refractive index greater than a refractive index of the substrate, and the refractive index of the substrate is greater than a refractive index of the medium, at wavelength, λ.