Double-pass diffraction grating

Abstract

An optical assembly for double passing a transmission grating may include a prism having first, second and third surfaces. A transmission grating may be bonded to the first surface. A first mirror coating may be bonded to the second surface and a second mirror coating to the third surface. The first, second and third surfaces, the transmission grating and the first and second mirror coatings are configured such that light of a predetermined wavelength entering the prism that is incident on the transmission grating is diffracted a first time by the transmission grating towards the second surface, reflected from the second surface to the third surface, reflected from the third surface back to the transmission grating, and diffracted a second time by the transmission grating as the light exits the prism.

Dependencies are inferred from the claim text.