Recent developments in the production of silicon carbide diffraction gratings

Abstract

Laminar and sinusoidal diffraction gratings, which are ion-etched into chemical vapour deposited (CVD) silicon carbide, are now being produced. Silicon carbide has a high resistance to synchrotron radiation damage, is compatible with ultrahigh vacuum environments, and has a much better heat handling capability than fused silica. The CVD material is single phase, and can be polished to a supersmooth finish. This is then used as a substrate for the diffraction grating, which is produced by interference techniques and then etched into the silicon carbide. Control of the etching process has produced different grating profiles, with a range of groove depths.