Theory of Blazed Holographic Gratings

Abstract

Geometric theory of the blazed aberration-corrected holographic grating is derived. This involves generalising the holographic component of the light-path function to permit aberration correction for recording geometries that arrange the two recording wavefronts to be incident from opposite sides of the grating substrate, thereby realising triangular or blazed groove profiles. The equation for the effective grating constant and an equation for the blaze angle are combined to yield a general expression for the recording angles in terms of the blaze angle, and the refractive indices of the grating substrate and the medium in front of the photoresist. This equation may then be solved simultaneously with the holographic aberration equations, to introduce the effective blaze angle and refractive indices as solution parameters. Also included are appendices that give essential equations for ray tracing, and for computing the blaze angle and blaze wavelength at any point on this type of grating.