Abstract
In this work we present an analysis of non-slanted reflection gratings by using a corrected Coupled Wave Theory which
takes into account boundary conditions. It is well known that Kogelnik's Coupled Wave Theory predicts with great
accuracy the response of the efficiency of the zero and first order for volume phase gratings, for both reflection and
transmission gratings. Nonetheless, since this theory disregard the second derivatives in the coupled wave equations
derived from Maxwell equations, it doesn't account for boundary conditions. Moreover only two orders are supposed, so
when either the thickness is low or when high refractive index high are recorded in the element Kogelnik's Theory
deviates from the expected results. In Addition, for non-slanted reflection gratings, the natural reflected wave
superimpose the reflection order predicted by Coupled Wave theories, so the reflectance cannot be obtained by the
classical expression of Kogelnik's Theory for reflection gratings. In this work we correct Kogelnik's Coupled Wave
Theory to take into account these issues, the results are compared to those obtained by a Matrix Method, showing good
agreement between both theories.
