Thick phase holograms

This report describes a two year research program to investigate thick phase holographic gratings. The first year effort primarily involved a study of hologram formation in dichromated gelatin. The results of that study can be found in the interim scientific report. The second year effort was a theoretical study of optical propagation through horizontally stratified, thick, phase reflection gratings. In this report, a general theory is developed for determining the complex reflection and transmission coefficients of such gratings as a function of incident angle, wavelength and polarization. Theorems are stated and proved about polarization effects and about the relationship between the spectral and angular characteristics of such gratings. The inverse scattering problem is considered. Given the spectral and angular characteristics of a horizontally stratified, quasi-sinusoidal, phases grating, first and second order approximate techniques are developed for determining the corresponding refractive index profile. It is also shown that horizontally stratified phase gratings can be used as position-invariant, frequency domain filters in coherent optical systems. Their basic filtering properties are presented. Finally, an interferometric technique is developed for fabricating horizontally stratified, quasi-sinusoidal, phase gratings.