Influence of index matching on AA/PVA photopolymers for low spatial frequency recording.

Photopolymers present appealing optical properties for holographic and diffractive applications. They enable modulation of the electrical permittivity and thickness and are self-processing, and layers with a wide range of thicknesses and properties can be fabricated on demand. In order to obtain a complete characterization of the material, low spatial frequency analysis has become a fundamental tool because the motion of the components inside of the material can be measured. We propose to use an index matching component to carry out a complete characterization and to differentiate the "apparent" and the real monomer diffusion. We also have quantified the minimum thickness to obtain the phase modulation of 2π required for the fabrication of many diffractive elements such as lenses, axicons, or blazed gratings. Finally, we have studied the influence of the thermal effects in the thickness variations.