One of the problems associated with photopolymers as optical recording media is the thickness variation during the recording process. Different values of shrinkages or swelling are reported in the literature for photopolymers. Furthermore, these variations depend on the spatial frequencies of the gratings stored in the materials. Thickness variations can be measured using different methods: studying the deviation from the Bragg’s angle for nonslanted gratings, using MicroXAM S/N 8038 interferometer, or by the thermomechanical analysis experiments. In a previous paper, we began the characterization of the properties of a polyvinyl alcohol/acrylamide based photopolymer at the lowest end of recorded spatial frequencies. In this work, we continue analyzing the thickness variations of these materials using a reflection interferometer. With this technique we are able to obtain the variations of the layers refractive index and, therefore, a direct estimation of the polymer refractive index.
© 2008 Optical Society of America
Original Manuscript: February 6, 2008
Revised Manuscript: April 16, 2008
Manuscript Accepted: April 16, 2008
Published: May 2, 2008
Sergi Gallego, Andrés Márquez, David Méndez, Manuel Ortuño, Cristian Neipp, Elena Fernández, Inmaculada Pascual, and Augusto Beléndez, "Analysis of PVA/AA based photopolymers at the zero spatial frequency limit using interferometric methods," Appl. Opt. 47, 2557-2563 (2008)