Holographic volume gratings in a glass-like polymer material

Abstract

We demonstrate a possibility to write efficient and thermally stable volume holographic gratings in a glassy polymer material based on PMMA and phenanthrenequinone with layers prepared, by casting the liquid solution of ingredients on a substrate and drying to a solid state. A high concentration of phenanthrenequinone (up to 4 mol. %) makes it possible to use photosensitive layers of lower thicknesses (50-180 µm) for the recording of efficient holographic gratings. The exposing is followed by a thermal amplification of the grating due to diffusion of residual phenanthrenequinone molecules and fixation by an incoherent optical illumination. We present experimental temporal curves of the refractive index modulation and diffraction efficiency both under the exposure and the heating process. The behavior of the gratings under temperatures up to 140 • C has been studied.

Two-dimensional higher-diffraction-order optical beam splitter based on phenanthrenequinone-doped poly(methyl methacrylate) photopolymer

“…However, photorefractive crystals such as LiNbO 3 and BaTiO 3 are all anisotropic, and a grating can be recorded in the c-axis direction only. In recent years, many experiments have demonstrated the feasibility of using isotropic polymer-based materials for holographic storage [3][4][5][6][7][8][9][10][11][12][13]. Among these materials, PMMA is one of the most popular polymer bases due to its good dimensional stability and good optical quality.…”

Light-Sensitive Media-Composites for Recording Volume Holograms Based on Porous Glass and Polymer

“…Of great interest is to obtain samples of given material, which have thickness in the range 50÷500 m, since the available product line of RM for holography has such samples represented by isolated laboratory-made specimens (e.g., Mahilny et al, 2006). The devised technological mode is unsuitable to obtain samples about 100 m thick by means of bulk polymerization.…”

PQ/PMMA photopolymer: Modelling post-exposure

“…Following exposure, appropriate post-exposure heat treatment of the material is typically applied, resulting in a more rapid diffusion of the excess unattached PQ molecules from the dark into the bright regions, leading eventually to their homogenous distribution inside the medium. This results in a significant change in the refractive index modulation [12,15,16,20]. After such treatment, it is the concentration distribution of the photoproduct PQ-PMMA alone which determines the grating strength.…”

“…A detailed description of the material preparation for the material studied in [13,14] is given in [15]. It is important to note that the process used to produce the layers, (not only their composition) can have dramatic impact on how it reacts during exposure.…”

“…Therefore the storage capabilities of self-processing photopolymer materials are under constant study with attempts being made to improve their ability to record low loss, mechanically stable, high diffraction efficient volume gratings in an inexpensive way. Among such materials PQ/PMMA layers [10][11][12][13][14] currently play a significant role as they have several properties that make them suitable for holographic applications [15,16], including as a data storage media [17,18] and in producing robust optical elements, i.e., solar concentrators [19].…”