The possibilities that offer the holographic optical elements for photovoltaic and “see through display” applications open new windows for holographic recording materials. In this sense, some specific characteristics are required for each particular application. Waveguides are one of the key elements for these applications. Photopolymers are one of the most competitive candidates for waveguide fabrication. In this work, we evaluate the performance of one example from each of three families of photopolymer material in fabrication of a 633nm waveguide. Firstly, polyvinyl alcohol acrylamide, PVA/AA, the second one, a nanoparticle-thiol-ene, NPC, and on the last place a penta/hexa-acrylate based polymer with dispersed nematic liquid crystal molecules, PDLC. We study the critical role of the material and in particular, spatial resolution for this application.

Multiplexed diffraction gratings were recorded in 300 μm thick layers of biophotopol photopolymer by using two peristrophic multiplexing schemes separately and in combination. In addition, it was shown that riboflavin may be used as polymer initiator in acrylamide photopolymer films and the holographic properties of these films such as diffraction efficiency and dynamic range were compared with those of the biophotopol photopolymer. A variable exposure scheduling method was adopted to store the gratings using a 488 nm Ar laser. Thirteen nearly uniform sinusoidal wave gratings could be recorded in a low toxicity recording medium with a variable exposure energy scheduling method. The diffraction efficiency and dynamic range obtained using the two multiplexing schemes were compared.

Photopolymers can be appealing materials for diffractive optical elements fabrication. In this paper, we present the recording of diffractive lenses in PVA/AA (Polyvinyl alcohol acrylamide) based photopolymers using a liquid crystal device as a master. In addition, we study the viability of using a diffusion model to simulate the lens formation in the material and to study the influence of the different parameters that govern the diffractive formation in photopolymers. Once we control the influence of each parameter, we can fit an optimum recording schedule to record each different diffractive optical element with the optimum focalization power.

We focus on the novelty of three elements in holographic data storage systems (HDSS): the data pager, where we introduce a parallel-aligned liquid crystal on silicon (PA-LCoS) microdisplay; the recording material, where we consider the highly versatile PVA/AA photopolymer; and also in the architecture of the object arm, where a convergent correlator system is introduced. We show that PA-LCoS devices cannot implement pure hybrid-ternary modulated (HTM) data pages but a rather close approximation. Validation of the HDSS expressions for the convergent correlator and comparison with the widespread 4-f system is performed. Experimental results with PVA/AA material showing bit-error rates (BER) in the range of 10⁻³, further show its potential application for HDSS, and also demonstrate the validity of the testing platform and PA-LCoS calibration and optimization.

In this work, we present a method of manufacturing an optical see-through display based on a holographic waveguide with transmission holograms that couple the incident light between air and the glass substrate, accomplishing total internal reflection. The holograms (slanted transmission gratings with a spatial frequency of 1700 lines/mm) were recorded on a polyvinyl alcohol acrylamide (PVA/AA) photopolymer. We will also show that the addition of N,N′-methylene-bis-acrylamide (BMA) to the composition of the photopolymer allows the achievement of the index modulations necessary to obtain high diffraction efficiencies in non-slanted diffraction gratings of 1000 and 2200 lines/mm, and also in slanted gratings of 1700 lines/mm (which are the base of the optical system proposed).

Photopolymers are appealing materials for many optical applications. For most of them, shrinkage plays an important role in the final properties of the display, especially in holographic data storage applications. In this paper, we demonstrate that to quantify correctly the shrinkage, it is mandatory to measure the angle of propagation for both diffracted orders ± 1, so that an accurate value of the grating vector can be calculated. Experimental evidence from three different photopolymers supports this affirmation. Firstly, polyvinyl alcohol acrylamide based photopolymer, which has been studied by many research groups; secondly, one environmentally compatible photopolymer developed by our group; and thirdly, a photopolymer with dispersed liquid crystal molecules. We studied the deviation from the sinusoidal profile analyzing the higher diffracted orders.