Fourier-domain holography (FDH) is investigated as a candidate for holographic optical coherence imaging to produce real-time images of structure inside living tissue and turbid media. The effects of spatial filtering, the background intensity distributions, and the role of background noise in determining dynamic range are evaluated for both FDH and image-domain holography (IDH). The grating wa...

1 The POLICRYPS structure In the last decades, great attention has been devoted to the realization of switchable holographic structures in liquid crystalline composite materials [1]. In particular, it has been shown that diffraction gratings based on Holographic Polymer Dispersed Liquid Crystals (HPDLC), that means droplets of Nematic Liquid Crystal (NLC) dispersed in a polymer matrix (see inse...

Dark polymerization of active radicals at post-exposure is investigated in SiO2 nanoparticles and phenathrenequinone dispersed poly(methyl methacrylate) photopolymer experimentally and theoretically. In experiments, the grating formation and improvement of photosensitivity due to SiO2 nanoparticles at short exposure and post-exposure are presented. For analyzing the contribution of dark reactio...

We measured the angular dependence of the 0th, +/-1 st, and +/-2 nd optical diffraction orders from a 50 microm thick transmission grating recorded in a UV-curable holographic polymer-dispersed liquid crystal (HPDLC) made from commercially available constituents. The analysis was performed for two orthogonal polarizations of the probe beams. The emphasis was laid on the temperature dependence o...

Recording of periodic variations of amplitude and phase by the interference of coherent laser beams in a hologram offers a natural means for creating one-, two-, and three-dimensional photonic crystals. For device applications such as waveguides in optical communications, one usually needs to create defects in photonic crystals. We present an analysis and an experimental demonstration of a doub...

The patterning of an acrylamide-based photopolymer surface by holographic recording is studied. The patterns are induced by light alone and no post-processing is required. Periodic surface modulation is observed in addition to a volume phase grating. An investigation has been carried out using white light interferometry into the dependence of the amplitude of the photo induced surface relief mo...

The nopal cactus (Opuntia ficus-indica) releases a substance through its mucilage, which comes from the degradation of pectic substances and chlorophyll. Combined in a polyvinyl alcohol matrix, this substance can be used as a recording medium. The resulting extract material has excellent photosensitizer properties, is easy to handle, has a low cost, and low toxicity. This material has the prope...