Window photopolymer hologram for solar applications

The progress of holographic technology depends upon the development of better recording medium. Of the available recording media for holography, photopolymer is proved to be a highly versatile medium and it plays a vital role in recording and reading holograms in real time with good efficiencies and has contributed significantly to the recent growth of holography. It is multifaceted due to its rapid dry processing, low cost, high optical quality and resolution, low diffusivity, easy preparation techniques, high diffraction efficiency and angular selectivity, transparency in the visible spectral region etc. However, availability of commercial grade photopolymer material is very limited due to its strategic importance. We developed a research grade red sensitive photopolymer in our laboratory and a window hologram (holographic concentrator in a window pane) was recorded successfully in the material using off-axis geometry. The fabricated window hologram was placed vertically at an angle to the illuminating plane of the solar simulator (just as a window positioned vertically to the solar irradiance) and then coupled to a dye sensitized solar cell. The enhancement in the energy conversion efficiency of the solar cell was found and hence the experiment investigates a simple proposal to make use of holograms in window panes of a house as a solar energy concentrator.