Holographic solar energy systems: The role of optical elements

The use of holographic optical elements for solar energy applications has increased interest in the recent years because of their potential to reduce production cost, their ability to select certain bandwidths of the solar spectrum and their suitability for architectural integration. Among the different typologies of holograms, volume holograms are the most widely utilised devices due to their high efficiency (up to 100%) and also because they have two important characteristics: angular selectivity and chromatic selectivity, which are crucial for the design of systems addressed for lighting, solar shading or solar concentrators. In the present article, an analysis of the main existing holographic solar energy systems is presented, with emphasis on the characteristics of the optical element.