Volume phase holographic gratings: large size and high diffraction efficiency

Volume phase holographic gratings (VPHGs) possess unique properties that make them attractive for numerous applications. After reviewing major VPHG characteristics through theory, we discuss some aspects of the dichromated gelatin recording material and the holographic recording process. The large-scale VPHG research facility set up at the Center Spatial de Liege enables production of VPHGs up to 380 mm in diameter, with fringe frequencies from 315 to 3300 Ip/mm. We describe the work that has been undertaken in our laboratory to remove the last limitations inherent in VPHGs. (C) 2004 Society of Photo-Optical Instrumentation Engineers