Bragg match with a diffuser for dual-wavelength method in volume holographic storage system

An effective application of band-limited diffuser is introduced to realize the dual-wavelength method which can reduce the grating decay while retrieving data in the volume holographic data storage. The Diffuser combined with the imaging system can generate enough wavefronts to match the Brag conditions of all the pixels in the whole image when two wavelengths are used. It is possible to enlarge the size of the retrieved image and get an approximately uniform diffraction efficiency. Experimental setup is presented and the results show that this technique is effective.