Optimized Holographic Scanner with Diode Lasers

Abstract

Diode Lasers are compact and potentially reliable for wide uses of digital audio disk. It is desirable to make a holographic grating scanner on dichromated gelatin (DCG) [1] at a wavelength that is different from the readout wavelength of diode laser because DCG suitable for a volume-phase holographic optical element (HOE) [2] is insensitive to exposures at red Light. The major problems associated with making this HOE are that the aberration due to a recording-readout wavelength shift is seriously existed and that the scan spots diffracted from scanner at different aperture inputs suffer from the aberration.