Systems for forming improved reflection holograms with a single beam

摘要

A hologram forming system for forming, from a single beam source and a reflective mirror, a reflective hologram in which spurious reflection and transmission hologram recordings are eliminated. Reflected rays are changed in phase relative to the primary beams during the recording period so that spurious holograms do not form. The remaining effect of the reflected rays is to slightly change the overall refractive index of a phase recording material (such as dichromated gelatin) with a resultant slight loss of available index of modulation or to slightly, uniformly, darken an amplitude hologram film, (such as silver halide) with a slight loss of available contrast. The invention includes hologram forming systems that move the cover plate relative to a fixed recording medium with and without a phase shifter in the primary beam and a hologram forming system that moves the substrate and mirror relative to the fixed cover plate.