| 摘要 |
A holographic resonant system includes a plurality of volume phase holograms superimposed on a single layer of photosensitive film. The volume phase holograms are oriented with respect to one another such that a first volume phase hologram selects an incoming light beam incident upon a surface of the holographic resonant system having a wavelength lambdplayback and an angle of incidence thetain and internally diffracts the incoming light beam to a second volume phase hologram. The second volume phase hologram then accepts the resulting diffracted light beam from the first volume phase hologram and diffracts the light beam to form an image reflected from the surface of the holographic resonant system at wavelength lambdplayback and an angle thetaout. The result is a holographic resonant system that only permits light beams from a predetermined direction to illuminate the system, thereby reducing the effect of ambient light upon the system and thus increasing the contrast ratio of the image.
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