| 摘要 |
<p>A holographic resonant system includes a plurality of volume phase holograms superimposed on a single layer of photosensitive film (20) which are oriented with respect to one another such that a first hologram selects an incoming light beam (22) incident upon a surface (28) of the holographic resonant system having a wavelength and an angle of incidence and internally diffracts the incoming light beam to a second hologram. The second hologram then accepts the resulting diffracted light beam (150, 152) from the first hologram and diffracts the light beam (150, 152) to form an image reflected from the surface of the holographic resonant system at (the same) wavelength. 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.</p> |
