| 摘要 |
<p>An optical system for selectively enhancing and/or suppressing the spectral intensity of components in an object beam, is disclosed. In one exemplary application, the optical system includes means for performing a forward transform operation on an input beam, a non-linear optical medium such as, for example, Bi12SiO20 or Bi12GeO20 and means for performing an inverse transform operation. In operation, the forward transform is performed on an input beam that contains a complex function characteristic of an object or subject, the resulting transform of the object beam is applied to the non-linear optical medium to form a hologram, then the hologram is read-out and the inverse transform operation is performed to provide an output optical beam that contains, for example, selectively enhanced intensity components and/or selectively suppressed intensity components. In one specific application, the object beam is obtained by transmitting a laser beam through a photomask such as, for example, the type used for fabricating semiconductor integrated circuits, the non-linear properties of the photorefractive crystal provide filtering or inversion of the intensity of the periodic aspects of the mask in the hologram and phase conjugate read-out and inverse transformation provide an image in which the intensity of the non-periodic defects is enhanced. In a second application, image inversion is employed to provide real-time inversion of intensity in the output image.</p> |
