METHOD OF MAKING TOTALLY INTERNALLY REFLECTED HOLOGRAMS 



A method is described for making holograms by means of linearly polarized object and reference beams, the reference beam being reflected inside the photosensitive emulsion. The plane of polarization of a linearly polarized reference beam includes an angle of 45.degree. with its plane of incidence. The beam is reflected under the critical angle of total internal reflection at the lower face of a photographic emulsion. The reflected beam is linearly polarized, too, its plane of polarization being turned by 90.degree., so that no interference between these two beams is possible. An object beam passes a mask and is linearly polarized vertically either to the reference beam or to the reflected beam so that only one hologram can be formed and no undesired interaction between two holograms is possible when the mask is reproduced for exposure of a photoresist-covered semiconductor wafer. 

Method for a solar concentrator manufacturing 



A method of manufacturing a solar concentrator employing a prism having a radiation input face, a reflection face and at least one radiation output face. The method comprises the steps of providing the prism with its reflection face angularly disposed with respect to the input face. A layer of light-sensitive material is deposited on the input face of the prism. An auxiliary prism and a substance having a refractive index close to that of the light-sensitive material is provided with the substance placed between the light-sensitive material and the auxiliary prism. Next, an interference pattern is recorded in the light-sensitive layer to obtain a three dimensional hologram. This is accomplished by using a reference laser beam and an object laser beam. The reference laser beam is sent to the light-sensitive layer via the auxiliary prism and the substance in the direction of propagation of the incident radiation to be concentrated. The object laser beam is directed via the auxiliary prism at an angle with respect to the light-sensitive layer such that fringe planes are formed in the light-sensitive layer in order to diffract incident radiation at the angle. The auxiliary prism and the substance are removed, and the light-sensitive layer is developed. The angular relationship between the reflection face, the input face and the angle are chosen to preclude the diffraction of a beam which has been reflected from the reflection face. 

Phase quantization error decorrelator for phased array antenna 



An improved means of decorrelating phase quantization errors in a phased array radar antenna using digital randomization at each of the array elements to reduce peak steering erorrs and to reduce peak sidelobe levels of the antenna. A random phase adjust term is provided to each of the array's antenna elements which comprises a distributed controller (DC) co-located with a digital phase shifter. The distributed controllers are each programmed with a random phase adjust term which represents a phase shift adjustment statistically independent from element to element. The random phase adjust term is stored in a memory located in each disbtributed controller. The distributed controller drives each element's digitally controlled phase shifter in response to a beam steering command received over a serial line. The performance improvement achieved with this decorrelation method is equivalent to that obtained by using more expensive phase shifters and adding costly randomized cables in the path to each element. 

Method and apparatus for copying and manufacturing hologram plate 



A hologram plate manufacturing apparatus comprising a copying optical element disposed in opposed relation to a photosensitive surface of a hologram plate. The copying optical element is arranged so that its one surface facing the photosensitive surface of the hologram plate has a plane configuration and its other surface has a convex or concave configuration. On the convex or concave surface there is formed a reflection film for effectively reflecting incident light. Also included a refraction index adjusting layer which is provided between the photosensitive surface of the hologram plate and the convex or concave surface of the copying optical element, the refraction index adjusting layer having an index of refraction substantially equal to indexes of refraction of the hologram plate and the copying optical element. Further, a prism is disposed in opposed relation to the incident surface of the hologram plate and arranged such that light incident on the incident surface of the hologram plate and reflected on the reflection film is not re-reflected on the incident surface of the hologram plate so as not to be directed toward the hologram plate. This arrangement can suppress generation of noise images due to unnecessary reflection.