Abstract: A system and method for sensing phase errors in a multiple receiver array use three non-collinear transmitters transmitting first, second, and third signals to a target and receiving corresponding signals reflected from the target using the multiple receiver array. In one embodiment, each transmitter transmits a characteristic signal which can be distinguished from each other by the receivers. In one embodiment, each transmitter transmits a slightly different monotone frequency that is preferably outside any imaging bandwidth. The sheared products computed from heterodyne measurements at the receivers in the array based on the reflected signals from the three transmitters are used to determine and correct for the combined transmitter/receiver phase errors at each of the receivers in the array.

Abstract: A system and method for sensing phase errors in a multiple receiver array use three non-collinear transmitters transmitting first, second, and third signals to a target and receiving corresponding signals reflected from the target using the multiple receiver array. In one embodiment, each transmitter transmits a characteristic signal which can be distinguished from each other by the receivers. In one embodiment, each transmitter transmits a slightly different monotone frequency that is preferably outside any imaging bandwidth. The sheared products computed from heterodyne measurements at the receivers in the array based on the reflected signals from the three transmitters are used to determine and correct for the combined transmitter/receiver phase errors at each of the receivers in the array.

Abstract: The merit function of an optical system employing a holographic optical element (HOE) is optimized by determining the ideal phase transfer functions of the hologram over a set of field angles and then arriving at the phase transfer function of the hologram by averaging over the ideal phase transfer functions.

Abstract: An optically transmissive article having predetermined net reflectance characteristics and a method of forming such an article is disclosed. The article includes a holographic layer with fringe patterns generally paralleling a major surface of the article. The fringe patterns have been formed in such a way that the amplitude and phase of the light diffracted therefrom is in a predetermined relationship with the amplitude and phase of the reflected light. The relationship between the respective amplitudes and phases of the diffracted and reflected light determines the net reflectance characteristics of the article. In a preferred embodiment, the hologram is formed such that the diffracted light has the same amplitude but is 180.degree. out of phase with the reflected light so as to provide an antireflective coating for the article.

Abstract: Method and apparatus for making a hologram that controls both the amplitude and the phase of a reconstructing beam of light at each point on the surface of the hologram. The hologram is a transparency made from a conventional, color reversal photographic film that has multiple emulsion layers that are each selectively photosensitive to light of different wavelengths. The desired image to be produced from the hologram is initially processed into a matrix of Fourier transformed amplitude coefficients and a matrix of Fourier transformed phase coefficients. The hologram is made by first exposing the photographic film to an illumination pattern of the Fourier amplitude coefficients using light having a spectrum to which one of the emulsions is selectively photosensitive. The film is next exposed to an illumination pattern of the Fourier phase coefficients using light having a wavelength to which another emulsion of the film is selectively photosensitive.