Abstract: A trilaminar semiconductor device is placed at an intermediate focus is an optical instrument having a sensitive photodetector. The layers of the device are successively in the form of a two-photon absorber, a sacrificial layer, and a multiple quantum well. The composition of the semiconductor is varied in the layers to achieve the desired bandgap and function.

Abstract: A passive broadband sensor protection and enhancement system and technique. ncident light is focused with a cylindrical lens on the optical axis into an intense light strip onto the input face of a photorefractive crystal on the optical axis. The crystal includes optional anti-reflection coatings proximate to the input and output face. A broadband high reflection coating is proximate to the input face for reflection of all radiation from approximately 0.68 to at least out to 1.5 micrometers wavelength. Light exiting from the output face of the crystal results from a photorefractive process that includes a transmitted beam and beam fan. The beam fan is fanned out of the optical path in a direction determined by the c-axis, dominant electro-optic coefficient, and charge carriers participating in the photorefractive process.

Abstract: A universal IFF technique and system utilizes a real-time communication l established between both parties allowing the approximate immediate transferral of digital information with positive direction and identification of both parties achieved. A pump laser emits a first signal at a first position and a remote laser beacon emits a second signal at a second position, both signals at nominally the same wavelength. A MPPCM receives the first signal which establishes a beam fan. The MPPCM and first signal scans about a region of interest to intercept the second signal. The second signal provides a second input signal into the MPPCM so that a two-way phase conjugation signal builds up and lock-on is established.

Abstract: This is a new use for known photorefractive crystals. If input radiation taining both non-coherent and multiple-line coherent radiation is directed into such a crystal from a predetermined range of directions with respect to the C axis of the crystal, rainbow scattering of the coherent radiation occurs, whereas normal scattering of the non-coherent radiation occurs. A detector toward which input radiation is directed through the crystal is thus protected from high-power, multiple-line coherent radiation such as that provided by a threat laser.