Abstract: In order to protect a delicate photodetector from high-intensity radiation, such as from a laser, a device for limiting optical power to the detector is interposed between the radiation and the detector. This device has an optical interface that totally reflects high-intensity radiation, but which freely transmits normal (low intensity) radiation to the detector. The interface is between two optical materials, one with a linear index of refraction with respect to radiation intensity, and the other with a non-linear index. At low intensity radiation levels, the two materials have the same indices of refraction, and such radiation is freely transmitted through the interface, but with high-intensity radiation, a mismatch of indices of refraction allows total reflection at the interface.

Abstract: A solid-state laser slab amplifier arrangement for the output of a laser m at optimal working conditions. Pump energy is applied to a solid state lasing material so as to irradiate the solid-state lasing material and effect a laser beam with resultant waste heat output. At least one micro-heatpipe bundle which includes multiple micro-heatpipes allows waste heat to be transported away by the working medium through an approximate center of an individual micro-heatpipe from the solid-state lasing material. After condensation, liquid working medium is returned substantially by capillary action through approximate off-center areas of the individual micro-heatpipe.

Abstract: A liquid crystal modified by the addition of an organic dye is used as a non-linear optical material in two devices which limit the optical radiations to sensitive photodetectors.

Abstract: A nonlinear optical fluid with radiation-absorbing small particles uniformly suspended in the fluid. For radiation below a threshold value, radiation passes through with slight attenuation. Above the threshold, only a limited level of radiation is passed, the limit being below the damage level of a sensitive optical detector.

Abstract: A ternary or more complex semiconductor alloy is treated to form simultansly a junction beneath its surface and to passivate the same surface. The treatment consists of connecting the semiconductor to one electrode of an electrolytic circuit, immersing it in an electrolyte which may contain a leachant, and energizing between electrolytic circuit electrodes with a substantially square electric current wave with a direct current average value. After a predetermined time, the semiconductor is removed from the electrolyte, is disconnected from the electrolyte, and is washed, rinsed, and dried. During the process the electric current causes ions of the semiconductor to migrate toward its surface, where they enter the electrolyte. This depletion of ions effectively forms a junction; the current also causes oxidation of the semiconductor surface for passivation.

Abstract: Passivation of a mercury cadmium telluride surface is done by using square ave direct current, with the positive portion of the wave larger than the negative part.