Abstract: A natural gas detection system is provided for use with a vehicle. A natural gas detector apparatus is mounted to the vehicle so that the vehicle transports the detector apparatus over an are of interest at speeds of up to 20 miles per hour. The detector apparatus includes a transmitter section and a receiver section displaced a preselected distance from each other. The transmitter section has a light source transmitting a light beam to the receiver section forming a beam path therebetween. The apparatus is arranged such that natural gas intercepts the beam path and absorbs representative wavelengths of the light beam. The receiver section receives a portion of the light beam onto an electro-optical etalon for detecting the gas. A method of detecting natural gas is also provided. The method has the steps of providing a vehicle and mounting a natural gas detector apparatus to the vehicle. The detector apparatus has a transmitter section and a receiver section displaced a preselected distance from each other.

Abstract: Crystals formed of Tl.sub.3 AsS.sub.3 provide very good materials for the nonlinear optical conversion efficiency. The crystals are useful in nonlinear optical devices such as harmonic generators and optical parametric oscillators, and in linear applications such as acousto-optical devices. The method of preparing such crystals is also disclosed.

Abstract: Crystals formed of a solid-solution of Tl.sub.3 AsSe.sub.3 and Tl.sub.1 AsS.sub.3 provide very good materials for the nonlinear optical conversion efficiency. The crystals are useful in nonlinear optical devices such as harmonic generators and optical parametric oscillators, and in linear applications such as acousto-optical devices. The method of preparing such crystals is also disclosed.

Abstract: An optical architecture for receiving and slowing down high-speed data for high-speed digital testing applications is provided in which an input generating means transmits high-speed input test vectors to an apparatus under testing. In response, the apparatus under testing generates output test vectors. These high speed output test vectors are converted to slow-speed data signals by optically demultiplexing the high-speed vectors into high-speed parallel data signals and then expanding the parallel data signals to for slow-speed data signals. The slow-speed data signals are then compared with slow-speed reference vectors on a personal computer to determine whether the apparatus under testing is in error for any of its output channels.

Abstract: An optical architecture is provided that can be used for generating high-speed input test vectors from low speed digital data and transferrring those test vectors to a device under test. The optical architecture employs gain-switched laser diodes or optical mixers to produce high-speed optical pulses from the low speed digital data. Optical multiplexing and variable delay devices process the high speed optical pulses to form a high-speed test vector. The architecture can generate test data with psec-type accuracy.

Abstract: Disclosed is a crystal 1 of thallium arsenic selenide, thallium arsenic sulfide, thallium vanadium sulfide, thallium phosphorous selenide, lead halide, cadmium sulfide, cadmium selenide, cadmium tin arsenide, cadmium germanium arsenide, indium phosphoride, indium arsenide, or mixtures thereof, doped with a precious metal in an amount of about 25 ppm up to the solubility limit of a precious metal in the crystal. The crystal is useful in nonlinear optical devices, acousto-optical devices, piezoelectric devices, and other types of optical and acoustic devices.

Abstract: The invention provides a method for controlling the transmission of radiant energy through a light transmissive medium and an apparatus whereby the method can be effected.

Abstract: A light distribution system for optical encoders includes a light guide plate and a light input coupler for distributing input incident radiations into the light guide plate as a flat distributed beam of beam segments intercepted by a pattern of discrete light output couplers reflecting narrow output beams for providing a uniform pattern of encoding illuminations.

Abstract: An acousto-optic Q-switch consisting of an acoustic transducer and an acoustic absorber affixed in opposing relationship with a portion of a laser medium having a relatively high figure of merit, M, disposed therebetween, provides an integral structural combination for the function of the laser medium and Q-switch which avoids the resonating wave power losses, and eliminates the problem of reflection and alignment encountered in laser systems employing acousto-optic Q-switching devices which are separate and spaced apart from the laser medium.