Abstract: A switching circuit (100) is provided, comprising: a signal coupler (110) configured to receive first and second input signals and provide first and second coupled signals; a first phase shifter (130) configured to shift a first phase of the first coupled signal by zero degrees or ninety degrees based on a first control signal to generate a first shifted signal; a second phase shifter (135) configured to shift a second phase of the second coupled signal by zero degrees or ninety degrees based on a second control signal to generate a second shifted signal; and a combiner (150) configured to combine the first and second shifted signals. The first coupled signal includes an in-phase copy of the first input signal and a ninety-degree-shifted copy of the second input signal; and the second coupled signal includes an in-phase copy of the second input signal and a ninety-degree-shifted copy of the first input signal.

Abstract: Devices for X-ray topography determine structures and compositions of objects. In accordance with an embodiment of the invention, a scanning system forms images using small angle scattering. A spatial filter selects radiation an object scatters at small angles and blocks other radiation. A coordinate-sensitive detector behind the filter records the scattered radiation. An object image is constructed based on the small-angle scattering information and the compositions of regions of the object are determined from scattering curves for the regions. One embodiment of the invention includes a source of penetrating radiation, a detector system for radiation transmitted through an analyzed object, a detector system for radiation the object scatters at small angles, and a unit for moving the object during scanning. A three-dimensional absorption factor distribution is determined for the object by X-raying the object at different angles.

Abstract: An optical fiber evanescent wave fuel sensor, employing a light source with a wavelength selected to be at the strong infrared absorption lines of the fuel, typically hydrocarbons. The amount of light leaking from the optical fiber is an exponential function of the length of the fiber in the liquid, and is independent of the relative indices of refraction of the fuel and fiber cladding material.

Abstract: An evanescent wave liquid level sensor for measuring the density-compensated level of a liquid in a container. The sensor employs an eccentric core optical fiber fully immersed in the liquid to be measured. Light is injected into one end of the fiber. Some of the light will be lost due to evanescent wave losses. Changes in the ratio of the intensity of the input light and the reflected light are due solely to changes in the density of the liquid. Changes in the liquid density can then be used to compensate a liquid level measurement. Since the liquid temperature is related to its density, the sensor can also be used to measure changes in the liquid temperature.

Abstract: Optical phased arrays employing a large number of light emitters and optical phase delays between adjacent emitters to steer and focus an optical beam from the contributions of all the light emitters. The array can include a laser oscillator (22) as the light source, with the laser light being conducted via optical waveguides (26, 30 and 32) into optical fibers (34), with phase delays being effected by piezoelectric or electro-optic effects on the optical waveguides. The array can be used in a low cost display device for generating optical images or in an optical memory.

Abstract: An electro optical random access memory uses a film of bacteriorhodopsin or similar photochromic substance which can change between two light absorbing states in response to light of each of two wavelengths. In one embodiment combined red and green laser beams are steered in two orthogonal directions to memory locations on the film. The relative amounts of the light of the two wavelength reflected from memory cell is sensed and discriminated to indicate "1" or "0". A crowbar circuit holds one or the other of the two laser beams on to compensate for degradation that occurs in a read cycle. In another embodiment a single wavelength is employed for read and write operations, but at a much greater strength for the write operation.

Abstract: A dislocation-free, composite-substance crystal having a lattice constant which decreases over the length of the crystal (38) convergently focuses beams of hard X-rays or gamma rays (11). A single-substance, dislocation-free crystal (34) collimates diffuse beams of hard X-rays or gamma rays and projects the collimated radiation (11') to the focusing crystal (38). A mask (36) is interposed between the collimating crystal (34) and the focusing crystal (38) causing the collimated radiation (11'') to carry an image of the mask (36). The focusing crystal (38) produces a convergent hard X-ray beam or gamma ray beam (11''') to focus a reduced image of the mask (36) upon the photosensitive layer (41) of a wafer (39). An example of a dislocation-free crystal having a lattice constant which decreases over its length (38) is a dislocation-free silicon-germanium crystal (20) wherein the proportion of germanium to silicon varies over the length of the crystal.

Abstract: Apparatus and methods for identifying the nature of an unidentified substrate present in trace amounts of known gaseous or liquid media such as air or water include collecting a sample of the substance in the media, filtering and concentrating the sample, depositing at least a portion of the same on a known substrate, analyzing the deposited sample utilizing SETM, NFOM and/or AFM techniques to form one or more images characteristic of the unidentified substance, and then identifying the substance by comparing the images so obtained to images of known substances obtained using the same techniques.

Abstract: A radio-frequency (rf) power combiner or divider structure containing distributed amplifier components and having broadband operating characteristics, and operable with net gain or practically no insertion losses. The divider structure includes an input transmission line having series-connected impedances that interconnect with active devices, such as field-effect transistors to form a practically lossless line. The active devices provide gain between distributed points in the input transmission line and distributed points in multiple output transmission lines, which are similarly structured as series-connected impedances. Each output transmission line supplies one of the divider outputs. In the combiner form of the device, there is a single output transmission line and multiple input transmission lines, coupled to the output line in a distributed manner by active devices.