Abstract: An in-situe chemical gas or fluid analyzer for vehicles, industrial, environmental and process control applications. As applied to a vehicle (1) having an internal combustion engine, the analyzer includes: (i) a source of electromagnetic radiation (14, 16); and (ii) a sampling cell (12) which collects emission gases of interest and which is capable of withstanding hostile environments while preserving a "clear" optical path between the sensor sampling cell and the source of radiation. The analyzer further includes: (iii) a solid state sensor (24, 26, 28, 30, 32 ) of monolithic construction which selectively detects electromagnetic radiation that is absorbed or emitted by one or more chemical species of interest, that compensates for temporal and spatial variations in illumination level provided by the source, and that provides an electrical signal output, in either analog or digital format, that is related to the measured concentrations.

Abstract: A system (10) for detecting nitric oxide (NO) within an exhaust plume (14) includes a source (18) for generating an optical beam (20) and for directing (22, 24) the optical beam through the exhaust plume, the optical beam having wavelengths within a predetermined band of wavelengths within the infrared (IR) radiation spectrum. The system includes a sensor (32)/filter (30) assembly having a first channel for determining a measured NO transmission value for a first predetermined band of wavelengths; a second channel for determining a measured water transmission value for a second predetermined band of wavelengths; a third channel for determining a measured reference transmission value for a third predetermined band of wavelengths selected so as not to be significantly absorbed by the exhaust plume; and a fourth channel for determining a measured combustion by-product transmission value for a fourth predetermined band of wavelengths.

Abstract: An alcohol sensing device is provided for determination of the alcohol content within an alcohol/gasoline fuel mixture which is being provided for the operation of an internal combustion engine. The sensing device uses infrared spectrometry measuring techniques. The infrared sensing device determines the ratio of light absorption by the alcohol/gasoline mixture at two discrete wavelengths within the near-infrared spectrum. The two particular wavelengths of interest are preferably chosen so that at one of the infrared wavelengths, alcohol is strongly absorbing while the gasoline exhibits very little absorption, and at the second wavelength both the alcohol and the gasoline exhibit are essentially non-absorbing. An alternating current is used to switch the light beam between two power settings so as to vary the intensity of transmitted light at both wavelengths. The light beam is transmitted through the alcohol/gasoline fuel mixture so that the two discrete wavelengths traverse the same optical path.

Abstract: A Frequency Domain Infrared Superconducting Transmission Line (FIRST) detector is comprised of a folded superconducting transmission line (36) interposed between a bottom electrode (32) and a top, radiation absorbing electrode (40). Dielectric layers (34, 38) separate the transmission line from the top and bottom electrodes. An optically induced change in the kinetic inductance of the transmission line shifts the transmission line phase velocity and resonant frequency. The shift in resonant frequency attenuates the propagating wave amplitude proportionally to the product of the transmission line Q and the frequency shift. A stacked pair of such detectors (50), sharing a common ground electrode (60), is disclosed to provide an inherent rejection of noise events due to ionizing radiation such as gamma radiation and package-generated Compton electrons.

Abstract: A multilayered radiation detector device (50) including a resonant cavity structure wherein one cavity wall electrode includes a portion of a photovoltaic radiation detector (52). Specifically, a RFM detector has a superconducting transmission line electrode (54) electrically coupled to a high mobility semiconductor layer (58) of the photovoltaic detector. The superconductor transmission line electrode inductance forms, in combinations with a photodetector depletion region capacitance, a series resonant or a parallel resonant circuit. A radiation-induced change in the capacitance results in a change in the circuit resonant frequency and a corresponding variation in the amplitude of an on-resonance RF signal applied to the circuit. In another embodiment the resonant cavity structure includes a gap having a width that is modulated by an amount of absorbed radiation, the radiation-induced change in the distributed cavity capacitance resulting in a change in the cavity resonant frequency.

Abstract: A radiation detecting array 10 has a frequency domain architecture wherein incident radiation is imaged in parallel by an array of radiation detectors 12-16. Each radiation detector has an associated amplitude to frequency conversion device 18-22 for providing output signals wherein the output of each photodetector is represented as a frequency within a uniquely identified band of frequencies, the specific frequency being a function of the output signal amplitude of the photodetector. The readout of one or more selected detectors is accomplished by providing a swept frequency band or bands associated with the desired detector or detectors and mixing the detector frequencies with the swept band. The frequency representing the photodetector output may be input directly to a low dispersion transmission line 30.

Abstract: A Frequency Domain Infrared Superconducting Transmission Line (FIRST) detector is comprised of a folded superconducting transmission line 18 coupled at an input port 18a to a narrow band microwave source and coupled at an output port 18b to a microwave power monitor 22. An optically induced change in the kinetic inductance of the transmission line shifts the transmission line phase velocity and resonant frequency. The shift in resonant frequency attenuates the propagating wave amplitude proportionally to the product of the transmission line Q and the frequency shift. When fabricated with a densely folded superconducting line and operated at a nominal resonant frequency of several GHz the use of either linear or logarithmic Schottky barrier detectors enables a realization of a dynamic range of eight orders of magnitude.

Abstract: A method of forming in a semiconductor material a region having a different chemical composition or a different concentration than a chemical composition or concentration of material surrounding the region. The method includes an initial step of providing a substantially single crystalline body of material, such as an epitaxial layer 10 of HgCdTe. Another step forms a cap layer 12 over a surface of the body, the layer having a thickness T. The cap layer 12 is comprised of a layer of polycrystalline material, such as CdTe, or is comprised of a layer of an organic material, an amorphous dielectric or a single-crystalline layer. A further step implants a selected chemical species through an upper surface of the cap, the species being implanted to a depth such that substantially no implant damage is sustained by the underlying body. In p-n junction formation the species is selected to form a region having an opposite type of electrical conductivity than the conductivity of the layer 10.

Abstract: A transistorized monolithic focal plane array is formed on a semiconductive substrate and comprises a plurality of detectors associated with a corresponding plurality of source follower or inverter transistors. The array is row addressable. The gate of the source follower transistor comprises a floating node which is charged by the corresponding detector in proportion to the incident photon flux, the gate being periodically reset. The invention combines the advantages of compactness and low capacitance of charge coupled device imagers and low noise characteristics of prior art imagers comprising discrete transistors.

Abstract: A monolithic imager utilizing a plurality of detector cells for detecting the presence of radiation and producing a two dimensional mapping thereof. The detector cells are arrayed in a matrix having a square center surrounded by a number of polygonal rings so that a relatively high resolution mapping of detected radiation is achieved at the center of the imager.

Abstract: A monolithic imager utilizing a plurality of detector cells is formed on a common intrinsic substrate. Backside illumination in the near-IR region generates hole-electron pairs in the intrinsic material which may be depleted throughout its thickness by CCD-range voltages applied by the imager's readout structure to a over-lying, thinly doped epitaxial layer. Minority carriers migrate toward a collection node which is formed in the epitaxial layer (and protrudes into the substrate), accumulating in an inversion layer at the surface of the epitaxial layer. The accumulated charge is advanced to an output diffusion in the epitaxial layer by means of a readout system which provides semi-random addressing of the transfer gate electrodes of the individual detector cells.