摘要:
A 3D ultraviolet (UV) imaging LADAR system includes a UV source configured to generate a UV interrogation beam, a sensor configured to receive a UV return beam reflected from a target and to produce an electrical signal, and an imaging module coupled to the sensor and configured to receive the electrical signal and to generate a corresponding 3D image of the target. In one example, the sensor includes a down-shifting device configured to down-shift the UV return beam to a down-shifted light beam of a different wavelength, for example, in the visible or SWIR wavelength ranges.
摘要:
A radiation sensor. The inventive sensor has a two-level detector structure formed on a substrate in which a thermal detector element is suspended over the substrate as a microbridge structure. A receiver of electromagnetic radiation is provided on the same side of the substrate in a manner that efficiently couples the radiation field to the thermal detector element. The thermal detector element has a sandwich structure including a heater metal layer, a dielectric layer, and a thin film thermo-resistive material. The thermal detector element is suspended out of physical contact with the receiver. In one embodiment, the receiver is an antenna having a crossed bowtie configuration that efficiently couples the radiation field to the detector element. The inventive radiation sensors are especially useful for mm-wave and microwave sensing applications. The sensor can be used individually or in linear or two-dimensional arrays thereof. The invention also is directed to a method of fabricating such a radiation sensor.
摘要:
An integrated dual sensor package comprises a housing, a first sensor assembly and a second sensor assembly. The housing includes an internal vacuum chamber, a first window and a second window. The first window is transparent to a first wavelength of propagating energy and the second window is transparent to a second wavelength of propagating energy. The first sensor assembly and the second sensor assembly each have an active region responsive to a respective one of the first wavelength and second wavelength of propagating energy. The first sensor assembly and the second sensor assembly are each mounted within the vacuum chamber with the active region of each of the first sensor assembly and the second sensor assembly adjacently aligned with a respective one of said first window and said second window. The common alignment structure also serves as a common thermal interface to the external environment.
摘要:
A system (10) for simultaneously measuring temperature and CO, CO.sub.2 and HC gas content of vehicle (11) exhaust detects and analyzes a beam of infrared electromagnetic radiation (21) projected through a plume (13) of vehicle exhaust to assess the concentration of CO, CO.sub.2, and HC in the vehicle exhaust and detects and analyzes infrared electromagnetic radiation (15) emitted by the plume (13) to assess the temperature of the plume (13) and, consequently, whether the vehicle's (11) catalytic converter is operating in the cold or hot mode. Essentially simultaneous measurement is taken by intermittently interrupting the beam (21) of projected infrared electromagnetic radiation and detecting and analyzing the emitted infrared radiation (15) during the intervals of interruption when the beam (21) is not projected through the plume (13). Intermittent projection of the beam (21) is accomplished by insertion of a chopper wheel (22) between an infrared beam projector (20) and the plume (13).
摘要:
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. The sensor includes, in combination, a plurality of highly sensitive electromagnetic radiation detectors (26), spectral filters (24) which may utilize multiple layers of deposited dielectric thin films and/or selectively absorbing layers, and low noise electronics which performs a variety of functions including amplification (28), multiplexing (30), analog to digital (A/D) conversion (33), signal processing (32), and input/output (I/O). In a presently preferred embodiment each radiation detector is a thermopile detector that is integrated upon a common substrate with the support electronics and an associated optical bandpass filter.
摘要:
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. Two detectors are adjacently disposed so as to receive the emitted light from each wavelength after their transmission through the alcohol/gasoline fuel mixture. Once the signals corresponding to the two wavelengths are obtained, the ratio of the absorbances by the fuel mixture at both wavelengths is computed. From this ratio, and the temperature of the fuel mixture, the concentration of alcohol in the fuel is determined.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.