Abstract: A system and method for monitoring toxic chemicals in groundwater includes the use of a groundwater vaporizer and a CRDS (Cavity Ring Down Spectroscopy) block. The CRDS block includes a three-mirror ring down cavity in which a fiber is coupled to a top prismatic mirror in order to permit vertical entry of a laser beam. One of the mirrors can be piezo-electrically tuned so that the ring down cavity is in resonance with the laser beam and a third mirror includes a read out detector to measure the laser beam intensity. Vapors from the groundwater vaporizer pass through vapor inlet channels, which include a permeable membrane in order to permit vapors to flow into the ring down cavity. The system monitors, for example, trichloroethylene (TCE) concentrations and other chemicals present in groundwater utilizing data transmitted from the read out detector.

Abstract: An optical system having a closed loop light path with a source for providing light in a direction parallel to the normal of an input to the light path. The light may be provided via a diffracting mechanism to the input. The system may be a cavity ring-down sensor or some other optical device. The light path may be formed in a laser gyroscope type cavity. A light source may have a beam aligned to a spot, indicator or mark near the input of the cavity. The location of the spot, indicator or mark may be determined in accordance with parameters of the diffracting mechanism and/or cavity. A fixture for holding the light source may be secured so that placement of the source in the fixture will automatically result in an aligned light source. Then the diffracting mechanism may be inserted to further complete fabrication of the optical system.

Abstract: An infrared detection system that may note changes of temperature over time in various fields of view of a scene. The system may use an array of long wave infrared detectors to sense early or late stages of a fire. The system may check numerous fields of view. It may have a fixture with a lens for each field of view. Each lens may have its respective field of view focused on the array. All but one lens may be shuttered or closed from detecting its respective field of view at a time. The system may have a processor with a memory to record the temperatures from the array over time. Variation of temperature in one spot or another of a field of view may be an indication of an imminent fire or another situation of concern.

Abstract: A multi-substrate package assembly having a first substrate, a second substrate and a package, each with a number of bond pads. The package includes a cavity for receiving either or both of the first and second substrates, with a number of bond pads positioned along at least part of the periphery of the cavity. The first substrate and the second substrate are preferably positioned in the cavity of the package, with selected bond pads of the first substrate and second substrate electrically connected to selected bond pads of the package. In some embodiments, the bond pads of the first substrate are only connected to bond pads on one or more sides of the cavity, and the bond pads of the second substrate are only connected to bond pads on one or more of the remaining sides of the cavity. The packaging assembly of the present invention can be used in many applications, including spectrally tunable optical detectors.

Abstract: A light detector having spaced electrodes preset by pins or a spacer within a sealed enclosure. The detector may have a MEMS structure that is separate from the sealing of the enclosure. Further, the detector may have a lens for the transmission of light onto the elements. The lens may be coated to affect the amount of light admitted into the enclosure. Light detectable by the sensor may be ultra-violet.

Abstract: A smoke detector having a closed internal optical path can detect airborne particulate matter, such as smoke from a fire, via a light scattering sensor and/or a light absorption sensor. The path can be implemented with a plurality of reflectors, such as piezoelectric minors. Input light can be coupled to the path, on a pulsed basis, for example via one of the minors, in a resonant condition.

Abstract: A two chamber system with fill gas in one chamber and vacuum in the other provides a means of burning in one or more vacuum tubes while avoiding contamination from environmental gases. Vacuum tubes are often burned in after being sealed. Some processes burn-in the tubes before sealing them. The burn in process can take days and provide ample opportunity for environmental gases to contaminate the vacuum tube. The vacuum tube's fill tube passes through the vacuum chamber and into the fill gas chamber. Environmental gases leaking past the fill tube are evacuated by the vacuum. Similarly, fill gas leaking past the fill tube is also evacuated to vacuum. As such, the environmental gases are drawn away before contaminating the vacuum tube.

Abstract: One embodiment includes an electromagnetic sensor which includes a header, an anode connected to a first terminal extending through the header, the anode in electrical isolation from the header, a cathode connected to a second terminal extending through the header, the cathode in electrical isolation from the header, a conductive case including a window transparent to electromagnetic energy, the conductive case enclosing the anode and the cathode and hermetically sealed to the header and an insulative sleeve disposed between the anode and the case and between the cathode and the conductive case.

Abstract: A fire detection system for detecting fires may include an infrared detector array. The fire detection system may use the infrared detector array to monitor the temperature of a target environment over time. In some cases, a positioning apparatus may be used to move the field of view of the infrared detector array, allowing the infrared detector array to scan a relatively large target environment while still achieving a given resolution.

Abstract: One embodiment includes an electromagnetic sensor which includes a header, an anode connected to a first terminal extending through the header, the anode in electrical isolation from the header, a cathode connected to a second terminal extending through the header, the cathode in electrical isolation from the header, a conductive case including a window transparent to electromagnetic energy, the conductive case enclosing the anode and the cathode and hermetically sealed to the header and an insulative sleeve disposed between the anode and the case and between the cathode and the conductive case.

Abstract: A cavity ring-down sensor having an optical path of mirrors and an interface proximate to a mirror with a normal incidence optical fiber coupling. The interface may be a block of transmissive materials having different indices of refraction for receiving a light beam of normal incidence from an optical fiber and directing the beam into the optical path. The sensor may be used applications where the optical fiber needs to be straight into the sensor without unusual bending because of space limitations. One application of this sensor may be for ground water testing via a narrow well casing.

Abstract: Heavier noble gases such as xenon and argon can reduce the run-in period for vacuum tubes and in particular flame detector tubes. The tubes can be filled with a run-in gas and then run-in. The run-in gas can then be exchanged for an end gas, such as neon, and the tube sealed. A final conditioning step of running in the tube with the end gas can further smooth the tube's anode and cathode to thereby improve performance and operating life.

Abstract: The invention is a method and apparatus capable of detecting constituents of a gas at extremely low concentrations comprising providing a medium that is absorbent of at least a first particular gas under a first environmental condition and desorbent of the particular gas under a second environmental condition, exposing the medium to a sample gas for a first period of time under the first environmental condition, during a second period of time after the first period of time, exposing the medium to the second environmental condition to cause the medium to desorb gas into an optical cavity of a cavity ring down spectrometer and introducing electromagnetic radiation into the cavity, during a third period of time after the second period of time, ceasing introduction of the electromagnetic radiation into the cavity and detecting the decay of the electromagnetic radiation in the cavity, and analyzing the decay of the light in the cavity to obtain a spectral analysis of the sample gas.

Abstract: A light detector having a cathode wafer, a cavity wafer and an anode wafer. The cathode wafer may be bonded to one side of the cavity wafer and the anode wafer may be bonded to another side of the cavity wafer. The cathode wafer may have numerous cathodes, the anode wafer numerous anodes and the cavity wafer numerous cavities which may be aligned on a one-to-one basis to form a wafer structure of a plurality of detectors which may be diced into separable detector chips. When there is a voltage potential across a cathode and an anode, and a gas such as Ne or the like in the cavity, a reception of light such as ultra violet may result in an electronic discharge between the cathode and anode of the light detector.

Abstract: An apparatus is provided for measuring a gas within a semiconductor thin film process. The apparatus includes an optical resonator disposed within an environment of the thin-film process, a tunable laser that excites the optical resonator at a characteristic frequency of the gas and a detector that detects an energy within the resonator.

Abstract: A surface enhanced Raman scatter (SERS) analyte analyzer. The analyzer has floating surfaces for enhancement of the Raman scattered light from sample molecules. An injector may provide a spray of charged nanoparticles suspended in droplets of an evaporable solution into a chamber. When the solution quickly evaporates, droplets of nanoparticles are left without a supporting solution. These droplets or cloud of charged nanoparticles may then explode into a dispersion or aerosol. The charged nanoparticles may attract molecules of a sample for attachment to their surfaces. A laser light may impinge the attached molecules which may result in surface enhanced Raman scattered light received by a detector or a light spectrometer. Wavelength signatures may then be obtained from the spectrometer. The signatures may provide information about the molecules.

Abstract: A photoelectrocatalytic sensor system for measuring oxidizable impurities in air. The sensor system may include a transistor having an electrode and a channel for the flow of current, a photocatalytic material coated onto the electrode of the transistor, a light source for producing an ultraviolet light beam onto the photocatalytic material, and a sensor for measuring the flow of current.

Abstract: A sensor comprises two photodiodes sensitive to different wavelengths. The photodiodes or detectors are stacked in a vertical relationship to each other. A bandpass filter is provided to limit the wavelengths of light reaching the detectors. The photodiodes are formed of various combinations of materials such as AlGaN or InGaN, or different compositions of the same material. Charge detectors are coupled to each detector to provide a signal representative of the amount of radiation detected in their corresponding bandwidths. A biological sample is provided proximate the filter. A laser is used to illuminate the biological sample to create biofluorescence corresponding to intrinsic tryptophan of bacteria.

Abstract: A spectrally tunable optical detector and methods of manufacture therefore are provided. In one illustrative embodiment, the tunable optical detector includes a tunable bandpass filter, a detector and readout electronics, each supported by a different substrate. The substrates are secured relative to one another to form the spectrally tunable optical detector.

Abstract: A structure having a substrate, patterned metal layer and a catalyst island formed on the metal layer. The surface of the substrate upon which the metal layer is formed may be oxidized. As an illustrative example, the metal may be HfN and the catalyst island may be iron, nickel, or the like. The resulting structure may be placed in an environment having a carbon-containing gas, a temperature between 500 and 1200 degrees C., and an electric field. A nanotube may grow from the catalyst island. A method including the combining of hafnium and nitrogen may be used to make the nanotube growing structure.