Abstract: An apparatus for measuring fluorescence of potable liquids contained within an optical quartz cell includes a deep UV laser or a compact UV LED that generates a light beam. A UV blocking and visible light transmitting optical filter reduces out-of-band emission from the LED. The optical quartz cell is between a pair of plane mirrors so that light from the light source travels through it several times. A concave mirror collects a fluorescence signal and has a common optical axis with a lens. The common optical axis is normal to an optical axis of the light beam. The concave mirror and lenses are positioned on opposite sides of the optical quartz cell. A fluorescence detector is in optical alignment with the concave mirror and the lens. A boxcar averager is in electrical communication with the fluorescence detector. Optical wavelength selection of the fluorescence emission uses optical filters or a spectrometer.

Abstract: An apparatus for measuring fluorescence of potable liquids contained within an optical quartz cell includes a deep UV laser or a compact UV LED that generates a light beam. A UV blocking and visible light transmitting optical filter reduces out-of-band emission from the LED. The optical quartz cell is between a pair of plane mirrors so that light from the light source travels through it several times. A concave mirror collects a fluorescence signal and has a common optical axis with a lens. The common optical axis is normal to an optical axis of the light beam. The concave mirror and lenses are positioned on opposite sides of the optical quartz cell. A fluorescence detector is in optical alignment with the concave mirror and the lens. A boxcar averager is in electrical communication with the fluorescence detector. Optical wavelength selection of the fluorescence emission uses optical filters or a spectrometer.

Abstract: A method for detecting trace levels of dissolved organic compounds and leached plastic compounds in drinking water includes the steps of employing deep ultraviolet light-emitting diode induced fluorescence at sensitivity levels of several parts per trillion in real time so that a more compact and inexpensive excitation source, relative to a deep UV laser-induced fluorescence, for fluorescence detection of dissolved organic compounds in water is provided. The deep UV light-emitting diode is operated at an excitation near 265 nm and the laser induced fluorescence is detected at an emission near 450 nm to 500 nm for the dissolved organic compounds and near 310 nm for leached plastic compounds. Optical absorption filters and optical bandpass filters are employed to reduce out-of-band light emitting diode emissions and to eliminate second order optical interference signals for the detection of a fluorescence signal near 450 nm to near 500 nm.

Abstract: A triacetone triperoxide cloud associated with a triacetone triperoxide explosive attached to a hard target is remotely detected by operating differential-absorption lidar lasers to transmit a laser beam toward the hard target at differing wavelengths. A backscattered laser beam reflected from the lidar target (hard target, person, aerosols, clouds, buildings) is detected because a cloud of triacetone triperoxide in front of the lidar target and between the lidar target and the differential-absorption lidar system produces a differential-absorption signal having characteristics that identify the triacetone triperoxide. In a second embodiment, a triacetone triperoxide cloud that is absorbing optical radiation from its ambient environment and which is attached to a hard target is detected from a location remote from the triacetone triperoxide explosive by detecting an optical radiation absorption signature characterized by triacetone triperoxide absorption lines.

Abstract: An open-path/free-space optical communication system using reflected light has modulated optical or laser sources and provides communication between the modulated source and a detector in an obstructed line-of-sight relationship. The system detects backscattered light impinging on a target illuminated by the source of light. Barrier objects positioned in a line-of-sight path between the source and detector are circumvented and a first device that provides the modulation signal for the source controls a remote second device.

Abstract: An open-path optical communication system has either optical or laser sources and communicates between the source and a detector. In a first embodiment, the laser source includes a gas cell in the laser cavity to regulate laser wavelengths based on the minimum absorption between spectral lines of the gas in the cell. The laser is tuned close to a minimum absorption wavelength and the minimum absorption line locks the laser wavelength to the minimum position. In a second embodiment, the strong absorption lines of a gas in a gas cell positioned at a receiver site are used to provide channel isolation of the receiver. In a third embodiment, an atmospheric gas provides the channel isolation. In the fourth embodiment, individual wavelength channels are positioned between the absorption lines of atmospheric or non-atmospheric gases to prevent cross-talk between adjacent channels.

Abstract: An open-path optical communication system has either optical or laser sources and communicates between the source and a detector. In a first embodiment, the laser source includes a gas cell in the laser cavity to regulate laser wavelengths based on the minimum absorption between spectral lines of the gas in the cell. The laser is tuned close to a minimum absorption wavelength and the minimum absorption line locks the laser wavelength to the minimum position. In a second embodiment, the strong absorption lines of a gas in a gas cell positioned at a receiver site are used to provide channel isolation of the receiver. In a third embodiment, an atmospheric gas provides the channel isolation. In the fourth embodiment, individual wavelength channels are positioned between the absorption lines of atmospheric or non-atmospheric gases to prevent cross-talk between adjacent channels.

Abstract: An open-path/free-space optical communication system using reflected light has modulated optical or laser sources and provides communication between the modulated source and a detector in an obstructed line-of-sight relationship. The system detects backscattered light impinging on a target illuminated by the source of light. Barrier objects positioned in a line-of-sight path between the source and detector are circumvented and a first device that provides the modulation signal for the source controls a remote second device.

Abstract: An open-path optical communication system has either optical or laser sources and communicates between the source and a detector. In a first embodiment, the laser source includes a gas cell in the laser cavity to regulate laser wavelengths based on the minimum absorption between spectral lines of the gas in the cell. The laser is tuned close to a minimum absorption wavelength and the minimum absorption line locks the laser wavelength to the minimum position. In a second embodiment, the strong absorption lines of a gas in a gas cell positioned at a receiver site are used to provide channel isolation of the receiver. In a third embodiment, an atmospheric gas provides the channel isolation. In the fourth embodiment, individual wavelength channels are positioned between the absorption lines of atmospheric or non-atmospheric gases to prevent cross-talk between adjacent channels.

Abstract: The present invention includes a method of detecting nerve cell damage representative of glaucoma including the steps of: imaging a human retina in vivo, measuring the reflected light intensity at a first predetermined wavelength wherein values returned from healthy and damaged areas of retina are substantially identical, measuring a second reflected light intensity at a predetermined wavelength wherein values of healthy and damaged retina substantially diverge, and recording the differences between the first and second values, which values are indicative of glaucoma damage.