Abstract: A system and method includes a tunable light source and a gas cell configured to detect the presence of gases at terahertz frequencies. The light source is operable to emit a light signal at terahertz frequencies. The gas cell includes at least two high frequency mirrors adapted to reflect signals at terahertz frequencies. The gas cell is adapted to be tuned based on the frequency of the emitted light to obtain a Fabry-Perot resonance of the reflected light signal. A pair of detectors are operable to detect the original light signal and the light signal reflected through absorption paths in the gas cell. The system and method are operable to determine a presence and identity of a gas present in the gas cell.

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 system having a multiple-mirror ring-down cavity with one mirror where light may be input into the cavity and light from the cavity may be detected. A valve may permit light to enter or not to enter the cavity. An amplifier may be connected to a detector for detecting light from the cavity. The amplifier may be off or set at a low gain when light is entering the cavity and be on at a medium or high gain at a time when light is not entering the cavity.

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: Methods are disclosed for forming optoelectronic devices. In one example of such a method, a substrate is provided and a partially conductive bottom mirror formed thereon. An active region is then formed on the bottom mirror, and a top mirror formed on the active region. A gain guide is then formed in the top mirror. Finally, a substantially dielectric isolation layer, as well as a resonant reflector, are formed on the top mirror. The isolation layer is interposed between the resonant reflector and the top mirror, and the isolation layer is formed so as to substantially prevent energy in an evanescent tail of a guided mode associated with the resonant reflector from entering the top mirror.

Abstract: A tunable laser assembly, including a laser, a mirror, and a grating, wherein said grating is pivotably mounted between said laser and said mirror, wherein movement of said grating relative to said laser varies the wavelength of the energy emitted from the laser. A tunable laser assembly, including a laser comprising an emission surface, a top portion and a bottom portion, the cavity top portion being transparent to energy emitted from the laser, a detector positioned in the cavity, and a grating, pivotably mounted adjacent the laser, the grating cooperatively transmitting energy emitted from the laser to the detector, wherein changing the angle of the grating changes the wavelength of the energy incident upon the detector.

Abstract: Methods are disclosed for forming optoelectronic devices. In one example of such a method, a substrate is provided and a partially conductive bottom mirror formed thereon. An active region is then formed on the bottom mirror, and a top mirror formed on the active region. A gain guide is then formed in the top mirror. Finally, a substantially dielectric isolation layer, as well as a resonant reflector, are formed on the top mirror. The isolation layer is interposed between the resonant reflector and the top mirror, and the isolation layer is formed so as to substantially prevent energy in an evanescent tail of a guided mode associated with the resonant reflector from entering the top mirror.

Abstract: An optoelectronic device that provides isolation between a resonant reflector and an adjacent conducting layer of the optoelectronic device. Isolation may be accomplished by providing a buffer or cladding layer between the resonant reflector and the adjacent conducting layer of the optoelectronic device. The cladding or buffer layer is preferably sufficiently thick, or has a sufficiently low refractive index relative to the refractive index of the waveguide of the resonant reflector, to substantially prevent energy in the evanescent tail of the guided mode in the waveguide from entering the adjacent conductive layer of the optoelectronic device.

Abstract: A portable or wearable cytometer that can be used at remote locations, such as in the field or at home. The flow cytometer of the present invention may help improve the healthcare of many weak, sick or elderly people by providing early detection of infection. By detecting the infection early, the infection may be more readily treatable. In military applications, the portable cytometer of the present invention may help save lives by providing early detection of infection due to biological agents.

Abstract: A tunable laser assembly, including a laser, a mirror, and a grating, wherein said grating is pivotably mounted between said laser and said mirror, wherein movement of said grating relative to said laser varies the wavelength of the energy emitted from the laser. A tunable laser assembly, including a laser comprising an emission surface, a top portion and a bottom portion, the cavity top portion being transparent to energy emitted from the laser, a detector positioned in the cavity, and a grating, pivotably mounted adjacent the laser, the grating cooperatively transmitting energy emitted from the laser to the detector, wherein changing the angle of the grating changes the wavelength of the energy incident upon the detector.

Abstract: An optoelectronic device that provides isolation between a resonant reflector and an adjacent conducting layer of the optoelectronic device. Isolation may be accomplished by providing a buffer or cladding layer between the resonant reflector and the adjacent conducting layer of the optoelectronic device. The cladding or buffer layer is preferably sufficiently thick, or has a sufficiently low refractive index relative to the refractive index of the waveguide of the resonant reflector, to substantially prevent energy in the evanescent tail of the guided mode in the waveguide from entering the adjacent conductive layer of the optoelectronic device.

Abstract: The present invention provides an optical system that includes an array of opto-electronic devices, an array of micro lenses, and a fore optic. The array of opto-electronic devices lie substantially along a plane, but the fore optic has a non-planar focal field. To compensate for the non-planar focal field of the fore optic, each opto-electronic device has a corresponding micro lens. Each micro lens has a focal length and/or separation distance that compensates for the non-planar focal field of the fore optic. As a result, light that is provided by the fore optic is reconfigured by the micro lenses to be substantially focused along the plane of the array of opto-electronic devices.

Abstract: An optical detection system for flow cytometry that uses two or more light sources positioned laterally at different distances from the central axis of the flow stream for providing light through different parts of the flow stream. By using two or more light sources, the particle position can be detected, and the alignment and width of the core stream can be monitored and controlled. In addition, the velocity and size of the particles can be more accurately determined than when only a single light source is used.

Abstract: The present invention provides an optical system that includes an array of opto-electronic devices, an array of micro lenses, and a fore optic. The array of opto-electronic devices lie substantially along a plane, but the fore optic has a non-planar focal field. To compensate for the non-planar focal field of the fore optic, each opto-electronic device has a corresponding micro lens. Each micro lens has a focal length and/or separation distance that compensates for the non-planar focal field of the fore optic. As a result, light that is provided by the fore optic is reconfigured by the micro lenses to be substantially focused along the plane of the array of opto-electronic devices.

Abstract: Disclosed is a tunable multispectral optical apparatus for forming a spectrally processed image of a scene having finite angular extent or alternatively a point source of light, both of which may include multispectral components. A spatial filter is selectively positioned between a hybrid fore-optic and a hybrid reimaging optic, both of which include a diffractive optic. Spectral selectivity is obtained by proper positioning of the spatial filter relative to the intermediate image formed by the hybrid fore-optic before impinging on the hybrid reimaging optic. The tunable multispectral optical apparatus of the present invention may take the form of a bandpass filter or a bandstop filter depending only on the choice of spatial filter--blocking or passing selective wavelength components of the intermediate image.

Abstract: Optoelectronic devices such as VCSEL and RCPD devices that have integrated resonant reflectors. The integrated resonant reflector may be made conductive so that bias current can pass therethrough. This may allow more flexibility in the design of the VCSEL and RCPD devices.Since making the resonant reflector more conductive typically reduces the overall reflectivity of the resonant reflector, the resonant reflector may be provided in combination with a Distributed Bragg Reflector (DBR) mirror to achieve the desired overall reflectance for a VCSEL or RCPD design. A broad bandwidth resonant reflector may also be provided. The bandwidth may be sufficiently wide to increase the reliability of data communication between such devices, and may be sufficiently narrow to maintain adequate mode control and mode stability. These devices may be used to support polarization-, space- and/or wavelength-division multiplexing applications.