Abstract:
An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a frequency shifter in the path of one laser beam allows the terahertz beam to be finely adjusted in one or more selected frequency bands.
Abstract:
A spectroscopic method and spectroscopy system therefrom for analyzing samples. A sample includes a first chemical component that has a characteristic first absorption peak is provided. The sample is irradiated in a measurement waveband proximate to the first absorption peak, and at a first and a second reference waveband where the first chemical component lacks characteristic absorption features. Reflected or transmitted detection data is obtained including a measured power proximate to the first absorption peak and first and second reference powers at the reference wavebands. A plurality of different waveband ratios are evaluated using pairs of detection data to generate a plurality of measured waveband ratio values. A parameter of the first chemical component is then determined by evaluating a multidimensional polynomial calibration equation that relates the parameter of the first chemical component to the plurality of different waveband ratios by substituting the measured waveband ratio values into the calibration relation.
Abstract:
The invention provides systems and methods for detecting aerosols. The systems and methods can be used to detect harmful aerosols, such as, bio-aerosols.
Abstract:
A digital spectrophotometer and a spectrologial method for determining spectrum wavelength of an unknown illuminant, and the digital spectrophotometer has a base, an operating assembly and a photographic assembly. The operating assembly is attached to the base and has an operating pedestal, a rotating frame and a spectrometer. The rotating frame is connected rotatably to the operating pedestal. The spectrometer is connected solidly to the rotating frame. The photographic assembly is connected to the operating assembly. The spectrologial method is calculated the diffraction angle α i and the wavelength of the unknown illuminant by putting the parameters into the into the first and second functions.
Abstract:
The invention provides systems and methods for detecting aerosols. The systems and methods can be used to detect harmful aerosols, such as, bio-aerosols.
Abstract:
Multiple wavelength spectrometers can be tuned to particular wavelengths. A dual wavelength spectrometer can include a spectrometer configured to detect at least some wavelengths that fall within the ultraviolet (UV) spectrum and a spectrometer configured to detect at least some wavelengths that fall within the visible spectrum. In some embodiments, a UV light spectrometer and a visible light spectrometer are disposed adjacent one another on a single substrate. A dual wavelength spectrometer can be used for analyzing bioaerosols, as well as for numerous other applications.
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:
The present invention relates to a semiconductor processing system that employs infrared-based thermopile detector for process control, by analyzing a material of interest, based on absorption of infrared light at a characteristic wavelength by such material. Specifically, an infrared light beam is transmitted through a linear transmission path from an infrared light source through a sampling region containing material of interest into the thermopile detector. The linear transmission path reduces the risk of signal loss during transmission of the infrared light. The transmission path of the infrared light may comprise a highly smooth and reflective inner surface for minimizing such signal loss during transmission.
Abstract:
A spectral reflectance sensor including: a light source for emitting a modulated beam of red light; a light source for emitting a modulated beam of near infrared light; a receiver for receiving reflected light produced by either the red source or the near infrared source; a receiver for receiving incident light from either the red source or the infrared source; a signal conditioner responsive to the modulation such that the signals produced by the receivers in response to reflected and incident light from the source can be discriminated from signals produced by ambient light; and a microprocessor having an input such that the microprocessor can determine the intensities of incident red light, reflected red light; incident near infrared light; and reflected near infrared light. From these intensities, and by knowing the growing days since emergence or planting, the sensor can calculate the mid-growing season nitrogen fertilizer requirements of a plant.
Abstract:
A two color radiation detector. A dispersive lens with a spectrally selective central obscuration focuses a first radiation band on a central location on focal plane array. The dispersive lens also focuses an annulus of out of focus radiation of a second radiation band concentric with the central location on the focal plane array. For point target detection the dispersive lens transmits plume band and guard band radiation to the staring focal plane array sensor. The staring focal plane array is located at the focal point of the plume band radiation. A spatial filter detects target signatures using information from the plume band and guard band radiation.