Abstract:
Remote absorption spectroscopy uses coded electromagnetic transmission directed through a medium under investigation to one or more remote receivers. The coded transmission includes at least one wavelength coincident with an absorption band of interest and one wavelength in an off-line band and a predefined relationship between spectral components in and outside the absorption band is controlled. The relationship between spectral components may be evaluated at the receiver to determine whether deviation thereof from the controlled relationship at the transmitter exists at the receiver. The deviation of the received optical signal from the prescribed relationship is processed to indicate the absorption of the radiation in the absorption band.
Abstract:
A system for reducing effects relating to stretching of an optical fiber includes an optical control source, the optical source outputting an optical signal, a terahertz transmitter and receiver both being optically coupled to the optical source, and a means for providing the optical signal to both the terahertz transmitter and terahertz receiver such that the terahertz receiver is synchronized to the terahertz transmitter by the optical signal. The means prevents the stretching of an fiber carrying the optical signal provided to the terahertz transmitter or terahertz receiver or allows for the stretching an optical fiber such that the terahertz receiver will still be synchronized to the terahertz transmitter by the optical signal.
Abstract:
Methods in a spectral measurement apparatus are disclosed. Light is received with a plurality of sensors. Each sensor generates an output signal having a frequency proportional to an intensity of light received by the sensor. First, second and third signals are generated each having a frequency proportional to an intensity of light received by a sensor of a wavelength or spectral band. A spectral characteristic of the received light is determined based on at least the first, second and third signals, which are are coupled to a processing element and input in parallel. The spectral characteristic is determined based on measuring a frequency or period of the at least first, second and third signals. Spectral data based on the determined spectral characteristic is generated by the processing element and displayed on a display device for perception by a viewer or transmitted to a data interface for transmission to an electronic device external to the spectral measurement apparatus.
Abstract:
A colour measuring unit (1) comprising a radiation device (2) which emits light onto a surface (9) to be examined, wherein the radiation device (2) comprises at least one semiconductor-based light source (6), and a radiation detector device (12) which receives at least a portion of the light scattered by the surface and outputs a signal characteristic of this light, wherein the radiation detector device (12) allows a spectral analysis of the light impinging thereon. According to the invention, the colour measuring unit comprises at least one sensor device (10) which determines at least one electrical parameter of the light source (6), and also a processor device (14) which outputs from this measured parameter at least one value characteristic of the light emitted by the radiation device (2).
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:
In a method for manufacturing a spectral module 1, a photodetecting unit 10 constructed by bonding a photodetector 5 and a light transmitting plate 56 together is attached to a front face 2a of a substrate 2 by an optical resin agent 63. Here, a light transmitting hole 50 of the photodetector 5 is covered with a light transmitting plate 56, whereby the optical resin agent 63 is prevented from intruding into the light transmitting hole 50. When preparing the photodetecting unit 10, a semiconductor substrate 91 provided with a photodetecting section 5a and the light transmitting plate 56 are bonded together, and then the semiconductor substrate 91 is formed with the light transmitting hole 50, whereby matters which may cause refraction, scattering, and the like to occur can reliably be prevented from intruding into the light transmitting hole 50.
Abstract:
A multi-channel detector assembly for downhole spectroscopy has a reference detector unit optically coupled to a reference channel of a source and has a measurement detector unit optically coupled to a measurement channel of the source. The reference and measurement detectors detect spectral signals across a spectral range of wavelengths from the reference and measurement channels. Conversion circuitry converts the detected spectral signals into reference signals and measurement signals, and control circuitry processes the reference and measurements signals based on a form of encoding used by the source. Then, the control circuitry can control the output of spectral signals from the source based on the processed signals or scale the measurement signal to correct for source fluctuations or changes in environmental conditions.
Abstract:
The invention relates to an apparatus and method for optically analysing samples contained in sample sites of a sample holder by means of fluorescence. The apparatus comprises a first light source comprising a plurality of individual light sources having narrow wavelength bands, means for further limiting wavelength bands of the light emitted by the individual light sources, means for guiding the reduced-wavelength light to the sample sites of the sample holder, and a detector for detecting light from the sample sites. According to the invention said means for further reducing the wavelength bands emitted by the individual light sources comprise a wavelength-tunable single monochromator. The invention allows manufacturing of a microplate reader having the capability for fluorescence measurements at a continuous wavelength range, while maintaining the cost of the device at a reasonable level.
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:
A method of sensing a process utilizing a sensing apparatus consisting of more than one diode laser having select lasing frequencies, a multiplexer optically coupled to the outputs of the diode lasers with the multiplexer being further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to a pitch optic operatively associated with a process chamber which may be a combustion chamber or the boiler of a coal or gas fired power plant. The pitch optic is oriented to project multiplexed laser output through the process chamber. Also operatively oriented with the process chamber is a catch optic in optical communication with the pitch optic to receive the multiplexed laser output projected through the process chamber. The catch optic is optically coupled to an optical fiber which transmits the multiplexed laser output to a demultiplexer. The demultiplexer demultiplexes the laser light and optically couples the select lasing frequencies of light to a detector with the detector being sensitive to one of the select lasing frequencies.