101results about "Correlation spectrometry" patented technology

An apparatus and method for measuring Raman-type spectra using optical dispersion to convert an optical spectrum into a waveform which can be detected directly in the time domain without the use of a conventional spectrometer. In the example of stimulated Raman spectroscopy, the apparatus and method exposes a sample to a chirped, pulsed probe beam and a Raman pump beam and the resulting Raman spectra is detected by an optical detector in the time domain, and analyzed. Alternatively, the Raman spectra from the probe and pump beams is chirped with a dispersive element prior to detection and analysis. Each probe pulse provides a snapshot of the Raman spectrum that is sampled in time so that neither repetitive waveforms nor static samples are required. Therefore, high speed acquisitions and high throughput assays can be conducted. To facilitate detection, these spectral signals can also be amplified using distributed Raman amplification directly in the dispersive element.

A spectrometry device according to an aspect of the present invention is including a light source (101), a lens 104 concentrating a light beam from the light source (101) on a reference sample (120), an objective lens (106) concentrating a light beam that has passed through the first lens (104) on a measurement sample (121), a spectroscope (109) dispersing light having a different wavelength from that of the light beam generated in the measurement sample (121) and the reference sample (120) by irradiation of the light beam into a spectrum, a detector (110) detecting light that is dispersed by the spectroscope (109), and a beam splitter (103) separating an optical path of light from the reference sample (120) and the measurement sample (121) toward the spectroscope (109) from an optical path of a light beam that propagates from the light source (101) toward the measurement sample (121).

A tunable optical filter for simulating the waveband spectrums of selected substances. The filter includes an optical waveguide with a core material for transmitting light energy and a nominal core refractive index for the core material. Predetermined periodic variations are formed in the core material of the optical waveguide between the input and output ends that alter the core refractive index of the waveguide at the location of the periodic variations. Depending upon the periodic variations, the waveguide produces a predetermined reference waveband spectrum output that matches the waveband spectrum of a selected substance. A modulator is coupled to the waveguide to selectively modulate the periodic variations to intermittently shift the reference waveband spectrum output to fine tune the filter and reduce signal noise. The filter is useful as a reference cell for correlation spectroscopy, DIAL LIDAR, equipment calibration, and other uses where a predetermined or known waveband spectrum is useful or desirable.

The present invention is directed to an apparatus, method and software product for enhancing the dynamic range of a CCD sensor without substantially increasing the noise. Initially, the area of a N×M pixel CCD sensor array is subdivided into two regions, a large region having (M−a) pixels in each column for outputting large-amplitude signals with low noise and a smaller region having a pixels in each column for outputting small-amplitude signals with improved dynamic range. At integration time, the CCD is read out one region's rows at a time into the horizontal shift registers by shifting the pixel charges in either a or M−a vertical shifts. The charges in the horizontal shift registers are then shifted out of the horizontal shift registers in N horizontal shifts. Next, the remaining pixels in the region of the CCD are read out into the horizontal shift registers by shifting the pixel charges in the other of a or M−a vertical shifts. Those charges are then shifted out of the horizontal shift registers in N horizontal shifts. In a spectrographic application, the data from the two regions is read out in the form of a large-amplitude channel from the larger region's rows and a small-amplitude channel from the smaller region's rows.

A sensor system featuring a field angle compression telescope optical system for measuring atmospheric trace gases is provided. According to an embodiment of the present invention, the telescope optical system condenses the field angle of received light with respect to a cross track plane, while leaving the field angle with respect to an along-track plane uncompressed. Such an anamorphic telescope design provides a wide field of view, while allowing information regarding the altitude or height distribution of a gas to be obtained. According to another embodiment of the present invention, the field angle of received light is compressed by magnifying the received light by a value less than 1.0 in all directions.

A correlation filter is provided having passbands at wavelengths corresponding to the absorption spectrum of an atmospheric gas of interest. In particular, the correlation filter features narrow, non-linearly spaced passbands having center wavelengths that are correlated to the non-linearly spaced absorption lines of an atmospheric gas. A correlation filter in accordance with an embodiment of the present invention includes a compensation stack having a number of thin film layers, at least some of which have an optical thickness that is not equal to an integer multiple of one-quarter of a wavelength of an absorption line of the gas of interest. The correlation filter may be provided in association with an etalon, or may comprise a number of optical cavities. In accordance with an embodiment of the present invention, a number of absorption lines associated with an atmospheric gas may be simultaneously viewed, providing a signal indicating the presence and quantity of such gas in the atmosphere having a high signal-to-noise ratio.

The invention relates to an apparatus for optical spectroscopy having means to produce an interference pattern and having a spatially resolving detector which can record the interference pattern produced. In accordance with the invention, the wavefronts of at least one of the part rays involved in the interference pattern is influenced in dependence on the wavelength by spectrally dispersive or diffractive optical elements.

An Internet-based integrated technology platform that simultaneously supports the management of Public Information Sites—Web sites used to both (1) inform the public; and (2) capture and manage public comment (including submission of images—while at the same time providing support for electronic communication for project teams that manage public involvement projects. The support includes sharing of graphic, text and collaborative tasks. The system and method allow revisions to comments and dynamic feedback in agency decision making based on comments with greater responsiveness. The system is also suited for implementing charettes with a large number of participants.

A device and method for optimally estimating the transmission spectrum simultaneously modulates complementary sequences employing a signal transmitter, an encoder, a transmitter having a modulator; a convolver, an antenna, a receiver having a demodulator, and a decoder having an output filter. The device uses complementary sets of sequences, simultaneously transmitted to a physical means, the sum of autocorrelations of which corresponds to a Krönecker delta, allowing the extraction in reception of the spectral and temporal features of the means minimizing the effect of the noise.

Measuring of an electro-optic coefficient and a thermo-optic coefficient of an optical device and an optical material, and more specifically, to measurement systems and methods of evaluating the electro-optic and thermo-optic coefficients by using interference fringe measurement techniques, wherein those optical characteristics can be precisely measured over a wide wavelength intended without using a complicated measuring equipment. The system for measuring an electro-optic coefficient includes: a light source for outputting an optical beam of multi-wavelengths, an optical interferometer including an optical beam splitter for dividing the optical beam received from the light source into two separate beams, a reference arm for receiving any one of the divided optical beams, a sample arm for receiving the other of the divided optical beams and applying a voltage to an optical sample to be measured by being connected to the optical sample, and an optical beam combiner for combining and mutually interfering optical beams that are output through the reference arm and the sample arm, and an optical spectrum analyzing device for receiving the mutually interfered optical beam from the optical interferometer and analyzing a spectrum of the mutually interfered optical beam.

A system and method is provided for improved fluorescence decay time measurement. A digital heterodyning technique is disclosed in which a photon detector is sampled at a rate slightly faster than a digitally pulsed excitation signal. A resulting cross correlation frequency is low enough to be read by inexpensive electronics such as by a field programmable gate array. Phase information in the signal provides correlation with corresponding photon detections.

An optical absorption spectrometer is provided for determining the concentration of a substance within a sample. The optical absorption spectrometer comprises a first radiation source for supplying radiation to the sample to be measured; at least one cavity for containing the sample during measurement; and a detector assembly for detecting radiation transmitted along first and second optical paths through the sample, the length of the first optical path being greater than that of the second optical path.

A spectrometer for identifying a mixture is provided. The spectrometer includes a detector configured to generate a signal based on an interaction of light with a sample of the mixture, and a memory device having a library and a correlation matrix stored therein, wherein the library includes a plurality of spectra, each spectrum associated with a respective compound, and wherein the correlation matrix includes a correlation between each possible pair of spectra in the library. The spectrometer further includes a processor coupled to the memory device and configured to determine a spectrum of the mixture based on the signal generated by the detector, calculate a correlation vector that includes a correlation between the mixture spectrum and each spectrum in the library, and identify the mixture based on the correlation matrix and the correlation vector.

An airborne/spaceborne oil spill detection method includes the step of providing a moderate-resolution-imaging-spectroradiometer and sensing the spectral reflections from two optical bands one of which is in the near inferred range. The spectral contrast shift from two adjacent areas of water are calculated and a warning issued when an oil spill or other contaminant is detected. A system for detecting an oil spill or other contaminant on the surface of water is also disclosed.

Provided are a system and a method for detecting a number of layers of few-layer graphene employing multispectral image reproduction process to provide rapid detection of numbers of layers of few-layer graphenes on transparent or non-transparent substrates. The application of the system and method in relevant industries expedites validation and/or verification of the number of layers of an FLG product and improves the quality control efficiency thereof.