Abstract:
A time-domain waveform of a terahertz wave is measured by a method based on time-domain spectroscopy by using an optical delay unit to adjust an optical path length along which excitation light propagates thereby adjusting a difference between a time at which the excitation light arrives at a generating unit configured to generate the terahertz wave and a time at which the excitation light arrives at a detection unit configured to detect the terahertz wave. The optical delay unit is driven according to a first speed pattern to acquire a first time-domain waveform. The optical delay unit is then driven according to a second speed pattern different from the first speed pattern to acquire a second time-domain waveform. The first time-domain waveform and the second time-domain waveform are averaged.
Abstract:
A method is provided that includes receiving and processing a sample signal scan. Processing the sample signal scan includes applying an inner-product operation on the sample signal scan and each of a plurality of eigenvectors to generate a plurality of corresponding coefficients, and subtracting the sample signal scan from a linear combination of the eigenvectors and corresponding coefficients to thereby produce a corrected sample signal scan. In this regard, the eigenvectors have been generated by decomposing a plurality of background reference signal scans according to a singular value decomposition technique. The signal scans include a plurality of electromagnetic signal measurements at a discrete set of frequencies, where each measurement has been taken by a spectrometer system passing an electromagnetic signal through a sample cell including just a base medium (for the background reference signal scans), or both a base medium and a sample medium (for the sample signal scan).
Abstract:
Method and apparatus for detecting, by absorption spectroscopy, an isotopic ratio of a sample, by passing first and second laser beams of different frequencies through the sample. Two IR absorption cells are used, a first containing a reference gas of known isotopic ratio and the second containing a sample of unknown isotopic ratio. An interlacer or reflective chopper may be used so that as the laser frequencies are scanned the absorption of the sample cell and the reference cell are detected alternately. This ensures that the apparatus is continuously calibrated and rejects the baseline noise when phase sensitive detection is used.
Abstract:
An absorption spectrometer provides improved rejection of background radiation signal by employing a frequency-swept laser signal without frequency dithering and performing an effective differentiation of output light from a test cell to eliminate these constant or slowly varying background radiation levels.
Abstract:
An apparatus includes an optical source providing an optical beam; a splitter configured to split the optical beam into a sample beam and a reference beam; a sample path containing a sample material to be analyzed, the sample beam being directed through the sample path so as to interact with the sample material; a reference path containing a reference material, the reference beam being directed through the reference path so as to interact with the reference material; a disperser configured to receive the sample beam after it exits the sample path and to receive the reference beam after it exits the reference path, the disperser outputting a dispersed sample beam and a dispersed reference beam; and a photodetector disposed to receive the dispersed sample beam and the dispersed reference beam and outputting electrical signals comprised of data indicative of a spectra of the sample beam after it exits the sample path and a spectra of the reference beam after it exits the reference path. In one embodiment the apparatus further includes a data processor connected with a memory storing a software program configured to process the data to detect a presence of at least one type of molecular species that includes the sample material; and a transmitter configured to transmit the processed data to a receiver. In another embodiment the apparatus includes a transmitter configured to transmit the data to a remote receiver for processing.
Abstract:
The present invention provides devices, systems and methods for imaging and sensation of objects. In particular, the present invention provides devices, systems and methods for spectroscopic imaging and sensation of objects.
Abstract:
A combined spectral and spatial sensing unit having a lens for receiving light from an object or substance and for directing at least a portion thereof through a diffraction device to an area imager for creating a digital spectral image of a plurality of segments of different wave lengths of light on a first set of pixels of said imager and for creating a digital spatial image on a second set of pixels of said imager, and an analytical unit having a microprocessor for receiving each of said images and comparing same to images stored in a memory associated with said microprocessor to determine the identity, condition or other information about the object or substance. Alternatively, a portion of said light may be directed through a diffraction grating to a first imager and another portion to a second imager, each of which is associated with a microprocessor for determining the identity, condition or other information about the object or substance.
Abstract:
A photoconductor device and a method of manufacturing the same are provided. The photoconductor device includes a photoconductor substrate, a photoconductor thin film deposited on the photoconductor substrate, and a photoconductive antenna electrode formed on the photoconductor thin film. The photoconductor thin film includes polycrystalline GaAs.
Abstract:
A transmission quantification approach that is effective at quantifying the concentration of key atmospheric gases, including water vapor and methane, does not require a background spectrum and is immune to changes between background and absorbance spectra. By using local minima and maxima in transmission of a target gas, this approach creates two spectral arrays as long as a single beam input spectra. One of these spectral arrays represents the points in wave-number space that are less absorbing points, and the other represents the more absorbing points. A concentration for a given gas is calculated by determining what reference concentration creates a residual after division by a pure gas spectrum that forces these two arrays to converge.
Abstract:
A virtual microscope system capable of obtaining a stained sample image and a statistical data of spectra in a short period of time is provided, the virtual microscope system includes an image obtaining unit for obtaining a stained sample image, a spectrum obtaining unit for obtaining a spectrum of the stained sample image, an optical path setting unit for setting an optical path of a light flux passed through the stained sample with respect to the image obtaining unit and the spectrum obtaining unit and a control unit for controlling to repeat obtaining the stained sample image by the image obtaining unit and obtaining the spectrum of the stained sample image by the spectrum obtaining unit in the observation field of the stained sample to create a virtual slide and a spectrum table of the stained sample.