Abstract:
A method of arranging and utilizing a multivariate optical computing and analysis system includes transmitting a o first light from a light source; generating a second light by reflecting the first light from the sample; directing a portion of the second light with a beamsplitter; and arranging an optical filter mechanism in a normal incidence orientation to receive the portion of the second light, the optical filter mechanism being configured to optically filter data carried by the portion of the second light.
Abstract:
A method and apparatus for enhancing the accuracy of spectroscopic measurements using a cavity ringdown spectrometer (CRDS) is provided. A first aspect of the invention consists of a novel algorithm for the processing of ring-down data that significantly reduces the amplitude of an exponential fitting artifact, and thereby gives a better estimate of the actual loss. The primary cause of the artifact is the presence of an unwanted backwards-traveling wave that counter-propagates within the ringdown cavity. Scattering due to small imperfections at the cavity mirrors produces this wave and its intensity may be minimized by adjustment of the mirror positions during cavity construction. A second aspect of the invention consists of an apparatus for measuring the backscattered wave within a cavity to allow such cavity mirror adjustments to be made.
Abstract:
A simple matrix method and computer program product for stray-light correction in imaging instruments is provided. The stray-light correction method includes receiving raw signals from an imaging instrument and characterizing the imaging instrument for a set of point spread functions. For high resolution imaging instruments, the raw signals may be compressed to reduce the size of the correction matrix. Based on stray-light distribution functions derived from the point spread functions, a correction matrix is derived. This fast correction is performed by a matrix multiplication to the measured raw signals, and may reduce stray-light errors by more than one order of magnitude. Using the stray-light corrected instrument, significant reductions may be made in overall measurement uncertainties in radiometry, colorimetry, photometry and other applications. Because the PSFs may include other types of undesired responses, the stray-light correction also eliminates other types of errors, e.g., interreflection between a CCD and the detector window.
Abstract:
In a calibration reference light source and a sensitivity calibration system using the same, a plurality of single-wavelength light sources for emitting reference lights having mutually different single-wavelengths are used instead of a black body radiation source for radiating a white light, and not only the intensities of the single-wavelength reference lights, but also the wavelengths thereof are measured to obtain sensitivity correction coefficients of intensity-to-radiance conversion data. Thus, obtained reference radiance are highly reliable and sensitivity correction of spectrophotometers and spectral illuminometers can be performed with high accuracy and reliability at a user side, whereby the calibration reference light source and the calibration system using the same can be obtained at low cost.
Abstract:
This system collects light emitted by at least one light source (52) and focuses it onto at least one light detection device (54). Preferably, it comprises a first mirror (58) that collects light emitted by the source and focuses it on a second mirror (60) that focuses it in turn onto the device. The system is provided with a chamber that is opaque to all light, particularly ultraviolet radiation, and in which the light source, the light detection device and the mirrors are placed, and means of creating a vacuum in this chamber and filling it with a gas that is transparent to ultraviolet radiation.
Abstract:
A system and method processes a structure comprising embedded material. The system includes a laser adapted to generate light and to irradiate an interaction region of the structure. The system further includes an optical system adapted to receive light from the interaction region and to generate a detection signal indicative of the presence of embedded material in the interaction region. The system further includes a controller operatively coupled to the laser and the optical system. The controller is adapted to receive the detection signal and to be responsive to the detection signal by selectively adjusting the laser.
Abstract:
A detection system is used during irradiation of an interaction region of a structure with laser light. The structure includes embedded material. The detection system includes means for receiving light emitted from the interaction region. The detection system further includes means for separating the received light into a spectrum of wavelengths. The detection system further includes means for analyzing at least a portion of the spectrum for indications of embedded material within the interaction region.
Abstract:
A method is provided for calibrating a spectrometer device used for Raman scattering analysis. A predetermined dispersion curve for a diffraction grating or spectrograph of the spectrometer device is modified based on spectrum data associated with detected dispersed light from a calibration light source to produce a modified dispersion curve. The wavelength of a Raman light source on a light detection device is determined. Calibration data for the spectrometer device is computed from the Raman line peak positions for the first chemical, the wavelength on the detection device of the Raman light source and the modified dispersion curve.
Abstract:
The present invention relates to a method for correcting spectral interference in a spectrum which is determined using an inductively coupled plasma spectrometer (ICP) for analysing element contents of a liquid or gaseous sample, comprising the following steps: recording the spectrum of a matrix solution containing all spectrally interfering components, which are also contained in the sample, in a first concentration; recording the spectrum of the matrix solution in at least one dilution of the first concentration; regressing the signal intensities obtained in steps a. and b. against the concentration for a number of wavelength positions; calibrating the spectrometer, background correction using the values determined from the regression in step c. and determining the calibration function c=f(I); recording the sample spectrum using at least one analyte which is contained therein; determining the concentration of the spectrally interfering components in the sample using the results obtained in step c. for wavelength positions at which no line of the analyte of the sample is present; and determining the sample signal which is characteristic of the analyte concentration by forming the difference between the spectrum from step e. and the calculated matrix spectrum in a dilution which was calculated in step f., wherein the calibration function c=f(I) is used.