초록 ▼

A multi-gas sensor is provided which modulates a polarized light beam over a broadband of wavelengths between two alternating orthogonal polarization components. The two orthogonal polarization components of the polarization modulated beam are directed along two distinct optical paths. At least one

A multi-gas sensor is provided which modulates a polarized light beam over a broadband of wavelengths between two alternating orthogonal polarization components. The two orthogonal polarization components of the polarization modulated beam are directed along two distinct optical paths. At least one optical path contains one or more spectral discrimination element, with each spectral discrimination element having spectral absorption features of one or more gases of interest being measured. The two optical paths then intersect, and one orthogonal component of the intersected components is transmitted and the other orthogonal component is reflected. The combined polarization modulated beam is partitioned into one or more smaller spectral regions of interest where one or more gases of interest has an absorption band. The difference in intensity between the two orthogonal polarization components is then determined in each partitioned spectral region of interest as an indication of the spectral emission/absorption of the light beam by the gases of interest in the measurement path. The spectral emission/absorption is indicative of the concentration of the one or more gases of interest in the measurement path. More specifically, one embodiment of the present invention is a gas filter correlation radiometer which comprises a polarizer, a polarization modulator, a polarization beam splitter, a beam combiner, wavelength partitioning element, and detection element. The gases of interest are measured simultaneously and, further, can be measured independently or non-independently. Furthermore, optical or electronic element are provided to balance optical intensities between the two optical paths.

대표청구항 ▼

[ What is claimed is:] [8.] A multi-gas sensor for simultaneously measuring the concentration of two or more gases of interest within a measurement path, comprising:a polarization modulator for modulating a polarized light beam, the light beam having passed through the measurement path, over a broad

[ What is claimed is:] [8.] A multi-gas sensor for simultaneously measuring the concentration of two or more gases of interest within a measurement path, comprising:a polarization modulator for modulating a polarized light beam, the light beam having passed through the measurement path, over a broadband of wavelengths between two alternating orthogonal polarization components;a polarization beam splitter for switching the polarization modulated beam by transmitting one orthogonal polarization component of the polarization modulated light beam along a first optical path and reflecting the other orthogonal polarization component of the polarization modulated light beam along a second optical path;at least one spectral discrimination means located in at least one of the first and second optical paths, each spectral discrimination means having spectral absorption features of one or more gases of interest;means for intersecting the two optical paths at an intersection point;a beam combiner located at the intersection point of the first and second optical paths, the beam combiner transmitting one orthogonal component of the intersected components and reflecting the other orthogonal component, whereby a combined polarization modulated beam is formed comprising the two orthogonal components in alternate order;means for partitioning the combined polarization modulated beam into a detection path for each wavelength region of interest corresponding to an absorption band for the gases of interest;a detector in each detection path for receiving the incident partitioned beam in the corresponding wavelength region of interest and for sensing a difference in the intensity between the two orthogonal polarization components of the incident partitioned beam as an indication of the spectral emission/absorption of the light beam by the gases of interest in the measurement path, the spectral emission/absorption being indicative of the concentration of the one or more gases of interest in the measurement path; anda control and data acquisition means for exciting the polarization modulator, controlling the temperature of each detector, and processing the output of each detector.