Peter J Lebel

US Patent:

20030206325, Nov 6, 2003

Filed:

Jun 2, 2003

Appl. No.:

10/452654

Inventors:

Glen Sachse - Yorktown VA, US
Peter Lebel - Newport News VA, US
Tommy Steele - Yorktown VA, US
Mauro Rana - Hampton VA, US

International Classification:

G02F001/03
G02F001/07
G02F001/01

US Classification:

359/246000, 359/247000, 359/252000

Abstract:

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 means, with each spectral discrimination means 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 means, and detection means. The gases of interest are measured simultaneously and, further, can be measured independently or non-independently. Furthermore, optical or electronic means are provided to balance optical intensities between the two optical paths.

US Patent:

60089288, Dec 28, 1999

Filed:

Feb 5, 1998

Appl. No.:

9/019473

Inventors:

Glenn W. Sachse - Yorktown VA
Peter J. LeBel - Newport News VA
Tommy C. Steele - Yorktown VA
Mauro Rana - Hampton VA

Assignee:

The United States as represented by the Administrator of the National
Aeronautics and Space Administration - Washington DC

International Classification:

G02F 103

US Classification:

359246

Abstract:

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.