Arrangement for sensing the wavelength shift of light from a polychromatic light source
AssigneeAlliedSignal Inc.
InventorIvan B. Steiner
Life of this patent
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Abstract
An arrangement for sensing the wavelength shift of light from a polychromatic light source features a tilted concave holographic reflection grating that diffracts light from the light source and disperses the light across the focal plane of the arrangement. A pair of matched detectors disposed behind the focal plane senses the light transmitted by a variable neutral density filter at the focal plane. The difference in output signal electrical currents generated by the detectors is a measurement of the shift in polychromatic wavelength distribution.
Claims16
An arrangement for sensing the wavelength shift of light from a polychromatic light source, comprising:
- a spherical, concave, tilted holographic reflection grating supported by supporting structure and receiving light from the polychromatic light source, said reflection grating dispersing an image chromatically across the focal plane of the arrangement;
- a pair of adjacent detectors disposed behind the focal plane and aligned so that the boundary between the detectors is parallel to the cross-dispersion direction of the light and is located at an initial diffracted effective interferometric wavelength image;
- a variable neutral density filter in the focal plane for providing a transmittance weighting factor at the initial diffracted effective interferometer wavelength so that each of the pair of detectors initially generates identical output signals;
- and
- a shift in the light source wavelength distribution from a calibration set point causing the detectors to generate different output signals, with the difference between the output signals being commensurate with an interferometric wavelength shift.
An arrangement for sensing the wavelength shift of light from a polychromatic light source, comprising:
- a spherical concave, tilted holographic grating that diffracts light from the light source and disperses the light across the focal plane of the arrangement;
- a variable neutral density filter disposed in the focal plane for transmitting the dispersed light;
- a pair of matched detectors disposed behind the focal plane for sensing the transmitted light and for providing corresponding signals;
- and
- means responsive to the signals from the detectors for providing an output signal commensurate with a shift in polychromatic wavelength distribution.
Dependencies are inferred from the claim text.