Method and apparatus for spectrum analysis and encoder
OwnerThomas W. Haglerinventor
Life of this patent
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Abstract
A disc serving as a spatial radiation modulator has dispersed radiation filters thereon. Each filter has a transmittance or reflectance modulation function of the form sin2(mθ+pπ/4), where m is a positive integer and p has one of the four values 0, 1, 2, 3. A radiation beam including selected wavelength components is diffracted into an elongated image dispersed according to wavelength. Different wavelength components are focused onto different filters on the modulator and are encoded by correspond filters. Since the modulation functions of the filters are orthogonal to one another, it is possible to extract the amplitude of each wavelength component after it has been encoded or modulated by corresponding filter from the total detected signal during one measurement.
Claims73
An radiation spectrum analyzer comprising:
- a source providing radiation of a plurality of selected wavelength components;
- first means for collecting and focusing a beam of radiation from the source to form an elongated image dispersed by wavelength along a length of the image onto a plane,
- a two dimensional spatial light modulator rotated about an axis and positioned in said plane so that said image is dispersed along a radial direction, said modulator having dispersed radiation filters at different radii from said axis, said filters modulating the amplitudes of said wavelength components to provide encoded components, wherein said amplitudes of the encoded components changes between three or more distinct levels of contrast when the modulator is rotated about the axis;
- a detector;
- second means for collecting and directing said encoded beam onto said detector;
- and
- means for analyzing signals generated by said detector in response to the encoded beam.
A two dimensional spatial light modulator adapted to be rotated about an axis, said modulator having a plurality of dispersed radiation filters at different radii from said axis for modulating amplitudes of different wavelength components of an incident radiation beam to encode said beam, the amplitude of each component being a smooth unction or a digitized replica of a smooth function of a rotational angle of the modulator about the axis.
A two dimensional spatial light modulator adapted to be rotated about an axis, said modulator having at least one dispersed radiation filter between two different radii from said axis modulating amplitudes of components of an incident radiation beam at or between two different wavelengths when the modulator is rotated about said axis.
A two dimensional spatial light modulator adapted to be rotated about an axis, said modulator having at least one dispersed radiation filter, said at least one filter in the shape of a continuous band around the axis, wherein said band has a width that varies as a function of a rotational angle of the modulator about the axis.
A method for analyzing an radiation spectrum, comprising:
- providing radiation of a plurality of selected wavelength components;
- collecting and focusing a beam of radiation from the source to form an elongated image dispersed by wavelength along a length of the image onto a plane,
- positioning a two dimensional spatial light modulator in said plane and rotating the modulator about an axis so that said image is dispersed along a radial direction, said modulator having dispersed radiation filters at different radii from said axis, said filters modulating the amplitudes of said wavelength components to provide encoded components of an encoded beam, wherein said amplitudes of the encoded components changes between three or more distinct levels of contrast when the modulator is rotated about the axis;
- collecting and directing said encoded beam onto a detector;
- and
- analyzing signals generated by said detector.
A spectrum analyzer for analyzing a sample, comprising:
- a source to provide excitation radiation comprised of a first plurality of wavelength components,
- means for collecting and focusing a beam of radiation from said excitation source to form a first image dispersed by wavelength onto a first plane,
- a first two dimensional spatial light modulator positioned in said first plane, said modulator modulating the amplitude of said first plurality wavelength components to encode said excitation beam,
- said amplitudes being periodically modulated using three or more distinct levels of contrast;
- means for collecting and refocusing said encoded excitation beam onto said sample,
- means for collecting and focusing an emission or scattered beam of radiation from said sample comprised of a second plurality of wavelength components caused by the excitation beam to form a second image dispersed by wavelength onto a second plane,
- a second two dimensional spatial light modulator positioned in said second plane,
- said modulator modulating the amplitude of said second plurality of wavelength components to encode said emission or scattered beam, said amplitudes being periodically modulated using three or more distinct levels of contrast;
- a detector,
- means for collecting and focusing said encoded emission or scattered beam onto said optical detector, and
- means for analyzing a time-based signal generated by said detector.
A spectrum analyzer comprising:
- a source to provide radiation comprised of a plurality of wavelength components,
- a means for collecting and focusing a beam of radiation from said source to form an image dispersed by wavelength onto a plane,
- a two dimensional spatial radiation modulator positioned in said plane, said modulator modulating the amplitude of said wavelength components to encode said beam, said amplitudes being modulated with smooth functions or digitized replicas of smooth functions having three or more distinct levels of contrast,
- a detector,
- means for collecting and refocusing said encoded beam onto said detector, and
- means for analyzing a time-based signal generated by said detector.
Dependencies are inferred from the claim text.