Method and apparatus for spectrum analysis and encoder

A method for analyzing a radiation spectrum, comprising:

• providing radiation having at least one selected spectral component, said component having an intensity, a center wavelength and bandwidth;
• collecting, dispersing and focusing said radiation to form an image dispersed by wavelength along a dispersion axis onto a plane;
• positioning a two dimensional spatial radiation modulator in said plane and rotating said modulator about a rotation axis so that said dispersion axis is substantially along a radial axis, said modulator having at least one radiation filter at a radius from said rotation axis, said filter having a radial width substantially defining the bandwidth of a corresponding spectral component of said radiation, said filter modulating the intensity of said corresponding spectral component substantially independent of said bandwidth to provide an encoded beam comprising at least one encoded component, wherein the amplitude of said encoded component changes between three or more substantially distinct levels of contrast as said modulator is rotated about said rotation axis;
• collecting and directing said encoded beam onto a detector;
• and
• analyzing signals generated by said detector in response to said encoded beam.

A spectrum analyzer for analyzing a sample, comprising:

• at least one source to provide an excitation beam of radiation comprising at least one excitation spectral component, said excitation component having an intensity, a center wavelength and a bandwidth;
• first optics collecting, dispersing and focusing said excitation beam to form an excitation image dispersed by wavelength along a first dispersion axis onto a first plane;
• a first two dimensional spatial radiation modulator rotated about a first rotation axis and positioned in said first plane so that said first dispersion axis is substantially along a radial axis, said first modulator having at least one radiation filter at a radius from said first rotation axis, said filter modulating the intensity of a corresponding excitation component to provide an encoded excitation beam comprising at least one encoded excitation component, wherein the amplitude of said encoded excitation component is a substantially smooth function or changes between three or more substantially distinct levels of contrast as said first modulator is rotated about said first rotation axis;
• second optics collecting, dispersing and focusing said encoded excitation beam onto a sample;
• third optics collecting, dispersing and focusing a response beam of radiation from said sample to form a second image dispersed by wavelength along a second dispersion axis onto a second plane, said response beam comprising at least one response spectral component emitted or scattered in response to said encoded excitation beam, said response component having an intensity, a center wavelength and a bandwidth;
• a second two dimensional spatial radiation modulator rotated about a second rotation axis and positioned in said second plane so that said second dispersion axis is substantially along a radial axis, said second modulator having at least one radiation filter at a radius from said second rotation axis, said filter modulating the intensity of a corresponding response component to provide an encoded response beam comprising at least one encoded response component, wherein the amplitude of said encoded response component is a substantially smooth function or changes between three or more substantially distinct levels of contrast as said second modulator is rotated about said second rotation axis;
• a detector,
• fourth optics collecting, dispersing and focusing said encoded response beam onto said detector, and
• computer analyzing signals generated by said detector in response to said encoded response beam.

A method for analyzing a response beam of radiation from a sample resulting from an excitation beam of radiation, comprising:

• providing an excitation beam of radiation comprising at least one excitation spectral component, said excitation component having an intensity, a center wavelength and bandwidth;
• collecting, dispersing and focusing said excitation beam to form an excitation image dispersed by wavelength along a first dispersion axis onto a first plane,
• positioning a first two dimensional spatial radiation modulator in said first plane and rotating said first modulator about a first rotation axis so that said first dispersion axis is substantially along a radial axis, said first modulator having at least one radiation filter at a radius from said first rotation axis, said filter modulating the intensity of a corresponding excitation spectral component to provide an encoded excitation beam comprising at least one encoded excitation component, wherein the amplitude of said encoded excitation component is a substantially smooth function or changes between three or more substantially distinct levels of contrast as said first modulator is rotated about said first rotation axis;
• collecting and refocusing said encoded excitation beam onto a sample;
• collecting, dispersing and focusing a response beam of radiation from said sample to form a second image dispersed by wavelength along a second dispersion axis onto a second plane, said response beam comprising at least one response spectral components emitted or scattered in response to said encoded excitation beam, said response component having an intensity, a center wavelength and a bandwidth;
• positioning a second two dimensional spatial radiation modulator in said second plane and rotating said second modulator about a second rotation axis so that said second dispersion axis is substantially along a radial axis, said second modulator having at least one radiation filter at a radius from said second rotation axis, said filter modulating the intensity of a corresponding response component to provide encoded response beam comprising at least one encoded response component, wherein the amplitude of said encoded response component is a substantially smooth function or changes between three or more substantially distinct levels of contrast as said second modulator is rotated about said second rotation axis;
• collecting, dispersing and focusing said encoded response beam onto a detector;
• and
• analyzing signals generated by said detector in response to said encoded response beam.

A radiation spectrum analyzer comprising:

• at least one source providing radiation having at least one selected spectral component, said spectral component having an intensity, a center wavelength and a bandwidth;
• first optics collecting, dispersing and focusing said radiation to form an image dispersed by wavelength along a dispersion axis onto a plane;
• a two dimensional spatial radiation modulator rotated about a rotation axis and positioned in said plane so that said dispersion axis is substantially along a radial axis, said modulator having at least one radiation filter at a radius from said rotation axis, said filter having a radial width substantially defining the bandwidth of a corresponding spectral component of said radiation, said filter modulating the intensity of said corresponding spectral component substantially independent of said bandwidth to provide an encoded beam comprising at least one encoded component, wherein the amplitude of said encoded component is modulated as a substantially smooth function of the rotation angle of the modulator about said rotation axis;
• a detector;
• second optics collecting and directing said encoded beam onto said detector, causing the detector to provide an output;
• and
• computer analyzing signals generated by said detector in response to said encoded beam.

A method for analyzing a radiation spectrum, comprising:

• providing radiation having at least one selected spectral component, said spectral component having an intensity, a center wavelength and a bandwidth;
• collecting, dispersing and focusing said radiation to form an image dispersed by wavelength along a dispersion axis onto a plane;
• positioning a two dimensional spatial radiation modulator in said plane and rotating said modulator about a rotation axis so that said dispersion axis is substantially along a radial axis, said modulator having at least one radiation filter at a radius from said rotation axis, said filter having a radial width substantially defining the bandwidth of a corresponding spectral component of said radiation, said filter modulating the intensity of said corresponding spectral component substantially independent of said bandwidth to provide an encoded beam comprising at least one encoded component, wherein the amplitude of said encoded component is modulated as a substantially smooth function of the rotation angle of the modulator about said rotation axis;
• collecting and directing said encoded beam onto said detector;
• and
• analyzing signals generated by said detector in response to the encoded beam.

A method for analyzing a radiation spectrum, comprising;

• providing radiation of at least two selected spectral components;
• collecting, dispersing and focusing said radiation to form an image dispersed by wavelength along a dispersion axis onto a plane,
• positioning a two dimensional spatial radiation modulator in said plane and rotating the modulator about an axis so that said dispersion axis is substantially along a radial axis, said modulator having at least two radiation filters at different radii from said rotation axis, said filters modulating the amplitudes of their corresponding spectral components to provide an encoded beam comprising at least two encoded components, wherein the amplitudes of said encoded components are modulated with imperfect orthogonal modulation functions, wherein at least one of said encoded components having residual interference with another of said encoded components;
• collecting and directing said encoded beam onto a detector so that the detector provides an output;
• and
• analyzing signals generated by said detector to determine first zeroth-order amplitudes of encoded components, said first zeroth-order amplitudes having decoding errors resulting from said residual interference;
• increasing or decreasing the radiation incident on at least one of said filters to provide a modified encoded beam;
• analyzing signals generated by said detector in response to said modified encoded beam to determine modified amplitudes of encoded components;
• comparing at least two of said modified amplitudes to said first zeroth-order amplitudes to determine interference coefficients;
• using said interference coefficients to compensate subsequent zeroth-order amplitudes for said decoding errors.