Spectrally shaped light source
A spectrally-shaped source includes a source that generates a round beam. An optical element transforms the round beam to a rectangular beam. An image forming dispersive device angularly disperses wavelengths and images the rectangular beam at a modulation plane. A pixelated SLM is illuminated by the dispersed wavelengths of the rectangular beam such that each column of illuminated pixels is illuminated by a different wavelength. Toroidal optics projects light directed from the SLM to an output plane and focuses the angularly dispersed wavelengths of the beam so that a selected portion of the optical beam is reflected toward the toroidal optic by the SLM. A controller instructs the pixelated SLM to selectively reflect the portion of the optical beam toward the toroidal optic and to selectively reflect another portion of the beam away from the toroidal optic so as to provide a desired spectral shape.
1 . A spectrally-shaped source comprising:
a near infrared optical source that generates a near infrared optical beam;
a near infrared light input positioned at a near infrared input plane that receives the near infrared optical beam;
a visible to ultraviolet optical source that generates a line-shaped visible to ultraviolet optical beam;
a visible to ultraviolet light input positioned at a visible to ultraviolet input plane that receives the line-shaped visible to ultraviolet optical beam;
an image forming grating positioned in a path of the near infrared optical beam and the line-shaped visible to ultraviolet optical beam, the image forming grating spatially separating a spectrum of light in the near infrared optical beam and a spectrum of light the line-shaped visible to ultraviolet optical beam into spatially separated beams and imaging the line-shaped visible to ultraviolet optical beam to a modulator plane such that the spatially separated beams of the spatially-separated near infrared spectrum is parallel to the spatially separated beams of the spatially-separated visible to ultraviolet spectrum, wherein the near infrared input plane, the visible to ultraviolet input plane, and the modulator plane are different planes and the path of the near infrared optical beam and the path of the line-shaped visible to ultraviolet optical beam is a same optical path;
a pixelated spatial light modulator positioned in the modulation plane, the pixelated spatial light modulator comprising an array of pixels that are illuminated by the spatially separated beams separated by the image forming grating such that each column of illuminated pixels in the array of pixels is illuminated by a different spectral segment of light formed in an image of the line-shaped visible to ultraviolet optical beam such that the image of the line-shaped visible to ultraviolet optical beam matches a shape of a column of pixels; and
toroidal optics positioned after the pixelated spatial light modulator and being configured to collect and focus the optical beam from the modulation plane formed in the image of the line-shaped visible to ultraviolet optical beam to an output plane of the spectrally-shaped source and to focus the spatially separated beams such that they overlap at the output plane, the toroidal optics projecting a selected portion of the optical beam from the modulation plane formed in the image of the line-shaped visible to ultraviolet optical beam that is reflected toward the toroidal optics by the pixelated spatial light modulator to provide an output optical illumination at an output of the spectrally-shaped source that is positioned at the output plane.
2 . The spectrally-shaped source of claim 1 wherein the optical source comprises a laser driven light source.
3 . The spectrally-shaped source of claim 1 wherein the optical source comprises a super continuum fiber laser.
4 . The spectrally-shaped source of claim 1 wherein the image forming grating comprises a single optical element.
5 . The spectrally-shaped source of claim 1 wherein the toroidal optics comprises a single optical element.
6 . The spectrally-shaped source of claim 1 wherein the image forming grating is configured to provide aberration correction of the spectrally-shaped source.
7 . The spectrally-shaped source of claim 1 wherein the pixelated spatial light modulator comprises a digital micromirror device.
8 . The spectrally-shaped source of claim 1 wherein the pixelated spatial light modulator comprises a liquid crystal device.
9 . The spectrally-shaped source of claim 1 further comprising a liquid light guide optically coupled to the output of the spectrally-shaped source.
10 . The spectrally-shaped source of claim 1 further comprising a spectral extension source that generates light in a desired spectrum and an optical coupler that couples the generated light in the desired spectrum to the output of the spectrally shaped source.
11 . The spectrally-shaped source of claim 10 wherein the spectral extension source comprises one or more NIR LED.
12 . The spectrally-shaped source of claim 1 wherein the pixelated spatial light modulator further comprises an order-sorting filter.
13 . A method of spectrally shaping, the method comprising:
generating a near infrared optical beam at a near infrared input plane;
generating a line-shaped visible to ultraviolet optical beam at a visible to ultraviolet input plane;
spatially separating a spectrum of light in the near infrared optical beam and a spectrum of light in the line-shaped visible to ultraviolet optical beam into spatially separated beams and imaging the line-shaped visible to ultraviolet optical beam to a spatial light modulator plane such that the near infrared spectrum is parallel to the visible to ultraviolet spectrum, wherein the near infrared input plane, the visible to ultraviolet input plane, and the modulator plane are different planes and the path of the near infrared optical beam and the path of the line-shaped visible to ultraviolet optical beam is a same optical path;
spatially modulating the imaged spatially separated spectrum of light in the near infrared optical beam and the spatially separated spectrum of light in the line-shaped visible to ultraviolet optical beam using a pixelated spatial light modulator so that the pixelated spatial light modulator reflects a desired selected portion of the imaged spatially separated spectrum of light in the near infrared optical beam and the spatially separated spectrum of light in the line-shaped visible to ultraviolet optical beam toward toroidal optics, wherein a column of pixels in the spatial light modulator array selectively reflects a desired portion of light illuminating the column of pixels toward the toroidal optic; and
projecting the selected portion of the imaged spatially separated spectrum of light in the near infrared optical beam and the spatially separated spectrum of light in the line-shaped visible to ultraviolet optical beam with the toroidal optics to an output.
14 . The method of claim 13 wherein the spatial modulating is performed to reflect the desired selected portion of the optical beam toward the toroidal optic so that at least two columns of pixels in the array of pixels are illuminated at a same height.
15 . The method of claim 13 wherein the spatial modulating is performed so that a desired spectral shape of the output optical illumination is provided.
16 . The method of claim 13 further comprising coupling light from a spectral extension source with a desired spectrum to the output.
17 . The method of claim 16 wherein the desired spectrum is in the near infrared region of the spectrum.
18 . The spectrally-shaped source of claim 1 wherein the visible to ultraviolet light source comprises a multi-strand fiber bundle.
19 . The spectrally-shaped source of claim 1 wherein the near infrared optical source comprises a point source.