Abstract:
The invention aims to integrate a two-wave stationary interferometer on a photodetector during fabrication in order to constitute a miniature stationary Fourier transform spectrometer. The interferometer essentially comprises a plate having a first plane face coinciding with an image plane on semiconductor photosensitive elements and a second face that is not parallel to the first face. The second face reflects a wave that has a phase difference relative to the incident wave interfering with it that is a function of the local thickness of the plate.
Abstract:
The present invention relates to an interferometer, comprising at least a beamsplitter (10), at least one end reflector (11) for returning beams (S2, S3), and a set of reflectors (14, 15) for reflecting the beams (S2, S3) between the beamsplitter (10) and the end reflector (11) or the end reflectors, at least some of said set of reflectors (14, 15) being adapted to be rotatable around an axis (ω). Said set of reflectors comprises two angle reflectors (14, 15), constituted by plane reflectors, and the said end reflector (11) is or the end reflectors are an angle reflector constituted by plane reflectors (11′, 11″). An angle line of the end reflector (11) is or the angle lines of end reflectors are arranged perpendicular to an angle line of both of the angle reflectors (14, 15).
Abstract:
An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.
Abstract:
A long-wave infrared hyperspectral sensor device employs a combination of an interferometer with an uncooled microbolometer array camera to produce hyperspectral images without the use of bulky, power-hungry motorized components, making it suitable for UAV vehicles, small mobile platforms, or in extraterrestrial environments. The sensor device can provide signal-to-noise ratios near 200 for ambient temperature scenes with 33 wavenumber resolution at a frame rate of 50 Hz, with higher results indicated by ongoing component improvements.
Abstract:
The tilt-compensated interferometers of the present invention are novel variations of Michelson's interferometer that use tilt- and shear-compensation to provide excellent photometric accuracy even when there are imperfections in the scanning motion used to produce variation of path difference. The tilt-compensation mechanism of the present invention consists of antiparallel reflections from a beamsplitter element and a roof reflector element, which elements are held rigidly in alignment. Several particularly useful embodiments of the invention are described. Other advantages of the present invention include photometric stability and reduced cost because manual alignment is not required. This interferometer has applications in spectrometry, spectral imaging and metrology.
Abstract:
The invention relates to an interferometer comprising a beamsplitter (10), a mirror (11) for retroreflecting beams (S1, S2), at least one pair of mirrors (12, 13) made up of two plane mirrors for reflecting the beams (S1, S2). The pair of mirrors (12, 13) is fitted in a rigid structure (15), which is arranged to rotate around an axis (A). It is characteristic that the beamsplitter (10) is attached to a body (20) supported on the mount and that the axis (A) passes through the body (20). According to a recommended embodiment, the retroreflecting mirror (11) is also attached to the body (20).
Abstract:
An apparatus for effecting spatial Fourier transform spectroscopic detection of light from a surface luminescent object with high sensitivity by use of a quadrangular common path interferometer. The apparatus includes an improvement which consists of an additional imaging optical system which converges a light beam from the specimen so as to enter the beam splitter. The additional imaging optical system is disposed so that an image position is substantially coincident with the position of the second of three mirrors in the apparatus.
Abstract:
A compact holographic SLM spectrometer without an optical diffraction element is provided. The compact holographic SLM spectrometer performs the basic spectrometer function using a spatial light modulator (SLM). The compact holographic SLM spectrometer includes a light source, an input element, a collimator, an SLM, an analysis and detection optics, at least one detector, and a digital and/or analog control device.
Abstract:
A microelectromechanical (MEMS) interferometer is provided. The MEMS interferometer includes a pair of movable mirrors that are positioned along perpendicular axes, wherein each of the pair of movable mirrors is coupled to a mechanism. The mechanism includes an electrostatic actuator driving a displacement amplification mechanism, and the displacement amplification mechanism driving each of the pair of the movable mirrors. The MEMS interferometer includes a beam splitter that is positioned at an intersection of the perpendicular axes extending through each movable mirror and the beam splitter. The MEMS interferometer also includes a metasurface microbolometer placed in line with the beam splitter to measure an intensity of a recombined beam from the pair of movable mirrors.
Abstract:
An interference fringe pattern generator forms an interference fringe pattern from the light rays diffused from a region of an object positioned against a background. A planar array of detector pixels is arranged to capture an image of the interference fringe pattern. A storage medium records information indicative of intensity values of the image of the interference fringe pattern captured by a selected group of pixels of the planar array of detector pixels. The information is recorded as a function of the optical path difference values traversed by the diffused light rays through the interference fringe pattern generator for each of the pixels in the selected group of pixels. A processor determines the spectral characteristics of the object based on the information indicative of the intensity values recorded by the storage medium and the optical path difference values traversed by the diffused light rays.