Abstract: Systems, including methods, apparatus, and algorithms, for spectrally imaging a two-dimensional array of samples.

Abstract: A spectrometer system includes an array of micro-zone plates (MZP) each having coaxially-aligned ring gratings, a sample plate for supporting and illuminating a sample, and an array of photon detectors for measuring a spectral characteristic of the predetermined wavelength. The sample plate emits an evanescent wave in response to incident light, which excites molecules of the sample to thereby cause an emission of secondary photons. A method of detecting the intensity of a selected wavelength of incident light includes directing the incident light onto an array of MZP, diffracting a selected wavelength of the incident light onto a target focal point using the array of MZP, and detecting the intensity of the selected portion using an array of photon detectors. An electro-optic layer positioned adjacent to the array of MZP may be excited via an applied voltage to select the wavelength of the incident light.

Abstract: A spectrometer includes a micro-ring grating device having coaxially-aligned ring gratings for diffracting incident light onto a target focal point, a detection device for detecting light intensity, one or more actuators, and an adjustable aperture device defining a circular aperture. The aperture circumscribes a target focal point, and directs a light to the detection device. The aperture device is selectively adjustable using the actuators to select a portion of a frequency band for transmission to the detection device. A method of detecting intensity of a selected band of incident light includes directing incident light onto coaxially-aligned ring gratings of a micro-ring grating device, and diffracting the selected band onto a target focal point using the ring gratings. The method includes using an actuator to adjust an aperture device and pass a selected portion of the frequency band to a detection device for measuring the intensity of the selected portion.

Abstract: Systems, including methods, apparatus, and algorithms, for spectrally imaging a two-dimensional array of samples.

Abstract: A biosensor detection apparatus having increased processing power for measurement without complicated structure and increased size. The apparatus includes one or more spectrometers configured to spectrally separate each light beam reflected from each of a plurality of measurement regions defined on a biosensor simultaneously, and one or more optical receivers configured to receive each light beam spectrally separated by the one or more spectrometers simultaneously and to obtain a spectral intensity distribution of each light beam separately.

Abstract: Digital cameras for spectrally imaging an object or scene comprise an imaging component, a fixed one-dimensional disperser and an image sensor having sensor pixels, the disperser and image sensor arranged with matching optical parameters and in a predetermined spatial relationship. Each sensor pixel detects multiplexed spectral information from at least two adjacent object points and the spectral information detected by each sensor pixel is demultiplexed and processed into spectral-spatial data to provide spectral images.

Abstract: The invention relates to angle-limiting optical reflectors and optical dispersive devices such as optical spectrum analyzers using the same. The reflector has two reflective surfaces arranged in a two-dimensional corner reflector configuration for reflecting incident light back with a shift, and includes two prisms having a gap therebetween that is tilted to reflect unwanted light and transmit wanted light. A two-pass optical spectrum analyzer utilizes the reflector to block unwanted multi-pass modes that may otherwise exist and degrade the wavelength selectivity of the device.

Abstract: Generation of a meta-model for scatterometry analysis of a sample diffracting structure having unknown parameters. A training set comprising both a spectral signal evaluation and a derivative of the signal with respect to at least one parameter across a parameter space is rigorously computed. A neural network is trained with the training set to provide reference spectral information for a comparison to sample spectral information recorded from the sample diffracting structure. A neural network may be trained with derivative information using an algebraic method wherein a network bias vector is centered over both a primary sampling matrix and an auxiliary sampling matrix. The result of the algebraic method may be used for initializing neural network coefficients for training by optimization of the neural network weights, minimizing a difference between the actual signal and the modeled signal based on a objective function containing both function evaluations and derivatives.

Abstract: A Spectrometer is provided including a camera and an axial symmetric camera mount configured to receive the camera and to rotate. The spectrometer furthers include an input for providing optical radiation to a spectrometer system; a diffraction grating for dispersing the optical radiation along a prescribed plane; at least one lens for focusing wavelength-dispersed light onto at least one array of a detector of optical radiation, wherein the camera has at least one linear array of elements for detecting optical radiation; a mechanical housing, wherein the axial symmetric camera mount is configured to couple the camera to the mechanical housing; and a means for rotating the camera coupled to the mechanical housing about an axis. Related systems and methods are also provided.

Abstract: The invention is directed to a highly sensitive spectrum analysis unit with a diffraction grating, wherein a parallel light bundle having a wavelength range impinges on a diffraction grating which splits the different wavelengths into spectra by diffraction in first directions, and wavelength partial ranges of the spectrally split light bundle can be focused on a detector row by means of camera optics, and evaluation electronics are connected to the detector row and acquire the generated spectrum as information and display it. The invention is characterized in that the light bundle passes a first optical element, and then wavelength partial ranges of a spectrally split light bundle impinge on respective partial regions of a diffraction grating, the diffraction grating having the same grating constant across all partial regions and a changing profile shape, the profile shapes generating different blaze wavelengths that lie in the respective wavelength partial ranges.

Abstract: An optical coupling relay system has an imaging optical system having an object plane, an exit pupil and an image plane. An image analyzer has an image plane and an entrance pupil, and a detector is located in a detector plane and contains photosensitive material. An optical coupling relay couples the optical system to the image analyzer, for projecting the image produced by the imaging optical system into the image plane of the image analyzer and simultaneously for projecting the exit pupil of the imaging optical system into the entry pupil of the image analyzer.

Abstract: An optical characterisation system is described for characterising optical material. The system typically comprises a diffractive element (104), a detector (106) and an optical element (102). The optical element (102) thereby typically is adapted for receiving an illumination beam, which may be an illumination response of the material. The optical element (102) typically has a refractive surface for refractively collimating the illumination beam on the diffractive element (104) and a reflective surface for reflecting the diffracted illumination beam on the detector (106). The optical element (102) furthermore is adapted for cooperating with the diffractive element (104) and the detector (106) being positioned at a same side of the optical element (102) opposite to the receiving side for receiving the illumination beam.

Abstract: A spectral photoelectric measurement transformer comprises an array (10) of photoelectric transformer elements and dielectric interference bandpass filters (22a, 22b) disposed on a common filter support (21) connected upstream of them for sensitizing the transformer elements to different wavelength ranges of the measurement light. The bandpass filters are divided into a number of filter groups, each of which contains the same different bandpass filters within the filter group. An optical deflector element (30) spectrally shifts the effective bandpass curves of the bandpass filters of all the filter groups except one so that the effective bandpass curves of all the bandpass filters have different spectral positions. As a result, a multiplication of the filter channels effectively made available can be achieved using only a few different bandpass filters. Due to the small number of different bandpass filters, the measurement transformer is inexpensive to manufacture.

Abstract: The present invention provides a grating photometer comprising a light splitting box, a preamplifier box, a photodiode array and optical assembly. The light splitting box has a light splitting chamber. There are provided a first extinction hole and second extinction hole respectively on the side wall of the light splitting chamber and on the preamplifier box to correspond to zero order spectrum line. The first hole is a through hole and the second hole is a blind hole. The configuration of the first and second extinction holes direct the zero order spectrum to go into the second extinction hole, as a result, generates a rather small number of stray light in the light splitting chamber coming from the scattering of the zero order spectrum from the second extinction hole, thus suppresses effectively the stray light and improves the signal-to-noise ratio of the photometer.

Abstract: A sensor assembly including a detector; a first arrangement for enhancing the resolution of the detector; and a second arrangement for increasing the field-of-view of the detector. In a specific implementation, the detector is a focal plane array of detectors, the first arrangement is a Hadamard mask and the second arrangement is a telescope array with a field-bias element operationally coupled thereto. The field bias optical element is implemented with a prism and grating such as a grism. An arrangement is included for actuating the mask to selectively enable a desired level of resolution and another arrangement is included for actuating the field bias element to select a desired field of view. An arrangement for effecting image motion compensation is included along with an imager, an image processor and a data processor. The telescope array may include refractive elements, reflective elements, and/or catadioptric elements. Likewise, the imager may be refractive, reflective and/or catadioptric.

Abstract: The present application discloses a system comprising a compact curved grating (CCG) and its associated compact curved grating spectrometer (CCGS) or compact curved grating wavelength multiplexer/demultiplexer (WMDM) module and a method for making the same. The system is capable of achieving a very small (resolution vs. size) RS factor. In the invention, the location of the entrance slit and detector can be adjusted in order to have the best performance for a particular design goal. The initial groove spacing is calculated using a prescribed formula dependent on operation wavelength. The location of the grooves is calculated based on two conditions. The first one being that the path-difference between adjacent grooves should be an integral multiple of the wavelength in the medium to achieve aberration-free grating focusing at the detector or output slit (or output waveguide) even with large beam diffraction angle from the entrance slit or input slit (or input waveguide).

Abstract: To provide a highly-reliable spectroscopy module. In a spectroscopy module 1, a light passing hole 5b through which a light L1 advancing to a spectroscopic portion 4 passes is formed in a light detecting element 5. Therefore, it is possible to prevent the relative positional relationship between the light passing hole 5b and a light detecting portion 5a of the light detecting element 5 from deviating. Moreover, the light to be measured L1 advancing to the spectroscopic portion 4 via the light passing hole 5b and the diffracted lights L2 advancing to the light detecting portion 5a from the spectroscopic portion 4 pass through a void formed between the light detecting element 5 and the substrate 2 by an opening portion 10a of a wiring substrate 10. Thereby, it is possible to prevent a situation in which the light to be measured L1 and the diffracted lights L2 are scattered or the like due to a resin adhesive 16 or the like interposed between the light detecting element 5 and the substrate 2.

Abstract: A system and method processes a structure comprising embedded material. The system includes a laser adapted to generate light and to irradiate an interaction region of the structure. The system further includes an optical system adapted to receive light from the interaction region and to generate a detection signal indicative of the presence of embedded material in the interaction region. The system further includes a controller operatively coupled to the laser and the optical system. The controller is adapted to receive the detection signal and to be responsive to the detection signal by selectively adjusting the laser.

Abstract: In the spectrometer 1, a lens portion 3 having a spherical surface 35 on which a spectroscopic portion 4 is provided and a bottom plane 31 in which a light detecting element 5 is disposed, has a side plane 32 substantially perpendicular to the bottom plane 31 and a side plane 34 substantially perpendicular to the bottom plane 31 and the side plane 32. Then, a package 11 that houses a spectroscopy module 10 has side planes 16 and 18 respectively coming into planar-contact with the side planes 32 and 34, and contact portions 22 coming into contact with the spherical surface 35. Therefore, the side planes 32 and 34 of the lens portion 3 are respectively brought into planar-contact with the side planes 16 and 18 of the package 11 while bringing the spherical surface 35 of the lens portion 3 into contact with the contact portions 22 of the package 11, that positions the spectroscopic portion 4 and the light detecting element 5 with respect to a light incident window plate 25 of the package 11.

Abstract: A grating-based biosensor is disclosed where the biosensor is constructed and arranged such that the grating lines of the sensor align with an optical axis of a birefringent substrate, so as to improve resonance peak uniformity. Methods of manufacturing biosensors to provide alignment of the grating lines with the optical axes of a birefringent substrate are also disclosed. One embodiment uses a grating master wafer to form a grating on a continuous web of substrate material. The grating master wafer is rotated relative to the web until the lines of the grating in the master wafer are in substantial alignment with the optical axis of the web. A UV curable material is applied to the wafer and cured in place to form the grating on the surface of the substrate web. With a web of some preferred materials, such as PET film, one need only determine the optical axis orientation once for a given web since the optical axis orientation is essentially constant along the length of the web.

Abstract: The invention relates to a device for the positioning of optical elements with retractable stop enabling accurate positioning of an optical element selected among a plurality of optical elements, including a stand (1); a turret fitted with a element holder and a disc (4), said disc (4) being a ratchet wheel having a peripheral surface (5) fitted with a plurality of blocking means (6), each blocking means (6) corresponding to an optical element, a motor (7) and a crash stop (9) bearing against the peripheral surface of the disc (5). According to the invention the stop (9) contains an anti-friction element (13) in contact with the peripheral surface (5) of the ratchet wheel so that the retractable stop (9) moves according to the contour of the peripheral surface (5) of the ratchet wheel without any friction.

Abstract: An optical wavemeter includes a slit, a diffraction grating, a mask, a complementary grating, and a detector. A monochromatic source is incident on the slit. The diffraction grating produces an image of the slit in an image plane at a horizontal position that is wavelength dependent. The mask has a two-dimensional pattern of transmission variations and produces different vertical intensity channels for different spectral channels. The complementary grating produces a stationary image of the slit independent of wavelength. The detector measures vertical variations in intensity of the stationary image, and the mask is created so that the number of measurements made by the detector is less than the number of spectral channels sampled.

Abstract: A spectrometer apparatus includes a refractor element, a slit, a detector, a diffraction grating, and a corrector lens. The refractor element includes a rear surface and a front surface. The slit provides an optical path to the rear surface of the refractor element, and is configured to transmit an image incident thereupon along the optical path. The detector is positioned facing the rear surface of the refractor element. The diffraction grating faces the front surface of the refractor element, and is configured to spectrally disperse and reimage the image of the slit toward the front surface of the refractor element. The corrector lens is positioned between the refractor element and the diffraction grating such that the image is provided to the detector corrected for a spherical aberration caused by a separation distance between the detector and the rear surface of the refractor element.

Abstract: A single detector based spectroscopy system using FAST (fiber array spectral translator) fibers and two excitation sources in conjunction with a holographic spectrum analyzer (HSA) to obtain simultaneous and selective display of spectroscopic regions of interest. A sample can be illuminated with different laser excitation wavelengths and resulting multiple spectra can be comparatively observed on a single display screen for more fruitful analysis of sample spectral responses (and, hence, sample chemical or physical properties) under different excitations. The HSA may be configured to focus on user-selected spectral regions of interest from different such spectra and a single CCD detector may be configured to collect spectral data from all selected spectral regions of interest in corresponding portions of the CCD pixel array, thereby allowing subsequent simultaneous display of such selected spectral regions of interest.

Abstract: An improvement is added to a spectroscope for performing wavelength dispersion of measured light with a wavelength dispersion element and receiving the light at a light reception element. The spectroscope has a first compound lens made up of a plurality of lenses for converting measured light into parallel light and emitting the parallel light to the wavelength dispersion element; a second compound lens made up of a plurality of lenses for gathering the measured light subjected to the wavelength dispersion in the wavelength dispersion element and causing the light reception element to receive the light; and a base for fixing the wavelength dispersion element, the first compound lens, and the second compound lens. The linear expansion coefficient of the compound focal length of the first compound lens, the linear expansion coefficient of the compound focal length of the second compound lens, and the linear expansion coefficient of a material forming the base are substantially equal.

Abstract: An optical reader system is described herein that uses a scanned optical beam to interrogate a biosensor to determine if a biomolecular binding event occurred on a surface of the biosensor. In one embodiment, the optical reader system includes a light source, a detector and a processor (e.g., computer, DSP). The light source outputs an optical beam which is scanned across a moving biosensor and while this is happening the detector collects the optical beam which is reflected from the biosensor. The computer processes the collected optical beam and records the resulting raw spectral or angle data which is a function of a position (and possibly time) on the biosensor. The processor can then analyze the raw data to create a spatial map of resonant wavelength (peak position) or resonant angle which indicates whether or not a biomolecular binding event occurred on the biosensor. Several other uses of the raw data are also described herein.

Abstract: A robust, compact spectrometer apparatus for determining respective concentrations or partial pressures of multiple gases in a gas sample with single as well as multiple and even overlapping, absorption or emission spectra that span a wide spectral range.

Abstract: A spectrometer 1A is made up of: an optical body 10 within which a light separation path is set along which an object light to be separated propagates; a light entry slit 16 through which the object light enters; a diffraction grating 17 for spectrally separating the incident object light; and a photodiode array 18 for detecting the object light separated by the diffraction grating 17. As an optical member for optically interconnecting the optical body 10 and the photodiode array 18, an optical connection member 20 is provided, with its light entry surface 21 for the separated object light in contact with the upper surface 11 of the optical body 10, with its light exit surface 22 in contact with the photodiode array 18, with the light exit surface 22 tilted by a specified angle relative to the light entry surface 21. Thus, the spectrometer capable of bringing about sufficient accuracy of placing optical elements in a simple constitution while bringing down cost is realized.

Abstract: Optical device comprising: a spatial filter means for eliminating, from the light rays emanating from an observed scene those coming from a direction or restricted range of directions in space, while letting through most of the light rays coming from said scene; means for varying the direction or the restricted range of directions in space in correspondence with which the spatial filter means eliminates said light rays; a spectral dispersion means for imparting to the light rays coming from said spatial filter means a deviation that is dependent on their wavelength; and an image detector for recording the light rays dispersed by said spectral dispersion means, each point on said image detector receiving light rays coming from said scene and having a different wavelength depending on the direction in space from which they come.

Abstract: A spectrometer comprising a collimating element for receiving input light and collimating the same, a dispersive optical element for receiving light from the collimating element and dispersing the same and a focusing element for receiving light from the dispersive optical element and focusing the same on a detector assembly wherein, where the wavelength dispersion of the dispersed light extends in the x-y direction, the collimating element and the focusing element are formed so as to maintain the desired optical parameters in the x-y plane while having a reduced size in the z direction.

Abstract: A method for estimating a property of a fluid downhole is disclosed, the method including but not limited to exposing the fluid to light downhole; directing different wavelengths of light that have interacted with the fluid light toward a first optical grating; measuring light at different wavelengths reflected from the first optical grating; and estimating a property of the fluid from the measured light. An apparatus for estimating a property of a fluid downhole is disclosed, the apparatus including but not limited to a downhole tool for estimating a property of a fluid downhole, including but not limited to a light source that illuminates the fluid downhole; a first optical grating having a plurality of elements that selectively light that have interacted with the fluid; and a sensor that measures the light reflected from the first optical grating elements.

Abstract: A spectrometer having a housing, where the housing also includes a structure located within the housing, the structure being adapted to hold a reflective dispersive element and being movable in a direction substantially perpendicular to an interior longitudinal axis. An actuator arm extends from a location exterior to the housing to another location inside the housing. The actuator arm is disposed through an opening in the housing and is operatively connected to the structure. A cryogenic actuator motor is operatively connected to the actuator arm, thereby enabling movement of the structure and the reflective dispersive element in a direction substantially perpendicular to said interior longitudinal axis, whereby alignment of the spectrometer is enabled.

Abstract: A spectrometer apparatus includes a refractor element, a slit, a detector, a diffraction grating, and a corrector lens. The refractor element includes a rear surface and a front surface. The slit provides an optical path to the rear surface of the refractor element, and is configured to transmit an image incident thereupon along the optical path. The detector is positioned facing the rear surface of the refractor element. The diffraction grating faces the front surface of the refractor element, and is configured to spectrally disperse and reimage the image of the slit toward the front surface of the refractor element. The corrector lens is positioned between the refractor element and the diffraction grating such that the image is provided to the detector corrected for a spherical aberration caused by a separation distance between the detector and the rear surface of the refractor element.

Abstract: Described herein are systems and methods of tomographic imaging using hyperspectral absorption spectroscopy, which may comprise simultaneously performing absorption measurements at multiple different wavelengths and then performing a tomographic inversion process to exploit the hyperspectral absorption spectroscopy information obtained. The methods and systems described herein can be used to a) exploit the hyperspectral information content to reduce the number of projections required and to improve the stability of the tomographic reconstruction in the presence of measurement errors, b) enable flexible incorporation of various a priori information, c) ameliorate the ill-posedness of the tomographic inversion problem. These advantages are useful in the practical application of tomographic techniques.

Abstract: A novel scanning monochromator uses a PM stepper-motor to directly drive a diffraction grating. By employing interpolated encoder feedback in combination with the PM stepper-motor feedback, a resolution of over 250,000 pulsed steps is available for each revolution of the PM stepper-motor. This translates into more than 20,000 incremental angular-displacement steps over a usable 30° range of dispersion-element rotation. High field accuracy is achieved by a direct PM stepper-driven diffraction grating, and a unique calibration approach based on Wood's anomalies. A plurality of diffracted light beams emerge from the oscillating grating, and these are scanned past a detector for detection, whereby the relative rotation information of the grating can be detected with great accuracy. A number of tolerance-correcting measures are also included to yield an extremely accurate, self-lubricating scanning monochromator that can be economically produced.

Abstract: Various embodiments include spectrometers comprising diffraction gratings monolithically integrated with other optical elements. These optical elements may include slits and mirrors. The mirrors and gratings may be curved. In one embodiment, the mirrors are concave and the grating is convex. The mirrors and grating may be concentric or nearly concentric.

Abstract: Apparatus for inspecting a surface of a sample, including a detector and folding optics. The folding optics are configured to receive radiation arising from a first region of the surface and from a second region of the surface. The first region and the second region have a first spatial relationship with respect to each other. The folding optics form from the radiation a first image of the first region and a second image of the second region on the detector, wherein the first image is a linear transformation of the first region and the second image is the linear transformation of the second region. The first image and the second image have a second spatial relationship, different from the linear transformation of the first spatial relationship, with respect to each other.

Abstract: A method is provided for calibrating a spectrometer device used for Raman scattering analysis. A predetermined dispersion curve for a diffraction grating or spectrograph of the spectrometer device is modified based on spectrum data associated with detected dispersed light from a calibration light source to produce a modified dispersion curve. The wavelength of a Raman light source on a light detection device is determined. Calibration data for the spectrometer device is computed from the Raman line peak positions for the first chemical, the wavelength on the detection device of the Raman light source and the modified dispersion curve.

Abstract: An optical spectroscopy tool is provided. In one embodiment a highly efficient means by which moderate resolution spectroscopy may be performed in the vacuum ultraviolet (VUV) is described. In one embodiment the techniques can be used as a high throughput spectrometer to spatially disperse wavelengths in and around the VUV in such a manner as to generate a substantially flat field focal plane, suitable for use in combination with an array detector. Some embodiments utilize prism based spectrometers. Some embodiments utilize detector elements that may be movable and/or located within the spectrometer. In some embodiments, collimated light may be provided as an input to the spectrometer.

Abstract: A method and apparatus are provided for determining a property of a fluid downhole by using a tunable optical grating to collect a fluid's spectrum over a wavelength region of interest. A property of the fluid is estimated from spectra that are obtained from light that has interacted with the fluid and then been reflected off of the tunable optical grating onto a photodetector.

Abstract: A planar nanospectrometer formed as a single chip that uses diffraction structures, which are combinations of numerous nano-features placed in a predetermined configuration and providing multiple functionalities such as guiding light, resonantly reflecting light at multiple wavelengths, directing light to detectors, and focusing light on the detectors. The diffraction structure can be described as a digital planar hologram that comprises an optimized combination of overlaid virtual sub-gratings, each of which is resonant to a single wavelength of light. Each device includes at least one sensor, at least one light source, and at least one digital planar hologram in an optical waveguide. The device of the present invention allows detection of small amounts of analytes in gases and liquids or on solid surfaces and can be particularly advantageous for field analysis of environmental safety in multiple locations because of its miniature size and low cost.

Abstract: A spectroscope includes a diffraction grating having a plurality of ruled parallel lines; and a plurality of spectroscopic paths, each of which has a collimator for collimating incident light, emits the collimated light to the diffraction grating, and emits return light, which returns from the diffraction grating, through a slit provided on the path. In the spectroscope, measured light is emitted through the plurality of spectroscopic paths so as to extract light which is included in the measured light and has a predetermined wavelength; and the collimators of the spectroscopic paths are arranged so that irradiation areas of light emitted from the collimators are offset from each other at least in a direction along the ruled parallel lines. The collimators of the spectroscopic paths may be arranged so that incident angles of light emitted from the collimators coincide with each other.

Abstract: Systems and techniques for improved spectroscopy. In some embodiments, mechanical and/or optical zoom mechanisms may be provided for monochromator systems. For example, movable detector systems allow a detector to be positioned with respect to a dispersive element in order to obtain a first resolution. The detector systems may then allow the detector to be positioned with respect to a dispersive element to obtain a second different resolution. In some embodiments, spectroscopy of a first sample region may be performed using a plurality of excitation wavelengths. Multiple detectors may be positioned to receive light associated with different ones of the plurality of excitation wavelengths.

Abstract: A system mounted in a vehicle for classifying light sources. The system includes a lens and a spatial image sensor. The lens is adapted to provide an image of a light source on the spatial image sensor. A diffraction grating is disposed between the lens and the light source. The diffraction grating is adapted for providing a spectrum. A processor is configured for classifying the light source as belonging to a class selected from a plurality of classes of light sources expected to be found in the vicinity of the vehicle, wherein the spectrum is used for the classifying of the light source. Both the image and the spectrum may be used for classifying the light source or the spectrum is used for classifying the light source and the image is used for another driver assistance application.

Abstract: Computed tomography imaging spectrometers (“CTISs”) employing a single lens are provided. The CTISs may be either transmissive or reflective, and the single lens is either configured to transmit and receive uncollimated light (in transmissive systems), or is configured to reflect and receive uncollimated light (in reflective systems). An exemplary transmissive CTIS includes a focal plane array detector, a single lens configured to transmit and receive uncollimated light, a two-dimensional grating, and a field stop aperture. An exemplary reflective CTIS includes a focal plane array detector, a single mirror configured to reflect and receive uncollimated light, a two-dimensional grating, and a field stop aperture.

Abstract: A calibrated spectroscopy instrument and a method for calibrating a spectroscopy instrument are disclosed. The spectroscopy instrument includes a monochromator having a drive mechanism comprising a pair of spur gears for rotating a diffraction grating of the monochromator for selecting a desired wavelength. The drive mechanism is calibrated to account for eccentricities in the spur gears to provide an accurate conversion between selected angular settings for the drive mechanism and the wavelength of the diffracted light from the monochromator. The drive mechanism comprises a pinion spur gear and a main spur gear which each have an AGMA (American Gear Manufacturers' Association) rating of at least 10, which allows errors due to random tooth to tooth variations to be neglected. A calibration algorithm is derived which is based on the error due to eccentricities in the spur gears following a precise geometric cyclic pattern.

Abstract: A method and apparatus for characterizing the spectral response function of hyperspectral electro-optical instruments or imaging spectrometers are provided. The system includes a test instrument that provides energy comprising multiple discrete wavelengths to the entrance slit of an instrument under test simultaneously. The provided energy can be scanned in the spectral dimension by changing the optical distance between the plates of a Fabry-Perot etalon incorporated into the test instrument. In addition, the energy provided to the instrument under test can be scanned in the spatial dimension by changing the location along the slit of the instrument under test at which the energy from the test instrument is provided.

Abstract: In a method and apparatus for detecting optical spectra, two or more partial beams are generated from an incident beam, each of said partial beams being assigned to a different spectral region. The partial beams travel through a spectrometer lens system and are detected in a spatially separated manner. For this purposes, the partial beams generated from the incident beam are directed to respective spatially separated diffraction gratings that are virtually superimposed in the beam path, and are assigned to different spectral regions. After passing through the diffraction gratings, the spectrally separated partial beams are combined to a joint beam path traveling through the spectrometer lens system. Preferably, the partial beams comprising the different spectral regions can be spectrally separated after passing through the spectrometer lens system and can be detected in spatially separated detectors assigned to the different spectral regions.

Abstract: A compact and robust imaging Raman spectrograph has a collimating input lens assembly, a spectral filter assembly, a transmission diffraction grating, a focusing lens assembly, and a light detector. The spectral filter assembly is located between the two lenses and comprises a notch or long-pass filter optical interference filter, a plurality of optical channel plates for limiting the optical acceptance angle of the light passing the optical interference filter, and a transmission diffraction grating, all mounted in a single assembly. The spectral filter assembly permits a very high degree of elastically scattered light rejection and excellent stray-light reduction and management, while permitting a high level of optical throughput to maximize the signal of the weakly scattered Raman signal.

Abstract: A method and apparatus for accurately retrieving the position of an optical feature. The method uses the optical properties of biaxial crystals to conically refract the optical feature and transform the image of the optical feature to a circular ring structure. The position of the optical feature is then calculated by locating a center point associated with the circular ring structure.