Abstract: An optical spectrum analyzer includes an optical section 130 for executing light dispersion into a spectrum and wavelength sweep for input measured light, converting the measured light into an electric signal, and outputting the electric signal, a control section 101 for controlling the wavelength sweep of the optical section and outputting a sampling clock of a period shifting from a cycle period of the measured light for each wavelength of the wavelength sweep, and a measurement section 140 for executing sequential sampling of the electric signal from the optical section for each sampling clock.

Abstract: A light scanning type confocal microscope includes a light source unit that projects an excitation light beam, a scanning optical system that scans the excitation light beam, an objective lens that applies the excitation light beam to a sample, a separation optical element that separates the excitation light and detection light generated by the sample, a confocal detection unit that obtains a confocal effect, and a spectral detection device that spectrally detects the detection light. The spectral detection device has a spectroscopic element that spectrally separates the detection light, a light extracting unit that extracts light in a wavelength band from the light spectrally separated by the spectroscopic element, a detector that detects the light extracted by the light extracting unit, and a wavelength band shifting unit that shifts a wavelength band of light to be extracted by the light extracting unit.

Abstract: A monochromator for use in a spectrograph admits light from an aperture to a primary reflector (preferably an off-axis parabolic mirror) which collimates the input light with low aberration and directs it to a diffraction grating. The component wavelengths of the input light are then directed to first and second secondary reflectors (preferably spherical or toroidal mirrors), which are chosen to cooperatively focus the component wavelengths in ordered bands across an array detector while each at least substantially cancels the effects of any aberrations introduced by the other. By choosing optical elements which supply the grating with input light with low aberration, and then choosing optical elements which receive the component wavelengths from the grating and which offset any aberrations introduced by the other receiving optical elements, wavelength resolution at the detector can be enhanced.

Abstract: A spectrophotometer having an optical system for directing a beam of substantially monochromatic excitation light to a liquid sample contained in a well (3) of a well plate for interaction with the sample for absorption or emission measurements to analyse the sample. The optical system includes two apertures (46, 28) for establishing a Kohler illumination region outside the well, that is an excitation beam region between conjugate images (18, 21) of the two apertures. This excitation beam region is then demagnified and imaged (10, 9) into the well (3). The invention provides for the shape of the Kohler illumination region to correspond to the shape of the well space so that all of the liquid sample is uniformly illuminated without the well obstructing any portion of the illuminating excitation beam of light.

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 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 transmission mask or cooled aperture is used in spectroscopy to compressively sample an optical signal. The locations of transmissive and opaque elements of the mask are determined by a transmission function. The optical signal transmitted by the mask is detected at each sensor of a plurality of sensors dispersed spatially with respect to the mask. A number of estimated optical signal values is calculated from sensor measurements and the transmission function. The optical signal is compressed by selecting the transmission function so that the number of measurements is less than the number of estimated optical signal values. A reconstructed optical signal is further calculated using signal inference. An imaging system created from plurality of encoded subimaging systems compressively samples an optical signal.

Abstract: The present invention discloses a system comprising a compact curved grating (CCG) and its associated compact curved grating spectrometer (CCGS) module and a method for making the same. The system is capable of achieving very small (resolution vs. size) RS factor. In the invention, the location of 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 and the second one being specific for a particular design goal of a curved-grating spectrometer. In an embodiment, elliptical mirrors each with focal points at the slit and detector are used for each groove to obtain aberration-free curved mirrors.

Abstract: Devices and methods for processing multi-wavelength light beams and the single-wavelength components of such light beams are disclosed. In accordance with some embodiments, a spectral filter includes collimating and focusing optical elements, an apodizing filter, a diffraction grating, and a spatial filter. The collimating optical element collimates an input light beam while the apodizing filter spatially filters this beam. In general, the apodizing filter includes a range of transmissivity that varies according to a distance from a predetermined location on the apodizing filter. The diffraction grating diffracts the input beam which is focused by the focusing optical element onto the spatial filter to generate a filtered output beam. Embodiments of the invention may be employed as spectral filters, optical spectrum analyzers, optical mutiplexers, optical de-multiplexers, and the like.

Abstract: A spectrograph with a first concave spectrographic diffraction grating is positioned to receive light from an input light source. The first concave spectrographic diffraction grating is configured to provide a diffracted light output dispersing the components of the input light source in a first dispersion direction with a first angular orientation with respect to the plane of the grating. The dispersion forms the input light into an intermediate spectrum. The intermediate spectrum is formed in a focal surface by the once diffracted light. A slit is substantially positioned on the focal surface. A second concave diffraction grating is positioned to receive once diffracted light from the slit and configured to provide a twice diffracted light output, the second concave diffraction grating dispersing the components of the input light source in a second diffraction direction with a second angular orientation with respect to the plane of the grating.

Abstract: A quasi-monochromatic light beam carrier for a particular telecommunication channel is likely to experience drift because of age, temperature, or other factors, and may cause the centroid wavelength of the carrier to shift. Temperature adjustments by wavelength lockers to compensate for drift on one channel may affect the performance of other channels. Embodiments of the present invention couple a quasi-monochromatic light beam through a substrate-based grating, diffract the light beam from the edge of the substrate to free space, and detect the light beam from free space at a position detector to determine the centroid wavelength based on a position of the light beam incident on the detector. The diffracted light beam may be reflected within the substrate a number of times prior to exiting the substrate towards the detector.

Abstract: An optical spectrum analyzer (OSA) 10 sequentially or selectively samples (or filters) a spectral band(s) 11 of light from a broadband optical input signal 12 and measures predetermined optical parameters of the optical signal (e.g., spectral profile) of the input light 12. The OSA 10 is a free-space optical device that includes a collimator assembly 15, a diffraction grating 20 and a mirror 22. A launch pigtail emits into free space the input signal through the collimator assembly 15 and onto the diffraction grating 20, which separates or spreads spatially the collimated input light, and reflects the dispersed light onto the mirror 22. A ?/4 plate 26 is disposed between the mirror 22 and the diffraction grating 20. The mirror reflects the separated light back through the ?/4 plate 26 to the diffraction grating 20, which reflects the light back through the collimating lens 18. The lens 18 focuses spectral bands of light (?1–?N) at different focal points in space.

Abstract: A system for spectral analysis of a multi-wavelength signal is disclosed. The illustrative embodiment of the present invention, like the prior art, uses a grating or prism to disperse the spectral components of a multi-wavelength signal, and then uses a reciprocating or rotating mirror to direct the spectral components, one at a time, into a photodetector. The illustrative embodiment uses a telescope between the grating and the mirror to improve the spectral resolution of the system.

Abstract: An apparatus for filtering an input beam of light to produce an output beam of light is provided. The apparatus facilitates tuning an input beam of light to a desired wavelength by directing the input beam of light, via a mirror, onto a diffractive optical element and returning the diffracted portion of the input beam of light as an output beam of light. The apparatus may also include a polarization recovery element adapted for receiving the input beam of light and outputting a first and second spatially offset beam of polarized light. The apparatus may also be configured as a tunable receiver by utilizing a detector to detect a characteristic of a filtered output beam. The output beam may be additionally filtered by a spatial filter.

Abstract: A spectrometer assembly (10) is disclosed. The assembly includes a light source (11) with a continuous spectrum. A pre-monochromator (2) generates a spectrum with a relatively small linear dispersion from which a spectral portion is selectable, the spectral bandwidth of the spectral portion being smaller than or equal to the bandwidth of the free spectral range of the order in the echelle spectrum. The centre wavelength of the selected spectral interval is measurable with maximum blaze efficiency. The assembly also includes an echelle spectrometer (4) with means for wavelength calibration, an entrance slit (21) at the pre-monochromator (2), an intermediate slit assembly (50) with an intermediate slit (3) and a spatially resolving light detector (5) in the exit plane of the spectrometer for the detection of wavelength spectra.

Abstract: The present invention is directed to apparatus and method for measuring the spectral characteristics of an object surface. The apparatus comprises a light source for generating an input signal comprising a plurality of wavelengths of energy and a diffraction grating for diffracting the input signal into a plurality of diffracted wavelengths of energy. A resonant mirror assembly associated with the diffraction grating sequentially directs a select diffracted wavelength to the object surface to generate a corresponding reflected wavelength of energy. The apparatus further comprises a sensor for determining each select diffracted wavelength of energy directed to the object surface and a detector for detecting one or more of the reflected wavelengths. The detector is coupled with the sensor for associating each select diffracted wavelength with each corresponding reflected wavelength.

Abstract: A diffractive optical element device for use in spectroscopy, where broadband light is emitted from a light source (31) towards the optical element (24) and from there is transmitted to at least one detector (29; 29?). The optical element has a plurality of diffractive dispersively focusing patterns, preferably partly integrated into each other, whose respective centers are two-dimensionally offset relative to each other in order to produce a plurality of spectra (25–28), where at least two are separate, but offset relative to each other and/or partly overlapping. In an alternative embodiment, the optical element consists of either one diffractive optical element (60) that is related to a wavelength and produces a spectrum, or at least two diffractive optical elements (60, 61) which are related to respective wavelengths and which produce at least two mutually partly overlapping spectra to give a composite spectrum.

Abstract: A field multiplexed dispersive imaging spectrometer (20). The novel system includes foreoptics (22) for receiving incoming electromagnetic energy, a disperser (24) disposed to receive energy from the foreoptics (22), and a focal plane array (28) disposed to receive energy from the disperser (24). The disperser (24) is a computer generated holographic disperser designed to disperse light into several, overlapping diffraction orders. In the preferred embodiment, the disperser (24) is designed with greater energy in the central, undiffracted order than in the other diffracted orders. The system (20) also includes a processor (30) which takes the data detected by the focal plane array (28) and generates a representation of the input image in several color bands using an iterative restoration algorithm (32).

Abstract: A spectrometer is described which comprises a dispersive element for spectrally decomposing a light beam, whose spectral distribution is to be determined, into spectral components, as well as a suspension for supporting the dispersive element and for biasing the same into a resting position with a biasing force, when the dispersive element is in a deflected position. A control means controls a holding means to vary the deflected position, so that different spectral components become detectable for a detector of the spectrometer having a first and a second detector element. A combining means combines shots made by the detector at different positions of the dispersive element.

Abstract: In a spectrophotometer, the following formula is stored in advance as a correction formula of a rotation angle in a correction formula storing portion; ??=?+A•sin (C1•?+?a)+B•sin (C2•?+?b)+?c, wherein C1, C2 represent coefficients theoretically determined in advance by a structure of a reduction mechanism, and A, B, ?a, ?b, ?c are coefficients specific to the reduction device which are calculated based on measurement results of a plurality of bright line spectrums through fittings by a coefficient determining portion. In case a sample is measured actually, when a desired wavelength is set, a rotation angle correcting portion corrects a rotation angle ? corresponding to the desired wavelength to calculate ?? by applying the above-stated correction formula, and then, controls a motor so that a diffraction grid is rotated by the angle ??.

Abstract: An optical spectrometer comprises at least two coupling apertures with different mode field diameters, a means for dispersing the light beams exiting each of the coupling apertures along a dispersion axis and at least two decoupling apertures on which the dispersed light beams are imaged and whose mode field diameters each correspond to the mode field diameters of the associated coupling apertures. Due the enlarged mode field diameter, a larger spectral fraction of dispersed light beams, i.e., light of a larger spectral bandwidth, can be coupled into the decoupling aperture than into the decoupling aperture.

Abstract: A method and apparatus for measuring characteristics of a single-wavelength optical signal constituting part of a wavelength division multiplexed (WDM) optical signal is provided. The WDM optical signal is adjustably diffracted to select the single-wavelength optical signal. An optical-to-electrical conversion is performed. An electrical sampling signal representing the selected single-wavelength optical signal is generated by one of (a) optically sampling the selected single-wavelength optical signal to generate an optical sampling signal on which the optical-to-electrical conversion is performed, and (b) electrically sampling an electrical signal generated by performing the optical-to-electrical conversion on the selected single-wavelength optical signal.

Abstract: This invention relates to a real-time infrared chemical imaging spectroscopic apparatus, including a light source for generating infrared radiation. A test sample absorbs a narrow-bandwidth infrared radiation as a result of a monochromator dispersing the infrared radiation and emits thermal radiation. IR camera collects the thermal radiation to form an image. As such, the present invention inspects the test sample in real time without a huge amount of complicated computation. Thus, the efficiency of inspection is increased and the optical design of the apparatus is more compact.

Abstract: A high-resolution tunable optical filter uses a dispersive element in a double pass configuration. The double pass configuration is provided by a reflective quarter-wave plate that conveniently reduces polarization dispersion loss (PDL) of the filter. The filter also includes a fibre tube for supporting an input optical fibre and an output optical fibre, and a lens having an optical axis, which is disposed such that a focal point thereof is substantially at one of the input and output optical fibres. To provide increase resolution the filter is tuned by rotating the reflective quarter-wave plate. To provide high power capabilities the fibre jackets of the input and output fibres are optionally stripped back. To provide a symmetrical spectral response the fibre tube is optionally mounted at an angle to the optical axis of the lens.

Abstract: In an optical spectrum analyzer comprising a spectrograph and a photodevice array, and an optical spectrum detecting method, a wavelength deviation, from an assigned wavelength, of a light detected by a photodevice array which detects a wavelength of a diffraction light or a non-diffraction light from an acoustooptic device, is detected and a feedback control to a diffraction angle of the acoustooptic device is performed. Also, without using a feedback control, an exit light and a diffraction light from the acoustooptic device are respectively received by two photodevice arrays and the photodevices are arranged in order to mutually compensate gaps between the photodevices, whereby a center of each photodevice is similarly made coincide with a peak of an optical beam to be received.

Abstract: In a wavelength-variable light outputting apparatus, a diffraction grating 8 and a shielding member 11 which make wavelength and light quantity variable are attached to galvanometric scanners 12, 13, respectively, and the latter are swung, whereby the wavelength can be made variable at a high speed while in a state where the light quantity is kept constant. Such an apparatus is useful for capturing a fluorescent image of a biological sample in particular. By way of the shielding member 11, light is made incident on the optical fiber 10 and is outputted therefrom, whereby a biological sample SM can effectively be irradiated with light.

Abstract: A spectrometer for measuring the intensity of light, comprises a grating having a major axis, a first entrance aperture aligned with the grating major axis and configured to direct light energy onto the grating, wherein the grating is adapted to produce a focused light beam, a first exit aperture aligned with the grating major axis and configured to accept the focused light beam, a second entrance aperture configured to direct the light energy onto the grating, wherein the second entrance aperture is offset from the grating major axis, and a second exit aperture configured to accept the focused light beam.

Abstract: A spectrograph with a first concave spectrographic diffraction grating is positioned to receive light from the input light source is configured to provide a diffracted light output dispersing the components of the input light source in a first direction. The dispersion forms the input light into an intermediate spectra. The intermediate spectra is formed in a focal surface by the once diffracted light. A slit is substantially positioned on the focal surface. A second concave diffraction grating is positioned to receive once diffracted light from the slit and configured to provide a twice diffracted light output, the second concave diffraction grating dispersing the components of the input light source in a second direction. The second direction is different from the first direction, the dispersion forming the input light into an output spectra.

Abstract: A dual-channel, double-filtering, multi-pass OSA having a narrow spectral linewidth response and high ORR comprises a diffraction grating (DG), two input ports (P1?, P1?) for directing first and second input light beams (LR, LT) onto the grating; a retroreflector (RAM1) for returning the dispersed light beams to the grating for dispersion again; two intermediate output ports (P2?, P2?) for receiving the twice-dispersed light beams; two secondary input ports (P3?, P3?) coupled to the intermediate output ports by polarization-maintaining waveguides (PMF2?, PMF2?) for directing the light beams onto the grating a third time, with their SOPs having a predetermined orientation relative to the SOPs of the first and second light beams when first incident upon the grating, the retroreflector (RAM1) returning the three-times-dispersed light beams to the grating for dispersion a fourth time; and two output ports (P4?, P4?) for receiving the light beams after dispersion the fourth time.

Abstract: In order to provide a multi-path monochromator capable of reducing the size of optical parts with a high resolution and a wide dynamic range, the multi-path monochromator has a lens 2 used as a first collimator for converting an incident light into a parallel light, a diffraction grating 4 for diffracting an output light outputted from the lens 2, plane mirrors 3 and 5 for reflecting a diffraction light diffracted by the diffraction grating 4 to return the diffraction light back to a same path, a parabolic mirror 7 used as a second collimator for collecting a diffraction light which is again diffracted by the diffraction grating into which a reflected light is again outputted from the plane mirror, and an output slit positioned at a focal position of the parabolic mirror 7. The parabolic mirror 7 used as the second collimator has a focal length which is longer than a focal length of the lens used as the first collimator.

Abstract: A conical diffraction grazing incidence spectroscope for performing wavelength scanning by rotating a diffraction grating about an axis set parallel to groves in a grazing surface of the grating.

Abstract: The present invention relates to a spectrometer whereby the accuracy of wavelength measurement can be improved without being affected by the environment of use. The present invention is characterized by improvements made to a spectrometer for spectrally dividing the light under measurement by transmitting the components thereof at different, wavelength-by-wavelength angles, and receiving and detecting the light under measurement thus spectrally divided by the chromatic dispersion device using an optical detector. The apparatus according to the present invention comprises a refractive index compensation means for compensating changes in the angle at which the chromatic dispersion device transmits the light under measurement, according to changes in the refractive index of the medium in which the chromatic dispersion device is placed.

Abstract: A monochromator including: a concave mirror which converts incident light into parallel light and emits the parallel light, a plane diffraction grating for diffracting the parallel light emitted from the concave mirror, first reflection means which reflects first light diffracted by the plane diffraction grating and causes the diffracted light to enter the plane diffraction grating as second incident light, second reflection means which reflects second diffracted light and causes the reflected light to enter the plane diffraction grating as third incident light, and an exit slit disposed in the vicinity of a focal point such that third diffracted light is reflected by the first reflection means, to thereby enter the plane diffraction grating as fourth incident light and such that fourth diffracted light is converged at the focal point by the concave mirror, to thereby enable extraction of light having a specific wavelength.

Abstract: An optical beam having a randomly and unpredictably variable input polarization state propagates through an optical system containing a first optical surface, for example a diffraction grating, a first adjustable mirror, and means for rotating the respective parallel (P) and perpendicular (S) plane polarization components of the optical beam relative to the first optical surface by ninety degrees, thereby generating a polarization rotated optical beam having reversed orientations of the S and P polarization components relative to the input. The optical beam is reflected from the first adjustable mirror, which redirects the optical beam onto an optimized location on the first optical surface, thereby reducing PDL due to propagation through the optical system. In some embodiments the optical beam location on the first adjustable mirror remains substantially constant during adjustment.

Abstract: A wavelength variable light source emits a light whose wavelengths continuously change from a preset start wavelength up to a stop wavelength to a measuring object. A timing information output section generates timing information showing emission timings of lights emitted from the wavelength variable light source and having start and stop wavelengths and a plurality of wavelengths obtained by delimiting the wavelengths between the start and stop wavelengths in predetermined steps. A light receiving section receives the light output from the measuring object and outputs a signal showing a measured value of a received light. A plurality of amplifiers receive the signal output from the light receiving section and amplify the signal at each predetermined amplification factor.

Abstract: A monochromator comprises an optical ray input section which limits the width of optical rays input from a light source, a first concave mirror for converting the optical rays passing through the optical ray input section into parallel rays, a diffraction grating for separating the parallel rays by wavelength into diffracted rays, a second concave mirror for condensing the diffracted rays when the diffracted rays are input, an optical ray output section which limits a wavelength band width of the condensed rays, and a substrate to which the optical ray input section, the first concave mirror, the diffraction grating, the second concave mirror, and the optical ray output section are fixed. A coefficient of linear expansion of a focal length of the first concave mirror, a coefficient of linear expansion of a focal length of the second concave mirror, and a coefficient of linear expansion of a material forming the substrate in the monochromator are approximately the same.

Abstract: Optical systems are provided. One such optical system includes an optical source that propagates a source beam of light. A diffracting component is optically coupled to the optical source and is operative to receive the source beam and produce a diffracted beam. A target is located to receive the diffracted beam. Additionally, a compensating system repositions at least one of the optical source, the diffracting component, and the target in response to a detected change in refractive index of a medium through which the diffracted beam propagates so that the diffracted beam continues to be received by the target. Methods and other systems also are provided.

Abstract: A spectrum analyzer providing an integrated calibration function and for providing that calibration function automatically. The injection of light to be analyzed through a central aperture of a scanning grating onto a focusing reflector provides in combination four traversals of the space therebetween. The spectrometer thus is used to separate wavelength information spacially and receive it back at the same or adjacent aperture(s) to be analyzed by a processing system to establish the spectra for the incident light. The light is typically injected from and received back into optical fibers or other light carrying elements. Calibration light is also applied through the same or adjacent apertures in the grating from a known source and spectra such as Argon to use as a calibration reference by detecting the known spectra peaks and correlating it to grating scan angle.

Abstract: An optical signal performance monitoring apparatus in a multi-channel optical transmission system and a method for monitoring the optical signal performance.

Abstract: Inverting optics are used to invert, with respect to the dispersion plane, the wavefront of a monochromator employing a beam making more than one pass through the dispersing medium. Further, the inverting functionality can be turned-on or turned-off, thereby reversibly converting between additive and subtractive monochromator architectures. Inversion reversal is accomplished by rotating the inverting optics by 90 degrees coaxially with the beam, either back and forth or monotonically, or by translating portions or all of the inverting optics into and out of the beam. Examples of inverting optics include Dove prisms and equivalent multiple all-reflective surfaces. The system and method can be applied to two-pass and other multi-pass monochromators and to dual and other multiple serial monochromator configurations using diffraction gratings or other dispersing elements.

Abstract: To economically perform preparatory chromatography, a plurality of pumps each having a corresponding one of a plurality of pistons and a corresponding one of a plurality of cylinders are driven by one motor to draw and pump solvent simultaneously into corresponding columns. To form a gradient, the pumps are connected to two-way valves that are connected alternately to a first solvent and a second solvent, whereby the time said valve is in a first position controls the amount of solvent drawn from the first reservoir into said pumps and the amount of time in said second position controls the amount of said second solvent drawn from the second reservoir into said pumps and the solvent is mixed in the pumping systems. The detectors are photodiodes mounted to light guides in the flow cells that generate signals related to light absorbance and communicate with a controller, whereby the controller receives signals indicating solute between the light guides and causes collection of solute.

Abstract: A depolarizing plate comprising a first rectangular wedge plate that has a first crystallographic optical axis in a diagonal direction of the rectangle and which has a thickness thereof in a vertical direction vary continuously in a direction 45 degrees from said first crystallographic optical axis and a second rectangular wedge plate that has a second crystallographic optical axis in a diagonal direction of the rectangle crossing said first crystallographic optical axis at right angles and which has a thickness thereof in a vertical direction vary continuously in a direction 45 degrees from said second crystallographic optical axis, the two wedge plates being joined in such a position that said first crystallographic optical axis crosses said second crystallographic optical axis at right angles, wherein the slope formed by the joint of said wedge plates is rotated about the optical axis of an incident ray of light.

Abstract: The present invention is generally directed to a method and a structure for calibrating a scatterometry-based metrology tool used to measure dimensions of features on a semiconductor device. In one illustrative embodiment, the method comprises measuring a critical dimension of at least one production feature formed above a wafer using a scatterometry tool, measuring at least one of a plurality of grating structures formed above the wafer using the scatterometry tool, each of the grating structures having a different critical dimension, and correcting the measured critical dimension of the at least one production feature based upon the measurement of the at least one grating structure.

Abstract: The invention relates to a spectrometer (10) with a dispersive element (16) that can be displaced between at least two positions. In the first position, the simply dispersed radiation (44) of a selected wavelength is reflected directly back in the incident beam path (42), while in the second position the dispersed radiation (32) of the selected wavelength can be directed to a reflective element (30) that is positioned such that the radiation (34) can be directed at least one more time across the dispersive element (16) and then back to the incident beam path (38). The spectrometer is provided with a device, for example, a mirror, an echelle grating or a prism that deflects the beam from the plane of dispersion, which is arranged in such a manner that the simply dispersed beam (34) runs in another plane than the multiply dispersed beam (36). The mirror (30) is inclined by an axis (54) that extends parallel to the plane of dispersion and perpendicular to the incident beam (32).

Abstract: An optical beam having a randomly and unpredictably variable input polarization state propagates through an optical system containing a first optical surface, for example a diffraction grating, a first adjustable mirror, and means for rotating the respective parallel (P) and perpendicular (S) plane polarization components of the optical beam relative to the first optical surface by ninety degrees, thereby generating a polarization rotated optical beam having reversed orientations of the S and P polarization components relative to the input. The optical beam is reflected from the first adjustable mirror, which redirects the optical beam onto an optimized location on the first optical surface, thereby reducing PDL due to propagation through the optical system. In some embodiments the optical beam location on the first adjustable mirror remains substantially constant during adjustment.

Abstract: In order to provide a noise-free reliable projection type display apparatus which has no movable portion and can display a high quality full-color image, the following arrangement is proposed. In a projection type display apparatus which has an optical modulation device for displaying an image by controlling the reflected state of light, an illumination unit for irradiating the optical modulation device with light, and a projecting optical system for projecting reflected light components of the light components with which the optical modulation device is irradiated, and projects and displays an image formed by the optical modulation device, as the optical modulation device, a mirror array device for modulating light by controlling the tilt amounts of mirrors that form pixels is used.

Abstract: A spectrometer, or a spectral instrument using multiple non-interfering optical beam paths and special optical elements. The special optical elements for use with the instrument are used for directing the optical beam and/or altering the form of the beam. The instrument has the potential, depending upon the totality of the optical components incorporated into the instrument, to be a monochromator, a spectroradiometer, a spectrophotometer and a spectral source. The spectral instrument may further be a part of the spectral system. The system may include the spectral instrument, a power module and means for remote control of the instrument. Such remote control may be by use of a personal computer or a control system dedicated to the control, measurement and analysis of the collected information. The multiple non-interfering beam paths are created using specially designed optical elements such as a diffraction grating, a splitter box, a zero back-lash drive system for movement of the grating element.

Abstract: The present invention relates to different types of micromirror spectrometers using MEMS (Micro Electro Mechanical Systems) for various applications in the UV, VIS, NIR and MIR wavelength regions. The invention enables a wavelength selection using micro scanning mirror and integrated grating on a much smaller scale than previously encountered conventional diffraction grating monochromators. Especially small designs are obtained via simultaneous usage of collimation optics for both spatial filters, by using entrance and exit slit apertures, which are located very close together. Until now, the spatial filters themselves are not part of the miniaturization. The utilization of the precision from this technology allows for reproducible slits with defined geometries and surface roughness and accurate spatial classification towards the rotation axis of the diffraction grating. Therefore the assembly and adjustment effort of the monochromator is reduced.

Abstract: A diffracting portion is composed of optical elements including an optical element, and diffracts light. A drive unit rotates the optical element. An angle detector detects a rotation angle of the optical element. A reference wavelength light source includes a light source and an absorption cell sealed with a plurality of gasses of different kinds having mutually different absorption line wavelengths, and emits the reference light of a specific wavelength depended on the absorption cell toward the diffracting portion. A reference photodetector converts a diffracted light from the diffracting portion into an electric signal. A signal processor receives a rotation angle issued by the angle detector when detecting a predetermined value of the electric signal, and determines the predetermined rotation angle corresponding to the specific wavelength determined depending on the plurality of gases.

Abstract: An optical spectrum analyzer of novel design, in which several different spectra can be measured and analyzed simultaneously. A measuring signal is used as a reference signal for calibrating the optical spectrum analyzer. The light rays are admitted via a coupling device with several coupling apertures arranged in a line; and via a separate decoupling device comprising respective decoupling apertures arranged in a line, the light rays are decoupled. Height offset is realized by a 90° deviation prism. The arrangement makes possible simultaneous analysis of several optical lines with little retroreflection as well as uninterrupted calibration of the measuring process.