Abstract: A spectrometer sample head including a housing, at least one source of radiation in the housing, and a flip top sample cell. First and second hinged plates each include a window aligned with each other when the plate are coupled together. The housing includes a channel for receiving the plates when coupled together for placing the sample in the optical path of the radiation.

Abstract: This invention generally relates to a method and apparatus for direct detection of one or more markers in pressurized hydrocarbon fluids. The apparatus includes a vessel (130) and one or more valves (150, 160, 170). The hydrocarbon fluid (240) may be a liquid or gas. Markers may include a variety of optical markers, such as fluorescent markers. The apparatus may be coupled to a hydrocarbon fluid source (210), and the vessel (130) may be at least partially filled with hydrocarbon fluid from the hydrocarbon fluid source (210). A> detector (140) coupled to the vessel (130) may be used to detect at least one of the markers in the hydrocarbon fluid (240) while the apparatus is coupled to the hydrocarbon fluid source (210) and without the addition of reagents. Detection of markers may include, for example, fluorescence detection.

Abstract: An optical slicer for generating an output spot comprising an image compressor which receives a substantially collimated input beam and compresses the beam, wherein the input beam, if passed through a focusing lens, produces an input spot; an image reformatter which receives the compressed beam to reformat the beam into a plurality of sliced portions of the compressed beam and vertically stacks the portions substantially parallel to each other; and an image expander which expands the reformatted beam to produce a collimated output beam which, if passed through the focusing lens, produces the output spot that is expanded in a first dimension and compressed in a second dimension relative to the input spot.

Abstract: A method for the detection of contaminants in an optical measuring cuvette of a spectrophotometer, typically an oximeter for determining hemoglobin derivatives, is provided, in which measuring cuvette, in addition to at least one sample measurement to obtain a sample spectrum I(?), at least one reference measurement is performed using a reference liquid to obtain a reference spectrum I0(?). The reference spectrum I0(?) is compared to a known target spectrum I0soll(?), which is associated with the measuring cuvette, comparison parameters being obtained, it being decided automatically whether a contamination of the measuring cuvette exists as a function of predefined threshold values of the comparison parameters.

Abstract: A spectroscopic module 1 is provided with a spectroscopic unit 8 and a photodetector 9 in addition to a spectroscopic unit 7 and a photodetector 4 and thus can enhance its detection sensitivity for light in a wide wavelength range or different wavelength regions of light. A light-transmitting hole 4b is disposed between light detecting portions 4a, 9a, while a reflection unit 6 is provided so as to oppose a region R in a light-absorbing substrate 2, whereby the size can be kept from becoming larger. Ambient light La is absorbed by the region R in the substrate 2. Any part of the light La transmitted through the region R in the substrate 2 is reflected to the region R by the unit 6 formed so as to oppose the region R, whereby stray light can be inhibited from being caused by the incidence of the light La.

Abstract: A miniaturized spectrometer/spectrophotometer system and methods are disclosed. A probe tip including one or more light sources and a plurality of light receivers is provided. A first spectrometer system receives light from a first set of the plurality of light receivers. A second spectrometer system receives light from a second set of the plurality of light receivers. A processor, wherein the processor receives data generated by the first spectrometer system and the second spectrometer system, wherein an optical measurement of a sample under test is produced based on the data generated by the first and second spectrometer systems.

Abstract: A wireless sub-surface soil sensor having a switchable configuration antenna that can be optimized for various soils is disclosed herein. The wireless sub-surface sensor also measures the moisture and salinity of a material. The wireless sub-surface sensor preferably includes a cover for protecting circuitry of the sensor. The wireless soil sensor is designed to be buried underground and to transmit to above ground receivers, which provide feedback for configuring the switchable antenna.

Abstract: A method of conditioning a liquid crystal polymer (LCP) substrate for enhanced surface adhesion accomplished by exposing an LCP substrate to oxygen plasma. The plasma will chemically alter and modify the LCP substrate surface to promote increased adhesion of metal and subsequent LCP layers during lamination. Lamination is accomplished while dwelling under the melt temperature of the LCP substrate itself. A further method is disclosed of detecting impurities modified or deposited onto the LCP surface during plasma treatment.

Abstract: In the spectroscopy module 1, a light detecting element 4 is provided with a light passing opening 4b through which light made incident into a body portion 2 passes. Therefore, it is possible to prevent deviation of the relative positional relationship between the light passing opening 4b and a light detection portion 4a of the light detecting element 4. Further, an optical element 7, which guides light made incident into the body portion 2, is arranged at the light passing opening 4b. Therefore, light, which is to be made incident into the body portion 2, is not partially blocked at a light incident edge portion of the light passing opening 4b, but light, which is to be made incident into the body portion 2, can be guided securely. Therefore, according to the spectroscopy module 1, it is possible to improve the reliability.

Abstract: A spectrometer recognizes a measurement target on the basis of the spectral data set of observed light detected by a spectral sensor capable of measuring wavelength information and light intensity information. The spectrometer is provided with a spectral data processor. Spectral data sets are detected at two different positions by the spectral sensor, and the processor subtracts a first spectral data set from a second spectral data set, or divides the first spectral data set by the second spectral data set to calculate one phase correlation spectral data set, which is correlated to the spectral data sets at the two different positions. The processor simultaneously identifies the measurement target corresponding to the two different positions on the basis of the correlation spectral data set.

Abstract: An apparatus and method for detecting an intensity of radiation in a process chamber, such as an ultraviolet curing process chamber, is disclosed. An exemplary apparatus includes a process chamber having a radiation source therein, wherein the radiation source is configured to emit radiation within the process chamber; a radiation sensor attached to the process chamber; and an optical fiber coupled with the radiation source and the radiation sensor, wherein the optical fiber is configured to transmit a portion of the emitted radiation to the radiation sensor, and the radiation sensor is configured to detect an intensity of the portion of the emitted radiation via the optical fiber.

Abstract: The present disclosure provides for a correction filter that may be configured to comprise a predetermined arrangement of thin film layers. This arrangement of thin film layers may be such that it effectively enables a correction filter to generate a predetermined spectral response, wherein said predetermined spectral response is substantially the same as a determined instrument response correction associated with an instrument. The invention of the present disclosure therefore provides for effectively compensating for transmission inefficiencies associated with an instrument without the need for separate reference measurements to determine and correct for instrument response.

Abstract: The invention relates to methods for determining the sex of birds' eggs. It can be used for an early determination of the sex, in particular in poultry farming, and in this respect also with non-incubated eggs. In the method in accordance with the invention, electromagnetic radiation is emitted onto the blastodisk of an egg by a radiation source and, after a switching off of the radiation source, the decay behavior of the autofluorescence intensity excited by the electromagnetic radiation is detected by a detector at the irradiated region of the blastodisk with time resolution and spectral resolution for at least one wavelength of the autofluorescence. The fractal dimension DF is calculated using the determined measured intensity values and the value of the fractal dimension DF is compared with a species-specific and sex-specific limit value, wherein, when the limit value is exceeded, the respective egg is classified as female and, when it is not reached, the egg is classified as male.

Abstract: In one embodiment, a method and system is provided for detecting target materials using a combination of stroboscopic signal amplification and Raman spectroscopy techniques.

Abstract: A valid state of an analytical system that includes a light source and a detector can be verified by determining that deviation of first light intensity data quantifying a first intensity of light received at the detector from the light source after the light has passed at least once through each of a reference gas in a validation cell and a zero gas from a stored data set does not exceed a pre-defined threshold deviation. The stored data set can represent at least one previous measurement collected during a previous instrument validation process performed on the analytical system. The reference gas can include a known amount of an analyte. A concentration of the analyte in a sample gas can be determined by correcting second light intensity data quantifying a second intensity of the light received at the detector after the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound.

Abstract: There is provided an optical measurement analysis device capable of applying light to substantially the entire surface of a to-be-analyzed object for improving the analysis accuracy. The optical measurement analysis device according to the present embodiment includes a container, a light source, a light irradiation unit, a light reception unit, a spectroscope unit, and an analyzing unit for analyzing an optical spectrum obtained by the spectroscope unit. The container has an inner wall adapted to reflect light reflected by the to-be-analyzed object and light transmitted therethrough.

Abstract: A radiation generation device for generating resulting electromagnetic radiation having an adjustable spectral composition includes: a multitude of radiation elements (configured to generate a radiation element specific electromagnetic radiation, respectively, upon being activated, a first radiation element of the multitude of radiation elements being activatable independently of a second radiation element of the multitude of radiation elements; a dispersive optical element; and an optical opening; the dispersive optical element being configured to deflect the radiation element specific electromagnetic radiations, in dependence on their wavelength and on a position of the radiation element generating the respective radiation element specific electromagnetic radiation, such that a particular spectral range of each of the radiation element specific electromagnetic radiations may exit through the optical opening, so that the spectral composition of the resulting electromagnetic radiation exiting through the opti

Abstract: A single-shot spectral imager or imaging system which acquires multiplexed spatial and spectral data in a single snapshot with high optical collection efficiency and with the speed limited only by the readout time of the detector circuitry. The imager uses dispersive optics together with spatial light modulators to encode a mathematical transform onto the acquired spatial-spectral data. A multitude of encoded images is recorded simultaneously on a focal plane array and subsequently decoded to produce a spectral/spatial hypercube.

Abstract: An illumination apparatus to illuminate a sample surface with excellent illumination efficiency and a reflective characteristics measuring apparatus using the illumination apparatus. The illumination apparatus includes a plane light source positioned on a normal at a center of the sample surface and a mirror having an internal reflective surface positioned between the plane light source and the sample surface. The internal reflective surface has a circular or polygonal shape in a section perpendicular to the normal and the circular or polygonal shape substantially corresponds to an imaginary circle centered on the normal and having a radius equal to half a distance between the plane light source and the sample surface. In place of the mirror, a plurality of reflective faces may be positioned.

Abstract: An accessory for a spectrometer for carrying out measurements of specular reflectance of a sample. The accessory is designed so that all components can be located in a housing and the sample can be located horizontally on a top-plate of the housing with the components disposed below the plane of that plate.

Abstract: The invention relates to a measuring arrangement for an optical spectrometer, in particular a photon density wave spectrometer, having a measuring chamber, which can be loaded with a sample to be measured, and a coupling-in/coupling-out device which is configured to receive excitation light from a light source and couple it into the sample to be measured in the measuring chamber and to receive measuring light formed in the sample to be measured on account of the excitation light which has been coupled in and to emit said measuring light to a detection device, wherein the coupling-in/coupling-out device has an optical switching device and a plurality of light guide elements which couple to the latter, have a respective optical waveguide and can be connected according to at least one selectable measuring configuration using the optical switching device in order to couple in the excitation light and receive the measuring light according to the at least one selectable measuring configuration, and wherein outputs

Abstract: The invention discloses an optical measurement system for measuring the optical properties of a device under test (DUT). The optical measurement system includes a DUT, a light measuring module, a light guiding module and an analyzing module. The present invention utilizes the light guiding module to receive an axial ray of the rays emitted by the DUT so as to analyze the optical properties thereof. Thus, the present invention is not only capable of measuring the light intensity of the rays emitted by the DUT, but also capable of obtaining the properties of the axial ray emitted by the DUT.

Abstract: A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.

Abstract: A three-channel spectrometer including: a beamsplitter element that receives an incident radiation and transmits a first portion, a second portion, and a third portion of the incident radiation, a first slit that receives the first portion and transmits a first slit output radiation of a first wavelength range; a second slit that receives the second portion and transmits a second slit output radiation of a second wavelength range; a third slit that receives the third portion of the incident radiation and transmits a third slit output radiation of a third wavelength range; a common optical form that receives and collimates the first, second, and third slit output radiation; and a dispersive element that receives and reflects the collimated first, second, and third slit output radiation from the optical form.

Abstract: An apparatus and accompanying method to measure fiber twist. The method includes independent determination of fiber bending by measuring strain sensing in outer cores of the same fiber. The apparatus includes a multi-core optical fiber comprising a center core and a plurality of peripheral cores at a distance radially from the center core and running parallel to the center core. The center core includes at least one fiber Bragg grating with polarization-dependent reflectivity. The fiber Bragg grating reflects the launched light as reflected light. The apparatus includes a multi-core optical fiber bend sensing system operable to communicate with the multi-core optical fiber. The multi-core optical fiber bend sensing system is operable to sense a bend in the multi-core optical fiber. The apparatus includes a processor operable to communicate with the polarization controller.

Abstract: Various embodiments provide devices and methods of an optical coupled-cavity photo-acoustic spectroscopy (CC-PAS). The exemplary CC-PAS can include three mirrors configured in parallel to couple a Fabry-Perot (FP) cavity with a sample cavity. The sample cavity can be a resonant cavity for containing a sample. The FP cavity can be used as a tunable input coupler for the sample cavity to improve spectroscopic sensitivities when measuring an absorber in the sample.

Abstract: A lasing wavelength of a laser diode is determined by applying a forward current to the p-n junction of the laser diode and measuring a voltage across the p-n junction. The lasing wavelength can be determined by performing a simple wavelength calibration of the laser diode. This allows one to stabilize the lasing wavelength, and also to use the laser diode as a reference wavelength source.

Abstract: Large digital displays for entertainment, architectural and advertising displays have interconnected display panels with pluralities of light emitting elements. To solve calibration problems, each of the display panels stores measured luminance and chromaticity data for each of the light emitting elements of the panel. The luminance data is independent of the chromaticity data. A central controller can then perform calibration procedures so that the light emitting elements are matched across the entire display.

Abstract: An auto-aligning system is presented. One embodiment of the auto-aligning system includes a launcher unit configured to direct a first laser beam and a second laser beam through a chamber, wherein the first laser beam is co-linear with the second laser beam. The auto-aligning spectroscopy system further includes a receiver unit configured to receive the first laser beam and the second laser beam passing through the chamber. The receiver unit includes a first detector configured to determine an intensity of the first laser beam. The receiver unit also includes a second detector configured to determine a deviation of the second laser beam from a determined position. Further, the auto-aligning spectroscopy system includes a motorized stage configured to align the launcher unit to a base-line position based on the determined deviation of the second laser beam.

Abstract: A method for compensating for errors in a spectrometer is provided that includes measuring at least a portion of a path length for a signal traveling through the spectrometer during a measurement scan of a material. A detector signal corresponding to the measurement scan is generated. Compensation for errors in the detector signal is provided based on the measurement of the path length.

Abstract: A sampler is provided for taking samples from melts having a melting point higher than 600° C., in particular for metal or cryolite melts. The sampler includes a carrier tube having an immersion end and having a sample chamber assembly arranged on the immersion end of the carrier tube. The assembly has an inlet opening and a sample cavity for the melt and is arranged at least partly inside the carrier tube. The sample chamber assembly has on a part of its outer surface a coupling device, arranged inside the carrier tube, for coupling a carrier lance. A method is also provided for taking samples using such a sampler.

Abstract: The present invention comprises various embodiments of a retroreflectometer capable of measuring the retroreflectance of a material. The retroreflectometer comprises an illumination path and a retroreflection path. The illumination path comprises focusing optics, a source aperture, a beamsplitter and a collimating lens. The retroreflection path comprises a focusing lens, a beamsplitter, a receiver aperture and a receiver. The source aperture shapes the transverse profile of the light to make it appropriate to the measurement. Focusing optics, such as a biconvex lens, may be placed between the light source and the source aperture. After the beam is reflected by the object under test, it enters the retroreflection path of the instrument. The focusing lens focuses the light through the beamsplitter and onto the receiver aperture. The receiver aperture may be the input slit for a spectrometer, or there may be optics, such as a lens or an optical fiber, that transfer the light from the aperture to the receiver.

Abstract: An adaptive spectral sensor, and methods of using the sensor. The sensor uses a programmable band pass transmission filter to produce both contrast signals, which discriminate specific target materials from background materials by comparing spectral signatures in hardware, and scene radiance spectra. The adaptive spectral sensor may measure one or more scene spectra and may form a spectral image. The sensor may automatically adjust to changing spectral, spatial and temporal conditions in the environment being monitored, by changing sensor resolution in those dimensions and by changing the detection band pass. The programmable band pass can be changed on-the-fly in real time to implement a variety of detection techniques in hardware or measure the spatial or spectral signatures of specific materials and scenes.

Abstract: In a total luminous flux measurement apparatus according to an embodiment, a total luminous flux emitted by an object is calculated based on a result of measuring illuminances using a measuring unit when providing relative movement between the object and an integrating unit to expose a substantially entire light emitting surface of the object to an inner space of the integrating unit. Specifically, under conditions that the object is disposed to penetrate the integrating unit from one sample hole to the other sample hole, a luminous flux of a portion of the object within the inner space of the integrating unit is measured, then the integrating unit is moved relative to the object, and a luminous flux of a portion accordingly contained in the inner space of the integrating unit is measured.

Abstract: A system for the detection of components in a region of the atmosphere is disclosed, the system comprising a spectrometer assembly having a detector optically coupled to a optical assembly, the optical assembly receiving incident sunlight from the region of the atmosphere, the optical assembly having a field of view extending from the zenith to below the horizon; means for rotating the spectrometer assembly about a vertical axis; and a processor for receiving data from the spectrometer assembly and compiling data relating to the identity and concentration of components in the region of the atmosphere.

Abstract: A method of generating a library of reference spectra includes storing at least one reference spectrum, storing a plurality of different transmission curves, and for at least two transmission curves from the plurality of different transmission curves, calculating a modified reference spectrum from the reference spectrum and the transmission curve to generate a plurality of modified reference spectra. The transmission curves represent distortion to a spectrum introduced by variations in components in an optical path before a substrate surface.

Abstract: The invention is directed to a prescription imaging system for capturing, storing and displaying images of prescription bottles during the prescription fulfillment process to monitor the quality of the fulfillment process. The system includes one or more pill cameras for capturing images of pills dispensed into one or more prescription bottles and one or more label cameras for capturing images of the bottle labels. The images are stored on a storage device in a database record. The images can be used to verify that the pills in each bottle correspond with the associated prescription.

Abstract: A system and method for performing multispectral color addition imaging. An optical image is obtained for a sample scene comprising one or more target materials. Spectroscopic data is obtained for one or more target materials. A first and second waveband of interest are obtained for one or more target materials. A ratio of the first and second wavebands of interest is obtained and compared to one or more ranges of threshold values. Based on this comparison, a result is displayed wherein this result comprises a pseudo color overlay on said optical image. The pseudo color image may comprise one or more pseudo colors assigned to one or more target materials so as to differentiate and identify the target materials present in the sample scene.

Abstract: A system for grading an agricultural product employing hyper-spectral imaging and analysis. The system includes at least one light source for providing a beam of light, an interferometer or a prism array for dispersing electromagnetic radiation emitted from said agricultural product into a corresponding spectral image, a light measuring device for detecting component wavelengths within the corresponding spectral image and a processor operable to compare the detected component wavelengths to a database of previously graded agricultural products to identify and select a grade for the agricultural product. A method for grading an agricultural product via hyper-spectral imaging and analysis is also provided.

Abstract: A haemolysator having a sonotrode plate and oscillation generating elements acting thereupon, wherein the oscillation generating elements are set into mechanical oscillations by an electrical AC-signal generator. The haemolysater also includes a sample chamber to which the sonotrode plate transmits mechanical oscillations, and has oscillation generating elements that are excitable toward mechanical oscillations in a wide frequency band.

Abstract: A method for measuring the refractive index of a material with Bragg gratings includes the emission of a collimated radiation beam (9) from a radiation source (4) with a large spectrum and orientation thereof along a direction normal to the material (2) to be examined, the propagation of the collimated radiation beam (9) entering the material (2), then a Bragg diffraction grating (3) that is obliquely placed to the direction of the collimated radiation beam (9), and again the material (2), the subjection to spectral analysis of the collimated radiation beam exiting the material (2), the grating (3) producing a minimum in the spectrum subjected to the spectral analysis in accordance with Bragg's law, and the calculation of the refractive index of the material (2) from the measure of the wavelength corresponding to the minimum in thus spectrum. A relevant apparatus is described.

Abstract: Wavenumber linear spectrometers are provided including an input configured to receive electromagnetic radiation from an external source; collimating optics configured to collimate the received electromagnetic radiation; a dispersive assembly including first and second diffractive gratings, wherein the first diffraction grating is configured in a first dispersive stage to receive the collimated electromagnetic radiation and wherein the dispersive assembly includes at least two dispersive stages configured to disperse the collimated input; and an imaging lens assembly configured to image the electromagnetic radiation dispersed by the at least two dispersive stages onto a linear detection array such that the variation in frequency spacing along the linear detection array is no greater than about 10%.

Abstract: The present invention provides a small spectroscope that has a short response time. A spectroscope according to one embodiment of the present invention includes: a beam deflector that includes an electro-optic crystal, having an electro-optic effect, and paired electrodes used to apply an electric field inside the electro-optic crystal; spectroscopic means for dispersing light output by the beam deflector; and wavelength selection means for selecting light having an arbitrary wavelength from the light dispersed and output by the spectroscopic means.

Abstract: A method and apparatus for in-situ metrology of a workpiece disposed in a vacuum processing chamber. The apparatus may include an optical assembly external to the processing chamber configured to focus a relatively large optical spot over a relatively large working distance to acquire a TE and TM spectra from a periodic array on the workpiece. The workpiece may be disposed in the processing chamber with an arbitrary orientation which is first determined via a reflectance measurement. TE and/or TM spectra may then be acquired by initiating a periodic triggering of a flash lamp based on the determined workpiece orientation to account for variation in placement of the workpiece within the processing chamber. The periodic array from which spectra are collected may be a memory array being fabricated in a semiconductor wafer.

Abstract: A multidimensional spectrometer encodes frequency information into laser pulses so that a frequency insensitive detector may be used to collect data for a multi-dimensional spectrograph only from intensity information and knowledge of a modulation providing the encoding. In one embodiment the frequency encoding may be done by a conventional interferometer greatly simplifying construction of the spectrometer.

Abstract: A system for determining the asphaltene content of crude oil includes a first optical flow cell, a first spectrometer operably associated with the first optical flow cell, and a mixer in fluid communication with the first optical flow cell. The system further includes a crude oil injection/metering device configured to receive the crude oil, the crude oil injection/metering device being in fluid communication with the first optical flow cell; a titrant injection/metering device in fluid communication with the mixer, the titrant injection/metering device configured to receive a titrant; and a filtration unit in fluid communication with the mixer. The system further includes a second optical flow cell in fluid communication with the filtration unit, and a second spectrometer operably associated with the second optical flow cell.

Abstract: The present invention provides improved spectrometric devices useful for measuring optical quantities of a component, including a solid state LED emitter, having at least one wavelength that is matched to the wavelength that is useful for the spectral analysis of the component of interest, a photodetection cell and an optimizing configuration and permits control of the LED emitter and the detector sensitivity to provide a range of detection for the signals corresponding to the optical density of a sample being analyzed and that affords sensitivity for a desired component of a sample by minimizing the error associated with electronic components and signals. Preferred embodiments also include configurations for determining an anticoagulant therapy value that may be used to determine treatment for a patient.

Abstract: Even in the case of a sample exhibiting low photoresponse, such as a wide bandgap semiconductor, a measurement method which enables highly accurate CPM measurement is provided. When CPM measurement is performed, photoexcited carriers which are generated by light irradiation of a sample exhibiting low photoresponse such as a wide bandgap semiconductor are instantly removed by application of positive bias voltage to a third electrode which is provided in the sample in addition to two electrodes used for measurement. When the photoexcited carriers are removed, even in the case of the sample exhibiting low photoresponse, the controllability of a photocurrent value is improved and CPM measurement can be performed accurately.

Abstract: The apparatus for measuring concentrations of fuel mixtures using depth-resolved laser-induced fluorescence is a fluorometer equipped with a sample container holder that is movable in the path of the beam from the light source. Fluorescent emissions from the sample mixture pass at 90° to the excitation light path through a slit that is narrow enough that the emission intensity is effectively produced by a thin layer of the sample and focused on a monochromator, with successive thin layers receiving nonuniform excitation radiation due to reduction of intensity along the excitation light source path with increasing depth penetration and due to reabsorption of emitted fluorescence from adjacent layers. The method has a first mode in which the emission spectrum is scanned at a fixed depth, and a second mode in which the sample is moved relative to the emission monochromator slit to vary the depth while keeping the emission wavelength fixed.

Abstract: A spectroscopic ellipsometer comprising a light source (1) emitting a light beam, a polarizer (2) placed on the path of the light beam emitted by the light source, a sample support (9) receiving the light beam output from the polarizer, a polarization analyzer (3) for passing the beam reflected by the sample to be analyzed, a detection assembly which receives the beam from the analyzer and which comprises a monochromator (5) and a photodetector (4), and signal processor means (6) for processing the signal output from said detection assembly, and including counting electronics (13). Cooling means (12) keep the detection assembly at a temperature below ambient temperature, thereby minimizing detector noise so as to remain permanently under minimum photon noise conditions. It is shown that the optimum condition for ellipsometric measurement is obtained by minimizing all of the sources of noise (lamps, detection, ambient).