Abstract: A spectrometer for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the wave guide and a sample material. A tapered portion forms a part of the entry of the wave guide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis.

Abstract: An interferometric apparatus for monitoring changes of the refractive index of An interferometri1capillary tubes comprising a source of coherent light, which is arranged with respect to a capillary tube which is part of a capillary liquid chromatographic system or a capillary electrophoretic system, such that the coherent light beam strikes the capillary tube about perpendicular to its longitudinal extension. In the forward direction of the coherent light beam, behind the capillary tube, the apparatus comprises a photoelectric detector for monitoring a resulting interference fringe pattern and the shifts thereof, which is connected to an evaluation electronics.

Abstract: A device for quickly and accurately comparing the refractive index of an optical immersion liquid with the refractive index of a reference glass that the liquid is to be used with. The device comprises a cavity to at least partially contain the immersion liquid by the reference glass. The containment may be total, as in a hollow core, or may be between two windows composed of the reference glass and assembled in a spaced, facing relationship, one window having an inner face with a plano portion and a portion with a continuous slope, and a cavity intermediate the windows to contain the liquid being compared. The cavity is then filled with the liquid to be compared, transmitting laser light through the windows and the liquid to form an optical interference pattern.

Abstract: In method and apparatus for measuring a refractive index and a thickness of a thin film formed on a substrate, the thin film has m (m.gtoreq.1) layers and a transparent uppermost layer is set as a first layer. A total of (3m+1) parameters include a refractive index n(0) of an incident medium, a refractive index n(j) (j=1 to m) of a j-th layer, absorption coefficients k(j) (j=2 to m) of second to m-th layers, a refractive index n(m+1) and an absorption coefficient k(m+1) of the substrate, and thicknesses d(j) (j=2 to m) of the second to m-th layers. Arbitrary one of the (3m+1) parameters is unknown and the other 3m parameters are known. This method and apparatus measure the unknown parameter. Monochromatic light having a wavelength is incident to the film having the m-layers at a predetermined incident angle from a first layer side in the incident medium to measure reflectances about S and P polarized light.

Abstract: A method of measuring the refractive index of a thin film is composed the steps of: (a) forming a dielectric thin film which is transparent, uniform and geometrically and optically identical, on each of a first substrate and a second substrate, with the refractive indexes of the first substrate and the second substrate being different; and (b) measuring the reflectivities of the first and second substrates, each bearing the dielectric thin film thereon, with the application of a light with an identical wavelength to the two substrates, thereby measuring the refractive index of the dielectric thin film.

Abstract: According to the present invention, there is provided an optical sensor capable of detecting, identifying or measuring a property of a solid, liquid or gas which is in contact with its measuring surface. The preferred sensor comprises an optically transparent sensing element with at least one surface, an optical energy source, means for conducting optical energy from the source to the sensing element at a specific, precisely determined angle and a photodetector. The measuring surface of the sensing element forms an interface with the substance to be measured. Optical energy is partially reflected from the interface formed at the planar surface of the transparent element toward the photodetector. It has been discovered that the resulting signal from the photodetector is proportional to the refractive index of the medium covering the outer surface of the transparent element.

Abstract: The invention concerns a sensor with integrated optics, to detect chemical substances, including a double spiral interlaced with wave guides and integrated on a substrate (13) receiving the signal of a light source (14) through a first optical component (15) able to separate into two portions the light intensity emitted by the source and sending output signals onto at least one detector (17) through a second optical component (16), the first of the two guides (11) being a reference guide isolated from the influence of the substance to be measured, and the second (12) being a measuring guide affected by the substance to be measured.

Abstract: An apparatus useful in immunoassay of a fluid, light is directed to an optical sensor wherein the light is transmitted to a replaceable optical device that is responsive to index of refraction in a sensing region thereof that is exposed to the fluid. One portion of the light is transmitted via a compensation path that includes the sensing region to a first detector. Another portion of the light is transmitted via a sensing path that includes the sensing region to another detector. In one embodiment a ratioing device receives an output from each detector and provides a signal responsive to the ratio of the outputs. The replaceable optical device typically comprises a pair of channel waveguides in directional coupling arrangement, or a pair of channel waveguides in an interferometer arrangement, or a ridge waveguide having a curved or serpentine path configured so that nonspecific sensing effects are compensated.

Abstract: An apparatus is disclosed for measuring the refractive index of index matching gels. A light source (10) is directed into one (20) of the output legs (20, 22) of an optical splitter (18), where the input leg (26) is interconnected to a fiber optic cable (27). The end of the cable (27)is inserted into the gel (30) to be measured. The incident light source (10) directs an incident light source through the splitter, and through the end (29) of the fiber optic cable (27). The difference in refractive indexes between the fiber optic cable (27) and the gel (30) causes a reflection of the incident light back to the splitter (18) and through a measuring device (52). By measuring the reflected power, and by knowing the incident power and other known factors, the refractive index of the gel can be calculated.

Abstract: A method of sensing optically properties of an approximately cylindrical object, such as an optical fibre or optical fibre preform, which diffracts the illuminating beam into a plurality of beam portions each corresponding to its respective diffraction order, comprising the steps of illuminating the object with an illuminating beam substantially perpendicular to the axis of the object, moving an aperture so as to discriminate a beam portion exiting from the object and corresponding to a selected diffraction order, and detecting said beam portion.

Abstract: An optical waveguide portion is provided on one surface of a substrate portion. A luminous flux for measurement is caused to be incident on one end face of the optical waveguide substrate, and only leaking light having passed through the substrate portion is received. The cross-sectional distribution of the refractive index of the optical waveguide portion is measured from changes in the received quantity of light.

Abstract: The invention relates to a transmitted-light refractometer wherein a slit diaphragm is imaged on a diode array through a cuvette holding the sample. The cuvette itself is arranged in the telecentric beam path. The exit window of the cuvette has several regions in which the inner surfaces of the exit window are inclined differently to the inner surface of the entry window. In this way, several slit images are generated on the diode array and the relative spacings of these images are independent of a possible disadjustment of the condenser and the objective. An embodiment of the invention permits the simultaneous measurement of the refractive index and the absorption of the sample.

Abstract: A refractive index detector for use in fluid phase separation techniques such as liquid chromatography and capillary electrophoresis uses a laser beam incident on a capillary tube held in a fixture. The laser beam is refracted and reflected (backscattered) from the capillary tube surface and its contents back to a photodetector located adjacent to the laser source. Tilting of the capillary tube relative to the laser beam axis produces a diffraction pattern on the photodetector, allowing detection of refractive index. Other embodiments use a split incident laser beam part of which is incident on a reference photodetector, or use a split beam which is incident on two capillary tubes juxtaposed to one another. In this case a photodetector is provided for the portion of the beam reflected from each capillary tube. The system may also be used for detecting temperature and pressure of the fluid inside the capillary tubes.

Abstract: An optical system is provided with a laser device for emitting a multiplet laser beam with two types of frequencies F1, F2, and a sample rotator on which a reference sample and a test sample containing substances are set for rotating both the test sample and the reference sample to separate the substances contained in the test sample. The test sample and the reference sample are irradiated with the multiplet laser beam one after another to shift the phase of the laser beam. The optical system is further provided with a polarizer for polarizing the multiplet laser beams transmitting through the test sample and the reference sample to produce both a test sample signal with a frequency .DELTA.F=F1-F2 and a reference sample signal with the frequency .DELTA.F, and a signal analyzer for analyzing a phase difference between the sample signals to determine an index of refraction of the test sample. Therefore, the substances containing in the test sample are specified.

Abstract: A fiber optic refractometer is disclosed for use in on-line measurement of the refractive index of a process fluid. The refractometer does not require light to pass through the process fluid and is hence unaffected by the presence of light diffusing particulate matter in the process fluid. A particular application for which the refractometer is well-suited is the on-line measurement of the hydrogenation state of edible oils (which correlates with refractive index) during the partial hydrogenation process.

Abstract: A method for measuring a refractive index profile and distributed dispersion of a sample by measuring refractive indices at a plurality of wavelengths at measuring points on the sample and calculating a refractive index profile at a main wavelength of the sample from the measured refractive indices.

Abstract: This invention measures the change of a fluid's refractive index with changes in the concentration of a solute dissolved therein. A determination of this quantity is required for many types of chemical analyses especially for the determination of molecular weights. The fluid is restricted to a thin capillary channel (11) within a transparent material (10) such as glass. A fine light beam (18) is incident upon the capillary at an angle close to the critical angle. The axes of the light beam and capillary intersect at a point within the capillary defining thereby a plane within which the refraction occurs. A position sensing (27) device is placed to measure the displacement of the beam twice refracted during its passage through the capillary channel, said measure being used to generate a numerical value of the ratio dn/dc, where dc is the change of solute concentration resulting in a change dn of the solution's refractive index.

Abstract: There is provided a scintillometer for the measurement of the structure function constant and the inner scale of atmospheric refractive index fluctuations including a transmitter unit with a source emitting radiation. Included in the transmitter unit is a piece of birefringent material which splits the radiation into two displaced orthogonally polarized components. A receiver unit which substantially contains two detectors receives the two components of the radiation. The detectors are combined with polarizers in such a way that at least one detector has a preferred sensitivity to one polarization component and the apparent distance of the detectors in the plane perpendicular to the propagation direction approximately equals the beam displacement produced at the transmitter.

Abstract: According to the present invention, there are provided a projection system for emitting luminous flux for measurement, a light receiving unit or a prism member furnished with a light receiving unit, and an optical waveguide substrate comprising a substrate portion and an optical waveguide portion formed on the substrate portion, the light receiving unit or the prism is brought into close contact with the optical waveguide substrate, luminous flux for measurement from the projection system is passed from one end of the optical wavegide portion and a part of the luminous flux for measurement is leaked toward the light receiving unit, whereby cross-sectional distribution of refractive index of the optical waveguide is measured by change of light quantity of the leaking light sensed at the light receiving unit in case an incident point of the luminous flux for measurement is moved.

Abstract: According to the present invention, there are provided a projection system having an optical axis inclined toward one end surface of an optical waveguide portion arranged on one side of a substrate portion and for irradiating luminous flux for measurement from one end surface of the optical waveguide portion, and a light receiving unit for receiving luminous flux leaking from the optical waveguide portion among the luminous fluxes for measurement, projected light is effectively utilized for measurement, whereby cross-sectional distribution of refractive index of the optical waveguide is measured by change of light quantity entering said light receiving unit in case an incident point of the luminous flux is moved.

Abstract: A device measuring the optical absorption in thin layer materials by using the photothermal deflection spectroscopy (P.D.S.) comprises a laser source, an optical doubler between the laser source and the probe intended to divide the laser beam in two equal, parallel measurement and control beams, a cylindrical lens between the doubler and the probe, and a pair of position sensors which receive the beams focused by said lens and send them to an electronic circuit supplying a signal output which is not influenced by the noise due to the instability in the direction of the analyzer beam and to the mechanical vibrations.

Abstract: This invention relates to an optical sensor for testing a biochemical sample. The sensor includes a resonant mirror device 1 and a prism 2 disposed adjacent the device 1 for coupling an input beam of light to the device 1. The input beam of light having a comb spectrum with a uniform spacing between adjacent lines or bands of the spectrum is produced by a comb spectrum source 10. The comb spectrum may be produced by a diode laser with multiple longitudinal modes. The input beam of light is polarized by a polarizer 4 to provide equal TE and TM components. The resonant mirror device is arranged in the paths of said input beam of light such that resonance is excited for at least one of said components, An analyser 11 is arranged to receive said components of the beam of light reflected from the device 1 for producing an output beam having a spectrum including a series of bright and/or dark lines or bands corresponding to the lines or bands of the comb spectrum of the input beam.

Abstract: A detection cell (4) is part of an interferometer for measuring changes in the refractive index of a medium located in a capillary (2). In order to simplify the evaluation of an interference fringe pattern, the capillary (2) is arranged in a matching fluid (15), the refractive index of which corresponds to that of the material of the capillary. The matching fluid (15) acts at the same time as a temperature-control bath for the capillary, thereby substantially increasing the temperature stability.

Abstract: A rock specimen is selected from many rock specimens based on composition of released fluid inclusion volatiles being indicative of a selected class of fluid inclusions therein. Compositions of selected classes of inclusions or of selected individual fluid inclusions in the selected rock specimen are further characterized and the resulting information used in exploring for oil and gas.

Abstract: There is provided an apparatus for monitoring the relative concentration of an analyte in a fluid stream, with such apparatus including a capillary tube for containing the flowing fluid, optics for directing a single beam of monochromatic light through the capillary tube to produce a diffraction pattern having a number of interference fringes. A translatable photodiode is provided to monitor a portion of one of the fringes passing through a light limiting slit, whereby a signal proportional to the concentration of the analyte in the fluid is produced based upon the varying intensity of the monitored fringe. The capillary tube is preferably provided as a fused silica member having an inner flow diameter of 100 micrometers or less.

Abstract: A method and apparatus for measuring the change in refractive index of a material with respect to temperature. The invention contemplates measuring the change in length of the material with respect to temperature over a predetermined temperature range with a Fizeau Interferometer by measuring the change in length through a vacuum at a point adjacent the length to produce a first set of data. Also measured is the change in the same length of the same material with respect to temperature over the same predetermined temperature range with the Interferometer by measuring the change in the length through the material to produce a second set of data. Determining the difference between the first and second sets of data produces resulting data which is the change in refractive index of the material with respect to temperature.

Abstract: An optical sensor includes a resonant mirror device 1, and a prism 2 disposed adjacent the device for coupling a beam of light into the device 1. The device 1 and the prism 2 are mounted on a rotatable platform. A beam of light is produced by He-Ne laser 3 and is linearly polarized with equal TE and TM components by a polarizer 4 arranged at 45.degree. to TE and TM axis. A lens 6 is arranged in the path of the linearly polarized beam of light for focussing the beam of light onto the device thereby providing simultaneously a range of angles of incidence at which the beam of light can be coupled into said device. The platform on which the device 1 and the prism 2 are mounted, is rotated to a position, at which the angle of incidence of beam of light coupled into the device is such that a resonance is excited in said device for at least one of said components. The beam of light reflected from the device is passed through an analyser 11 arranged at 90.degree. to the polarizer 4.

Abstract: A method of preparing an optical fiber for user in an interferometric system includes introducing a portion of a single-mode, polarization preserving fiber having an asymmetric cladding into a medium capable of etching away the cladding and withdrawing the portion from the medium after sensing an optical intraction between light introduced into the optical fiber and the medium.

Abstract: A critical angle refractive index detector for production liquid chromatography systems with flow rates as low as 100 ml/min to 25 l/min or higher as the system requires and pressures up to 4000 psi. The detector includes a flow cell with a sensing chamber volume selected to provide maximum detector sensitivity and minimum pressure drop at the maximum flow rate of the system for accurate discernment of critical refractive index peaks of each constituent in the sample. Explosion protected controls for zero and span settings are located to the exterior of a purged safe enclosure containing the system.

Abstract: This invention describes a technique for improving the sensitivity of a resonant mirror sensor which has particular applications in areas involving sensing at an interface such as immunosensing using immobilized antibodies. By the introduction of a Bragg grating structure in the sensor, there is produced enhanced dispersion and hence enhanced sensitivity in the region close to the band edge. This improves the detection limit of the sensor without changing the composition or involving the sensor size and allows more sensitive operation at reduced incident angles.

Abstract: A method and apparatus is disclosed for measuring the thickness or other optical constants of a thin film on a sample. The apparatus includes a laser for generating a linearly polarized probe beam. The probe beam is tightly focused on the sample surface to create a spread of angles of incidence. The reflected probe beam is passed through a quarter-wave plate and linear polarizer before impinging on a quad cell photodetector. The output signals from the photodetector represent an integration of the intensity of individual rays having various angles of incidence. By taking the difference between the sums of the output signals of diametrically opposed quadrants, a value can be obtained which varies linearly with film thickness for very thin films. The subject device can be used in conjunction with other prior devices to enhance sensitivity for thicker films.

Abstract: In apparatus useful in immunoassay of a fluid, light is directed to an optical sensor wherein the light is transmitted to a replaceable optical device that is responsive to index of refraction in a sensing region thereof that is exposed to the fluid. One portion of the light is transmitted via a reference path to a first detector. Another portion of the light is transmitted via a sensing path that includes the sensing region to another detector. A ratioing device receives an output from each detector and provides a signal responsive to the ratio of the outputs. The replaceable optical device typically comprises a pair of channel waveguides in directional coupling arrangement, or a pair of channel waveguides in an interferometer arrangement, or a ridge waveguide having a serpentine path.

Abstract: In order to determine the nonlinear refractive index coefficient of a material which, once inserted into a Fabry-Perot cavity (1), has an optically bistable behavior, the output power (12; 13) of the cavity (1) is measured in function of the power (1) of an amplitude-modulated optical input signal to obtain the material hysteresis loop; the hysteresis loop saturation region is detected, where the phase (.phi.) of the electromagnetic field associated with the signal within the cavity is a linear function of the output power; the values of the phase (.phi.) in said region are obtained from the output and input power values (12; 13; 11) and the nonlinear refractive index coefficient (n2) is obtained from the angular coefficient of the straight line representing said phase.

Abstract: A species-specific metal clad segment on a waveguide, including a planar waveguide, allows controlled light leakage of light propagating through the waveguide by total internal reflection, to measure refractive index and identify chemical species. A waveguide sensor is designed for a particular chemical species by selecting a metal clad with an affinity for the species and by matching the refractive indices of the waveguide body, clad, metal clad segment and chemical species. Dual or multiple measurement methods use a pair or multiple metal clad segments of different specificity. The metal clad segment may include another material to provide a suitable refractive index while having the desired affinity for the chemical species or to provide a catalyst to react the species to form a reaction product which is more readily detected.

Abstract: The system uses a monochromatic radiation source (1) and an acousto-optic modulator (2), which is driven by a periodically variable frequency. The modulator emits a first beam having the same wavelength as the source and a second beam, whose wavelength and emission direction vary with the modulating frequency. After the second beam has been collimated, radiations of both beams are sent towards the component under test and an electrical signal with varying frequency is generated representative of the beat between such radiations at the output from the component. A spectral analysis of the beat signal is carried out, and the refractive index value is derived from the position taken by the various frequencies of the beat signal on a detection plane.

Abstract: A refractive index sensor senses the refractive index of a mixed liquid and generates a corresponding signal. A temperature sensor senses the temperature of the liquid and generates a corresponding signal. A signal mixer mixes the refractive index signal and the temperature signal with each other to provide a single mixed signal which is then fed through a single signal line to a liquid content calculator where the sensed refractive index is modified based on the sensed liquid temperature to provide a temperature compensated refractive index from which the content of a liquid component in the liquid is calculated. This simplifies the arrangement of the entire apparatus and improves the operational reliability thereof as compared with the case in which the two signals are separately supplied to the liquid content calculator through two signal supply systems.

Abstract: A liquid content detecting device is provided which can detect the contents of liquid components such as alcohol in a mixed fuel (both regular and premium gasolines) with a high degree of preciseness at all times over the entire operating temperature range in which the device is used. A refractive index sensor senses the refractive index of a liquid mixture which includes N kinds of liquid components. A liquid-kine identifying means identifies the kind of each of the liquid components. A temperature sensor senses the temperature of the liquid mixture. A liquid content calculator stores a temperature-dependent refractive index characteristic of various kinds of liquids including the liquid components in advance.

Abstract: The sensitivity of refractive gradient detectors for detecting refractive index gradients in samples flowing through samples chambers is increased by detecting the gradients formed in the direction perpendicular to the direction of flow of the sample through the sample chamber and by detecting such gradients simultaneously intermediate the central axis and sides of the sample chamber on opposite sides of the central axis. A preferred detector uses two spaced, parallel probe light beams passing through the sample chamber between the central axis and sides of the chamber on opposite sides of the axis, with each beam preferably centered about half way between the axis and the respective side. A sensor detects relative movement of the probe beams caused by a refractive index gradient in the sample but preferably compensates for parallel movement of the parallel light beams caused by positional instability or mechanical movement of the light source.

Abstract: A method of measuring a refractive index distribution of a lens is disclosed which comprises, immersing a glass sample and a lens under test within a matching fluid whose refractive index differs slightly from that of the glass to be tested, the glass sample having a refractive index and a shape which are both known and the lens to be tested having an unknown refractive index but a known shape, allowing coherent light to pass through the glass sample and the lens under test; superposing the transmitted light wave on a reference light wave to generate interference fringes, outputting the intensity distribution of interference fringes that are generated by the light wave that has passed through the glass sample, determining the refractive index of the matching fluid on the basis of the resulting output, outputting the intensity distribution of interference fringes that are generated by the light wave that has passed through the lens under test; separating from the resulting output the defocus term and aberratio

Abstract: A laser scintillometer measures the variance of the log intensity of diverged laser light received via a first path. A large aperture scintillometer measures the variance of the log intensity of light from an incoherently illuminated source received via a second path. The ratio of the two measured variances gives the inner scale of turbulence. The refractive-index structure parameter is derived from either measured variance and the inner scale. A processor then derives values of fluxes, such as heat flux and momentum flux, from the refractive-index structure parameter and the inner scale of turbulence using Monin-Obukhov similarity relationships.

Abstract: A critical angle refractive index detector for production liquid chromatography systems with flow rates as low as 100 ml/min to 25 l/min or higher as the system requires and pressures up to 4000 psi. The detector includes a flow cell with a sensing chamber volume selected to provide maximum detector sensitivity and minimum pressure drop at the maximum flow rate of the system for accurate discernment of critical refractive index peaks of each constituent in the sample. Explosion protected controls for zero and span settings are located to the exterior of a purged safe enclosure containing the system.

Abstract: A sample is located so as to be close to a prism and a light beam coming from a light source is projected to the prism while varying the incident angle to the prism as a parameter. The incident light beam to the prism is propagated therein and light emerging from the bottom surface of the prism, which is in contact with the sample, is projected to the sample. At the same time the intensity of light reflected by the bottom surface of the prism is measured. Optical constants such as the refractive index, the film thickness, the distribution of the refractive index, etc. are obtained by calculation, starting from measured values thus obtained.

Abstract: The present invention provides an apparatus and method for non-invasively monitoring turbulent fluid flows including anisotropic flows. The present invention uses an optical technique to filter out the rays travelling in a straight line, while transmitting rays with turbulence induced fluctuations in time. The output is two dimensional, and can provide data regarding the spectral intensity distribution, or a view of the turbulence in real time. The optical monitor of the present invention comprises a laser that produces a coherent output beam that is directed through a fluid flow, which phase-modulates the beam. The beam is applied to a temporal filter that filters out the rays in the beam that are straight, while substantially transmitting the fluctuating, turbulence-induced rays. The temporal filter includes a lens and a photorefractive crystal such as BaTiO.sub.3 that is positioned in the converging section of the beam near the focal plane. An imaging system is used to observe the filtered beam.

Abstract: An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.

Abstract: A method is provided for monitoring the refractive index of an optical film as it is being deposited on a substrate. The film is illuminated by a source of light at a wavelength that is outside and less than the reflectance band of the coating. If the refractive index of the film is initially matched to the refractive index of the substrate and has no abrupt changes in its gradient-index profile, reflectance from the surface of the film can be detected and measured. In the absence of interference fringing from internal reflections, surface reflectance of the interface of the film with the surrounding air or vacuum is closely related to the refractive index of the film at its surface. Thus, surface reflection is monitored to provide a control signal to the deposition apparatus to conform the refractive index of material being deposited to a predetermined refractive index profile specified for the desired optical film.

Abstract: There is disclosed an integrated spectrometer for chemical analysis by evanescent electromagnetic radiation absorption in a reaction volume. The spectrometer comprises a noninteractive waveguide, a substrate, an entrance grating and an exit grating, an electromagnetic radiation source, and an electromagnetic radiation sensing device. There is further disclosed a chemical sensor to determine the pressure and concentration of a chemical species in a mixture comprising an interactive waveguide, a substrate, an entrance grating and an exit grating, an electromagnetic radiation source, and an electromagnetic radiation sensing device.

Abstract: Determination of refractive index distribution is utilized, including data of all the positions of diffraction images on a plane, from the incident ray dispersed by the cylindrical glass rod when the ray passes therethrough. A linear approximation thereof is performed; and the angle of the outgoing ray is calculated using the intersection of the approximate lineation and a plane through which the incident ray passes. Much data can be employed to calculated the angle of the outgoing ray. This substantially improves the accuracy of measurement of the angle of the outgoing ray and further this makes it possible to determine the angle even if no image of the outgoing ray is present on the plane throgh which the incident ray passes.

Abstract: The optical sensor for the detection of specific substances and refractive index changes in gaseous, liquid, solid and porous samples is composed of integrated optical elements. It consists of a waveguiding film (1) equipped with a diffraction grating (4) and applied onto a substrate (2). For the selective detection of a specific substance contained in the sample (3) a selectively chemisorbing additional layer (5) covers the film (1) at least in the grating region. The sample (3) is applied at least in the grating region either directly onto the waveguiding film (1) or onto the selectively chemisorbing additional layer (5). Chemisorption of the substance, which is contained in the sample (3) and is to be detected, to the selectively chemisorbing additional layer (5) results in a further adlayer (6) coating the waveguiding film (1).

Abstract: A concentration measuring method and an apparatus measures the concentration of an objective solvent in a mixed solution by flowing a mixed solution through a tube, transmitting light through the mixed solution as it flows through the tubing and measuring the quantity of light transmitted through the fluid. The concentration of the objective solvent in the mixed solution is measured on the basis of either the quantity of light transmitted, the diameter of a light beam received, or a point of convergence of the light transmitted through the mixed solution. These factors being dependent on the concentration of the objective solvent in the mixed solution.

Abstract: A refractive index-based sensor uses a light source and an optical fiber to direct an optical beam towards a sensor/environment face at a specific angle. The sensor has a predetermined shape selected such that the light directed into the sensor will have a specific angle of incidence designed to detect a plurality of liquids. A second optical fiber carries the light reflected off the sensor/environment face to a photodetector. The optical beam will either be transmitted through or reflected off the sensor/environment face based upon the refractive indices of the sensor and the environment and upon the angle of incidence of the optical beam. The amount of light reflected is indicative of the refractive index of the material in a given area of the sensor/environment face and, thus, the type of material. By adjusting the angle at which the light is directed to the sensor/environment face, the photodetector response can be calibrated to identify the type of liquid present at the sensor/environment face.