Abstract: A photometric apparatus (100) for small sample volumes comprises a cell body (102), a light input means (104) arranged adjacent to a first surface of the cell body (102), a light source (105) emitting light of predetermined wavelength or wavelength range through the light input means (104), a light output means (106) arranged adjacent to a second surface of the cell body (102) opposite to the first surface, a light detector (107) arranged adjacent to the light out put means (104), and a flow channel (108) formed in the cell body (102), wherein surfaces of the walls of the channel (108) have a roughness smaller than the predetermined wavelength.

Abstract: Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

Abstract: A cavity ring down spectroscopy (CRDS) system uses a free-running continuous wave (c.w.) diode laser stabilized by frequency-shifted optical feedback in the presence of strong reflections from a high-finesse Fabry-Perot resonator. The frequency-shifted feedback stabilization eliminates the need for tightly controlling the relative positions of the laser and resonator. Non-frequency-shifted feedback is used for linewidth broadening. An acousto-optic modulator placed between the diode laser output and the resonator input frequency-shifts light reflected by the resonator input, causing the laser to cycle in phase with a period equal to the inverse of the frequency-shift. The laser diode linewidth can be stabilized from several MHz for high resolution spectroscopy of species at low pressures, to several hundred MHz for lower resolution spectroscopy of species at atmospheric pressures.

Abstract: An apparatus to effect multiple simultaneous separations to measure absorbance, comprising a photodetector array comprising a plurality of photosensitive elements connected to provide a serial output. The elements are typically pixels of a photodiode array (PDA). The elements are illuminated by a light source positioned to illuminate at least a portion of the photodetector array. The light source may be a an AC or DC mercury lamp or other useable light source for chromatography. An array of separation channels is disposed between the light source and the photodetector array, each of the separation channels having a lumen, a sample introduction end and a detection region disposed opposite the sample introduction end. Typically and as disclosed herein the array is a multiple parallel capillary electrophoresis system.

Abstract: Embodiments of the present invention feature devices and methods for analyzing the absorbance spectra of a sample, and a method of making such device. The device comprises a housing having an exterior surface and an interior surface. The interior surface defines a chamber having an input opening and an exit opening defined by rims. The input opening has a first geometric shape and the exit opening has a second geometric shape. Any point about the rim at the input end can be connected by a straight line to any point on the rim of the exit end. The interior surface end of the chamber corresponds to the sum of these lines from the rim of the input opening, to the rim of the exit opening.

Abstract: A cross-road motor vehicle exhaust gas analyzer uses tunable infrared laser differential absorption spectroscopy incorporating photon infrared detection to determine the absolute fractional absorption of a laser by the gaseous medium. Spectroscopic constants of the gaseous species of interest are applied to the absolute fractional absorption to calculate the pertinent absolute column densities. In addition to a laser that sweeps across one or more absorption line of an component of interest, the system of the invention includes a laser source tunable over an absorption line of a reference species; the calculated column density of the reference species is used to normalize the concentration of the component of interest to the fuel consumption rate of the motor vehicle.

Abstract: The fat content and an undissolved solids content of a milk sample, taken from a milk processing flow, are separately determined. In addition, the total solids content of the milk flow is determined. Based on the fat, undissolved solids, and total solids content, the amount of protein and/or casein in the flow is determined. In a control portion of the invention, the fat and undissolved solids are controlled dynamically to standard values, whereby the characteristics of the milk flow are adjusted to standard values useable for whole milk, cheese-making and other uses.

Abstract: The invention provides apparatuses for detecting light from, for example, closely spaced detection sites.

Abstract: The present invention relates to an analyzer for determining the concentration of substances, such as chemicals, present in a fluid medium, such as gas, vapor or liquid, using holographic optics. The analyzer of the present invention is based on the infra red absorbance of the gas, vapor or liquid to be measured, where the optical functions of an infra red absorbance gas analyzer are performed by holographic functional representations of the required optical components.

Abstract: An optical absorbance meter has a flow passage for liquid to be tested, each end of which is closed with a flat light-transmission plate, an introducing path for introducing liquid to the flow passage and a discharging path for discharging the liquid from the flow passage wherein light from a light source is incident from one side near the flat light-transmission plate and emits from the other side near the flat light-transmission plate, wherein a first optical aperture is disposed in front of the flat light-transmission plate at an incident side; a second optical aperture is disposed in rear of the flat light-transmission plate at an emission side; the aperture diameter of the first optical aperture in the direction perpendicular to the axial line of the flow passage is equal to or smaller than the smallest diameter of the flow passage in the direction perpendicular to the axial line of the flow passage, and the aperture diameter of the second optical aperture in the direction perpendicular to the axial line

Abstract: Hand apparatus for pipetting and photometrically evaluating samples which comprise a pipetting means, an integrated photometer and a replaceable pipette tip connected to said pipetting means, said pipette tip being defined as a cell and provided within the optical path of the photometer for photometrically evaluating absorbed samples.

Abstract: A broadband, ultrahigh-sensitivity chemical sensor is provided that allows etection through utilization of a small, extremely low-loss, monolithic optical cavity. The cavity is fabricated from highly transparent optical material in the shape of a regular polygon with one or more convex facets to form a stable resonator for ray trajectories sustained by total internal reflection. Optical radiation enters and exits the monolithic cavity by photon tunneling in which two totally reflecting surfaces are brought into close proximity. In the presence of absorbing material, the loss per pass is increased since the evanescent waves that exist exterior to the cavity at points where the circulating pulse is totally reflected, are absorbed. The decay rate of an injected pulse is determined by coupling out an infinitesimal fraction of the pulse to produce an intensity-versus-time decay curve.

Abstract: An improved method of monitoring particulates in stacks or ducts utilizes transmissometer/particulate monitor of the type which has an optical assembly containing a solid state light source of visible light such as a light-emitting diode or a solid-state laser. The light source emits a collimated beam that is split, part of which is focused onto a reference detector that monitors the intensity of the light source, while the other part is directed to a beam-steering apparatus that causes the beam to accurately pass through a gaseous sample to a desired location such as a retro-reflector. A position-sensing detector is used in a closed-loop manner to control the beam-steering apparatus. The ratio of the total energy of the detected light beam, relative to the reference detector output, is used to determine the opacity of the gaseous sample for the purpose of providing a basis for correlation to particulate loading of that portion of the particulates that are of a size comparable to the wavelength of light.

Abstract: Apparatus and a method are described for eliminating gas bubbles from a moving liquid stream. The apparatus includes a plurality of chambers having an open top. Each chamber directs the moving liquid stream upwardly through an area of reduced diameter and then downwardly to an opening into an adjacent chamber. The bubbles are thereby urged upwardly to the top of the liquid where they burst and are vented to the atmosphere. The apparatus and method are especially useful, for example, in a turbidimeter.

Abstract: A fluid turbidity or filter clog sensor comprises a light source and a detector having at least one sensor position to cross a flow path or a filter element in order to improve the correspondence of the light intensity received at the receiver in correspondence with the turbidity level or clogging level occurring in the test cell. The detector preferably includes a direct path sensor, a scattered path sensor positioned to cross the flow path from the transmitter, and the reference light sensor communicating with the source outside of the test chamber. Moreover, the direct path may be a straight line path or a reflected path through the flow path when a fluid having a low level of turbidity is passed through the test cell. Likewise, the sensor includes means for compensating for changes in the illuminating source, changes for temperature variations occurring at the test cell, and compact packaging for convenient installation and improved production capacity.

Abstract: Provided is a novel polygonal planar multipass cell and method of use for absorption spectroscopy. The cell comprises a sample region circumscribed by a plurality of walls. Each wall has a light reflective surface facing the sample region, and each wall is connected to at least one other wall so as to form in cross section substantially a polygon. At least one side of the polygon has a light entry/exit port therein, and the entry/exit port contains a light transmissive window which has a surface facing the sample region. The window is disposed so as to seal the cell in the circumferential direction. The cell has a central axis parallel to the light reflective surfaces of the walls and the surface of the light transmissive window which face the sample region. The cell can be used to measure molecular gas impurities in a sample. Particular applicability is found in semiconductor processing.

Abstract: An apparatus and method for the testing of materials by thermal oxidation is provided. The apparatus comprises a housing having at least one optic-isolated chamber. A photon counting photomultiplier and a heat source, for each optic-isolated chamber, are also provided within the housing. A cell, having a plurality of gas inputs and gas outlets, for holding a sample to be tested, is provided within the housing for each chamber. The gas inputs and outputs are distributed about the cell so as to disperse gas evenly about the material to be tested. The apparatus is used to count the number of photons which escape from a test sample as various oxidation conditions are employed.

Abstract: A long-path absorbance-cell optical imaging system, appropriate for use in cold vapor mercury analysis, which long-path absorbance-cell optical imaging system achieves decreased internal reflection mediated system-element-parameter-change-based sensitivity in use, by appropriate placement of apertures, is disclosed.

Abstract: Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

Abstract: A non-dispersive infrared (NDIR) multi-gas analyzer has an optical element that is positioned with respect to the axis of incident IR radiation such that it passes nearly all of the IR energy within a narrow band pass to one detector and reflects nearly all of the IR energy outside the narrow band pass to another detector. Thus, the optical element simultaneously functions both as a narrow band pass filter and a beam splitter, which transmits nearly all the IR energy within a band pass and reflects nearly all the IR energy outside the band pass. Additionally, the separation of the incoming energy can be achieved without an extended roll off. This allows using a reference transmission band that is very close to the absorption band of the gases of interest. It more specifically allows using a reference transmission band that is located between the absorption bands for hydrocarbons and carbon dioxide in an infrared analyzer that uses beam splitters.

Abstract: A hollow vacuum-tight shaped body made of ceramic material for measuring transmission and absorption of electromagnetic radiation in liquids and gases is characterized by the fact that the ceramic material consists principally of Al.sub.2 O.sub.3 and has one or a plurality of apertures of any size, which are permanently and integrally closed by a material which is permeable to electromagnetic radiation in the wavelength range from 180 nm to 5.5 .mu.m.

Abstract: A gas analysis apparatus includes an optical source for providing an optical signal, an interferometer for modifying the optical signal, and an optical signal detector. A first housing having folded path optical elements positioned therein; the elements defining a sample path through which the optical signal passes from the interferometer to the optical signal detector. The first housing has a sample introduction opening. A second housing defines a sample holding volume. The second housing is sealingly positioned with respect to the first housing for fluidly connecting the sample path of the first housing with the sample holding volume of the second housing through the sample introduction opening. A recirculating flow may be provided between the sample path and the sample holding volume. The second housing may include an access port with a detachable access closure through which a material may be placed in the sample holding volume. A method for using the apparatus is also described.

Abstract: A hand-held portable spectrophotometer that is contained in an enclosed housing and includes a source of illumination and a spectrograph, along with a transmittance cell and a reflectance cell. The transmittance cell is adapted to receive therein either a solid sample or a liquid sample through an access door in the top wall of the housing.

Abstract: The use as a cuvette in spectrophotometric assays of a sample-collecting device is disclosed, the said device possessing a cavity or cavities each having a dimension small enough to enable sample liquid to be drawn into the cavity by capillary action, wherein a surface of the cavity is a surface of a transparent solid plate having a substantially rectangular cross section and forming a wall of the cavity, the opposite surface of the cavity being an additional structure having a substantially rectangular cross section and forming a wall of the cavity, and wherein a portion of said plate carries a reflective coating and a portion of said additional structure is reflective.

Abstract: A method and apparatus for detecting presence of liquid in a pathway of known volume feature a molding with a sample receiving port, a pump connection port, at least one sample treating chamber and optionally at least one optical measuring chamber located between the sample receiving port and the pump connection port. The sample receiving port and the treating chambers are connected with each other through a pathway, which passes through the liquid detecting part, that has at least one air hole that is controlled to be in an open or closed state in response to the presence of liquid detected by the liquid detecting part. A sample is quantitatively fed from the sample receiving port into a sample treating chamber. Detection of the liquid involves projecting a light beam at an incident angle in a range of 42.degree. to 62.degree.

Abstract: A method is provided to test turbidity sensors using a solid block that is particularly formulated to have a predetermined turbidity value. The solid block, which is partially transparent, is made by mixing calcium carbonate with a clear acrylic. A plurality of sample sensors are selected to be used as an intermediate standard to correlate the results achieved when the block is tested to results that would be achieved if liquid turbidity samples are tested. The six sample sensors are used to measure the turbidity of a plurality of liquid samples. The six sample sensors are then used to test the solid block in order to make sure that the turbidity represented by the solid block is within an acceptable range that is normally dictated by either a national standard or a particular customer requirement. Each of the plurality of sample sensors is used to test the solid block a plurality of times to form an average ratio value that can be used as a first representative magnitude for each of the sample sensors.

Abstract: Disclosed is an apparatus for fluidic separation systems comprising a microfabricated conduit including a usefully long optical pathlength. The provision of a usefully long optical pathlength in the apparatus greatly improves the sensitivity of detection of separated analytes without compromising the resolving power of the apparatus.

Abstract: A non-contact optical backscatter insertion probe includes an outer chamber, an electromagnetic energy source positioned within the outer chamber for emitting photons towards a medium to be analyzed, and an inner chamber positioned within the outer chamber. The inner chamber has a reflective outer surface to prevent photons emitted by the electromagnetic energy source in the outer chamber from entering the inner chamber. The probe also includes a sensor positioned within the inner chamber for receiving backscattered photons from the medium. The inner chamber provides the backscattered photons emitted from the medium to the sensor. A processor receives and processes signals output by the sensor.

Abstract: An improved transmissometer/particulate monitor of the type which has an optical assembly containing a solid state light source preferably a solid-state laser. The light source emits a collimated beam that is split, part of which is focused onto a reference detector that monitors the intensity of the light source, while the other part is directed to a beam-steering apparatus that causes the beam to accurately pass through a gaseous sample to a desired location such as a retro-reflector. A position-sensing detector is used in a closed-loop manner to control the beam-steering apparatus. The ratio of the total energy of the detected light beam, relative to the reference detector output, is used to determine the opacity of the gaseous sample or to provide a basis for correlation to particulate loading of the sample or both.

Abstract: Method of assay of enzymatic activity, comprising projecting excitation light to a sample containing an enzyme, a substrate which forms a product by action of the enzyme, and a reference substance which is insensitive to the action of the enzyme but emits fluorescence; obtaining a first measured value of fluorescence intensity of the sample at a first wavelength region which includes fluorescence emitted by the substrate or the product at least, obtaining a second measured value of fluorescence intensity at a second wavelength region which is different from the first wavelength region for the first measured value and includes fluorescence emitted by the reference substance; and assaying the enzymatic activity from the ratio of the first measured value to the second measured value and apparatus for performing the method. The method assures high accuracy and high sensitivity of measurement in enzyme labeled immunoassay and enzyme labeled DNA hybridization.

Abstract: A sample cell of the multiple reflection type is used for analyzing a sample in the same cell. In the sample cell, incident light is reflected a plurality of times. The sample cell includes a mirror plate including a light incident window for introducing the incident light into the sample cell, a first concave mirror, and a light exit window for outputting the incident light form the sample cell. A side plate including a second concave mirror reflects the incident light to the first concave mirror and a third concave mirror for reflecting the incident light reflected by the first and second concave mirrors to the light exit window. The cell also includes a frame for fixing the mirror plate and the side plate so that the distances between the first concave mirror and the second and third concave mirrors are fixed at a distance equal to the radius of curvature of the three concave mirrors.

Abstract: The present invention provides a flow cytometer made of two components: a flow cytometer optical head and a disposable flow module. The flow module utilizes a V-groove flow channel micromachined in a silicon wafer. The optical head comprises a laser to provide an illuminating beam and small and large angle photodetectors. Anisotropically etched facets of the V-groove reflect the illuminating beam. Small angle scattered light is also reflected by the V-groove wall and is collected by the small angle photodetector. Large angle scattered light and fluorescent light can exit the channel without reflection and are collected by the large angle photodetector. In addition, fluorescent light can be back-reflected by the V-groove, which enhances the collection efficiency.

Abstract: A method of analyzing a specimen by infrared spectroscopy is disclosed wherein a specimen support having a plurality of unobstructed holes of substantially uniform size and a film of the specimen enclosing each hole is positioned vertically in the spectrometer and a beam of infrared light is directed through the holes to generate a wavelength spectrum characteristic of the specimen.

Abstract: A portable, hand-held spectrophotometric probe detects the concentration of a material dissolved in a liquid bath. The probe has an elongate hollow handle with an open lower end. A transparent cylindrical cell is attached to the lower end of the handle and fills with liquid when the cell is immersed in the bath. A source of light whose spectrum includes an absorption band of the dissolved material is mounted in the handle and transmits light through the cell to a photodetector. The photodetector produces a signal indicative of the intensity of the light, and the signal is transmitted along wiring to a signal outlet in the upper end of the handle. A hand-held processing unit is coupled with a cable to the outlet to receive the signal and then calculates and displays the concentration of the dissolved material.

Abstract: A device for holding and positioning a sample (22) during spectral analysis, having an optical cell (41) comprised of a base member (42), a glass cell (44), and being filled with oil (46) having substantially the same index of refraction as the glass cell (44). The device further includes a rotary stage device (48) attached to the optical cell (41) and a sample holder (50) attached to the rotary stage device (48) such that a sample (22) may be rotated over a range of angles relative to a projected beam (32) to provide a spectral analysis of the sample (22) over the range of angles.

Abstract: An apparatus for measuring light penetrability of liquids, including: a water-tight, heat, compression and chemical resistant casing, a light source mounted inside the casing and controlled to alternately, emit light of different wavelengths, a controller mounted inside the casing for detecting light and converting detected light into electrical signals, and a light guide mounted inside the casing for guiding light from the light source to the controller through a liquid to be tested.

Abstract: A measuring beam is incident upon a triangular cell storing a liquid sample, and transmitted light thereof is received by a linear sensor so that both transmitted light intensity and a position of the beam are detected. A refractive index calculating part calculates refractive indices from the position detected by the linear sensor, while an absorbance calculating part calculates absorbance values dependent on component concentration values correcting influence by transmittance change at the triangular cell through the transmitted light intensity values and the refractive indices of the sample calculated at the refractive index calculating part. A component concentration calculating part performs a multivariate analytical operation on the basis of the absorbance values dependent on the component concentration values at a plurality of measuring wavelengths calculated at the absorbance calculating part.

Abstract: An integrated-optic sensor includes a waveguide made from a substrate that is doped with rare-earth elements. A beam of light propagating along the waveguide excites these elements, causing them to emit light and thereby increase the total amount of light being propagated in the waveguide. The waveguide itself functions as a laser, so that any change in an optical property of an analyte material which forms a portion of the laser cavity can affect the operation of the laser. Consequently, the wavelength or power of light produced by the laser changes, in direct response to changes in the concentration of a material being sensed, and these changes are enhanced due to the inherent gain characteristics of the laser media.

Abstract: A present invention is directed to an apparatus which measures the optical absorption of a sample by photoacoustic measurement and has a configuration for improving the reliability and efficiency in this measurement and is directed to a sample holder applicable to this apparatus. In particular, this sample holder has a specific configuration for improving the reproducibility of acoustic propagation conditions.

Abstract: Ambiguity, in readings from an optical bubble detector used with tubing, can be reduced by shaping the tubing into the shape of a prism, so that when different contents of the tubing have differing indices of refraction, there is a clear difference in the exit angle of the light beam leaving the tube. A triangular prism shape is preferred for the compressed tubing. The optical bubble detector features an optics block formed with a V-shaped recess, and a clamp block. The optics block and clamp block cooperatively press or "sandwich" the flexible tubing into the V-shaped recess and deform it into a triangular prismatic cross-section. A generally U-shaped optical interrupter element, containing a photoemitter and a photosensor, fits into the optics block in such a manner that a light beam is directed radially into the triangular tubing section.

Abstract: An analyzer for performing automated assay testing. The analyzer includes a storage and conveyor system for conveying cuvettes to an incubation or processing conveyor, a storage and selection system for test sample containers, a storage and selection system for reagent containers, sample and reagent aspirating and dispensing probes, a separation system for separating bound from unbound tracer or labeled reagent, a detection system and date collection/processing system. All of the subunits of the machine are controlled by a central processing unit to coordinate the activity of all of the subunits of the analyzer. The analyzer is specifically suited for performing heterogeneous binding assay protocols, particularly immunoassays.

Abstract: A device for detecting a conduit and for determining at least one characteristic of its content includes a seat for housing at least a portion of the conduit. The seat has first and second zones which are opposite each other with respect to a recess intended to receive the conduit. A light emitter is arranged in the first zone, and has a preferential emission direction oriented towards the recess. A receptor sensitive to the light emitted by the emitter also has a preferential reception direction oriented towards the recess. A first deflector deflects light in the direction of the first zone when a conduit containing a substantially transparent liquid is engaged in the seat.

Abstract: A apparatus for sensing flow and/or other characteristics of a fluid, including an emitter adapted to project a light beam, a detector adapted to transmit a signal in response to receiving the light beam and a rotatable member for transmitting the beam of light from the emitter to the detector through a quantity of the fluid. Optic fibers/light pipes may be used to transmit light to the emitter from a light source, through the rotatable member and to a processor remote from the detector. The rotatable member may also include reflective and nonreflective zones for transmitting light passing through the fluid to the detector. A plurality of light pipes, blades, emitters and detectors may be used on the rotating member depending on a particular application of the present invention.

Abstract: An optical detection arrangement for small volume chemical analysis comprises a light source (22), a capillary tube (23) and a photoelectric detector (24). The arrangement of the light source (22) relative to the capillary tube (23) is such, that probing light (P) emitted from the light source (22) strikes a sample (S) to be analyzed, which is flowing through the capillary tube (23), whereas the photoelectric detector (24) is arranged relative to the capillary tube (23) such, that it is capable of detecting light comming from the capillary tube. The photoelectric detector (24) is connected with an evaluation electronics.

Abstract: A portion of a surface of a sample body is arranged to receive an incident optical beam having an optical intensity I.sub.0. On an opposing surface of the sample body is located an optical detector which senses the intensity I of the resulting optical radiation emerging from the opposing surface of the sample body. In order to measure the thickness t of the sample body, a thickness gauge is located either at another portion of the surface of the sample body or on the optical detector.

Abstract: An optical sensor system includes a housing having an open end; first and second windows situated in the housing; a fastener for situating the first window closer to the open end than the second window and permitting an air exchange between a sensing region and the second window; a hermetic seal between the second window and the housing; and an optical sensor situated between the second window and a wall of the housing such that the air exchange does not occur inside the optical sensor. The first and second windows can include materials selected from the group consisting of sapphire, quartz, and glass; the optical sensor to be protected can include silicon carbide; and the sensing region can include a combustion region.

Abstract: A coated flow cell and a method for making the coated flow cell are provided. The flow cell comprises a flow passage internally coated with a polymer having an index of refraction lower than that of water. In this manner, light directed into the flow cell is internally reflected or "piped" down the length of the flow passage. As a result, flow cells having path lengths significantly longer and accepting incident angles of light much greater than possible with prior art flow cells. A method for internally coating the flow cell is also provided.

Abstract: A flow cell (112) used for detecting a characteristic of a continuously-flowing fluid comprises a narrow inlet path (118) for the fluid, a flow cell portion (112) having a diameter larger than that of the narrow inlet path (118), and flow-regulating portion (122) which is disposed between the narrow inlet path (118) and the flow cell portion (112) and has a diameter substantially the same as that of the flow cell portion (112) and a plurality of holes (134a to 134d), such that the fluid is introduced from the narrow inlet path (118) into the flow cell portion (112) by way of each of the holes (134a to 134d) of the flow-regulating portion (122).

Abstract: An apparatus and method for optically measuring concentrations of components allow enhancement in measurement accuracy of concentration. The apparatus includes a cell, a light irradiator, a photodetector, and an arithmetic unit. The cell presents different optical path lengths at different locations and is to contain a sample therein. The light irradiator, which includes a variable-wavelength laser generator and a measuring system composed of convex lenses, outputs a collimated, enlarged laser beam, and makes the laser beam incident upon the cell. The photodetector comprises a multiplicity of photodetectors arranged in parallel to the surface of the cell, so that it can detect intensity of rays of transmitted light that have traveled over different optical path lengths at positions of an equal distance from the cell.

Abstract: A miniaturized detector cell (4) having a measuring chamber volume of 25 fl-1 .mu.l is described. In spite of its miniaturized construction, the detector cell has an optical path length of about 0.1-100 mm. The incident measuring light (R) is repeatedly reflected at the inner walls (23, 25, 26) of the interaction region (21 ) before it leaves the detector cell (4) again. In a preferred manner, the detector cell (4) is manufactured from silicon or quartz by photolithographic means.