Abstract: A photometer having a plurality of input fibers to its optical entrance, at least one of which is for transmission of calibration light and at least one of which is for transmission of sample light. The exit ends of these fibers are aligned into a linear array, thereby producing an effective entrance slit for the optical entrance of the photometer. The fiber(s) for calibration light are positioned at the center of the linear array to avoid miscalibration due to photometer astigmatism.

Abstract: A monochromator of the Czerny-Turner type includes an entrance slit, a collimating mirror for receiving light output by the entrance slit, a planar grating for receiving light reflected by the collimating mirror, a focusing mirror for receiving light reflected by the grating, and an exit slit for receiving light focused by the focusing mirror. Light generally proceeds from the entrance slit to the collimating mirror, form the collimating mirror to the grating, from the grating to the focusing mirror and from the focusing mirror to the exit slit. The improvement comprises the use of a single toroidal collimating mirror in the system in combination with a spherical focusing mirror.

Abstract: A scanning optical microscope or mapping system for spectrally-resolved measurement of light reflected, emitted or scatttered from a specimen is disclosed, in which the spectrally-resolving element is integrated into the detection arm of the microscope or mapping system to result in good photon collection efficiency as well as good spectral and spatial resolution. A confocal version of the microscope is disclosed which will be of particular interest in fluorescence microscopy, and the non-confocal mapping system will be of particular interest in photoluminescence mapping of semiconductor wafers.

Abstract: A dual beam spectrophotometer has a blazed concave reflective grating 25, formed using the interference fringes of a coherent light beam reflected back from a spherical convex mirror 73 having a center of curvature at a point 65. The point 65 is off the Rowland circle 79 of the grating 25, so as to provide a different surface of focus 81 at the position of a photodiode array 29 which detects the spectrum formed by the grating 25. This permits the angle of the photodiode array 29 to be selected for good linearity of the distribution of wavelength of the spectrum along the array while maintaining the spectrum in focus over the whole length of the array 29. In order to compensate for remaining non-linearities, the width of barrier zones 93 between adjacent diodes 49 in the photodiode array 29 may be varied, so that the pitch of the diodes 49 varies with position along the array 29.

Abstract: A double monochromator comprises an inlet slit 20, which is imaged in the plane of an intermediate slit 34 through a first grating monochromator 36. The intermediate slit 34 is imaged in the plane of the outlet slit 34 through a second grating monochromator 58 identical with the first grating monochromator 36. Deflecting mirrors 64 and 66 can be moved into the path of rays to enable such a double monochromator to be optionally used as a single monochromator with increased light flux. An additional slit is arranged between the deflecting mirrors 64 and 66. The arrangement is such so that essentially identical beam geometries result at the outlet in both of the operation modes.

Abstract: A solid colloidal optical wavelength filter includes a suspension of spheal particles dispersed in a coagulable medium such as a setting plastic. The filter is formed by suspending spherical particles in a coagulable medium; agitating the particles and coagulable medium to produce an emulsion of particles suspended in the coagulable medium; and allowing the coagulable medium and suspended emulsion of particles to cool.

Abstract: A monochrometer having a stray light trap which substantially directs stray light away from light of wavelength of interest and/or absorb the stray light so as to substantially reduce the stray light component in the light of interest. The monochrometer has internal surfaces each having one of several optical characteristics.

Abstract: The subject of the invention is a spectroscopic analysis device comprising a light source, a light analyzer comprising an entrance slit, a diffraction grating and at least one exit slit which are disposed along a Rowland circle, and an optical transmission system.According to the invention, the entrance slit (3) is mounted so as to be displaceable along the Rowland circle (1), on either side of a central position, the optical transmission system comprises a first, fixed part (I) associated with the light source (5; 8) and a second, movable part (II) associated with the entrance slit (3) and mounted so as to be displaceable parallel to itself in a direction (a.sub.1, a.sub.2 ; b.sub.1, b.sub.2 ; c.sub.1, c.sub.

Abstract: In its preferred embodiment, a scanning monochromator uses a pulse-driven micro-stepping motor to drive a spectral-dispersion element via a reduction-gear harmonic drive. The motor is directly coupled to the input hub of the reduction-gear drive, and the output hub of the reduction-gear drive directly supports the spectral-dispersion element. By selecting a motor with a great number of steps per revolution, and a harmonic drive with a great reduction ratio, a resolution of 5 million pulsed steps is available, per single rotation of the output hub of the reduction-gear drive. This translates into more than 600,000 incremental angular-displacement steps over a usable 45.degree. range of dispersion-element rotation.

Abstract: A spectroanalytical system includes entrance aperture defining structure for receiving radiation to be analyzed along a first path; collimating structure in the first path for providing collimated radiation along a second path; fixed refraction structure in the second path for spatially separating (refracting) radiation in the second path in a first direction as a function of wavelength; fixed echelle grating structure in the second path for spatially separating the refracted radiation as a function of wavelength in a second direction orthogonal to the first direction and directing the orthogonally dispersed radiation in a beam along a third path that does not pass through the first refraction structure; and two-dimensional array detector structure for detecting the beam of orthogonally refracted radiation.

Abstract: In spectrum measuring equipment the light to be measured is separated by a double-image polarizing element into two polarized wave components whose planes of polarization cross each other perpendicular and which have different optical axes. The two polarized wave components are applied to a dispersing element so that their planes of polarization intersect the direction of light separation at .+-.45.degree. thereto, respectively. The sum of optical powers of the two polarized wave components separated by the dispersing element is measured by a photodetector, so that spectrum measurement independent of the polarization of the light to be measured can be achieved.

Abstract: A plane grating, particularly for a monochronomator, is provided with varied-spaced straight and parallel grooves in a light beam path to compensate for other light affecting components, for example a spherical mirror used for collimating or focusing the light beam. The angle of incidence with respect to the light for each of the grooves may vary and the angle of diffraction with respect to the light for each groove may be required to vary with the imperfection of collimation and focusing of the beam. The grooves are varied in their spacing to compensate for the variation of both incidence and diffraction direction.

Abstract: In a spectrophotometer having an oscillating grating, an entrance slit and an exit slit and a light source to irradiate said grating through said entrance slit, the grating and the light source are mounted on a heat sink plate and a fan is provided to blow air over both sides of said heat sink plate. A temperature sensing transducer is mounted in the heat sink plate to sense the temperature of the heat sink plate and the output of the temperature sensor is amplified by an amplifier to energize the electric motor of the fan to control the speed of the fan in accordance with the temperature sensed by the temperature sensor to thereby maintain the temperature of the heat sink plate at a constant value upon the system reaching equilibrium. In this manner, the wavelength drift of the system is reduced to a very low value.

Abstract: An improved method and apparatus for focused stigmatic imaging with spherical concave diffraction gratings incorporates a concave spherical diffraction grating with parallel, normally ruled lines. An entrance light beam source or projector propagates a beam of light to be analyzed through an entrance point and onto the surface of the diffraction grating. A light detector or analyzer is positioned at or near a detection point for detecting or characterizing the light diffracted from the grating. The entrance point and detection point are positioned in spaced-apart relation to each other and to the grating according to disclosed formulae, such that they are in respectively corresponding stigmatic or near stigmatic focus with each other.

Abstract: A monochromator utilizing a single light source productive of a uniformly intense, single beam, single wavelength coaxial beam output or alternatively, a single beam selected dual wavelength coaxial beam output.

Abstract: Light measuring instruments have a sensitivity to polarization states of the light being measured. To minimize such sensitivity a depolarizer is used. The depolarizer includes a half wave polarization plate between the source of light being measured and the light measuring instrument or within the instrument, but ahead of the polarizing elements. The half wave plate is rotated through an angular sector of at least 90.degree. (.pi./2 radians) for each measurement period to ensure that all polarization states are measured. If the measurement period is sufficiently long, its half wave plate may be rotated asynchronously with respect to the measurement period through at least two and one-half revolutions.

Abstract: The Raman scattering detector of this invention includes a source of collimated monochromatic illumination, a cube formed of two right angle prisms, a holographic optical element disposed between the prisms, a concentrating lens, a focusing lens and one or more photo detectors. The illuminating beam passes through the cube and is concentrated by the concentrating leans to a sample. Scattered light returned to the concentrating lens is substantially collimated upon return to the cube. The holographic optical element diffracts light at desired Raman wavelengths approximately 90 degrees without substantially affecting the original wavelength. The holographic optical element further disperses light at desired Raman wavelengths permitting them to be separated. The diffracted and dispersed wavelengths are focused on one or more detectors by the focusing lens.

Abstract: A monochromator apparatus comprises a monochromator (9) and a reversing device (2) which, with the aid of four reversing mirrors (10, 11, 17, 18) shifts the exit ray (13), of a monochromator (9) introduced in an intermediate focus of an external path of rays (4, 5), in the external path of rays (5) so that the external path of rays (4, 5) will not be influenced by the presence or absence of the monochromator apparatus (2, 9).

Abstract: An optical system and method comprising a diffraction grating which consists of diffracting elements spaced from one another by unequal distances. Correction of residual defocusing in the image produced by such a grating is accomplished by translating it along its surface. As one embodiment, a monochromator is constructed on which a self-focusing grating scans the value in wavelength which is transmitted between fixed slits by rotation of the grating about an axis fixed in space. Combined with a translation of the grating along its surface, such a monochromator produces a symmetrical image exactly in focus at the exit slit for all scanned wavelengths.

Abstract: A method and apparatus for in-process transient spectroscopic analysis of a molten metal, wherein a probe containing a pulsed high-power laser producing a pulsed laser beam having a substantially triangular pulse waveshape is immersed in the molten metal and irradiates a representative quantity of the molten metal. The pulsed laser beam vaporizes a portion of the molten metal to produce a plasma plume having an elemental composition representative of the elemental composition of the molten metal. Before the plasma plume reaches thermal equilibrium shortly after termination of the laser pulse, a spectroscopic detector in the probe detects spectral line reversals, as caused by absorption of radiation emitted by the hotter inner portion of the plasma plume to relatively coller outer portions of the plasma plume, during a short first time window.

Abstract: A spectroscope apparatus includes a device for separating light from an object to be measured into spectral components, a device for mixing spectral components which exists in a desired wavelength range, and a device for forming an image of the to-be-measured body of mixed light. The image obtained is very useful for observing the state of a combustion flame, the progress a photochemical reaction, the progress of a biochemical reaction, tissue in a cell, and the state of a flame for analyzing a solution which contains a metal ion by flame spectrophotometry. The apparatus provides accurate analytical information and makes possible precise control operations.

Abstract: A calibration method and apparatus for economical and rapid calibration of a scientific instrument utilizing a monochromator to generate monochromatic light utilizing controllable means for determining the angular position of a light dispersing element in the monochromator and a filter having a narrow absorption band(s) to determine a relationship between the wavelength of the monochromatic light generated by the monochromator and an angular position of the dispersing element so that the dispersing element can be rotated to an exact position for the monochromator to generate a selected wavelength of monochromatic light.

Abstract: A dispersion-type spectral element designed for reflecting an incident sample light is rotated by a drive mechaism. The sample light reflected by the element is applied to a sample-light receiving device. The device converts the light into a first signal representing the intensity of the sample light. Reference light consisting of beams having various wavelengths over a broad range is supplied from a reference light source to the spectral element. Further, standard light consisting of one beam of a known wavelength is also supplied from a standard light source to the spectral element. The reference light reflected by the element is applied to a reference-light receiving device. The reference-light receiving device converts the reference light into a second signal representing the intensity of the light. An etalon is located in the optical path between the spectral element and the reference-light receiving device. The standard light reflected by the element is applied to the standard-light receiving device.

Abstract: An optical grating is oscillated at a high rate to scan a narrow wavelength band of light through the spectrum dispersed by the grating. The grating is connected integrally with the rotor of a motor, which is energized to oscillate its rotor between selected limits. The direction of rotation of the motor is controlled by an H drive circuit connected to a coil of the motor. The speed of the motor is controlled by a pulse train applied to the motor coil through the H drive. The pulse train has a duty cycle varying inversely with the motor speed. The duty cycle of the pulse train is controlled by a counter which is connected to count high frequency pulses and which is reset each time the grating rotates through an angular increment. The limits of the oscillation of the grating and the rate of rotation of the grating between the limits are selectively variable.

Abstract: The temperature of a surface undergoing a radiation assisted thermally driven process is sensed by observation of the thermal emission from that surface and used to control the process. In a preferred embodiment, the blue edge of the thermal emission spectral distribution is detected to determine the surface temperature of a workpiece during a process such as laser-assisted chemical vapor deposition, and used to control this temperature. The temperature measuring system has means for focusing workpiece thermal emission and defining the field of view, a spectrometer to separate shorter wavelength light from other spectral components of the thermal emission, and a photon-counting system to detect the shorter wavelength light and generate a surface temperature signal. Systems to determine surface temperature at a spot and along a line have an optical prism to disperse the thermal emission into component wavelengths, and a multichannel photon-counting detector comprised of an intensified photodetector array.

Abstract: An optical waveguide having a detour is disposed at either or both of the light-receiving and light-emitting ends of a dispersion optical system in a spectroscope. Even though light being propagated through the optical waveguide has specified polarizing characteristics, the light is depolarized by passing through the optical waveguide and many times reflecting therein. Accordingly, unpolarized light not affected by the polarization selectivity of the dispersion optical system or the like can be emitted from the spectroscope.

Abstract: A centrifuge sample is optically scanned during centrifuging. The sample, placed in a centrifuge rotor having a cell with top and bottom windows, is spun until stratification and discrete layering occurs within the sample. Such layering occurs on layers that are precisely normal to the radius of the centrifuge at the point of sample and parallel to the spin axis of the centrifuge. A slit scanner having a slit normal to the sample plane transverses the width of the sample below the cell to detect with precision the precise location of the strata in the cell. A light source is reflected by a toroidal mirror having two radius of curvature. One radius of curvature is selected to collimate rays of light parallel to the layer of the sample. The mirror is ruled with respect to the other radius of curvature to chromatically classify light to preselect band width. Rotation of the mirror preserved collimation but enables selected scanning light frequency.

Abstract: The wavelength selection device comprises a substrate (1); and a deflectable wavelength selection member constituted by a diffraction grating (10) provided by a torsion member (6) mounted to the substrate (1). A pair of electrode (4,5) are responsive to a control current to cause the torsion member (6) to deflect whereby radiation centered on a predetermined wavelength is selected from radiation having a number of wavelengths impinging on the selection member (10) by setting the selection member (10) at a predetermined angle to the incoming radiation.

Abstract: To provide sufficient sensitivity, spectral resolution and speed of measurement for field environmental measurements in a portable spectroradiometer, a silicon photodiode receives light: (1) having a bandwidth in the range of between 2 and 15 nm (nanometers) from a pivotable concave holographic diffraction grating within the wavelength range of between 250 and 1150 nm at a scanning rate in the range of 20 to 100 nm per second; (2) having stray light of high intensity and undesired frequencies and the shorter wavelength harmonics of the selected frequency range blocked by filters; and (3) having flux of at least 10 microwatts per square meter of diffuser plate for each nanometer of bandwidth. Automatic electrical zeroing is obtained by blocking all light once at the beginning of each scan, obtaining an electrical drift-related signal and using the drift signal to adjust the measured signal during the scan.

Abstract: An adjustable Echelle spectrometer arrangement which can be used in single- and multi-element analysis by the emission or absorption of optical radiation. To compensate all the manufacturing and setup errors, the only arrangements present are those to change the height of the entry slit arrangement above the base plate and to rotate the dispersion prism about a first axis, approximately parallel to its roof edge, and about a second axis, that is vertical thereto. This compensates for the effect of errors associated with component and setup parameters which results from greater tolerances, without impairing mechanical and thermal stability and imaging quality.

Abstract: A spectral analysis system which may operate as a spectrograph or monochromator comprises a folded optical path within a housing wherein the optical input is provided on one side and the optical output is provided on an opposite side at a spectral focal field, thereby separating optical and electrical functions. The folded optical path is provided within a vertically extending portion of the housing providing for a narrow profile to the optical instrument and keeping the entrance and exit apertures in-line in close proximity. The grating is caused to operate in a near Littrow condition with a reflecting prism having first and second inclined surfaces which respectively reflect entrance aperture light to said grating and disperse exit aperture light from said grating along paths slightly inclined to the Littrow axis of the grating.

Abstract: A method of making a corrected plane holographic grating within one band of wavelengths, intended for use in a diffraction apparatus in which light emitted by an entry source (1) is collimated by a spherical mirror (2) to the grating (4), which reflects parallel pencils to another spherical mirror (7), a focusing mirror, is disclosed. An auxiliary holographic grating (25) is created by the interference on a spherical surface (15) of a parallel pencil of light produced by the spherical mirror (7) subsequent to reflection onto a plane mirror (12) and of a divergent pencil deriving from the center of the surface (15). The auxiliary grating, corrected by the interference on a plane surface (22) of a parallel pencil produced by the spherical mirror (2) and of another parallel pencil produced by the auxiliary grating (25) illuminated from the center of the spherical surface, is then recorded.

Abstract: A calibration method and apparatus for economical and rapid calibration of a scientific instrument utilizing a monochromator to generate monochromatic light utilizing controllable means for determining the angular position of a light dispersing element in the monochromator and a filter having a narrow absorption band(s) to determine a relationship between the wavelength of the monochromatic light generated by the monochromator and an angular position of the dispersing element so that the dispersing element can be rotated to an exact position for the monochromator to generate a selected wavelength of monochromatic light.

Abstract: A centrifuge sample is optically scanned during centrifuging. The sample, placed in a centrifuge rotor having a cell with top and bottom windows, is spun until stratification and discrete layering occurs within the sample. Such layering occurs on layers that are precisely normal to the radius of the centrifuge at the point of sample and parallel to the spin axis of the centrifuge. A slit scanner having a slit normal to the sample plane transverse the width of the sample below the cell to detect with precision the precise location of the strata in the cell. A light source is reflected by a toroidal mirror having two radius of curvature. One radius of curvature is selected to collimate rays of light parallel to the layer of the sample. The mirror is ruled with respect to the other radius of curvature to chromatically classify light to preselect band width. Rotation of the mirror preserved collimation but enables selected scanning light frequency.

Abstract: A method and improved apparatus for aligning a diffraction grating, as, for example, one used in tuning the output of a laser. The total angular misalignment .epsilon. between the incident and diffracted beams is a function of three angles: the tuning angle .theta.16, the angle of tilt .beta. between the plane of the grating 15 and the tuning rotational axis, and the angle .alpha. between the grating lines and the projection of the turning rotational axis in the plane of the grating 15. The present invention provides a method of aligning the diffraction grating so that the residual alignment error is very small over the desired range of tuning angle .theta. 16, by adjusting only .alpha. or only .beta. to zero at two reference tuning angles .theta..sub.0 and .theta..sub.1. Knowledge of the value of either .alpha. or .beta. is not necessary. For a CO.sub.2 laser tuned over the wavelength range 9.11 to 10.88 .mu.

Abstract: A system for rapid-scan spectral analysis comprising a concave holographic diffraction grating continuously rotated at a substantially constant angular velocity to provide a rapid scanning monochromator (a monochromator is used to transfer nominal regions of wavelengths out of the continuous light source). The unique sampling circuitry uses an optical shaft encoder. The angular velocity and angular acceleration of the grating are calculated from time measurements, just before the first wavelength of interest falls on the detector. This information is used to control the Analog to Digital converter sampling rate across the region of interest. The samples as a function of time are stored in a memory buffer so that each data point corresponds to a wavelength.

Abstract: The advantage of sustained wavelength accuracy and mechanical simplicity of a spectrophotometer using a photodiode array as photometric detector and a fixed diffraction grating as dispersion means may be limited to a relatively short wavelength range by problems of stray light, second order errors and overloading of the detector at portions of the wavelength range. By utilizing repeat scanning of the array, each scan being modified by using a different source lamp and correction filters, freedom from the cited problems over part of each scanned wavelength range can be effected. A computer controls the scan sequence and combines the usable portion of each scan to produce error free operation over an extended range.

Abstract: A Rowland circle-type polychromator with the Rowland circle arc pivotally connected to the concave grating. Separate adjustments are provides for shifting the spectral lines and focussing. A tie rod is used to adjust the focus of the spectral lines. Dectectors are predeterminedly spaced along the arc to simultaneously detect unique spectral lines for analysis of multiple elements contained in a single sample.

Abstract: An optical system for use in a spectrometer or monochromator employing a mirror which reflects electromagnetic radiation from a source to converge with same in a plane. A straight grooved, varied-spaced diffraction grating receives the converging electromagnetic radiation from the mirror and produces a spectral image for capture by a detector, target or like receiver.

Abstract: A system for ascertaining the thickness of thin films, especially on semiconductor substrates, comprising a light source, a randomized bifurcated fiber optic bundle, a pentamirror, a rapid scanning monochromator with a rotating grating, a photodetector, and A/D converter, an interface and a data reduction computer. The randomized bifurcated fiber optic bundle via the pentamirror directs light to and receives reflected light from a surface of the thin film, the reflected light passes through the bifurcated bundle to the monochromator and to the photodetector whose output is read by the A/D converter. A timing control circuit is provided which has an input from an encoder coupled to the motor rotating the grating and clock and trigger outputs coupled to the A/D converter so that the A/D converter consistently samples the analog signal representative of the same portions of the reflected visible spectra returned from the thin film under test.

Abstract: A spectroscopic measurement system comprises at least two kinds of diffraction gratings whose grating surfaces are in line, an exchange device for exchanging the positions of the two kinds of diffraction gratings in connection with incident light to be measured while the two kinds of diffraction gratings are placed in a predetermined rotation angle, at least two kinds of detectors having characteristics corresponding to those of the two kinds of diffraction gratings respectively, a light path switch for switching a path of diffraction light toward either of the two kinds of detectors, and a switch circuit for switching the detection output of the two kinds of detectors in synchronization with the exchange operation of the two kinds of diffraction gratings.

Abstract: A compact, lightweight, yet sturdy imaging spectrometer, especially for use in satellites, flying bodies and the like, has elliptical mirrors for its objective or lens, for its collimator, and for its imager. The collimator and imager are formed by the same mirrors which reflect the beam twice. The optical arrangement of the objective or lens, the collimator, and the imager is such that any bending of an object strip by a diffraction lattice or grid is compensated. Such a spectrometer is usable for a wide field and wide spectral range, including the non-visible range.

Abstract: An optical system which provides wavelength tuning and which may be a spectrometer, monochromator or tunable laser uses a volume transmission diffraction element which is characterized by a periodic, spatial variation of refractive index or polarizability or other light transmission effecting parameter, and which is distributed throughout the volume of the element. The wavelength is tuned by (1) varying the angles of the incident and diffracted light symmetrically with respect to the periodic distribution in the element and/or (2) by varying the spatial period of the diffracting element's volume modulation distribution which is maintained symmetric with respect to fixed incident and diffracted beam angles.

Abstract: An improved rapid-scan spectrophotometer with an optical grating continuously rotating at a constant angular velocity. An optical trigger actuated by the rotating turntable supporting the grating, actuates an analog to digital converter to sample at discrete times an output signal from the sample detector over the desired wavelength range and to store the digitized information in a direct memory access (DMA) buffer. The information may be retrieved as desired from the buffer for further processing or permanent data storage. With each revolution of the optical grating, the range (typically 15.degree.) of wavelengths from the grating that provides useful information is sampled by the analog to digital converter and stored in the buffer. Because the grating is continuously rotating at a constant angular velocity and is not limited by the inertia of optical components, the spectrophotometer can be operated at a much higher scanning speed than an oscillating or vibrating grating spectrophotometer.

Abstract: A very wide spectral coverage grating spectrometer which gathers light from a scene being viewed and collimates that light. A mosaic grating is disposed in collimated space which disperses the collimated light. The dispersed light is focused onto a detector array.

Abstract: In a Littrow spectroscope including a concave mirror for reflecting light from a source, a diffraction grating for further reflecting the light reflected by the mirror, the grating being made rotatable to allow the mirror to re-reflect the light therefrom, and an exit on which the light re-reflected by the mirror is focused; a stray-light suppressor in the form of a strip is disposed in front of, and horizontally in parallel with the longitudinal central axis of, the mirror. The suppressor is held in front of the mirror at a distance of (L1-L2), where L1 is the distance between the mirror and the grating and L2 is the distance between the grating and the exit. The suppressor portion upon which the stray light from the diffraction grating impinges is tapered.

Abstract: A spectrophotometer wherein the diffraction grating is driven directly by a pulse motor and the wavelength of the monochromatic light used for measurement is calculated by a data processor from the amount of rotation of the pulse motor. The data processor is provided with an input unit for setting a parameter corresponding to the difference between the nominal and actual grating constants of the diffraction grating and so arranged as to calculate the wavelength in accordance with the nominal grating constant having been modified with the parameter set through the input unit.

Abstract: An image monochromator is arranged to receive light at an input thereof simultaneously from an entire object field to be viewed and to produce and transmit a viewable image of the entire object field simultaneously through an output thereof at a selected wavelength band. The monochromator has inner and outer optical systems, the inner system comprising an input slit which is projected on an output slit through imaging means such as lenses or mirrors, via dispersive means such as a diffraction grating or prism operable to transmit light at a tunable narrow wavelength band.

Abstract: A monochromator, capable of functioning as either a single monochromator or a double monochromator by positioning of either reflective means or dispersion means in the optical path. Both the reflective means and the dispersion means are placed on a rotary bed which may be rotated by rotary drive means so that one of the above-mentioned optical means may be placed in the optical path, whereby the monochromator functions optimally, depending on the object to be measured.

Abstract: A flash tube (1) illuminates the inlet slit diaphragm of a monchromator illuminator (3) the outlet slit diaphragm of which is applied to an optical conductor (5) forming a statistically balanced derivation towards a measuring cell (6M) and a reference cell (6R). Quantic photodetectors (7M and 7R) measure respectively the light conveyed by the two cells. The electric signals obtained are amplified and digitalized, and a microcomputer (9) calculates the relation between the measuring signal (M) and the reference signal (R), other things being equal.