Abstract: The spatial resolution of Hartmann-type sensors can be increased by moving a wavefront being sensed relative to the sensor by a non-integral number of apertures. The apertures may have a tilt on at least one side thereof. The lenslets themselves in a lenslet array may serve as the apertures or material may be provided on the lenslet array to create the apertures.

Abstract: A light-transmissive support disk supports a tube for attracting an LED chip, and a light-transmissive electrically conductive film is disposed on the support base. The LED chip is electrically connected to a negative terminal of a DC power supply by the light-transmissive electrically conductive film. An imaging unit is disposed coaxially with the tube and has a CCD camera for capturing an image of a light-emitting state of the LED chip via the support disk and a cover member when the LED chip attracted by the tube emits light. The light-emitting center of the LED chip can be detected accurately, and bonded easily and highly accurately on a board at a desired position thereon.

Abstract: In one embodiment, the present invention includes a method including the following acts. A light source is scanned over a surface of an integrated circuit. A photo-induced current is measured from a fiducial in the integrated circuit. The current is correlated to a position of the light source as the scanning progresses.

Abstract: A device, method of measurement and method of data analysis are described for imaging and quantifying in a practice sense the luminous intensity of the effective illumination source of an image system. The device, called a source metrology instrument, produces images and other quantitative measurements of the combined condenser and light source that are taken in-situ and without any significant alteration of the optical or mechanical set up. As such, the device can be used to monitor and assess the coherence properties of the illumination source with a minimum of interruptions to the optical tools productive time. It can be used with photolithographic step and repeat reduction or nonreducing imaging systems (steppers), scanning image systems, fixed field step and repeat aberration systems, scanning aberration systems, or any other projection imaging or aberration systems.

Abstract: A light-transmissive support disk supports a tube for attracting an LED chip, and a light-transmissive electrically conductive film is disposed on the support base. The LED chip is electrically connected to a negative terminal of a DC power supply by the light-transmissive electrically conductive film. An imaging unit is disposed coaxially with the tube and has a CCD camera for capturing an image of a light-emitting state of the LED chip via the support disk and a cover member when the LED chip attracted by the tube emits light. The light-emitting center of the LED chip can be detected accurately, and bonded easily and highly accurately on a board at a desired position thereon.

Abstract: A method and an apparatus for measuring viewing-angle dependent luminance (luminance characteristic) of an LCD panel by condensing radiation from LCD pixels by means of a condensing device which includes a mirror, and by forming a real image of the pixels on an CCD imaging device. Correct luminance characteristic of the LCD panel is calculated by making a correction of the data thus obtained using a predetermined condensing function. The correction removes blurring of data due to condensing effect of the condensing device, thereby preventing degradation of the resolution of the angular luminance measurement apparatus. The condensing device and the CCD imaging device are moved depending on the viewing-angle of the pixels. When the intensity of light entering the condensing device decreased by the move, the correction is performed.

Abstract: A method and device for determining the intensity and phase distribution of a coherent light beam, in a plane, including measuring the intensity Ii, i=1 . . . N, of the beam, in N planes, N≧3, having the plane wherein intensity and phase distribution is to be determined, choosing, for plane i=1, an initial phase matrix &phgr;1 and calculating a complex amplitude matrix, by term-wise multiplying the phase matrix ei&phgr;1 by the corresponding amplitude matrix A1, for each plane j>1: determining a propagated complex matrix B′j from the measured amplitude matrix Aj−1 of plane j−1 and the phase matrix &phgr; of plane j−1, extracting, from B′j, a phase matrix of plane j, and iterating the method up to convergence, with j=1 when j−1=N.

Abstract: A method and apparatus for detecting positions which can accurately detect the position of light emitting elements and improves the ease in operation are disclosed. Light emitting elements of a PLZT shutter array that are arranged in one dimension are lighted. A light receiving element transfer system makes a light receiving element or receiver scan along an imaging face of the PLZT shutter array by sampling analog data which has been taken in by the light receiving element 22 so that a data series can be obtained. A minimal value of the data series is determined to be a threshold. Then by comparing the threshold and the data series sequentially from the beginning, the first place where the threshold is exceeded is detected. A maximum value within a searching range of one cycle from this first place is detected. The position of the maximum value is considered to be a beginning or first light emitting element position among the lighted light emitting elements.

Abstract: An illuminance measurement apparatus for measuring the illuminance of illumination light on an image plane of a projection optical system of an exposure apparatus designed to project the image of a pattern from an illuminated mask on a substrate held on a substrate stage by the projection optical system, including an illuminance meter detachably attached to the substrate stage, the illuminance meter having an illuminance detector, a transmitter for wirelessly transmitting a measurement result of the illuminance detector, a storage cell, and a photoelectric converter for converting part of the illumination light photoelectrically and storing it in the storage cell, and a receiver for receiving the wireless signal including the measurement results transmitted by the transmitter.

Abstract: Apparatus for real time measurement of optical beam parameters includes an assembly of known dimensions, carrying multiple apertures, occupying parallel planes. The assembly can be moved so that the apertures sequentially intersect an optical beam which is not propagated in the plane of the apertures. At least one pair of the apertures are non-circular and identical with accurately established positions and which are not disposed in the same angular alignment when they intercept the beam but are disposed in the same plane in order to allow determination of the two-dimensional position of the centroid of the beam in that plane.

Abstract: The invention concerns a method and device for determining the direction of an object (10) which emits or reflects optical radiation. An optical element (14) which structures the wavefront of the radiation converts the conventional dot-type image (20) into an intensity distribution (14′) with more than one maximum on a locally resolving opto-electronic detector (13). From the intensity distribution (14′) and the structure function of the optical element (14), the direction of the object (10) can be determined with a high degree of accuracy over a wide measurement range. In addition, this gives a design with a shorter optical path length and very few optical components.

Abstract: A line scan apparatus having a linear array of objective lenses which pair up with an associated linear array of optical sensors. The apparatus further comprises a bundle of tapering optical fibers which optically couple the pairs of objective lenses and optical sensors. Each fiber is arranged such that it optically couples at a wide end to one of the objective lens, and at a narrow end to one of the optical sensor. In operation, the linear array of objective lenses are scanned across the object, with the linear array of optical sensors capturing a one dimensional image line by line to build up a two dimensional image of the object.

Abstract: The present invention provides an adaptive optic system for an earth-viewing telescope on board an orbiting spacecraft. The adaptive optic system includes a deformable mirror, a synthetic guide star laser, and a control module that corrects not only on-axis wavefront error but also off-axis wavefront error.

Abstract: A Shack-Hartmann wavefront sensor having an aperture which is smaller than the size of an object being measured is used to measure the wavefront for the entire object. The wavefront sensor and the object are translated relative to one another to measure the wavefronts at a plurality of subregions of the object. The measured wavefronts are then stitched together to form a wavefront of the object. The subregions may overlap in at least one dimensions. A reference surface may be provided to calibrate the wavefront sensor.

Abstract: Device for detecting and calculating focus point position (2), shape (3) and power distribution of a laser beam after a focussing lens, and which at least incorporates a laser source (10), the focussing lens (4), a light affecting body (5, 6), a light sensor (7), and means for calculation (9).

Abstract: The present invention relates to a laser pointing and tracking system which forms and maintains a small laser spot size at a selected aimpoint on a target and compensates for optical distortion in the intervening media. The invention comprises an illumination laser for directing a first wide divergence beam of short-pulse laser radiation toward a stationary or moving target. The target reflects a portion of the incident beam as return radiation which is interfered with a properly-timed short-pulse reference beam on an electronic radiation detector array. The detector array signals are processed to produce an electronic hologram which is imposed as a phase pattern on a spatial light modulator. A laser reads out the hologram to direct a beam of radiation at the target. Multiple sequential illumination and hologram formation/readout steps produce a small spot size at the selected aimpoint. The small spot is maintained at the aimpoint during the duration of an engagement by repeating the above steps.

Abstract: Large space-based optical systems are expected to produce optical beams with large wavefront phase aberrations due to their size, weight limitations, optical misaligments and primary mirror imperfections. The present invention combines a phase diversity wavefront sensor with a real-time programmable two-dimensional array of liquid crystal variable retarders for wavefront correction.

Abstract: An imaging system for measuring the field variance of distorted light waves collects a set of short exposure "distorted" images of an object, and applies a field variant data processing methodology in the digital domain, resulting in an image estimate which approaches the diffraction limited resolution of the underlying physical imaging system as if the distorting mechanism were not present. By explicitly quantifying and compensating for the field variance of the distorting media, arbitrarily wide fields can be imaged, well beyond the prior art limits imposed by isoplanatism. The preferred embodiment comprehensively eliminates the blurring effects of the atmosphere for ground based telescopes, removing a serious limitation that has plagued the use of telescopes since the time of Newton.

Abstract: A compact wavefront sensor includes an array of microlenses supported above a microchip. The microchip includes an array of gratings and photodetectors, which correspond to a particular microlens. Light incident on a grating will be diffracted back towards the array of microlenses, where it is focussed onto a corresponding photodetector. The photodetector receives light from gratings adjacent thereto, and detects a resulting interference therebetween. The detected interference is then used to reconstruct the wavefront. The detected interference can also be used to correct wavefronts by controlling a modulating element reflecting the wavefront.

Abstract: An apparatus and method for characterizing a pulsed energy beam with a two-dimensional wavefront sensor. The data acquisition is synchronized with the output of the beam from the pulsed source, so that a beam characterization, including phase, can be determined in a single pulse.

Abstract: A driving current is supplied to a semiconductor laser and an optical output from the semiconductor laser is measured by an optical output measuring circuit. The measured optical output is differentiated with respect to said driving current and a first characteristic data indicative of a relation of the differentiated optical output and the driving current is calculated by a first differentiating circuit. The calculated first characteristic data is differentiated with respect to the driving current and a second characteristic data indicative of a relation of the secondary differentiated optical output and said driving current is calculated. The calculated second characteristic data is converted into a determination code. The converted determination code is compared with a preregistered code for determining the defectiveness/non-defectiveness of a semiconductor laser and it is determined based on the comparing result the defectiveness or non-defectiveness of the semiconductor laser.

Abstract: A device to control the aiming and focusing of laser systems on a target comprises at least one reflecting false target (21) positioned and oriented substantially identically to the target (3), a lens (12) for the focusing of the beam on this false target, a separator device (11), a wavefront analyzer (35), a mirror (33) and a semi-reflective plate (32), the beam (1) getting focused, at the end of the system, on the false target (21) after getting reflected on the separator device (11). A part (31) of the beam with the same wavelength as that of the part reflected by the separator device (11) goes through this device and the semi-reflective plate (32) to get directed towards the wavefront analyzer (35). The beam reflected by the false target (21) goes through the separator grating (11) to get reflected on the mirror (33) and the semi-reflective plate (32) to get directed towards the wavefront analyzer (35).

Abstract: Device for the detection of optical parameters consisting of a first sensing element that is sectioned into a plurality of equal regions each able to produce an electric signal, proportional to the power of the incident laser beam. Before said first sensing element with respect to the direction of the incident laser beam, at least a second sensing element is provided, lined up with the first sensing element and thermally insulated from it, that has a hole with a shape equal to the shape of the incoming laser beam and with dimensions increasing with the distance from that first element.

Abstract: A device for determining the phase errors of electromagnetic waves (OE) which are generated by a light source and transmitted by an optical instrument includes a reception system (SM) having at least one measurement plane (PM, PM3, PM4) provided with a plurality of measurement zones (ZM) which can measure the intensity of the received light and a collimation means (L1) for sending to the measurement plane (PM, PM3, PM4) the electromagnetic waves (OE) transmitted by the optical instrument.

Abstract: A system for the control of light beams includes a beam splitter placed on the path of the beam to be controlled and deriving a measurement beam from this beam; a detection device receiving the measurement beam and measuring the shape of the wave front of the measurement beam; a wave-front shape correction device placed on the path of the beam to be controlled, activated by the detection device and correcting the shape of the wave front of the beam to be controlled. The detection device includes a light spatial modulator providing for the selective transmission of the portions of the measurement beam; a focusing device receiving the different portions of the measurement beam; a series of photodetectors placed along the focusing plane of the focusing device; a device for the identification of the photodetector or photodetectors, detecting a light wave and computing the shape of the wave front as a function of the photodetectors identified.

Abstract: A beam monitoring assembly (10) that provides near-field imaging, far-field imaging and power measurements of a laser beam (12) in real-time for alignment and performance verification purposes. The monitoring assembly (10) includes a holographic beam splitter (24) that splits the laser beam (12) from the laser resonator cavity into a series of separate split beams (28, 30, 32) having varying beam powers. One of the split beams (28) is directed to a power meter (36) to measure the power of the beam (12). One of the split beams (28) is directed to a near-field camera (42) that provides a near-field image of the beam (12). Another one of the split beams (30) is directed to a heat dump (52) that absorbs and removes the beam's energy from the assembly. Another one of the split beams (32) is directed to a far-field lens (46) that focuses the split beam (32) onto a far-field camera (50) that provides a far-field image of the beam (12).

Abstract: A moving body surface or paper web (1) to be investigated is irradiated at at least one irradiation site by 3 laser light sources of a surface structure measuring device (FOS1, FOS2). Reflected and scattered light is detected and evaluated in order to calculate ellipse points. An ellipse major axis ratio corresponding to a fiber orientation ratio, and a fiber orientation angle are calculated from the ellipse parameters thus obtained. Identical measurements and calculations are carried out periodically on an isotropic sample (NO) and a sample (Nx) having a fiber orientation similar to that of the body surface to be measured, in order to calibrate the measurements at the body surface (1).

Abstract: The invention relates to the evaluation of the pupil illumination profile in a projection lithography system using an imaging reticle featuring a plurality of holes of few microns in diameter. The imaging reticle is placed at the lens object plane and a photoresist coated substrate is exposed in a defocused position from the lithographic image plane. The image reticle has a plurality of identical holes that are regularly spaced at predetermined distances for a more detailed evaluation of the effective pupil illumination across the entire exposure field.

Abstract: A large area energy beam intensity profiler and method of profiling are disclosed. The profiler includes intensity detectors which generate electrical signals corresponding to the intensity of the beam. The output of the detectors is processed by a computer and displayed on a monitor. The invention provides for adjustment of the beam in response to a nonuniform intensity profile, or an indication that the beam is misaligned.

Abstract: In a method and apparatus for evaluating the performance characteristics of fiber-optic endoscopes, a beam of light defining a predetermined intensity pattern is transmitted through the endoscope from a tip end through an eyepiece end of the endoscope. The intensity pattern of the beam defines either a uniform intensity, or an intensity which varies sinusoidally in a predetermined direction across the beam. The following tests are performed in order to evaluate both the optical fibers and the lens system of the endoscope, and the intensity pattern is selected in accordance with the requirements of the respective test: (i) a light loss test, (ii) a reflective symmetry test, (iii) a lighted fibers test, (iv) a geometric distortion test, and (v) a MTF test. A video system generates signals indicative of the optical intensity of the beam after transmission through the endoscope at each of a plurality of predetermined locations within the beam.

Abstract: A gonioradiometric scanning apparatus and method for measuring the near and/or far field radiation pattern of radiating optical sources such as laser diodes (LD), light emitting diodes (LED), optical fibers, flat panel displays, and luminaires is described. The scanning apparatus incorporates a deflector for selecting an azimuth angle through the optical source to be measured, a rotating apparatus which collects light while scanning about the source, an optical commutator, and a detector. The rotating apparatus comprises a cylindrical hub and an optical collector using either an optical fiber or a train of reflectors, such as mirrors or retro-reflectors. The optical collector provides a means for both collecting light and for directing the beam emanating from the deflector to a place opposite the detector at which optical commutation occurs.

Abstract: An apparatus and method for characterizing an energy beam (such as a laser) with a two-dimensional wavefront sensor, such as a Shack-Hartmann lenslet array. The sensor measures wavefront slope and irradiance of the beam at a single point on the beam and calculates a space-beamwidth product. A detector array such as a charge coupled device camera is preferably employed.

Abstract: An apparatus and method for aiming a vehicle headlight to a standard image pattern includes a frame movable relative to the vehicle. A housing carried on a vertically adjustable housing includes a lens focusing a headlight beam onto a reflective screen which reflects the beam image to a camera. A control compares the digitized image output from the camera with a standard image pattern and generates a correlation factor based on the difference between the reflected image and a standard image. Based on the difference, the control generates output signals to an adjustment device engagable with the headlight mounting frame to adjust the position of the mounting frame to reduce the difference to zero.

Abstract: A radiant energy transducer system includes a base. The base has a diffusely reflective surface and an optical area defining a horizon district with respect to the transducer system. A mask occludes a portion of the optical area so as to present a substantially constant portion of the optical area over a range of angles above the horizon district. An electromagnetic transducer converts between radiation associated with the optical area and corresponding signals. Examples of the transducing systems provide emission of radiant energy with a tailored intensity distribution over an area illuminated by the system. Other examples of the transducing systems detect radiant energy, and the position of the mask relative to the optical area of the detector system serves to tailor the sensitivity of the detector over a field of view. The emitters and detectors can be used together, for example in a system for tracking the position of an object.

Abstract: An ellipsoidal mirror having an axis of rotational symmetry is disposed so that a first focal point thereof is positioned in vicinity of a measurement area of a light source to be measured. The ellipsoidal mirror reflects parallel light beams from the measurement area onto an optical focal plane on which the reflected light beams are focused, whereby a luminous intensity distribution image of the measurement area is formed on the optical focal plane. The luminous intensity distribution image is directed via a relay lens system onto a sensing surface of an image pickup unit. A distribution of luminous intensity of the measurement area is obtained based on the luminous intensity distribution image.

Abstract: An optical wavefront sensor for measuring phase tilt in two dimensions across the cross section of a beam (14), using only a single lenslet array (26) and a single camera sensor array (28). The rectangular lenslet array (26) is oriented at 45 degrees to first and second orthogonal sets of axes defining multiple points of interest (22') in the beam cross section, such that each lenslet subaperture is centered (at 40) between adjacent points of interest on the first and second axes. The points of interest (22') are locations corresponding to the positions of actuators (22) in an adaptive optics system. The camera sensor array (28) has more cells per unit area than there are subapertures per unit area. Only selected cells are activated, to provide for measurements at the approximate mid-points of lines between adjacent points of interest (22') on the first and second orthogonal axes.

Abstract: Device for the characterization of a laser beam according to a "Knife edge" method as defined by Standard ISO 11146. The device has a lens for the focalization of an incident laser beam, and a detector. Interception elements are located between said lens and said detector in order to intercept sequentially the focalized laser beam in a plurality of different positions along its axis of propagation. The interception elements are suitable to allow, in each one of said positions, the passage of a progressively increasing (or decreasing) portion of the vocalized laser beam starting from a condition of substantially total (or null) interception up to a condition of substantially null (or total) interception.

Abstract: An illuminance measuring method and apparatus measures the illuminance on a wafer in an exposure apparatus for projecting a pattern formed on a mask onto a wafer. The illuminance of the mask causes the formation of ghost light on the mask. The apparatus and method use a first technique to measure the illuminance on the wafer while a mask used for actual exposure is mounted in the exposure apparatus and the mask is illuminated. The apparatus and method also use a second technique, different form the first technique, to measure the illuminance on the wafer while the mask used for actual exposure is mounted in the exposure apparatus and the mask is illuminated. The apparatus and method also find the distribution of the ghost light caused by the mask, based on the illuminance measured by these two techniques.

Abstract: A quadrant light detector that employs the concept of constructed occlusion to improve its accuracy and by incorporating baffles within the design to improve its detection response to incoming light having an incidence angle neat the horizon, and to divide a diffusely reflective cavity into quadrants. The quadrant detector is able to determine the direction, or azimuth and elevation, to the light source anywhere within a sector of a hemisphere or a sphere.

Abstract: A method and system is disclosed in which the local variation of an extended radiation source is monitored with single-element detector. The chromatic aberration of the imaging optics induces the different transmittance curves for different wavelengths, and the different shape in the transmittance curve is used as a spatial filter which is multiplied to the chromatic intensity profile of the extended radiation source to detect the local variation in the intensity profile of the extended radiation source. The signal processing of the chromatic signals is implemented to detect the size variation and the environmental effects on the extended radiation source. A fiber is also used for remote operation.

Abstract: Apparatus for determining the luminous intensity distribution of an automotive head light employs a curved mirror and a curved screen. A solid state camera is used to obtain a pattern of the head light output from the screen. The system requires a relatively small black box into which the head light output is directed. A beam splitter may be employed to relax the constraints on the positioning of the various components within the box. The setting of the test lamp to first and to second preset lateral angular positions at each of which a pattern is captured and the combining of the two patterns permits the use of components which are practical. The use of a linear CCD array permits economies to be obtained by rotating the test lamp or by scanning the linear array over a sequence of angular positions and by constructing a composite pattern from the patterns so generated. In an alternative embodiment, no beam splitter is used.

Abstract: The present invention is a system and method to expeditiously and accurately measure the luminance, weave, jump and flicker of an object so that the best luminance available for that object may be achieved by making adjustments to the light source, the reflecting surface and the like. A scanning light receiver which produces a two dimensional optical image of the object whose luminance is to be tested, is set up so that it may view a substantial portion of the object. The light receiver is connected to a analyzer and interface unit ("AIU") to which it sends an electronic image representing the reflected luminance of the object during each scan. The reflected light that is detected by the light receiver is then analyzed by the AIU to determine the luminance levels, weave, jump and flicker of the luminance across a substantial portion of the object by measuring the voltage of each pixel detected by the light receiver measured against the voltage produced by a black level.

Abstract: An optical axis of a headlight of a vehicle is adjusted by picturing an illuminating pattern of the headlight to appear on a screen which is disposed in front of the vehicle. A position of a center of gravity of a region above a predetermined illuminance in the illuminating pattern is obtained. A position of a stepped region in which a stepped portion of a light/dark border line of the illuminating pattern is present is obtained. A position of a point of inflection, in the stepped region, of an iso-illuminance curve having a predetermined rate of illuminance relative to an illuminance in the center of gravity is measured. The optical axis is adjusted based on this point of inflection.

Abstract: When producing an object by subsequent solidification of material layers 1 at places corresponding to the object there is a problem of limited production speed because the scanning speed or laser power of the light beam scanning the material layer 1 cannot be increased at will, if the light beam 4 used for solidification is focused as required for exact resolution. According to the invention this problem is solved by providing a variable focusing device 8 in the light beam 4, whereby the focus of the light beam 4 can be varied during the solidification of the layer 1. Thus, a different focus, laser power and scanning speed can be used in different regions of the layer 1.

Abstract: An apparatus and method for aiming a vehicle headlight to a standard image pattern includes a frame movable relative to the vehicle. A housing carried on a vertically adjustable housing includes a lens focusing a headlight beam onto a reflective screen which reflects the beam image to a camera. A control compares the digitized image output from the camera with a standard image pattern and generates a correlation factor based on the difference between the reflected image and a standard image. Based on the difference, the control generates output signals to an adjustment device engagable with the headlight mounting frame to adjust the position of the mounting frame to reduce the difference to zero.

Abstract: A new adaptive optics system and method of operation, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation:G'=(I-X(X.sup.T X).sup.-1 X.sup.

Abstract: Apparatus for determining the luminous intensity distribution of an automotive head light employs a curved mirror and a curved screen. A solid state camera is used to obtain a pattern of the head light output from the screen. The system requires a relatively small black box into which the head light output is directed. A beam splitter may be employed to relax the constraints on the positioning of the various components within the box. The setting of the test lamp to first and to second preset lateral angular positions at each of which a pattern is captured and the combining of the two patterns permits the use of components which are practical. The use of a linear CCD array permits economies to be obtained by rotating the test lamp or the linear array over a sequence of angular positions and by constructing a composite pattern from the patterns so generated.

Abstract: A quadrant light detector that employs the concept of constructed occlusion to improve its accuracy and by incorporating baffles within the design to improve its detection response to incoming light having an incidence angle near the horizon, and to divide a diffusely reflective cavity into quadrants. The quadrant detector is able to determine the direction, or azimuth and elevation, to the light source anywhere within a sector of a hemisphere or a sphere.

Abstract: A device for sampling a section of a laser beam using an elongated reflective element that is moved in a main direction that corresponds to the direction of elongation of the element and in a direction perpendicular to the main direction. This sampling device forms a part of a laser beam analyzer and provides a small reflected beam segment to the analyzer that corresponding to the part of the laser beam that impinges upon the moving elongated reflecting element.

Abstract: Apparatus for measuring laser power includes a target disc of a predetermined thickness located within, and in thermal contact with, a heat-sink. The heat-sink has an opening therein for directing laser radiation to be measured onto the target disc. A thermal gradient is established in the target disc when laser radiation to be measured is directed onto one surface of the disk. The opposite surface of the disc includes means for detecting the thermal gradient. The heat-sink includes a cylindrical core having an opening in one end thereof for admitting laser radiation to be measured. Cooling-vanes are disposed around the cylindrical core extending radially outward therefrom and extending therealong. A housing surrounding the heat sink includes a fan which causes air to be drawn into the housing, flow between the cooling-vanes, and the be expelled from the housing.