Showing papers on "Beam splitter published in 1984"

Optical device for detecting coded symbols

Abstract: An optical device for detecting bar codes (markings or patterns which symbolize data such as the name and vendor of a product) are detected by an optical device which serves as a bar code scanner. A laser diode and associated optics provides an invisible beam. A visible marker beam coincident with the laser beam is generated by a lamp and associated optics and directed coaxial with the laser beam so as to enable the laser beam to be scanned across the bar code by moving a housing in which the laser and the lamp and their associated optics are disposed. Also contained in the housing is a photodetector on which scattered light from the code is incident after passing through a collection lens located at an outlet port for the beams. An aperture is positioned between the collection lens and the detector. The location and size of the aperture and the focal length of the lens are related such that the illumination by the reflected light of the detector is substantially constant and the output signal from the detector which represents the bar code is also constant amplitude over a wide depth of focus in front of the beam port. Unwanted reflections (gloss over the bar code) are rejected by selecting the polarization of the reflections opposite to the polarization of the laser beam, as by the use of a polarizing beam splitter. A spectral beam splitter is used near the detector to select the scattered laser light for the photodetector which generates electrical signals corresponding to the bar code.

Ultra-fast photometric instrument

Abstract: This is a static photometric polarimeter for use with a sample S upon which a beam passed through a beam splitter (which reflects the beam to a detector D o ) and which beam is 45° polarized. The reflection of the beam from the surface of sample S is passed to a polarizing beam splitter with one portion of the reflected beam going to a detector D s which measures the perpendicular polarization component of the beam and the other portion of the beam going to the detector D p which measures the parallel polarized portion of the reflected beam.

Optical signal recorders employing two lasers and methods therefor

Abstract: An optical head for an optical signal recorder includes a nonpolarizing beam combiner for combining the light beams from two like-frequency, sic wavelength, lasers along one light path. The combined beams travel slightly diverging paths so that a first one of the beams can record signals on a disk while a second beam follows the first beam on the disk for direct reading-after-recording. Intermediate the combiner and the disk are a polarization type beam splitter and a focuser. One or more detectors receive reflected light from the disk via the beam splitter for detecting focus, sensed recorded signals and for tracking the beams to tracks of the disk. The combiner and splitter are preferably secured together as a single unit. The combiner uses refraction and internal reflection properties to combine the two like-frequency beams without polarization changes of either beam.

Optical flip-flops and sequential logic circuits using a liquid crystal light valve

Abstract: This paper is concerned with the application of optics to digital computing. A Hughes liquid crystal light valve is used as an active optical element where a weak light beam can control a strong light beam with either a positive or negative gain characteristic. With this device as the central element the ability to produce bistable states from which different types of flip-flop can be implemented is demonstrated. In this paper, some general comments are first presented on digital computing as applied to optics. This is followed by a discussion of optical implementation of various types of flip-flop. These flip-flops are then used in the design of optical equivalents to a few simple sequential circuits such as shift registers and accumulators. As a typical sequential machine, a schematic layout for an optical binary temporal integrator is presented. Finally, a suggested experimental configuration for an optical master-slave flip-flop array is given.

Dual field of view sensor

Abstract: A dual field of view sensor, particularly adapted for use as a forward-looking infrared night vision detector, includes a single detector (24) for receiving a light signal and developing an output electrical signal therefrom. A rotating polygon scanner (16) having a plurality of reflective facet (14) thereon receives light (12, 34) from two separate optical systems (10, 32) and directs the light onto the facets (14) of the scanner (16) at positions offset by one-half the facet angle such that the light beams alternately strike a facet and the juncture between two facets. The reflected light is then directed through a beam splitter 40 onto the detector in an alternating, interleaved sweeping motion. The beam splitter permits only one at a time of the light (12, 34) from entering the detector. In one embodiment, both optical systems include a steerable dual field of view telescope. In a second embodiment, a transparent display (60) such as an LCD panel, impresses a data image on one light beam (52) and the signals developed from that and another light beam are combined to drive a display. In a third embodiment, the two light beams represent the input to a stereoscopic viewing system, and the separate signals developed therefrom are used to drive a pair of small helmet-mounted displays for individual viewing by the wearer's left and right eyes to provide stereoscopic night vision viewing.

Angle sensitive interferometer and control method and apparatus

Abstract: An angle-sensitive interferometer includes a first beam splitter for splitting a beam of coherent radiation into two portions and a second beam splitter for recombining the two beam portions to produce an interference pattern. It also includes reflecting mirrors and lenses for recombining the two beam segments in such a manner that an angle of deviation in the incident beam results in the recombined beams diverging from the interferometer axis to create a wedge angle. A corner cube reflector, cat's eye reflector, or a telescope with either convex lenses or concave mirrors are used for this purpose. The invention also includes a mirror in one of the beam portion paths to reflect it out of alignment with that beam portion path emerging from the first beam splitter so that the second beam splitter where the beam portions are recombined does not produce feed back into the radiation source. A quadrant diode is used to detect asymmetrical changes of intensity in the fringe pattern indicative of angle change of the incident beam. Apparatus for detecting, measuring, and controlling beam angles are also included.

Single-mode fibre-optic holography

Abstract: A fibre-optic holographic system is described in which the functions of all the optical components conventionally used to produce holograms-such as beam splitters, mirrors and beam expanding spatial filters-are performed with single-mode optical fibres. Design considerations are discussed, and an electronic servo system which provides compensation for thermally induced phase shifts is described.

Optical system for three color liquid crystal light valve image projection system

Abstract: A two lens optical system for a three primary color liquid crystal light valve image projection system. The first lens projects the red and green primary colors, while the other lens projects the blue primary color. The light from the illumination system is partially prepolarized by a first prism before being split into two optical paths by a first beam splitter. Red light having a first and second polarization and green light having a first polarization is transmitted along a first optical path to a second, or main beam splitter, from the first beam splitter. The red light is transmitted to a first light valve, the green light being reflected to a second light valve. With the first and second light valves "on" state, the light incident thereon is directed back to the main beam splitter, recombined and then directed to the first projection lens. Green and blue light of the second polarization is reflected along a second optical path by the first beam splitter, the blue color light being transmitted through a third beam splitter to a third light input valve. The third light valve "on" state, the blue light incident thereon is directed to the third beam splitter and then to the second projection lens. By utilizing the two different optical paths, high image contrast is achieved. The optical system utilizes a minimum of optical components such that light losses in the system are reduced, thus increasing overall system collection efficiency.

Ultrawide Waveband Optics

Abstract: Optical systems are normally usable over a restricted spectral waveband A refractive optical system will only transmit radiation over a limited range of wavelengths, and it may produce well color-corrected images over only part of this transmission band This paper discusses the design of lens systems for use over the extended waveband from about 04 gm to 12µm, which encompasses the visible, the 3 to 5µm mid-infrared, and the 8 to 12 um thermal wavebands Discussion is given to the available optical materials, including glasses formed by chemical vapor deposition and crystalline materials The relationships between the refractive and dispersive properties required for wideband color cor-rection are formulated, and several designs are described that use two or three optical materials Some discussion is given to the coatings required for such optics, viz, ultrawideband antireflection, mirror, and beam splitting coatings The potential use of this type of optical system is in multisensor applications such as dual visual/thermal observation systems, perhaps employing staring array technology and/or CO2 laser incorporation

Magnetooptic reproducing device provided with rotary polarizer

Abstract: PURPOSE:To facilitate a position adjustment of detectors which photodetect light split by a PBS in a magnetooptic reproducing device which uses the PBS as a substitute for an analyzer, by arranging the detectors at 0 or 90 deg.. CONSTITUTION:A P-polarized beam from a laser light source 1 irradiates a recording medium 3, and its reflected light is rotated by Kerr rotation thetak or -thetak according to the upward or downward magnetism of a recording medium to obtain a light vector P1 or P2 containing an S component. The reflected light is incient to a half-wavelength plate as a rotary polarizer 2 through an objective lens 7 and a beam splitter 2, and the azimuth angle of the rotary polarizer is set to 22.5 deg. to rotate the plane of polarization of the incident light, which is transmitted. Consequently, the polarized light (P1 or P2) transmitted through the rotary polarizer 10 is rotated by 45 deg. to enter the PBS8, so that the light is split into polarized light (A1, A2) and polarized light (B1, B2) which have the planes of polarization at right angles to each other and are nearly equal in intensity. The plane formed of the polarized light (A1, A2) and polarized light (B1 and B2) is the same as the original plane P of polarization of the light incident to the PBS8 and photodetected by detectors 5a and 5b.

Optical splitter for dynamic range enhancement of optical multichannel detectors

Abstract: An optical beam splitter divides an incoming converging optical beam into two or more spatially separated output beams that both have a desired attenuation ratio between consecutive output beams and also focus all output beams in substantially the same plane.

Digital magnetooptic disk drive

Abstract: A magnetooptical disk drive employing some useful techniques for high performance has been developed for digital file use. A quadrilayer structure with AlN films promises high reliability of the medium as well as enhancement of Kerr rotation. The azimuth of the polarization plane is also increased by the beam splitter, of which Rs (reflectivity of S wave) is larger than Rp (reflectivity of P wave). Parallel control of both actuator and linear motor is used for high tracking accuracy. 4/5 MNRZI modulation is found to be a useful modulation method for the magnetooptical memory system.

Optical system in a magneto-optical memory device

Abstract: A magneto-optical memory device includes a recording medium having a magnetic anisotrophy in a direction perpendicular to the main surface thereof. A semiconductor laser is employed in an optical system of the magneto-optical memory device for reproduction purposes. A beam splitted is disposed in the optical system. A multi coated dielectric thin-film is deposited on the reflection surface of the beam splitter in order to establish a desired relationship between the reflection of the P-polarisation and the S-polarisation. A smaller proportion of the P-polarisation is reflected than the S-polarisation, so that the beam acquires a rotation angle greater than the Kerr rotation angle a applied to it by the recording medium.

Length measuring apparatus based on the dual laser beam interferometer principle

Abstract: Length measuring apparatus with position sensor (12), in accordance with the dual beam laser interferometer principle, having a laser light source (16) supplied by a power source (48), a beam splitter (18) disposed in its optical axis for dividing the light beam into a measuring light beam and a reference light beam aligned at an angle thereto, a movable mirror (19) joined to the position sensor and reflecting the measuring light beam parallel to the optical axis with a transverse offset, and an at least partially reflecting additional optical element (20). This optical element (20) can be either in the form of a second mirror or in the form of a second beam splitter. In the area of interference of the beam paths lies at least one photodetector (21) whose output or outputs are connected to an evaluating circuit (37) which has a counting system for counting the light/dark sequences including a detection of direction of movement, and to a digital display system (3). In accordance with the invention, the laser light source is a laser diode (16 ) for the production of laser light which is essentially monomodal both laterally, transversely and longitudinally and has a coherence length that corresponds at least to the length to be measured. The evaluation circuit (37) also has at least one system for eliminating the influences of operational and environmental parameters of the length measuring apparatus. The apparatus is extraordinarily compact, and easy to learn to operate as regards signal processing and regulation. It is consequently suitable both for manual measuring devices (gauges) and for machine devices.

Optical axis monitoring system

Abstract: A device for monitoring the amount of deviation of a light beam in an optical system with which the freedom of design of the system is significantly improved. For each position at which the amount of deviation is to be measured, a beam splitter is provided to divide the light beam at that point into a main beam and a sub-beam. The sub-beam is applied to an optical position detector which detects the amount of deviation of the sub-beam from a predetermined position on the detector, that deviation being related to the amount of deviation of the main beam from its designated optical path. The output of the position detector is used to correct the position of the main beam.

Heads up display for microscope using remotely controlled instrument

Abstract: Information relevant to a remote instrument is made viewable within a microscope 10 by a heads up display using a beam splitter 15 arranged in a collimated light region between binoculars 12 and objective 11 of microscope 10. An electronic digital display 16 relevant to a control setting for the remote instrument is arranged off the optical axis of microscope 10 and viewed by a convex mirror 20. A folding mirror 21 directs diverging light from convex mirror 20 toward beam splitter 15, and a collimating lens 22 collimates the diverging light enroute from folding mirror 21 to beam splitter 15. Collimated light from the lens is incident on beam splitter 15 to position an image of the digital display in a marginal region of the apparent field of one of the binoculars 12.

Light source device for close spacing of two light beams

Abstract: There is disclosed a light source device in which first and second semiconductor lasers are disposed relative to a polarizing beam splitter so that the laser beam from the first is transmitted while that from the second is reflected by the beam splitter, and that the major and minor directions in the cross section of the first beam are respectively co-ordinated with those of the second beam An optical element capable of rotating the plane of polarization of an incident beam by approximately 90° is disposed between one of the semiconductor lasers and the polarizing beam splitter In this manner the beams from the seconductor lasers can be guided, with respectively co-ordinated major and minor directions in the beam cross section, in the same direction without any decrease in the quantity of light

Recrystallization of silicon film on insulating layers using a laser beam split by a birefringent plate

Abstract: 20‐μm‐wide, 1‐mm‐long, single‐crystal Si films on SiO2 have been produced using a cw Ar laser beam split by a birefringent quartz plate. The single‐scan recrystallized region width has been widened by multiple beam splitting. The resultant single‐crystal region obtained by multiple scan from the seed is a 90‐μm‐wide and 100‐μm‐long area with rare grain boundaries. This split beam method uses the stable and highly efficient TEM00 mode and needs no prepatterned antireflection layers.

Interferometer having an integrated length standard

Abstract: An interferometer for length measurement, which operates using a high-intensity IR laser diode, contains a small beam splitter and a 90 DEG deflecting prism connected thereto by means of which an incident laser beam is coupled onto two parallel planes. One plane contains a measuring interferometer, and the other plane, which is located therebelow or thereabove, a control interferometer. The first of these contains a beam splitter in which an incident laser beam polarised by 45 DEG is split into a reference beam and a measuring beam at right angles thereto, as well as a 90 DEG prism or triple prism in which the two beams are reflected displaced in parallel, whereupon they are reunited in the beam splitter and then split into two signals phase-shifted by 180 DEG . Arranged to follow is a polarising beam splitter through which one portion of the signals is guided directly and the other portion is guided via a 90 DEG prism, four signals with a phase shift advancing by 90 DEG in each case being produced by splitting into a horizontal and a vertical component, respectively. The control interferometer likewise contains a beam splitter, in which the same laser beam is split into a reference beam and a measuring beam at right angles thereto, as well as a 90 DEG prism or two prisms in which the two beams are reflected displaced in parallel, whereupon they are reunited in the beam splitter and then ... Original abstract incomplete.

Direct slope measurement shearing interferometer

Abstract: An improved method and apparatus for measuring the aberrated wave slope of an optical beam. The apparatus includes a shearing interferometer having a reference mirror 14 and a steerable mirror 16 mounted perpendicularly to one another with a beam splitter 10 disposed at a 45° angle to each. The beam splitter 10 directs a portion of the incident beam to the reference mirror to form a reference beam 20 and transmits a portion 22 of the incident beam to the steerable mirror. The steerable mirror 16 is pivoted about two mutually perpendicular axes to form a shearing interference pattern at a detector array 24 when a portion of the incident beam is reflected off the steerable mirror 16 and combines with the reference beam 20 reflected off the reference mirror. The reference mirror 14 is periodically displaced to modulate the reference beam 20. In operation, the steerable mirror 16 is first oriented pivotally about a first axis perpendicular to the propagation axis of the incident beam to a pre-selected angle and the reference mirror is then periodically displaced. The variations in detector intensities are sampled and stored N times during this reference mirror displacement. The steerable mirror is then oriented at the same pre-selected angle about a second axes perpendicular to the first pivotal axis and the beam propagation axis and the reference mirror 14 again periodically displaced. The resulting detector intensity values can be manipulated to yield the phase of the initially distorted beam which can be converted into aberrated wave slope data.

Interferometric thickness analyzer and measuring method

Abstract: Each measurement ray (10) in an incident beam (3a) is made to be reflected at symmetrically opposite points (11,12) on the front and rear surface of the object (6) before being brought to interference with a coherent reference ray (10a). The object is arranged between two parallel flat mirrors (5a,b) and the measurement beam is provided at an oblique angle of incidence (alpha). The measurement beam reflected at the object surface is deflected by a blazed grating (7) or by a pair of folded mirrors whose bisector is coincident with the plane of symmetry of the plane mirrors. The reference and measurement beams are obtained from a laser beam (3) which is incident on a beam splitter (4).

Infrared viewing apparatus

Abstract: An infrared viewing apparatus is described which comprises an infrared objective, a pivotal mirror, a linear infrared detection array, an amplifier arrangement connected to this array, and a display array which is driven by the amplifier arrangement and is imaged onto a plane of observation via the back of the pivotal mirror. By arranging a beam splitter in the radiation path between the display array and the pivotal mirror, which beam splitter transmits a part of the visible radiation to a line sensor, and by controlling the read-out of this sensor by synchronizing device which detects the movement of the pivotal mirror, an electric signal for remote display purposes can be obtained.

Optical information reader

Abstract: PURPOSE:To perform defocusing detection with high precision over a wide range by performing focusing operation based upon a defocusing signal from a two- division photodetecting element over a wide range through a specific optical system and obtaining an RF signal, and then switching said signal to a defocusing signal from a four-division photodetecting element and performing high-precision focus servocontrol. CONSTITUTION:Light emitted by a semiconductor laser 1 is converged on a disk 6 through a polarization beam splitter (PBS)2, lambda/4 plate 3, collimator lens 4, and objective lens 5. Its reflected light travels backward and passes through the PBS2 and is split through a beam splitter 7 in directions crossing an optical axis at right angles to enter two-division photodetecting elements 8 and 8' which are provided at image non-formation points B and B' at equal distance from conjugate points A and A' of the laser 1 and have division lines parallel to a track direction and the four-division photodetecting elements 10 through a cylindrical lens 9 on the optical axis. Wide-range defocusing is detected from defocusing signals of the photodetecting elements 8 and 8' and high-precision focus servocontrol is performed with the defocusng signal of the photodetecting element 10.

Photomagnetic pickup device

Abstract: PURPOSE: To improve the S/N of a reproduction signal by using a total reflection prism, a beam splitter, etc. to correct the phase difference between the incident linear polarization component of the reflected light sent from a photomagnetic recording medium and the polarization component orthogonal to said linear polarization component. CONSTITUTION: The light delivered from a semiconductor laser 11 is turned into parallel beams by the linear polarization parallel to the paper surface and through a collimator lens 12 and formed into an approximately circular intensity distribution by a shaping prism 13. The these beams are made incident on a beam splitter 14 with P polarization and the beams transmitted through the splitter 14 are made incident on a total reflec tion prism 15 with S polarization. Here a phase difference occurs by the reflection of the prism 15. However the light incident on the prism 15 contains just the P polariza tion and no P polarization component and is never formed into an oval. The light formed into an oval by the reflection through a recording medium 23 is reflected again by the prism 15 to undergo the linear polarization. This linear polarized light is reflected by a beam splitter 16 and transmitted through a photodetector 19. Then a signal is detected by a light detector 21. Thus the S/N of a reproduction signal is improved. COPYRIGHT: (C)1986,JPO&Japio

Automatic focus control system for video camera

Abstract: An automatic focus control system for a video camera comprises a main optical system for conducting light from an object and including an adjustable diaphragm for adjusting the amount of light conducted therethrough, a beam splitter disposed in the main optical system for diverting a portion of the light from the main optical system into an optical subsystem which has a second adjustable diaphragm for adjusting the amount of light conducted through the optical subsystem, a converter for converting the portion of the light diverted through the optical subsystem into focusing signals, and an automatic focus control circuit including a contrast detecting circuit for detecting a focused state of the light from the object in response to the focusing signals.

Multi-coordinate measuring machine

Abstract: The invention contemplates a multi-coordinate measuring machine with interferometric detection of the path of displacement in each of the measurement axes. Each measurement axis is provided with at least one interferometer head which consists of a beam splitter, reference mirror and photoelectric detector. The interferometer heads are supplied by a monomode fiber from a single stationary laser generator.

Turbid media viewing system

Abstract: A coaxial, spacially gated, range gated, pulsed-beam, scanning system for use in turbid media, such as seawater, fog, snow, rain, blowing dust or sand. A laser emits a pulsed beam of light which travels to a beam splitter where part of the beam is transmitted and part is deflected. The transmitted beam is then deflected by an x-y scanning element such that a target is sequentially illuminated in a point-by-point manner. Light refected from the target travels back along the same path as the transmitted beam and is deflected by the beam splitter to a light sensor, such as photomultiplier tube. The field-of-view of the light sensor is limited and controlled in such a manner that it receives light only from that portion of the target that is illuminated by the portion of the transmitted beam light that has not been scattered by the turbid medium, and the system is range gated to accept only that portion of the output of the light sensor which is representative of the intensity of the non-scattered beam pulse which is reflected by the target. Range gatting may be triggered by detection of the leading edge of the reflected light pulse as it enters the sensor or by detection of the portion of the emitted beam that is deflected by the beam splitter. This allows use of a free-running laser.

Advanced cube processor

Abstract: An apparatus and method provide for the electrooptic performing of matrix-matrix multiplication, computation of the cross-ambiguity function and calculation of triple correlations. A collimated light source is pulsed to illuminate a first matrix of optically encoded information. Since the first matrix functions in the transmissive mode the same pulsed light is deflected by a polarizing beam splitter to a second matrix of optically encoded information. This matrix, functioning in the reflective mode reflects the pulsed, collimated light back through the beam splitter onto a third matrix of optically encoded information. The third matrix is operated in the reflective mode and reflects the pulsed, collimated light back to the polarizing beam splitter and onto a two-dimensional photodetector array. The photodetector array adds the successively arithmetically processed encoded informations from the first, second and third matrices of information. The information of the first matrix is advanced across the light path from the pulsed, collimated light source and the encoded information from the second and third matrices are advanced across opposite faces of the polarizing beam splitter in a mutually orthogonally displacement with respect to one another. Optionally, the information in the first matrix can be advanced across the path of the pulsed collimated light at right angles to that described above to effect substantially the same mathematical operations called for above.

High‐temperature laser interferometer for thermal expansion and optical‐length measurements

Abstract: A simple laser interferometer has been utilized to measure the thermal expansion and optical‐length variation with temperature of highly reactive fluorides at high temperatures. The interferometer is a modification of the Jamin interferometer in which a laser beam is split into two parallel beams which traverse nearly identical paths and are reflected from the sample and a reference mirror. The reflected beams recombine to produce an interference pattern. The displacement of the front sample surface, relative to the reference mirror at the back sample surface, allows the thermal expansion to be measured. The sample and reference mirrors are made reflecting by depositing a platinum film on the surface. The same arrangement of beam splitters has been used to measure the variation in optical length with temperature. In this case, the sample is not coated with platinum. Measurements of thermal expansion have been made up to 1000 K above which the platinum film becomes unstable. Optical lengths of various fluo...