Abstract: An object of the invention is to provide an acousto-optic tunable filter (AOTF) that realizes filter characteristics where the wavelength characteristics in the vicinity of a selected center wavelength are smooth, and the bandwidth thereof is sufficiently narrow. To this end, an AOTF of the invention has a construction where a mode coupling section and a wavelength characteristic flattening section provided with an optical filter configuration for selecting an optical signal based on mode conversion using the acousto-optic effect, are respectively connected via a mode branching device. The mode coupling section mode converts an optical signal corresponding to a selected wavelength, and the wavelength characteristic flattening section again mode converts only the optical component of a part of the selected optical signal mode converted in the mode coupling section in the vicinity of a center wavelength thereof.

Abstract: An optical reticle substrate inspection apparatus is provided with a laser, a first acoustooptical element which scans a laser beam output from the laser, and a second acoustooptical element which generates a virtual image with a concave lens effect to the laser beam output from the first acoustooptical element. The optical reticle substrate inspection apparatus is further provided with a concave lens arranged on the output side of the laser beam of the second acoustooptical element and an optical system which images the virtual image on a reticle substrate being an object to be inspected. The concave lens magnifies the laser beam in a perpendicular direction to the scanning direction by the first acoustooptical element.

Abstract: Pixel clock and beam scan timing of an acousto-optic scanner are controlled by an acoustic velocity-driven, phase locked loop containing an adjustable voltage controlled pixel clock generator, which is controlled by a detector that produces delayed and attenuated replica of the excitation waveform applied to an ATWL scanner used to scan a light beam across a workpiece. In a first embodiment of the invention, an end-of-cell transducer converts the pressure induced traveling lens into an electrical signal replica of the excitation input. In a second embodiment, an end-of-scan optical pick-off monitor is employed to detect the scanned optical spot as it crosses its field of view.

Abstract: An apparatus and method for producing a spectrally variable radiation source and systems including same is disclosed. An embodiment of a spectrally variable radiation source is disclosed including a broadband radiation source, a collimating element, a dispersive element, an imaging element, an output aperture and an optional output collimating element. An embodiment of a spectrally encoded infrared chromatograph incorporating the inventive spatially variable radiation source is disclosed. An arbitrary spectrum projector for simulating emission or absorption spectra for chemical and biological agents, as well as projecting calibration and test spectra for characterizing sensors is also disclosed.

Abstract: Consistent with the present invention, in-fiber Bragg gratings are used to demultiplex optical signals in a WDM optical communication system. The in-fiber Bragg gratings also perform dispersion compensation of the selected optical signals. As a result, additional segments of DCF for further dispersion compensation are rendered unnecessary. Improved performance is thus achieved with an inexpensive and simplified system design.

Abstract: An acousto-optic device comprises a first light source for producing a light beam, a light-transmitting material capable of transmitting the light beam along an optical path through the light-transmitting material, a light-absorbing material adjacent to the light-transmitting material, and a pulsed light source capable of directing a pulsed light beam at the light absorbing material so as to produce acoustic waves within the light-transmitting material that cross the optical path of the light beam from the first light source.

Abstract: The present invention relates to acousto-optic applications of parametric optical apparatuses that use the mechanical energy of elastic oscillations to convert light over a wide range of wavelengths and amplitudes and to generate coherent light.

Abstract: In an optical-radiation patterning apparatus, a scan mirror (29) so deflects laser light from a source (32) as to draw a pattern on a substrate (26). A focusing system (42) forms a light spot on the substrate that is significantly narrower than the line to be drawn, and it thereby minimizes the sensitivity of the line-edge position to variations in light-spot size. To achieve the intended line width, an acousto-optical device (32) introduces dither in the direction orthogonal to the light-spot motion that the scan mirror (30) causes. The focusing system (42) shapes the spot so that it is wider in the scan direction than it is in the dither direction, and this permits a relatively high scan rate for a given dither frequency.

Abstract: A laser imaging device is provided with a laser source that emits a laser beam including a plurality of wavelength components. The wavelength components are divided by a dividing optical system, and at least two wavelength components are extracted and each of which is directed to a beam dividing element. Each wavelength component are divided into a plurality of beams, and independently modulated by the modulating optical systems. The beams having different wavelengths are directed to respective scanning optical system, and deflected thereby to scan in different areas on an objective surface.

Abstract: The present invention has applications that include detecting color variation in a region, for example, color variations due to temperature changes in an area of ocean water, and, in a more specific application, detecting bioluminescence of certain organisms known to attach themselves to various objects. In one aspect of the invention, an acousto-optic tunable filter hyperspectral imaging system is moved across the region to collect a series of images in which each image represents the intensity of light at a different wavelength. In one embodiment, the acousto-optic tunable filter hyperspectral imaging system includes a motion platform for positioning the acousto-optic tunable filter hyperspectral imaging system over successive Y-coordinates of a region in a direction substantially parallel to a direction of motion of the motion platform.

Abstract: A device that includes a projection element positioned between first and second beam scanners configured in series and a two-dimensional display plane. An apparatus for controlling the first and second beam scanners is provided so that the angle of incidence and the point of incidence of a beam output from the series connected beam scanners onto the projection element are controlled. In that manner, each point on the projection element can be mapped to a line in the display plane. A method of mapping a point in the projection element to a line in the display plane is also disclosed.

Abstract: To weaken the light beam (12) in a microscope (100), especially in a scanning microscope, we propose an apparatus for the variable change of the illumination power that is arranged so that a light beam of zero diffraction order (17) emanating from a modulator (13) can be used directly for the purposes of microscopy. The acusto optical modulator (13) is the only element in the microscope influencing the power of light in a variable way.

Abstract: The multi-beam exposure apparatus includes a light source for emitting a specified number of multi-beams spaced apart in a direction of auxiliary scanning, a deflecting unit for deflecting the specified number of multi-beams collectively on main scanning lines by a specified number of deflections such that a space between adjacent ones of the specified number of multi-beams is exposed and a main scanning unit for performing main scan of a recording material as it is exposed with the specified number of multi-beams, wherein the space between adjacent ones of the specified number of multi-beams is an integral multiple of (the specified number of deflections +1) multiplied by a pitch of pixels in the direction of auxiliary scanning.

Abstract: A method for spatially modulating radiation includes directing at least one radiation beam upon at least one surface acoustic wave diffractive element, and driving at least one of the surface acoustic diffractive elements with a plurality of modulating signals to generate a plurality of modulated output radiation beams having parameters.

Abstract: The invention is intended to present a multi-channel optical modulator small in crosstalk, being used in a laser external modulator of an optical recording apparatus. To achieve the object, the multi-channel optical modulator comprises a plurality of first electrodes (13) provided on one side of an acoustic-optical medium (11), a plurality of piezoelectric elements (12) provided on the first electrodes (13), a plurality of second electrodes (14) provided on the piezoelectric elements (12), a plurality of first lead wires (15) connected individually to the second electrodes (14), and a plurality of second lead wires (16) connected individually to the first electrodes (13), and thereby the crosstalk is small.

Abstract: An acousto-optic tunable filter (AOTF) utilizing phased array transducers for use as dynamically reconfigurable wavelength division multiplexer. The new type of AOTF has the unique capability of simultaneous and independent selection of multi-wavelength signals and separation into multiple output ports. Preferred embodiments of the AOTF are described that provide increased resolution, narrow channel spacing, lower drive power and reduced coherent crosswalk.

Abstract: Disclosed is a laser optical system including a multiline laser source that emits a laser beam having a plurality of peak wavelengths, a wavelength separating optical system that separates the laser beam emitted from the laser source into two monochromatic beams, a pair of modulating optical systems that modulate intensities of the monochromatic beams, a beam combining optical system that combines the laser beams modulated by the modulating optical systems, a deflector for deflecting a plurality of laser beam combined by the beam combining optical system, and a converging optical system that converges the laser beams deflected by the deflector to form beam spots on an object surface to be exposed. The modulating optical systems, which include diffractive beam-dividing elements, are optimized for the respective monochromatic beams to form the beam spots at the identical pitches on the object surface.

Abstract: The present invention pertains to a polarization independent tunable acousto-optical filter and the corresponding method. The filter diffracts an input light beam into a first input light beam unaffected by acoustic waves and a second input light beam affected by acoustic waves. A polarization beam displacer/combiner is employed to separate the input light beam into two orthogonal beams. Several polarized rotators are used to rotate the polarization of light by 90 degrees. An acousto-optical device makes the polarization of light with a particular wavelength rotate by 90 degrees. The two beams are then properly combined to form orthogonal beams. The filtering method has nothing to do with the polarization of the incident light. The filter has such advantages as a high extinction ratio, a small volume and a lower cost.

Abstract: Multi-domain, phase-compensated, differential-coherence detection of photonic signals for interferometric processes and devices may be manufactured holographically and developed in situ or with an automatic registration between holograms and photonic sources in a single frame. Photonic or electronic post processing may include outputs from a cycling or rotation between differently phased complementary outputs of constructive and destructive interference. A hyper-selective, direct-conversion, expanded-bandpass filter may rely on an expanded bandpass for ease of filtering, with no dead zones for zero beat frequency cases. A hyper-heterodyning, expanded bandpass system may also provide improved filtering and signal-to-noise ratios. An ultra-high-resolution, broadband spectrum analyzer may operate in multiple domains, including complex “fingerprints” of phase, frequency, and other parameters.

Abstract: An acoustooptic device is structured by providing an interdigital transducer in which arch-shaped electrode fingers are interdigitated so that the interdigital transducer is circular or annular in shape as a whole, on an optical waveguide which is circular when viewed from the front. This acoustooptic device is used as a diffraction optical device on which light is incident from the front. When an alternating voltage of a predetermined frequency is applied to the interdigital transducer by an oscillator, a concentric acoustic compressional wave is generated on the optical waveguide. The concentric acoustic compressional wave diffracts the incident light, so that the diffraction optical device functions like a lens and converges the luminous flux.

Abstract: An optical system for scanning which facilitates, at a time of assembling a plurality of optical elements forming an optical system for scanning, adjustment of positional relationships between the optical elements so that an appropriate laser beam is irradiated. In a light source unit, an SHG module and a collimator lens are assembled on a first base which is formed of covar, and this first base is mounted via an adjustment spacer to a second base at one end thereof in a longitudinal direction. An AOM is mounted to the other end of the second base. In this way, in this light source unit, adjustment of the positional relationships between the optical elements at a time of assembly is facilitated. In addition, regardless of whether an impact is applied at the time of assembly or whether a temperature or the like changes after assembly, an appropriately modulated laser beam can be irradiated.

Abstract: Apparatus for receiving light containing image-representative information, and low-pass filtering the light. A pellicle is positioned in the path of the light. At least one transducer is coupled with the pellicle and an AC electrical signal is applied to the transducer to establish waves in the pellicle. The waves are operative to low-pass filter the image-representative information in light reflected from the pellicle.

Abstract: In an optical-radiation patterning apparatus, a scan mirror (29) so deflects laser light from a source (32) as to draw a pattern on a substrate (26). A focusing system (42) forms a light spot on the substrate that is significantly narrower than the line to be drawn, and it thereby minimizes the sensitivity of the line-edge position to variations in light-spot size. To achieve the intended line width, an acousto-optical device (32) introduces dither in the direction orthogonal to the light-spot motion that the scan mirror (30) causes. The focusing system (42) shapes the spot so that it is wider in the scan direction than it is in the dither direction, and this permits a relatively high scan rate for a given dither frequency.

Abstract: A computer-readable signal bearing medium (10) has components (11, 21, 31) which act via a data processor (86) in an imaging system having an acoustic energy source (81) and a birefringent detector (84, 70) to record first data (14) from a first portion (61) of an object (60), the first portion attenuating first acoustic energy (12) at least part way to a first attenuation maximum (13, 43) along a first acousto-optic response (41) of the birefringent detector; to record second data (24) from a second portion (62) of the object, the second portion attenuating second acoustic energy (22) at least part way to a second attenuation maximum (23, 53) along a second acousto-optic response (51) of the birefringent detector; combines the data (32), and outputs a result.

Abstract: A video image projection apparatus is disclosed. The apparatus uses a laser as a light source and modulates the light beam using a modulator according to an image signal. The apparatus projects the modulated light to a screen using a light scanning system. The laser display system includes three primary color laser light sources, an optical system needed for three-color light combining/separation, a light modulator loading the image signal into the three-color laser, and a driving circuit driving the system by processing the video signal electronically. A hybrid video laser color mixer has a structure that combines very small-sized hybrid light beam combining/separation optical elements and a 3-channel light modulator. It allows the size of the image projection apparatus to be about 6 by 5 by 3 centimeters. Additionally, the light alignment of the elements is close to self-alignment.

Abstract: An acousto-optic modulator including an ultrasonic medium for controlling light from an optical source through diffraction, two transducers each having one electrode formed on one side thereof, the electrodes being for generating an acousto-elastic wave, and a conductive adhesive layer interposed between the ultrasonic medium and each of the sides of the transducers opposite to the sides on which the electrodes are installed, in order to adhere each of the transducers to the ultrasonic medium.

Abstract: A system for extracting the complex Fourier coefficients from an unknown RF signal to classify the RF signal is disclosed. The extraction system utilizes optical signal processing in combination with the generation of electronic timing and control signals. The system employs an optical processor comprising a Bragg cell to yield the Fourier coefficients including the amplitude, phase and frequency parameters thereof. The system further includes a parallel arrangement that provide for parallel processing to reduce the computational time needed to determine the complex Fourier coefficients including the amplitude, phase and frequency parameters thereof.

Abstract: A scanning optical unit is provided which can prevent flare reflection of a laser beam at an end portion of a reflecting mirror which is provided outside an exposure region and which is for detecting a time of starting of exposure by the laser beam. In the scanning optical unit, given that a propagation distance from a transducer of an acousto-optic modulator (AOM) to a diffracted position of the laser beam passing through an acousto-optic modulating medium is L, a propagation speed of ultrasonic waves within the acousto-optic modulating medium is V, a main scanning speed of the laser beam is v, a distance from a position on a reflecting mirror at which the laser beam is reflected onto an SOS sensor to a recording medium side end portion of the reflecting mirror is l, and a focal length of an f&thgr; lens is f, a relationship L<l·V/{v·(f−t)/f} is established so as to prevent flare reflection of the laser beam.

Abstract: An acousto-optic modulator for use with a multi-channel laser beam system, for instance, is of conventional structure except that two different RF (radio frequency) signals drive the modulator. These signals each produce at least one output beam as diffracted by the modulator body. These two beams are angularly and spatially separated. One of the sets of beams is incident upon a beam stop, and therefore is not used for writing. Only the other set of beams, driven by the other of the frequencies, performs the actual writing. The optical stop in addition to blocking one of the sets of diffracted beams also blocks the transmission of the zero order (undiffracted) beam. The sum of the load power of the signals at the two frequencies is kept approximately constant, thereby maintaining a constant thermal condition within the modulator.

Abstract: Disclosed is a laser modulating optical system, which includes an argon laser that emits at a plurality of peak wavelengths, an acoustooptic modulator (AOM) that changes a direction of an emergent light by diffraction caused by input ultrasonic wave to take out a diffracted beam as a modulated beam, and a correction optical system. The correction optical system includes one pair of wedge prisms located in a parallel laser beam at the incident side of the AOM. The wedge prisms are arranged with a predetermined space therebetween. The apex of one prism is opposite in direction to the apex of the other prism to have the opposite chromatic dispersions to each other. The wedge prisms are designed to coincide the optical paths of two peak wavelengths that are deviated to each other due to a variation of the diffraction angle of the AOM.

Abstract: An optically defractive medium of a Bragg cell has a moving grating induced therein in response to acoustic waves propagating in the medium. First and second electro-acoustic transducers coupled to the medium launch first and second acoustic waves toward each other in response to electric excitation of the transducers to produce a moving grating having an amplitude proportional to the difference in the amplitude of the first and second acoustic waves. A laser illuminates the medium and an optical detector array including plural individual detector elements responds to optical energy from the source, as modulated by the moving grating. A processor responds to the detector elements to derive an indication of time difference of arrival of first and second electric signals that respectively drive the first and second transducers.

Abstract: A method and system are disclosed for curing polymeric materials including dental composites. Preferably, modulated light is used to control the formation of polymer chains in the polymeric material so that a cured polymeric material that has the desired physical characteristics for its intended function. Formation of short chain and long chain polymers from monomers in the polymeric material is initiated and controlled by using a light source with a wavelength suitable for one or more initiators found in the polymeric material.

Abstract: An acousto-optic deflector which has a thin film waveguide layer on a buffer layer formed on a substrate and an IDT and light incidence/emergence means on the thin film waveguide layer. As the thin film waveguide layer, a piezoelectric material such as a ZnO film is used. As the substrate, a material with a resistivity of not more than 20 &OHgr;cm is used. Sezawa waves are excited on the thin film waveguide layer by the IDT, and a laser beam traveling in the thin film waveguide layer is deflected by the Sezawa waves. If the ZnO thin film waveguide layer has a thickness of h and if the excited Sezawa waves have a wavelength of &lgr;, 0.2<h/&lgr;<0.5 is fulfilled.

Abstract: The invention relates to optical birefringent waveguides, acousto-optical devices using such optical waveguides and an acoustic waveguide as well as a manufacturing method therefore. The optical waveguides of the invention exhibit a small birefringent variation with respect to a change of waveguide parameters, if the fundamental mode propagating in the optical waveguide has a propagation constant near to the cut-off condition. The optical waveguide dimensions are typically chosen such that the cut-off wavelength of the waveguide is below 1650 nm for an operating wavelength in the window between 1530 nm and 1656 nm. The acousto-optic mode converter using such optical waveguides have a superior conversion characteristic over the conversion frequency with reduced side lobes. Therefore, using the thin and narrow optical waveguides of the invention, a superior performance of the acousto-optical devices using such an optical waveguide can be obtained.

Abstract: Apparatus for transmitting information at a data rate, comprising:

Abstract: The invention features systems and methods for generating optical beams having substantially orthogonal polarizations for use in distance measuring interferometry. In one embodiment, the invention features a system including a source which during operation generates two nonparallel propagating source beams; and a retarder element positioned to receive the two nonparallel propagating source beams and convert them into two nonparallel propagating output beams that are polarized substantially orthogonal to one another. The system can further include a birefringent prism positioned to receive the two nonparallel propagating output beams and produce two parallel output beams.

Abstract: An apparatus for extending the light deflection angle, so a light beam can be dynamically controlled within ±90°, pitch and yaw. The device comprises an initial dynamic beam deflector and a compound light beam direction mapper. The beam direction mapper includes a beam size reducer, a beam transmission adapter, and a projector. An initial light beam from a light source is deflected a small amount by the initial dynamic beam deflector. The initially deflected light beam is focused by the beam size reducer to a light energy spot on the beam transmission adapter, which transfers the light spot to the projector. The projector emits an output light beam at the far field of its output space with an output deflection angle larger than the initial deflection angle. All components are based on classical geometry optics and the energy of the output light beam is within an order of magnitude of that of the input light beam.

Abstract: The present invention preferably includes a shading band which is suitably electro-optically created in a grid pattern formed through a photolithographic process, so consequently, the electro optic shading band is easily eliminated or re-configured dynamically to substantially eliminate its shading effect for lower density optical disks which do not experience substantial adjacent track crosstalk (ATC). Eliminating or reconfiguring the shading effect also helps in accommodating different media types and generations and those of different manufacturers. Moreover, the electro-optic shading band suitably adjusts the amplitude, phase, frequency, polarization and/or the like of the light beam to compensate for possible material property variations, defects, misalignments or other imperfections in the reading process. The present electro-optic shading band substantially restricts or alters any portion of a light beam containing signal information read from an optical disk.

Abstract: A variable acousto-optic spectrum projector is disclosed. The invention may include a radiation source, an entrance slit, a lens or mirror, a Bragg cell, an arbitrary function generator for driving a transducer of the Bragg cell, another lens or mirror, an exit slit, and a collimating lens. In a first embodiment of the invention, the Bragg cell comprises a Tl3AsSe3 crystal and emits light in the 7 to 11 &mgr;m range (long-wave infrared) with a spectral resolution of between 4.5 and 7 cm−1. In a second embodiment of the invention, the Bragg cell comprises a TeO2 crystal and emits light in the 420 to 720 nm range (visible) with a spectral resolution of between 50 and 80 cm−1.

Abstract: A three channel acousto-optic modulator may be used to implement a projection display or a scanner. Each of three channels are deflected differently by the modulator. The channels may correspond to the primary color planes.

Abstract: The present invention is a method and apparatus for sequentially and repetitively diffracting multiple beams at a common predetermined angle. A coincident beam source introduces a plurality of coincident beams into an acousto-optic cell at a common location and angle, wherein each beam has a different wavelength. A signal controlling apparatus sequentially and repetitively introduces a series of signals to the acousto-optic cell. Each signal has a frequency, which corresponds to one of the multiple beams such that when the acousto-optic cell receives the signal, the acousto-optic cell operates at such frequency and diffracts the corresponding beam at the predetermined angle.

Abstract: A polarization-independent polychromatic light modulator applies one or more pairs of predetermined RF drive frequencies to an acousto-optic transducer of an acousto-optic modulator body upon which a single beam of randomly polarized or unpolarized polychromatic input light is incident. No precursor polarization separation elements are employed. For each optical wavelength to be extracted from the incident beam, two RF drive frequencies are employed. The acoustic waves launched into the acousto-optic medium by the application of the two frequencies of a given RF drive frequency pair produce respective +1 and -1 order output beam components of the selected output wavelength (as well as a zeroth order beam for that wavelength).

Abstract: A beam scanning system for scanning an imaging surface includes a phase shifter for issuing phase signals, a radiation emitter for emitting a beam of radiation and a deflection element, such as an acousto-optic modulator or translating lens, for deflecting the radiation beam. Depending on the implementation, the emitter can be configured to phase shift the radiation beam and/or the deflection element can be configured to deflect the radiation beam in accordance with the issued phase signals. By emitting and/or deflecting the radiation beam in accordance with the phase signals, the length of the scan line formed on the imaging surface can be controlled. A deflector, such as a spin mirror or rotatable prism, is provided to direct the radiation beam to form a scan line on the imaging surface.

Abstract: An exposure apparatus to expose a photo-sensitive layer formed on a substrate of a recording media is disclosed which comprises an exposure light source; a first means of focusing a light from the light source; an acousto-optic modulator disposed off the focal plane of the first focusing means to modulate the light focused by the first focusing means according to a signal to be recorded; and a second means of focusing the light modulated by the acousto-optic modulator onto the photo-sensitive layer formed on the substrate of the recording media.

Abstract: An acousto-optic modulator comprised of an acousto-optic element coated with an anti-reflection layer, and a method of manufacturing the same, are provided. The acousto-optic modulator includes an anti-reflection layer, comprised of at least two coating layers having different refractive indices, formed on the light incident/emitting surface of an ultrasonic medium for modulating a light beam incident from an optical source.

Abstract: A programmable acoustooptic device including an elastooptic medium configured to receive an input optical pulse and an acoustic wave; an acoustic transducer configured to generate the acoustic wave in the elastooptic medium along a defined direction; and a programmable circuit coupled to the acoustic transducer and configured to program at least one of a frequency modulation and phase modulation of the acoustic wave, whereby the acoustic transducer generates a modulated acoustic wave, wherein an output optical pulse is generated and is a convolution of the input optical pulse with the modulated acoustic signal.

Abstract: A replaceable modular opto-mechanical unit includes a light source in the form of, for example, a laser assembly; an optical modulator assembly which modulates light from the light source; and a lens located in a light path between the light source and the optical modulator assembly. The lens focuses the light from said light source toward a center of the optical modulator assembly. The unit further includes a base adapted to removably support the light source, the optical modulator assembly and the lens in an optically aligned manner. The base is further adapted to be removably attached onto a receiving structure of a printer, such that an attachment of the base having the optically aligned light source, optical modulator assembly, and lens supported thereon, permits light from the optical modulator assembly to be focussed onto an optical element of the printer.

Abstract: An optoacoustic modulator contains first and second optoacoustic media, to which first and second piezoelectric vibrators are attached respectively. Herein, both of the first and second optoacoustic media are designed in same measurements, wherein they are arranged in series along an optical axis of a light signal in such a way that crystal orientation of the first optoacoustic media differs from crystal orientation of the second optoacoustic media with an angle of inclination of 90.degree.. In addition, the first piezoelectric vibrator is attached to a first surface of the first optoacoustic media which is placed in parallel with the optical axis of the light signal, while the second piezoelectric vibrator is attached to a second surface of the second optoacoustic media which is placed in parallel with the optical axis of the light signal, wherein the first surface is directed perpendicular to the second surface.

Abstract: A laser beam intensity modulation system has a variable delay circuit that is used to control the relative delay in the delivery of a video signal between two cascaded AOM's. This delay circuit is controlled by a delay controller that monitors the intensity modulation of the laser beam to provide feedback control. This system maximizes the rise and fall times of the beam to generate precise beam modulation required for high speed image setters.

Abstract: A solid state acoustic travelling wave lens comprises a thin core layer of acoustic and light transmissive material, such as crystalline quartz, compression-bonded between a pair of outer or cladding layers, such as fused silica, having an acoustic velocity that is only slightly higher than (e.g., less than five percent of) that of the core material. The acoustic mode field characteristic of the weakly guiding device contains no spatial variations caused by Fresnel diffraction in an unguided wave device. In a second embodiment, shear stress coupling between the core and cladding layers is inhibited by interposing very thin liquid boundary layers between the core layer and the cladding layers. Such thin liquid boundary layers, which are relatively more compressible than the core and cladding material, allow longitudinal waves to be transmitted across the core/cladding boundary (through the liquid), but prevent transmission of shear waves therebetween.