Abstract: Device coherency and optical-mode stability are obtained in light sources having large apertures and output powers, by using an important property of arrays of antiguides or negative-index waveguides. One embodiment of the invention is a power amplifier into which a light beam is input from a master oscillator. The input beam is introduced into one or more waveguides of an array, and leaks into successive adjacent waveguides, forming a fan-out pattern as it progresses along the array. The antiguides have an interelement spacing that is selected to produce a resonance effect, as a result of which light is coherently coupled to all waveguides in the array. The structure also provides lateral mode control and assures mode stability of the output. In the amplifier embodiment of the invention, the end faces of the array are antireflective coated and light makes only a single pass through the structure.

Abstract: A semiconductor laser HL has an external resonator including a reflector R which reflects the emitted laser beam back into the front facet of the laser. The light emitted from the rear facet of the laser falls on a photodiode PD which generates a signal s which is evaluated by an evaluation unit AE. By differentiation or other processing of the shapes of pulses in the signal s, it is possible to determine the direction of change of any of several operating parameters of the laser system, such as the length L between laser HL and reflector R, the tilt angle of reflector R with respect to the optical axis of the laser or the refractive index n of the medium in the space N defined between the laser and the reflector. For example, one can detect when gas G is fed into space N to change the medium from ordinary air to carbon dioxide, or the reverse.

Abstract: The invention comprises a laser light source for a raster laser display. The laser light source comprises a laser cavity, a lasing medium within the cavity, a lasing light source and a series of mirrors within the cavity arranged to reflect the beam of laser light repeatedly through the lasing medium. An acoustic modulator is included having an acoustic medium within the path of the beam within the cavity. Video information on each pixel of the display is converted to an RF signal and fed to a piezoelectric crystal which is coupled to the acoustic medium. The acoustic medium is arranged within the laser cavity with respect to the incident laser beam such that, in response to the acoustic information, the laser beam is either directed towards the screen, or when not needed for the display is directed towards one of the mirrors such that the beam can continue to propagate through the lasing medium.

Abstract: Ultra short (pico second and shorter) laser pulses having components of different frequency which are overlapped coherently in space and with a predetermined constant relationship in time, are generated and may be used in applications where plural spectrally separate, time-synchronized pulses are needed as in wave-length resolved spectroscopy and spectral pump probe measurements for characterization of materials. A Chirped Pulse Amplifier (CPA), such as a regenerative amplifier, which provides amplified, high intensity pulses at the output thereof which have the same spatial intensity profile, is used to process a series of chirped pulses, each with a different central frequency (the desired frequencies contained in the output pulses). Each series of chirped pulses is obtained from a single chirped pulse by spectral windowing with a mask in a dispersive expansion stage ahead of the laser amplifier. The laser amplifier amplifies the pulses and provides output pulses with like spatial and temporal profiles.

Abstract: A low threshold resonator for an alexandrite laser receives a 680 nm pumping beam from at least one laser pump to provide alexandrite laser emission at around 751 nm. An alexandrite crystal or rod receives the 680 nm beam and has an exterior face provided with a dichroic coating highly transmissive to the 680 nm beam and highly reflective to the 751 nm emission and has an interior face provided with an AR coating antireflective to the 751 nm emission. A mirror, provided with a HR coating that is highly reflective to the 751 nm emission, has an appropriate radius of curvature and is appropriately spaced from the exterior face of the alexandrite rod to focus reflected 751 nm emission in a resonator mode on the exterior face of the alexandrite rod to assure low threshold pumping thereof. The mirror has a radius of curvature which is the same as the spacing between the exterior face of the alexandrite rod and the mirror to focus the reflected emission in the resonator mode in a spot size on the exterior face.

Abstract: A tunable laser source comprising a laser source emitting a pump beam towards a Raman cell. It transmits a beam at a Stokes wavelength to a non-linear crystal. Depending on the angle of this beam with the optical axis of the crystal, the non-linear crystal transmits two output waves at wavelengths that are different from the Stokes wavelength.

Abstract: Multiple discharge gas laser apparatus. A compact apparatus for simultaneously or individually generating a plurality of laser output beams in a selected pattern suitable for marking objects, for communications, or for remote chemical sensing or other remote sensing applications, among other uses, where all of the electrodes providing lasing gas excitation are located in a single gas volume and share a single output coupler is described. In this manner, all of the output beams are parallel in far field, to the extent variations in mode structure permit, without the necessity of undertaking detailed optical adjustments. Moreover, the focal plane of the output laser radiation is insensitive to significant positional variation of focusing optics utilized to increase the intensity thereof for marking purposes. Electrodes can be utilized for more than one discharge; that is, the direction of the discharge can be selected to involve any adjacent electrode having opposite charge polarity.

Abstract: An improved optically pumped NdYAG laser amplifier is provided having high average power and high pulse repetition rates with improved energy conversion efficiency. The amplifier employs a coating on the pump cavity surface which is highly reflective of light at the pumping wavelength and samarium coated flow tubes surrounding the flash lamps to enhance transmission of pumping wavelengths. A system of two amplifiers is described for metal cutting applications including cutting of aerospace metals without discoloration of the metal at the edge of the cut.

Abstract: Disclosed is a power laser in which several laser diodes emit pump beams towards amplifier media. The beams coming from these amplifier media are combined by an optical system to give a common beam transmitted to an output mirror. The mirror and a reflecting face of each amplifier forms an optical cavity.

Abstract: There is provided by this invention a binary alignment corrector for correcting the directional errors caused by non-linear placement or "bowing" of diodes within laser arrays. The binary alignment corrector is an array of diffraction gratings with each diffraction grating corresponding to an individual diode of the laser array. Based on the amount of angular misalignment for a particular laser diode, the grating period of its corresponding diffraction grating is calculated. The binary alignment corrector is then fabricated by very large scale integration techniques such that each individual diffraction grating of the binary alignment corrector has a grating period sufficient to properly align its corresponding laser diode. Furthermore, a bias angle may be introduced in the alignment of each laser diode so that laser diodes which are only slightly misaligned may also be corrected.

Abstract: A semiconductor laser chip comprises a semiconductor substrate, two laser stripes formed on the semiconductor substrate and each having a light waveguide path and a diffraction grating extending along the light waveguide path, and a groove for electrically isolating the laser stripes from each other. The facet phases of the diffraction grating at those facets of the plural laser stripes which are located at least in the same direction are different from each other. The diffraction gratings at the facets of two laser stripes comprise a plurality of grooves extending at an acute angle relative to the facets.

Abstract: A microlaser is disclosed comprising: a gain medium having one face which is adapted be coupled to a source of optical pumping radiation and having an opposite face; harmonic conversion means having a close face which is located adjacent to and spaced apart from the opposite face of the gain medium and which is coated for high transmission at a fundamental and high reflectivity at a harmonic and having an opposite face which is coated for high transmission at the fundamental and some transmission at said harmonic; and polarization control means, located adjacent to and spaced apart from the opposite face of the harmonic conversion means, for controlling the polarization of the fundamental.

Abstract: A two-cell Raman converter for generating a relatively large number of Stokes shifted waves from an input laser pump beam. A first lens focuses the pump beam into the first cell, whose output is recollimated and focused by second and third lenses into the second cell. The second cell output is recollimated by a recollimating lens to provide the final output. Each Raman cell employs stimuated rotational Raman scattering and Raman media at low pressures optimized to achieve maximum conversion into Stokes lines.

Abstract: This invention relates to a tunable solid-state laser which generates ultrashort output pulses with continuous wave pumping. The device includes a lasing medium having a gain cross section of 10.sup.-18 cm.sup.2 or less and mode beating characteristics, which lasing medium is mounted in a laser cavity. A continuous wave pumping beam is applied to the lasing medium causing an output, a portion of which is applied to an intensity dependent nonlinear cavity. The output applied to the nonlinear cavity is retroreflected back through the cavity and is interferometrically combined with the laser output. The relative lengths of the cavities are initially selected such that phase changes caused by the nonlinear medium result in substantially maximum enhancement of intensity peaks of the laser output, causing self starting of pulsed operation.

Abstract: A pulsed source of laser light (10) includes a diffraction grating (20) that splits light received from a laser output mirror (12) into a plurality of paths that lead to respective laser gain cells (14.sub.1, 14.sub.2, . . ., 14.sub.n). The gain cells individually amplify light components of different respective wavelengths and reflect them back to the diffraction grating (20), which reassembles them into a single beam for transmission to the laser output mirror (12). A mode locker (24), preferably in the form of a saturable absorber, locks the output components into equally spaced frequencies so that the sum of the individual continuous components will be a pulsed signal.

Abstract: A laser device includes an optical resonator comprising a laser medium and two totally reflecting mirrors disposed on respective sides of the laser medium. The laser device also has a wavelength selection element disposed between one of the totally reflecting mirrors and the laser medium. A partially reflecting mirror is disposed between the wavelength selection element and the laser medium. Any distortion and deterioration of the wavelength selection device are greatly reduced.

Abstract: A light amplifying device comprising an optical oscillator constituted by first and second reflective mirrors and a common reflective mirror disposed in an optically opposite relation to each other, a polarized beam splitter for making a laser beam incoming from the side of the common reflective mirror incident on the first or second reflective mirror, and for making laser beams incoming from the sides of the first and second reflective mirrors incident on the common mirror, first and second amplifying media disposed in optical paths of the respective laser beams for amplifying the laser beams, and an optical element for rotating the polarizing plane of the laser beam reflected by the common reflective mirror by a predetermined angle.

Abstract: A passively mode-locked laser suitable for use with homogeneously broadened lasing medium or a lasing medium having a high-power output, long relaxation time or a narrow bandwidth. The laser includes a main cavity in which the lasing medium is disposed and an external cavity including a non-linear element. The non-linear element is selected to induce a non-linear phase shift in a coherent beam from the main cavity. In operation, a portion of a laser beam in the main cavity is coupled to the external cavity and a phase-shifted output from the external cavity is reflected back into the main cavity to provide a narrow pulse, mode-locked output from the laser. In one embodiment the non-linear element of the external cavity is an optical fiber with a mirror disposed adjacent one end of the optical fiber to provide dual propagation of a laser pulse through the fiber. In high-power applications the external cavity mirror is disposed proximate but spaced apart from the optical fiber end.

Abstract: Mode-locked pulsed output is induced in a laser by introducing a varying frequency dependent loss in the cavity. The varying, frequency dependent loss allows a large number of longitudinal modes to oscillate. In one of the preferred embodiments of the subject invention, the varying frequency dependent loss is generated by reciprocating one of the mirrors of the resonator. In this embodiment, the laser has a resonator with a primary light path defined by first and second end mirrors. A gain medium is located between the end mirrors. A beam splitter is provided for redirecting the light into a secondary light path. A third mirror functions to feed back the light into the primary light path. Pulse formation is induced by varying the path length of one of the two paths by reciprocating an end mirror. Moving the mirror creates varying interference effects when the light energy is recombined at the beam splitter. The mirror is reciprocated relatively slowly, yet ultra-short pulses are generated.

Abstract: An apparatus for generating a coherent combined laser beam including an array of laser elements for generating a Fresnel diffraction pattern in a plane at a distance D from the laser array, the Fresnel diffraction pattern having a non-uniform phase distribution, D being at least as large as the distance at which the beams generated by the laser array begin to substantially overlap; and an array of phase corrector elements located in the plane for reducing the degree of non-uniformity in the phase distribution; and a partially reflecting mirror for forming a resonant cavity for the laser array.

Abstract: An optical parametric oscillator capable of operating in the 0.300 to 0.400 micrometer wavelength range is disclosed. The oscillator includes a cavity defined at its ends by a pair of cavity resonator mirrors. A nonlinear optical crystal is positioned on the optical axis of the cavity intermediate the mirrors and is rotatable about a crystalline axis to tune the oscillator. A pair of pump steering mirrors are mounted in the cavity, one mirror between each resonator mirror and the corresponding end of the crystal. A source of pumping energy supplies energetic light to the cavity, the pumping beam being directed into the cavity and onto a first steering mirror, thence through the crystal and to the second steering mirror which then directs the pumping beam out of the cavity. The pumping beam may be at a wavelength of 266 nm, for example, to produce an output wave from the oscillator within the range of interest.

Abstract: A high power injection-locked laser system (10) is disclosed which includes master and slave lasers (12, 14) both of which are solid state lasers having continuous wave outputs. The slave laser has an output power at least ten times greater than the master laser. In the preferred embodiment, the slave laser is at least one-hundred times as powerful as the master laser. In accordance with the subject invention, a servo-loop control system is used to maintain the injection locked condition. A discriminant signal is generated that is indicative of drift in the slave laser cavity. The discriminant signal is used adjust the length of the slave laser cavity to maintain the locked condition.

Abstract: A two-dimensional integrated laser array having a plurality of surface-emitting laser arrays and a plurality of waveguides for optically coupling the individual laser arrays together. Each surface-emitting laser array includes a plurality of injection lasers which are evanescently coupled together in order to emit a single beam of light. The coupling provided by the waveguides causes the surface-emitting laser arrays to operate in phase and at the same wavelength as an external master oscillator. Therefore, the surface-emitting laser arrays generate coherent beams of light, which are combined and focused by a micro-lens. The output of the micro-lens is a single, coherent high-power optical beam which is emitted perpendicular to the two-dimensional integrated laser array.

Abstract: An external optical resonator for a semiconductor laser is composed of an optical directional coupler which can be formed as an integrated optical coupler with a short structural length that enables a free spectral range in the order of 100 GHz and enables the resonator and the system fiber to be coupled to the same end face of the laser. The resonator structure includes two optical waveguides with feedback means applied on the end faces of one of the waveguides and the other waveguide having one end face coupled to receive the output of the laser and the other end face of the other waveguide being coupled to the system fiber. The arrangement is particularly useful for tunable semiconductor lasers, particularly for heterodyne reception.

Abstract: Method and apparatus for tuning an optical gyroscope, such as a MOG, to an operating frequency within a predetermined range of operating frequencies. The method includes an initial step of providing a compound resonator structure having a first optical waveguide resonator [16] optically coupled to a laser [14]. There is also provided a second optical waveguide resonator [18] optically coupled to the first resonator. The second resonator is constructed to extract a significant amount of energy from the first resonator when a coresonance frequency condition exists with the first resonator and to extract an insignificant amount of energy from the first resonator when a coresonance frequency condition does not exist. The method includes a step of varying an output frequency of the laser to a first frequency where a coresonance frequency condition exists.

Abstract: A ring laser gyroscope, which has a triangular quartz block with a triangular quartz tube assembly forming an outer cavity for one rotating beam and an inner cavity for an oppositely rotating beam, is provided. The problem of lock-in of the beams is avoided. A pair of anodes and cathode means are provided for energizing the beams. A mirror is mounted at each corner of the block for reflecting the beams with one mirror being a partly reflective mirror for passing through portions of the inner beam and the outer beam. Outside the partly reflective mirror are mounted a first mirror for reflecting the inner beam, a second mirror for reflecting the outer beam, and a beam combiner mirror for combining the beams. A frusto-conical mirror receives the combined beams and reduces the mean diameter of the outer beam. A fringe detector receives the inner beam and outer beam on an area or point on a face of the fringe detector, which provides a gyroscope output.

Abstract: A high power phase coupled waveguide laser comprising a plurality of symmetrically disposed lasing members disposed around the outer periphery of an annular enclosure. The laser includes an annular body of dielectric material having a multiplicity of laser cavities formed therein in a symmetrical annular array. The body includes a central bore having conduits extending therethrough for providing a flow of cooling fluid. The heat path between the cavities and the cooling fluid is symmetrical for all cavities. This provides equal conditions for all laser cavities in the array and ensures phase coupling of all cavities.

Abstract: A laser device includes a resonant cavity with a gain medium therein, and first and second reflectors at either end, to form a quasi-isotropic laser. A feedback section is formed between the second reflector and a third reflector. A polarizer and modifier are provided in the feedback section. The polarizer and modifier can modify a variety of parameters, for example the polarization, phase, intensity or frequency of the feedback. The light feedback into the resonant cavity has an intensity much less than that within the resonant cavity, but sufficient to overcome any residual anisotropies. Control of the modifier causes the device to be operated in one of two or more polarization modes.

Abstract: A laser oscillator system which transmits laser input beam pulses through optical diode and into a plurality of time-multiplexed phase conjugate amplifier which sequentially amplify in chronological order subsequent input beam pulses. The optical diode is positioned on the oscillator laser beam pulse axis and is comprised of a polarizer, a half-wave plate which rotates the pulse polarity by 45.degree. in one direction and a Faraday rotator which rotates the pulse polarity 45.degree. in the opposite direction. A plurality of grouped Pockels cells and polarizers are positioned on the oscillator axis past the Faraday rotator. The polarizers route the input beam pulse toward a phase conjugate amplifier when a half-wave voltage is applied to the Pockels cell. Each phase conjugate amplifier has a phase conjugate mirror, at its output for retroreflecting the once amplified input laser beam pulse back therethrough for a second amplification.

Abstract: A laser cavity providing high power laser radiation with diffraction-limi divergence and narrow-bandwidth comprises: a stable laser cavity including a gain medium, which generates and amplifies laser radiation, optically coupled to first and second reflectors and an optical coupler; and an unstable laser cavity including the gain medium, the first reflector, the optical coupler and a scraper mirror. The scraper mirror is located between the gain medium and the optical coupler for producing an output beam. The stable laser cavity is restricted to operate on a low order TEM mode by an aperture located between the optical coupler and the second reflector. A frequency narrowing element located between the optical coupler and the second reflector narrows the bandwidth of the laser radiation in the stable laser cavity. The optical coupler couples the narrow bandwidth laser radiation from the stable laser cavity to the unstable laser cavity, thereby producing narrow bandwidth laser radiation in the output beam.

Abstract: Modelocking of a solid state laser such as a Ti:Al.sub.2 O.sub.3 laser is achieved by employing an external cavity defined by spatially separated reflective elements wherein at least one of the reflective elements exhibits a nonlinear characteristic in response to an impinging light beam. Exemplary nonlinear reflective elements are described using bulk semiconductor material or semiconductor quantum well structures integrated with a rear reflector such as a stack of quarter-wave thick dielectric or semiconductor material. Tuning control of the nonlinear reflective element may be introduced with temperature control arrangements and with mechanical translation arrangements in conjunction with lateral band gap engineering of the semiconductor material.

Abstract: A length stabilized, dispersion compensated synchronously pumped mode locked dye laser is disclosed. The output of the dye laser is actively stabilized by monitoring the output power thereof and generating an error signal for actively adjusting the cavity length. The operation is enhanced by actively controlling the power of the pump pulses exciting the dye laser so that the power fluctuations in the dye laser are due primarily to fluctuations in cavity length. Stability is also enhanced by operating the cavity with a negative group velocity disperison. The resultant lengthening of the output pulses is compensated by a pulse compressor, located outside of the cavity, which adds a positive group velocity disperison to upchirp and shorten the pulses.

Abstract: A laser oscillator system which transmits laser input beam pulses through a olarizer onto the surface of a rotating mirror which routes the laser beam pulses sequentially into a plurality of stationary phase conjugate amplifiers. The pulse repetition frequency of the oscillator input beam pulses is much higher than any one of the amplifiers can handle without overheating. The amplifiers are positioned in a circle around the laser oscillator axis. The polarizer and rotating mirror are positioned on the oscillator axis. The mirror is synchronized with the input beam pulses so that each subsequent input beam pulse enters the next amplifier in sequence. Each phase conjugate amplifier has associated therewith a quarter-wave plate and a phase conjugate mirror at its output. The phase conjugate mirror is preferably comprised of a focusing lens and a stimulated Brillouin scattering cell.

Abstract: Disclosed is a semiconductor laser array including a plurality of semiconductor lasers each having an active layer having a quantum well structure with at least two quantum levels. The semiconductor lasers have reflecting means having different wavelength selection properties.

Abstract: As a beam converger, one having reflective surfaces including partial cylindrical curved surfaces and partial plain surfaces, which surround laser rod and pump lamp plane-parallelly and substantially uniformly in the axial direction thereof, is adopted, so as to make a high beam converging property in the case of adoption of an elliptic cylinder moderate. The axes of the pump lamp and/or the laser rod are shifted to positions closer to the partial cylindrical curved surfaces than the center lines of the partial cylindrical curved surfaces, so as to increase energy of light exciting the laser rod by the pump lamp, thus improving the efficiency. A laser system obtained by combining a resonant type laser device comprising two laser rods and one or two pump lamps with a prism having a regular equilateral triangle shape in cross section, highly contributes to the compactness and simplification of the laser system.

Abstract: A double conjugate laser beam amplifier which twice conjugates the laser ut beam and provides an output beam in exactly the same direction and of the same polarization as the input beam while retaining the alignment stability of singly conjugated amplifiers even when the thin film polarizer between two conjugate amplifiers is not stable. A half-wave voltage at a Pockels cell positioned on the beam axis immediately prior to the polarizer controls whether the oscillator beam is transmitted through the polarizer or is reflected off the polarizer toward a first conjugate amplifier for amplification and retroflection back through the first conjugate amplifier and the polarizer into a second conjugate amplifier for further amplification and retroreflection back and is reflected off the polarizer a second time. The double conjugate amplifiers may be cascaded to both increase output and laser beam pulse repetition rate.

Abstract: A semiconductor laser array with features providing good beam quality at high powers, first by employing a laterally unguided diffraction region in which light from a set of waveguides is re-imaged in accordance with the Talbot effect and two arrays of waveguides may be used to provide a spatial filtering effect to select a desired array mode. This provides a laser array with increased power per unit solid angle, and with additional advantages of ability to scale the device up to larger arrays, ability to control the electrical excitation of the device for better optimization, and improved modal discrimination. A second aspect of the invention is the use of a resonance condition in an antiguide array, to produce a uniform near-field intensity pattern and improved coupling and device coherence.

Abstract: In a semiconductor laser device for emitting a laser beam of a variable frequency depending on a current applied to the laser device, there are provided a semiconductor substrate, an optical waveguide structure formed on the substrate having two or more semiconductor light emission layers and barrier layers having a wider band gap then that of the light emission layers, alternately stacked, clad layers stacked on the opposite sides of the waveguide structure and having a lower refractive index than that of the waveguide structure, and a device for applying a current to the light emission layers, and the wave guide structure includes at least first and the second light emission layers which respectively emit lights having different wavelengths.

Abstract: A Q-switched laser having a gain medium disposed within a first cavity and a second cavity whose optical path length is adjustable such that the quality of the first resonant cavity is affected. One aspect of the invention is the changing of the physical path length of the second cavity so as to affect the reflectivity of a mirror common to both cavities as seen from the first cavity. Another aspect of the invention is the incorporation, within the second cavity, of a material whose refractive index or absorption coefficient can be varied by the application of an electric field, a magnetic field, a temperature change or an applied pressure.

Abstract: Monolithic high density arrays of independently addressable offset semiconductor laser emitters or elements are able to be placed in close center-to-center proximity, e.g., on 3-10 .mu.m centers, without experiencing any undesirable phase locking and with minimal amount of electrical and thermal interaction or crosstalk occurring between the independently addressed lasing elements and their independent operation in ROS printer applications. With a proper offset in the laser emitters, interlace scanning relative to an image bearing surface, which is required with other multiple emitter lasers in ROS printer applications, is eliminated thereby permitting adjacent line scanning of an image bearing surface without complicated optics and electronics.

Abstract: A semiconductor laser array comprising plural semiconductor layers formed on a substrate having a laser active layer. The plural semiconductor layers define first and second end-faces which are for emitting laser light. Plural stripe-like current injection areas are also formed in the plural semiconductor layers. Each two adjacent current injection areas have a respective first distance therebetween at the first end-face, and each two adjacent current injection areas have a respective second distance therebetween at the second end-face,the first distance being greater than the second distance. Plural electrodes are provided for supplying current to the current injection areas. At least one of the electrodes has a stripe-like portion formed corresponding to the current injection areas, and has a pad portion which has a width greater than that of the stripe-like portion. The pad portion is for wire bonding, and is formed in an area other than the current injection areas.

Abstract: In a controller for a semiconductor laser light source, a portion of light emitted from the source is fed back to regulate the spectral line width of the source and to regulate the oscillation frequency of the source in terms of the phase of the portion or the driving current for the source, the very small portion of the light is allowed to pass through an external resonator so as to be subjected to optical frequency discrimination by an optical frequency discriminator, the portion does not need to be divided from a communication signal light. Therefore, the communication signal light can be undergo a loss.

Abstract: A method and circuit for generating controlled light signals from electronic data signals in a semi-conductor laser transmitter of the type having a stimulated emission cavity with at least two electrical input contacts determining corresponding separate cavity regions. Electronic data input signals are applied to each input contact to drive the associated cavity region above a stimulated emission threshold level to generate cross-coupled stimulated emission by interaction of each region with carriers of the other region or regions. The electronic data signals are varied to control optic intensity and frequency according to pre-defined characteristics of the cross-coupled stimulated emission.

Abstract: In a multibeam emitting device provided with a plurality of semiconductive light-emitting elements monolithically formed on a semiconductor substrate, the semiconductor light-emitting elements are formed so that the directions of emission of the lights emitted from the elements differ from one another.

Abstract: A low-power, continuous wave laser beam is injected into the optical cavity of a high gain, high power, short pulsed laser. The output beam features excellent power and wavelength stability.

Abstract: A cavity which is resonant at a laser pumping frequency is defined by a reflective surface (92) and a mirror (110). A Raman medium (106) is contained within the cavity, as is a laser (90). A Q-switch (94), when not spoiling the Q of the cavity, allows photon density to increase within the cavity. When the Raman threshold of the Raman medium is exceeded, the Raman medium absorbs and then radiates photons. The radiated photons are at longer wavelength than the laser photons, and also occur in very short (less than ten nanoseconds) pulses. The radiated photons are reflected by a mirror (101) and exit the cavity through one of the reflectors defining the cavity (mirror 110). The invention shifts the wavelength and shortens the pulse duration of pulses produced by the laser (90).

Abstract: A laser transmitter utilizes optical far field combination of two independent lasers (80,90) and variation of RF exciting power (86) to one (80) to produce sufficient frequency modulation. Two bores (122,124) within the same dielectric body (120) are provided with two independent sets of electrodes (134,135, 138,139) and two independent RF power sources (150,152). The lasers are operated at different frequencies and the beams transmitted in parallel adjacent paths to provide a combined far field optical beam component at the beat frequency of the two lasers. Variation of the frequency of one of the lasers provides frequency modulation of the far field beat frequency, enabling reception and demodulation of the modulated beam without use of a local oscillator laser at the receiver. The transmitter may also be used in a laser radar.

Abstract: A system for producing two or more laser beams having stable frequency differences between them. The system includes two or more lasers that produce the respective laser beams, an optical resonator, and coupling optics for coupling portions of each laser beam into the resonator. The resonator produces feedback beams that are returned to the respective lasers to provide optical feedback. The feedback causes each laser to lock to a resonant mode of the resonator, to thereby stabilize the frequency difference between the lasers. The linewidth of each laser is also reduced.

Abstract: A Doppler velocimeter having a semiconductor laser which sends a laser beam through a polarization beam splitter onto an fractional-wavelength plate. The plate both reflects the beam back to the polarization beam splitter and sends the beam on through the beam expander to the target. The beam is returned by the target. The returned beam passes through the fractional-wavelength plate to the polarization beam splitter. The returned and reflected beams are directed by the splitter to a detector. The detector mixes the beams and sends a signal to a spectrum analyzer on which the velocity of the target can be accurately determined.

Abstract: Several gas-tight enclosures share a common optical cavity. The enclosures may be filled with neat gases or mixtures of gasses. The same gas or mixture, at the same or a different pressure, may occur in more than one enclosure. The gas or gasses in the various enclosures may be pulsed to lase in any desired sequence, simultaneously, or in any combination.