Abstract: A semiconductor laser array includes a plurality of stripe-shaped stimulated regions of the index guide type. A plurality of buried layers are disposed between each of the plurality of stripe-shaped stimulated regions. A light absorption layer is formed in each of the plurality of stripe-shaped stimulated regions so that the stimulated region has the optical loss greater than an buried layer, whereby optical coupling is performed with no phase difference.

Abstract: The present invention is a semiconductor diode laser array which favors oscillation in the zero degree phase shift mode. The array comprises first and second sets of waveguides which are interdigitated in a coupling region. Energy transfer between the first and second sets of waveguides by way of evanescent coupling is needed to define the feedback paths for sustaining laser oscillations in the waveguides. Such coupling is optimum and the threshold current for lasing lowest when all of the waveguides in both sets oscillate in phase.

Abstract: A wavelength filtering device and system in which an optical resonant cavity is laterally coupled to a trunk waveguide carrying a broad range of wavelengths in the optical spectrum. The filtering cavities may be linear optical fiber segments or fiber segments closed at their ends in the shape of a loop. The devices may include single or multiple optical cavities or hybrid filtering utilizing both dispersive and resonant functions.

Abstract: Dual waveguide lasers which are transversely excited in parallel from a con source of radio frequency are provided with one or more channels or bores connecting the laser cavities. The dimensions and configuration of the connecting channels are chosen so that the electric field from the applied RF excitation source will be higher in the connecting channels than in either of the paralleled waveguide gas discharge cavities, or that the electron collision loss to the nearby ceramic and metallic walls will be lower in the connectiong channels than in the aforementioned waveguide cavities. The initial gas breakdown is thus made to preferentially occur in the connecting channels and thus force initiation of both laser cavities simultaneously.

Abstract: A dye laser system for emitting laser beams of various wavelengths, which includes a plurality of dye vessels apart from each other and a mirror for oscillating the laser beams and for reflecting the beams to a beam splitter. Two wavelength selectors are provided for directing a specific wavelength portion of the beams to the beam splitter and for directing a specific wavelength portion of the beams to the mirror.

Abstract: A phase-conjugated Q-switched laser resonator. The resonator contains a laser active material and a polarizer/quarter-wave plate combination in a starter cavity. The polarizer optically couples one plane of polarization of laser radiation into a side arm containing a self-switching stimulated scattering phase-conjugate mirror.

Abstract: A gas oscillator consisting of a plurality of laser tubes with discharge electrodes arranged in a straight line so that the cathodes are next to each other, a gas drive, a heat exchanger to cool a laser gas and an exhaust device provided to expel the laser gas from the laser tubes and containing an injection device for non-ionized gas to separate and expel the ionized gas from the laser tubes so as to suppress electrical discharges between the cathodes of the laser oscillator.

Abstract: A transversely-excited waveguide laser made up from the two blocks of electrically-insulating material. One block (1) has three parallel slots (3, 4 and 5) formed in one face, while the other block (2) forms a cover which may be secured to the first block to close the slots. The two outermost slots (4 and 5) each contain a layer (7) of electrically-conductive material to which an electrical conductor (8) is attached to form an electrode, while the dimensions of the center slot (3) are such as to enable it to form a laser cavity which will support waveguide laser action.

Abstract: An injection laser fabricated in accordance with the teachings of the present invention comprises a laser cavity having first and second active laser regions disposed in tandem therein, means for injecting current into the first and second active laser regions to provide gain distributions over wavelength regions in the two active laser regions which partially overlap to form a combined gain distribution over a range of wavelengths and means for providing wavelength within the range. In various embodiments of the present invention, the means for providing wavelength selective reflector or means for coupling energy out of the active regions. Moreover, the wavelength of the output radiation in various embodiments is determined by the values of the injected current density in the two active laser regions and the relative magnitudes of the loss at specific wavelengths.

Abstract: An optical fiber structure having resonant characteristics useful for coupling to an optical transmission line for removing selected wavelengths of light energy includes a light guiding structure, such as an optical fiber waveguide, which conditionally operates as a resonant cavity responsive to resonance of at least one other resonant cavity. In one embodiment, an extrinsically defined or adscititious reflectance is formed in the waveguide segment by laterally coupling an etalon cavity to the waveguide segment. In another embodiment, the waveguide segment is coupled to one or more resonant loops to form a conditional resonant loop cavity which includes the other loops. The resonant wavelength spacing for the conditional cavity and its cooperating resonant cavity are made different from one another with only one wavelength coresonantly supported in both cavities.

Abstract: Two or more parallel waveguide lasers of different effective length are coupled together by their evanescent waves such that the composite structure functions as a single cavity having a longitudinal mode with resonances related to the resonances of the separate cavities. A very strong selection of the composite operating frequency, and suppression of most or all of the other longitudinal modes, with frequency tuning of the composite structure (both continuously and by mode hopping), can be accomplished by varying the relative currents supplied to each laser. Upon holding one cavity at one current level for a selected operating point and shifting the other, bistable operation can be achieved.

Abstract: The disclosed apparatus includes a diffraction grating illuminated by a plurality of lasers. Apparatus is provided for summing the plurality of lasers coherently by, (a) phase locking the plurality of lasers and by, (b) diffracting the plurality of beams into a single beam. The diffraction grating has a configuration to generate upon illumination substantially equal intensities of diffraction orders corresponding to the number of lasers while suppressing higher unwanted orders. The phase locking can be accomplished by a single master laser, or by a cavity mirror to generate reference beams. Then, the output beams of the plurality of lasers propagating in the reverse direction are coherently superimposed by that grating. It is preferred that the diffraction grating be binary. Both one and two-dimensional diffraction grating arrays are disclosed.

Abstract: Laser energy is combined using dynamic beam splitters that can automatically accommodate changes in the laser cavity mode structure. Nonlinear optical methods and real time holography are employed to achieve phase locking among multiple lasers. A single laser output beam can be produced from a multitude of laser cavities which collectively contribute to the output power. No outside monitoring and servo mechanisms are required, since nonlinear optical processes automatically perform the functions of both monitoring and control. A coupled laser system includes two or more lasers, each laser having a resonant cavity, a laser gain medium in the resonant cavity, and a nonlinear optical element. Each nonlinear optical element is positioned in its respective resonant cavity to diffract laser energy from the cavity to a coupling beam by means of four-wave mixing (phase conjugation).

Abstract: An extended laser sensor including a laser with an opticla gain lasing medium optically coupled to an optical resonant cavity including reference and sensor arms. Optical path length variations in the sensor arm induced by an incident physical field modulate the operating parameters of the laser. The field is sensed by monitoring these modulated operating parameters.

Abstract: A method of producing individual short laser pulses in which a stimulatable laser medium is excited by a pump pulse in order to produce a population inversion above a laser threshold value, the population inversion being kept below the threshold value after emission of the short radiation pulse. The laser medium is common to two resonators and from it energy in the form of the desired individual short laser radiation pulse is first taken from the first resonator by means of a first relaxation process of given threshold value, relatively short time constant and relatively low quality factor, after which the inversion in the laser medium is kept below the preset threshold value of the first resonance process by a second relaxation process of relatively long time constant and relatively high quality factor in the second resonator coupled to the first.

Abstract: Disclosed is a laser light source device having a laser and an external resonator, wherein as a base, a Faraday rotator is provided at the laser side front of a reflection plane of the resonator so that clockwise and counter-clockwise circular polarizations which have frequencies slightly different to each other are generated, and if a laser such as a semiconductor laser having an eigen-mode having a linear polarization is applied, elements which rotate a polarization by 90 degrees by one emission-and-return through the element, for example, quarter-wave plates, are arranged, The device does not need a strong magnetic field or a strong electric field, and can easily generate lights which are a constant strength. Thus the device can be miniaturized and a high efficiency obtained.

Abstract: A switching laser comprising, in a cavity, a cell of an amplification gas and a cell of an absorption gas, means for exciting said amplification gas and means for exciting said absorption gas. Said means for exciting the absorption cell comprise a radio frequency AC voltage source pulsed at a certain rate. The laser is namely used for infrared detection.

Abstract: A method and an apparatus are described by producing optical radiation pulses with a duration of the order of picoseconds (10.sup.-12 s) and less using external mode locking of the longitudinal laser modes of a semiconductor laser element operating in an external resonator. In the method of the invention the gain modulation, needed for synchronous mode locking, of the active semiconductor laser element is effected by modulation of the electrical pumping current by way of a high-speed optoelectronic switch, that for its part is controlled by a mode locked master laser. The present method combines the advantages of synchronous optical pumping, as used in commercial mode locked dye laser systems, with the simple type of electrical pumping of commercially available semiconductor laser diodes, more especially double heterostructure laser diodes.

Abstract: A control circuit for stabilizing the emission wavelength of the coupled cavity semiconductor laser is described which uses measurements of the voltage across the laser cavity to maintain stable single longitudinal mode output.

Abstract: Semiconductor lasers having cleaved optically coupled cavities operating electrically isolated produce output of a single longitudinal mode. Wavelength tuning of the single longitudinal mode is possible.

Abstract: A semiconductor diode laser for tunable single-frequency laser radiation has a plurality of laser-active strips associated with a semiconductor body having first and second reflective end surfaces. The first end surface has laser radiation emitted and coupled out therefrom. One of the strips is an emitting laser-active strip which emits the laser radiation and the further laser-active strips are provided at both sides of the emitting strip. The further strips are shorter than the emitting strip and are provided such that respective resonators corresponding to each strip are provided with mirrors or reflectors at both ends thereof. A first end of the strips terminates in front of the first end face of the semiconductor body.

Abstract: Mono-pulses of light are generated by time compression of laser energy. A Raman medium is located in a low Q energy storage cavity having low losses for light at a predetermined frequency and energy delivered by a laser is that frequency in the storage cavity. The Raman medium is also located in a Stokes cavity dimensioned for having a high gain at a Stokes frequency. Most of the stored energy at the Stokes frequency is extracted by a single to and fro travel through the Stokes cavity.

Abstract: A dye laser system wherein the dye medium is pumped by frequency doubled mode locked laser pulses from a Nd:YAG laser and also mode locked by colliding pulses in an anti-resonant ring having a saturable absorber.

Abstract: Described is an internally mode stabilized injection laser. Stabilization is obtained in a coupled cavity structure where one cavity is passive. The passive cavity is a high efficiency waveguide with dimensions chosen to suppress unwanted modes.

Abstract: A hard sealed CO.sub.2 laser tube includes an impermeable envelope with flanges and seals joined by weldment and ultrahigh vacuum. A total reflecting mirror at the input is hard sealed and cooled at its back side. The plasma tube and cooling jacket are made of glass or ceramic construction. Metal-glass or glass-ceramic high voltage feedthroughs provide for connection to the internal electrodes. Feedthroughs using glass-metal sealing connect to the internal cooling jackets. The feedthroughs for electrical and cooling connections are at the total reflecting mirror end. A plastic base connector is attached to the metal structure at the total reflecting mirror end.

Abstract: The use of a Galilean telescope, situated in between the two lasing mediums that are located within the resonant cavity of a single longitudinal mode hybrid laser, increases the effective mode volume and, hence, the amount of lasing energy that can be derived from such a hybrid laser.

Abstract: A laser employs a Fabry-Perot etalon, coupled to an optical cavity, to control either the power or the frequency of the laser substantially independently.

Abstract: An improvement for a ring laser gyro employs insertion of a wavefront conjugating coupling element inside a laser cavity to reduce the lock-in threshold and to reduce the imbalance between the amplitudes of the opposite direction traveling waves (ODTW) in homogeneously broadened rotating ring lasers.

Abstract: Along an axis (2) of an optical cavity there are: a mirror (3) having a W-shaped cross section to give inner and outer conical reflecting surfaces (4, 6) which are oppositely inclined, a plane mirror (8) having an axial opening and facing the W-shaped mirror (3), a convex mirror (16) receiving the oscillating radiation from the W-shaped mirror (3) via the opening in the plane mirror (8), and a mirror (17) disposed between the plane mirror (8) and the convex mirror (16), said mirror (17) having an aperture and being inclined to the axis so as to extract laser energy from the oscillator.

Abstract: A waveguide laser having a square bore and an external modulator has its power doubled by proper relationship of a coupled cavity external to a cavity in the waveguide medium.

Abstract: Method and apparatus for generating two distinct laser frequencies in an optical cavity, using a "T" configuration laser cavity and means for intermittently increasing or decreasing the index of refraction n of an associated transmission medium in one arm of the optical cavity to enhance laser action in one arm or the second arm of the cavity.

Abstract: A tunable laser assembly including a pair of radially graded indexed optical segments aligned to focus the laser to form an external resonant cavity with an optical axis, the respective optical segments are retativity moveable along the optical axis and provide a variable et aion gap sufficient to permit variable tuning of the laser wavelength without altering the effective length of the resonant cavity. The gap also include a saturable absorbing material providing a passive mode-locking of the laser.

Abstract: Multiple wavelengths are produced from a single laser gain medium by utilizing gain saturation effects within the laser cavity. Two or more partially reflecting mirrors are coupled to a totally reflecting mirror through the laser gain medium by a grating element. The optical path lengths defined by each of the partially reflecting mirrors are varied by the positioning of the partially reflecting mirrors. This permits a lower gain line to build up first, followed by a higher gain line, which then terminates the lower gain line through gain saturation. The frequency switching times and pulse intensities of the wavelengths can be varied by varying the optical path lengths.

Abstract: A laser system with a folded beam path is disclosed. The beam path is formed by a plurality of mirrors (18-21). Mirrors (18-21) reflect light in a closed loop from one mirror to the other. Electrodes are disposed on opposite sides of the path between the mirrors and form channels through which the path extends. In addition to serving to direct the beam in a closed loop, one of the mirrors may have the characteristic of reflecting one wavelength of light with a reflectivity of 100% while reflecting other wavelengths of light with a reflectivity of only 85%, such mirror thus acting to pass the other wavelength of light while completely reflecting the one wavelength of light. In one of the disclosed embodiments, four wavelengths of light are directed in a loop comprising mirrors 85% reflective to a wavelength while otherwise 100% reflective which promotes ring laser operations with respect to other wavelengths without passing such other wavelengths.

Abstract: The intracavity modulated laser includes a main cavity and an adjacent coed cavity with a gain cell in the main cavity and an electro-optic modulator in the coupled cavity, the cavities being coupled in such a way that the energy level in the coupled cavity during laser operation is much lower than that in the main cavity, and whereby the modulator can selectively affect the polarization of energy in accordance with a voltage applied thereto to selectively couple energy out of both cavities in a desired manner.

Abstract: An RF discharge waveguide laser is modulated by an electro-optic modulator positioned in a second optical cavity coupled to a gain cavity containing the waveguide.

Abstract: A laser construction is described having a single resonator structure for both a dye laser optical cavity and one or more pump laser optical cavities. In the described embodiments, such resonator structure is formed principally from a plurality of parallel rods.

Abstract: An argon-ion laser achieves low output power by using a plasma guide and mirror configuration which restricts lasing action to a portion of the resonator cavity at relatively high conversion efficiency.

Abstract: There is provided a gain medium capable of radiating spectral lines differing in intensity as a function of position along a selected, gain-medium axis. A first resonator is arranged along a first optical axis that crosses the gain medium in a first region along the selected, gain-medium axis; the first resonator is adapted to establish a first optical mode that selectively lases one group of the spectral lines of the gain medium, namely a group thereof having high intensity within the volume in which the first mode is established. A second resonator is arranged along a second optical axis that crosses the gain medium in a second region along the selected, gain-medium axis; the second resonator is adapted to establish a second optical mode that lases a second group of spectral lines differing at least in part, from the first group. The second group of spectral lines has high intensity within the volume in which the second mode is established.

Abstract: A hybrid laser system, consisting of two different laser units, namely a reference laser (4), possibly an injection laser or a laser amplifier, and a transversely excited laser (TE-laser) (5), possibly a longitudinally pulsed or Q-switched laser, both lasers residing in a common housing. The first laser consists of a tube enclosing an isolated low pressure space and is bathed by coolant. The second laser is a high-pressure space enclosing a folded electrode system (14, 15). In order to achieve uniformity of temperature conditions and wavelength relations, both lasers share a common resonator volume (3) and are in fixed relative adjustment. The reference laser is used as a calibrating laser for frequency tuning of the resonator or, simultaneously, as a local oscillator, whereas the TE laser serves to generate a laser pulse.

Abstract: A semiconductor diode laser system with microwave mode locking. The system includes a semiconductor laser diode and an external reflector positioned to receive radiation that emits from the diode and reflects the same back into the diode, the microwave mode locking serving to modulate the radiation and the external reflector being properly positioned to return the radiation to the diode at a return time equal to the period of the drive signal or a submultiple thereof.

Abstract: A passively Q-switched laser system uses a common Q-switch cell to control two lasers. The first laser to turn on Q-switches the other laser.

Abstract: An RF-discharge waveguide laser having two parallel waveguides is improved by the addition of coupling channels which permit the plasma in said waveguides to communicate.

Abstract: An RF-discharge waveguide laser incorporates two or more waveguides sharing a common set of discharge electrodes. The device may be used to provide two lasers operating on the same or different frequencies, or a single laser with two waveguides contributing to the power output.

Abstract: A novel electrical discharge gas laser device is provided which comprises a pair of laser discharge cavity portions optically interconnected within a U-shaped optical resonant cavity, the laser cavity portions configured to intercommunicate and share a common power supply.

Abstract: This external cavity laser utilizes an unstable resonator in conjunction with a high reflectivity stripe end mirror which is oriented substantially parallel to the plane of the maximum divergence of the laser diode output beam and whose axis is substantially parallel to the plane of the junction of the laser diode. This configuration operates with high efficiency to select only the fundamental mode of the laser diode with a minimal divergence in the output beam.

Abstract: A laser having an active region capable of lasings at different wavelengths includes an optical resonator cavity bounded at one end by one of several different wavelength-selective gratings. An adjustable mirror selects one of the wavelength-selective gratings by optically aligning the active region with the selected wavelength-selective grating. The position of the adjustable mirror is controlled by a combination of open loop-closed loop control. The open loop control includes a staircase generator, the closed loop control includes reference mirrors coacting with a feedback reflector in the back of the adjustable mirror for directing a control beam onto a position sensor. The length of the optical resonator cavity is dithered to retune the cavity for each wavelength selection. The beams produced at the various wavelengths are used, for example, to measure the optical energy content in a gas dynamic laser medium.

Abstract: A laser system generates high energy ultra-short pulses using a dye cell amplifier driven by ultra-short pulses from a dye laser and pumped by pump pulses from a laser amplifier. The laser amplifier and dye laser are synchronously driven and pumped by the same laser such that the signal pulse from the dye laser arrives at the dye cell amplifier immediately upon the completion of population inversion therein in response to the pump pulse. Efficient high-power, ultra-short laser pulses are obtained from the dye amplifier, since amplified spontaneous emission (ASE) is avoided. Doubler crystals are used to provide the pump pulses to the dye laser from the common driver laser and to provide pump pulses from the laser amplifier to the dye cell amplifier at the proper wave length for the materials used therein. This system is tunable by selecting appropriate dyes for the dye laser and dye cell amplifier and/or tuning elements within the dye laser cavity.

Abstract: A gas laser includes a pair of subsidiary electrodes to form a sharpening gap. These subsidiary electrodes are located within the envelope of the laser so as to be exposed to the same gas or mixture of gases that flow between the main electrodes and support the main lasing action. The efficiency of the laser and the lifetime of the electrodes of the sharpening gap are thereby improved, together with other advantages.

Abstract: A method and apparatus for producing stable and reproducible ultra-short lasing radiation pulses are disclosed. The duration of incoming pumping pulses for the dye laser arrangement is reduced in stages to produce the ultra-short pulses. A first dye laser cavity of a series of at least two cascaded dye laser cavities is excited with lasing radiation pulses. The lasing radiation pulses emerging from each dye laser cavity of the series are directed into the next successive dye laser cavity of the series. The photon cavity lifetime of each dye laser cavity of the series is sufficient for a given duration of the incoming pumping pulses to produce the ultra-short pulses emerging from the final dye laser cavity of the series. The maximum photon cavity lifetime of each dye laser cavity of the series is selected to thereby reduce in stages the duration of the incoming pumping pulses. This reduction yields from the final dye laser cavity of the series the ultra-short lasing radiation pulses.