Abstract: A mode locked as a seed source for a solid state regenerative amplifier system is disclosed. The system includes components for forming an external cavity laser with a semiconductor amplifier, exciting and mode locking the cavity laser to emit optical pulses with a linearly time varying optical frequency, collecting and collimating the optical pulses, isolating the optical pulses and amplifying the optical pulses for a selected application. The selected applications include but are not limited to medical imaging, fuel diagnostics, ultrafast spectroscopic measurements, network synchronization, distributed optical clock network, electro-optic sampling, timing Jitter reduction, a source for inducing nonlinear optical effects, and optical time domain relectometry. A mount mechanism support for an optic system is also disclosed.

Abstract: An apparatus and method for producing laser radiation from a vertical cavity semiconductor laser are disclosed. A preferred embodiment includes a quantum-well region formed over a semiconductor substrate. A first reflective surface is formed over the quantum-well region, and a second reflective surface is formed over the substrate, opposite the first reflective surface, forming a laser cavity. The quantum-well region is optically pumped, producing laser oscillation. The absorbed pump power causes a thermal lensing effect within the semiconductor material, stabilizing the transverse spatial mode of the laser cavity. The invention has applications in optical communication and laser printing.

Abstract: The invention relates to modelocked lasers including highly dispersive optical elements. The dispersive optical elements increase the oscillation pulse width inside the laser oscillators, which reduces the nonlinearity of the laser cavity for a given oscillating pulse energy. Compared to conventionally designed modelocked lasers, an increase in output pulse energy by one to three orders is achieved. As way of example, the technique is applied to an erbium fiber laser, where a chirped fiber Bragg grating is employed as the dispersive element. By using a Kerr-modelocking technique, a high nonlinearity may be sustained inside the fiber laser cavity, which leads to the generation of pulses with psec widths and energies up to 2 nJ. The large bandwidth of the chirped fiber Bragg grating allows a wavelength tuning range in excess of 10 nm, which is achieved by polarization control and a control of the gain spectrum of the laser.

Abstract: The present invention is generally directed to a laser, such as a soliton fiber laser, having an emission wavelength controlled by non-linear effects. Although the emission wavelength of such lasers is typically limited to the center of the gain profile, exemplary embodiments of the present invention provide relatively broad bandwidth control by producing significant gain-pulling using non-linear effects. Any non-linear effects in a laser cavity can be used to provide significant gain pulling and a broadband wavelength tuning range including, for example, the soliton self-frequency shift (SSFS) and cross-phase modulation (CPM). As a result, non-linear tuning can be achieved. Exemplary embodiments provide gain-pulling which allows a significant separation to be induced between the peak emission wavelength of the modelocked fiber laser (i.e., the modelocked emission wavelength, or MLEW) and the emission wavelength of the non-modelocked laser (i.e., the continuous wave emission wavelength, or CWEW).

Abstract: A CPM mode-locked fiber ring laser including an ion-implanted semiconductor saturable absorber providing sub-picosecond pulses at rapid repetition rates. The laser provides compact, turn-key capability and is polarization insensitive.

Abstract: A mode-locked solid state laser is disclosed for generating ultrashort optical pulses from solid state material. The laser can comprise a solid state gain medium, at least one mirror connected to the medium and a semiconductor multiple quantum well saturable (MQW) absorber in contact with the mirror, for mode-locking the solid state gain medium. The solid state medium can be composed of but is not limited to Titanium Sapphire, Cr:YAG, Cr:Fosterite, Nd:YAG, Nd:glass, color center lasers, semiconductor diode lasers, optically active fiber lasers, and the like. The absorber can include a structure consisting of 70 Angstrom wells of GaAs and 100 Angstrom barriers of AlGaAs. The generated optical pulses can be used in a wide variety of applications such as diagnostic testing, communications, computers, medicine, automotive applications and the like.

Abstract: A monolithic self-Q-switched laser generates laser pulses with short duration, high peak power, a single longitudinal mode, and extremely small pulse-to-pulse intensity fluctuations. The laser comprises of a length of solid-state laser material with a plurality of dopants, so that the material can generate coherent radiation for laser action and, in the same material, provide saturable absorption at the wavelength of the laser emission necessary for Q-switching. The distributed saturable absorber in the material provides a spectral stabilization mechanism that ensures single longitudinal-mode operation. The laser cavity is formed by the two end surfaces of the solid-state laser material with appropriate reflectivity coatings. When the laser material is pumped above the threshold condition, the laser device produces short pulses having high peak power in a single longitudinal mode and single transverse mode.

Abstract: An optically driven interactive Q-switch, i.e., a Q-switch that responds to a short pulse of light, for example, from external light-emitting diodes (LEDs) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium. Q-switching is thus achieved on demand by electrically pulsing the light source to produce a pulse of light directed onto a Q-switch medium in the laser cavity. Electronic control of the light pulse from the external source will thus provide not only efficient Q-switching frequency but also independent control of output laser pulse width with a fast rise time for each output laser pulse.

Abstract: The reflecting surfaces within the resonator are minimized in an unstable laser resonator having a radially-dependent output end reflection profile and a passive Q-switch so that the least possible competing resonator geometries can be formed. For this purpose, a saturable absorber foil can be provided as a passive Q-switch element mounted so as to be inclined with respect to the optical axis. Furthermore, it is advantageous to use an output reflector having highly precise parallel boundary surfaces and to align this output reflector with high precision parallel to the end surfaces which delimit the laser medium.

Abstract: A single semiconductor diode laser array with multiple laser beams is used in a laser printer. The single diode laser array is formed by joining two semiconductor diode lasers. Each diode laser emits multiple laser beams that can have a different wavelength than the multiple laser beams of the other diode laser. The diode lasers can be made from different materials, such as GaAs/AlGaAs and GaInP/AlGaInP. The polarization of one diode laser can be orthogonal to the polarization of the other diode laser. The first diode laser has the dimensions of a long width and a short length. The second diode laser has the dimensions of a short width and a long length. The lasing elements are formed centrally to the width of each diode laser. The diode lasers are mounted on separate heatsink mounts. When the diode laser array is assembled, an insulator separates the lasing elements of each diode laser. Contact wires are attached to bonding pads located near the exposed ends or sides of each diode laser.

Abstract: An apparatus and method for a passively Q-switched microlaser for producing high-peak-power pulses of light of extremely short duration are disclosed. The apparatus comprises a gain medium and saturable absorber disposed within a laser cavity. When the cavity is pumped, the saturable absorber prevents the onset of lasing until the inversion density within the cavity reaches a critical value. The length of the cavity, the material parameters, and the reflectivities of the mirrors are selected such that pulses of duration less than about 1 ns and of peak power in excess of about 10 kW are obtained. The invention has application in high-precision optical radar, nonlinear optics, micromachining, microsurgery, robotic vision, and other technologies requiring high-peak-power laser pulses of extremely short duration.

Abstract: A diode-pumped monolithic laser is fabricated from a self-doubling host material co-doped with two ionic species, where one ionic dopant converts pump radiation to continuous radiation at a fundamental frequency and the other dopant acts as a saturable absorber to Q-switch the fundamental radiation which is then frequency doubled to produce pulsed high-intensity green light, the green light being either outputted or further frequency-doubled, into pulsed coherent UV radiation, by means of a non-linear crystal.

Abstract: The present invention provides protection from lasers with a high nonlinear bsorption structure including a mirror which directs an incident beam to a beam splitter. A focusing lens receives and focuses the radiation to a higher intensity beam which is directed into an absorption material with a third order polarization property. Such materials will cause a two-photon absorption partial attenuation from the intensified beam when the incident radiation intensity is greater than ambient intensity. A focusing mirror receives the partially attenuated beam and reflects and refocuses the partially attenuated beam back through the absorption material, which now acts as a single photon absorption material to further attenuate the beam. The doubly attenuated beam passes through the focusing lens which recollimates the doubly attenuated beam and directs it to the beam splitter which in turn directs the beam to the receiving device.

Abstract: Whenever any laser is interfaced with any type of optics there is always backscatter back into the laser. For diode lasers this backscatter makes it emit chaotic radiation where the frequency spectrum is broad and contains many different frequencies. This means that the laser has limited use as a source of information transfer in fibers. This weakness can be overcome, by driving the laser with an external cavity filled with a Kerr material. The addition of a Kerr material in the external cavity suppresses the chaos, or coherence collapse. Thus the new apparatus of laser plus external cavity filled with a Kerr material increases the stability of the diode laser.

Abstract: Extended wavelength tunability is achieved in a saturable absorber for applications such as modelocking lasers by realizing a semiconductor structure having a tapered energy bandgap profile in a portion of the saturable absorber wherein the profile is given as a function of the distance along the propagation axis of the saturable absorber. For certain applications, at least one mirror is monolithically integrated with the saturable absorber.

Abstract: A saturable absorber comprising multiple quantum-well layers (32, 34, 36) of differing thicknesses and separated by barrier layers (38) so as to produce a wide-band absorption. Such a saturable absorber (30) is useful in a hybrid mode-locked laser having an optical cavity defined by two mirrors (10, 12) into which are placed the saturable absorber (30) and an optical amplifier (14) driven by both a DC bias and an RF modulation signal.

Abstract: Intracavity Raman lasers comprising a pump resonator and a Raman resonator that eliminates alignment problems associated with multi-mirror intracavity lasers. The pump resonators include a laser rod and a pump source. In one embodiment, a first retroreflector is disposed at one end of the pump resonator, and an output mirror is disposed at an opposite end thereof. A Q-switch, a dichroic mirror, and a prism are disposed between the laser rod and the output mirror. The pump resonator radiates pump energy at a first wavelength (1.06 .mu.m) between the first retroreflector and the output mirror. The Raman resonator includes a Raman gas cell having first and second lenses disposed on opposite ends thereof for focusing laser energy into the Raman cell, and a second retroreflector that forms one end of the Raman resonator. The output mirror forms an opposite end of the cell, and the dichroic mirror and the prism are disposed between the second retroreflector and the first lens.

Abstract: Saturation intensity and loss of a saturable absorber are substantially independently regulated by positioning the saturable absorber element within a Fabry-Perot etalon defined by first and second reflective elements so that the saturable absorber element responds to light at optical wavelengths in the anti-resonant portion of the Fabry-Perot spectral response, that is, between optical wavelengths corresponding to resonance peaks. The resulting combination of elements is called a Fabry-Perot saturable absorber. Thickness of the saturable absorber element substantially sets the loss of the Fabry-Perot saturable absorber while changes in the reflectivity of the first reflective element onto which the light is incident substantially determines the saturation intensity (degree of nonlinearity) and assists in compensating loss of the saturable absorber element.

Abstract: An optical switching device employs a rare earth bis-phthalocyanine having good third-order nonlinear susceptibilities. In a preferred optical switch, the rare earth bis-phthalocyanine is employed as a nonlinear optical material body that fills the space between two partially reflecting mirrors. When light incident on the switch is below a given intensity level, light passes through the switch and the switch is in an open state. When light is above a given intensity level, light is trapped in the nonlinear optical material and the switch is in a closed state.

Abstract: There is provided by this invention a laser cavity for producing a periodic output pulse and a passive Q-switch for use therein. The laser cavity is typically comprised of a lasing medium, a pair of reflecting elements, and a passive Q-switch. The Q-switch is composed of inorganic, solid-state materials which do not degrade through use. Exemplary materials include a Q-switch constructed from a host material having a tetrahedral site, such as GSAG (Gd.sub.3 Sc.sub.2 Al.sub.3 O.sub.12), GIGG (Gd.sub.3 In.sub.2 Ga.sub.3 O.sub.12), YAG (Y.sub.3 Al.sub.5 O.sub.12), or Mg.sub.2 SiO.sub.4 into which tetravalent chromium (Cr.sup.4+) is introduced as a dopant material. The passive Q-switch composed of such materials effectively modulates laser output having a wavelength within the range of 850 nanometers to 1250 nanometers.

Abstract: An optically switchable device (1) has a heterostructure (2) defining a first potential well (3) separated by a barrier layer (4) from a second potential well (5) which provides an electron energy level (e.sub.5) which is lower in electron energy than the lowest electron energy level (e.sub.3) of the first potential well (3). The barrier layer (4) provides an intermediate electron energy level (e.sub.4) and is sufficiently thick to inhibit tunnelling of holes from the first (3) to the second (5) potential well. The barrier layer (4) thus confines holes of electron-hole pairs generated in the first potential well (3) by an incident optical beam to the first potential well (3) while facilitating transfer of the electrons from the first potential well (3) to the second potential well (5) via the intermediate electron energy level (e.sub.4) provided by the barrier layer (4).

Abstract: A lens (12) converges a light beam (16) into a light absorbing body (14) having a material which exhibits reverse saturable optical absorption distributed therein with a non-uniform concentration. The concentration is maximum at the focal point (20) of the converged light beam (16), and decreases toward the lens (12) with a distribution selected in correspondence with the optical gain of the converged light beam (16) to limit the local fluence of the light beam (16) propagating through the absorbing body (14), and the output energy of the light beam (16), to predetermined maximum values. The non-uniform concentration further produces a self-protecting effect by causing the region of maximum fluence of the converged light beam (16) to shift toward the lens (12), thereby protecting the region of highest optical gain and highest molecular concentration, as the input energy of the light beam (16) increases.

Abstract: A method of manufacturing a diamond laser crystal having an excellent laser efficiency is performed by first, preparing a synthetic type Ib diamond containing at least 60 volume percent of a (111) plane growth sector (43) is prepared. This synthetic diamond is then thermally treated under high temperature/high pressure, so that type Ib nitrogen contained in the synthetic diamond is converted to type IaA nitrogen. Thereafter an electron beam is applied to the synthetic diamond in order to generate vacancies in the synthetic diamond. Finally annealing is performed on the synthetic diamond to form H3 centers by coupling the type IaA nitrogen atoms contained in the synthetic diamond, with the vacancies. According to this method, the H3 centers can be formed in the synthetic type Ib diamond at high concentration, while formation of NV centers which become an obstacle to laser action, can be suppressed.

Abstract: A lasing medium (3) and a Raman medium (20) share a common optical cavity. The lasing medium (3) projects laser light into the Raman medium (20) and, when a threshold intensity within the Raman medium is reached, the Raman medium absorbs the laser light and re-radiates coherent light at a shifted frequency. Optical elements within the system provide an optical cavity for the lasing medium and a second cavity for the Raman medium.

Abstract: The invention is a controlled laser having an optical resonator, a laser gain medium placed inside the optical resonator, the laser gain medium being capable of emitting light and of lasing with the light, a multiple layer heterostructure placed inside the optical resonator, and means for varying an optical absorption of the multiple layer heterostructure for the light in order to control an optical gain of the optical resonator, and thereby control lasing of the laser gain medium. Passive mode locking is achieved by the light emitted by the gain medium controlling the optical absorption of the multiple layer heterostructure. Active mode locking and modulation are achieved by controlling the optical absorption of the multiple layer heterostructure by applying an electric field to the multiple layer heterostructure.

Abstract: Higher efficiency in cavity dumping and frequency doubling in a laser used to produce modulated output beam pulses is achieved by deflecting light out of the resonant cavity to a third mirror through a frequency doubler using an electro-optic modulator and a polarizing beamsplitter in the resonant cavity, or using just an acousto-optic modulator to deflect light out of the laser cavity in response to a control signal (electric or acoustic). The frequency doubler in front of the third mirror rotates the frequency doubled light so that it will pass out of the laser cavity through the polarizing beamsplitter, while undoubled frequency light is reflected by the polarizing beamsplitter back into the gain medium of the laser. In the case of using a type-II frequency doubler, a dichroic beamsplitter deflects out the frequency doubled light and passes the undoubled frequency light to the polarizing beamsplitter for return to the laser gain medium.

Abstract: A passive laser Q-switch is fabricated from a crystal which can form saturable color centers, such as lithium fluoride. The arbitrarily long crystal is irradiated with electrons from the side, or radially, to impart a radial distribution of saturable color centers therein, with the highest density at the periphery of the crystal. Optionally, the crystal can also be irradiated axially with electrons or in any direction with another form of radiation having greater penetration into the crystal, such as gamma radiation, to establish a base level of saturable color centers throughout the crystal. The crystal having the radial distribution of color centers acts as a Q-switch, but additionally tends to reduce beam divergence and increase the brightness of the laser beam by virtue of the nonlinear bleaching mechanism.

Abstract: In an excimer laser system with wavelength bandwidth narrowing, a feedback loop for monitoring and correcting the tuning of the laser employs a wavelength calibration device in the form of a gas with an absorption peak at the desired narrow wavelength. A portion of the laser output received through the gas provides the information for generating the correction signal.

Abstract: An optical resonator for a power laser comprises between one of a pair of totally reflecting mirros flanking the end of a pumped active element such as a Nd:YAG crystal, a passive Q switch and between the passive Q switch and the active element, a polarizer which reflects the output transversely to the optical axis of the reflecting beams of the cavity. A phase shifter is provided between the polarizer and the approximal end of the active element. This system prevents the full output energy from impinging upon the passive Q switch so that the passive Q switch or other low-damage-threshold optical elements associated therewith do not have to take the full power.

Abstract: A dye laser capable of lasing at a plurality of wavelengths simultaneously, e.g. three, comprises a corresponding plurality of transparent containers 4, 5, 6 located between a partially-reflecting mirror 1 and a tiltably adjustable retroreflecting diffraction grating 2 with the containers transversely staggered. The staggered ends of the containers are irradiated by a shallow beam 9 from a pumping laser 7 and contain separate dye solutions whereof the emission spectra increase in wavelength from container to container starting from that container nearest the pumping laser. There are thus formed three parallel cavities which can lase simultaneously, tuned by the grating 2 operating in three different diffraction orders.

Abstract: A semi-passive Q-switch can be used at 1.00 to 1.80 micrometers laser radiation, in combination with a laser to give an effective high peak power output.

Abstract: An optical device that stabilizes the power in a cw laser beam comprises a material whose absorption coefficient increases wth increasing incident intensity. The same device acts as an energy limiter and pulse shortener for a pulsed laser. In either case, the device can be located either within the laser cavity or outside it. In another embodiment, the device is placed into the cavity of a passively mode-locked laser to permit mode-locking with laser materials that have high gain-saturation energy. Materials suitable for use in the device include Cr-doped crystalline solids and organic solutions, such as laser dyes, saturable absorber dyes, etc.

Abstract: This absorbant is of the type formed by superlattice constituted by a stack of films of two different semiconductor materials having gaps of different heights. Thus, a potential well is produced in each film corresponding to the semiconductor with the smallest gap and a potential barrier in each film corresponding to the semiconductor with the largest gap. This saturatable absorbant is characterized in that the films corresponding to the semiconductor with the smallest gap have a thickness, which can assume two values, one small and the other large.Application in optics to the production of mode locking lasers and all optical logic gates.

Abstract: A Q-switched laser resonator is constructed in the form of an integral, one-piece assembly, thus eliminating the requirement for an optical bench to support the individual components. The integral assembly is constructed by bonding a surface of the Q-switch device to an end of the laser rod, the bonding being accomplished with a layer of transparent adhesive. Similarly, the optical coupler is bonded to the opposite surface of the Q-switch device with a layer of adhesive. The resulting laser resonator assembly is optically aligned prior to the setting of the adhesive layers such that the alignment is permanently maintained after the adhesive sets.

Abstract: An optical device that stabilizes the power in a cw laser beam comprises a material whose absorption coefficient increases with increasing incident intensity. The same device acts as an energy limiter and pulse shortener for a pulsed laser. In either case, the device can be located either within the laser cavity or outside it. Materials suitable for use in the device include Cr-doped crystalline solids and organic solutions, such as laser dyes, saturable absorber dyes, etc.

Abstract: In a CRT display device the target comprises a multilayered semiconductor including a p-n junction and at least one current-blocking layer. The e-beam is locally absorbed in the current-blocking layer so as to open a narrow zone which allows charge to flow through the forward biased p-n junction. The injection current produces a local spot of light which radiates from the opposite side of the device and whose position is varied by scanning the e-beam. In one embodiment the current-blocking layer is a semi-insulating semiconductor layer, and in another embodiment the current-blocking layer comprises the base of a normally cut-off transistor.

Abstract: A passively Q-switched RF powered laser provides a variable output pulse format by controlling the duration of applied RF power and the time interval between application of power. High repetition rates may be used for scanning and target acquisition in a laser radar system and low repetition rates may be used for ranging.

Abstract: Method and apparatus for use of a Raman or Brillouin switch together with a conventional laser and a saturable absorber that is rapidly bleached at a predetermined frequency .nu.=.nu..sub.0, to ultimately produce a Raman or Brillouin pulse at frequency .nu.=.nu..sub.0 .+-..nu..sub.Stokes.

Abstract: A simplified, relatively inexpensive laser device, wherein the laser elements are fixed in a body exoskeleton of electrical insulating material having a low coefficient of thermal expansion. The preferred embodiment includes a shotgun type laser filter having parallel bores which receive the laser flashlamp and laser rod in fixed relation in a body chamber. The reflector surrounds the laser filter and retains the filter within the body chamber. In the preferred method of this invention, several controlled lasing pulses are generated with each illumination pulse of the flashlamp, substantially increasing the efficiency of the laser device. The number of pulses is generally controlled by increasing the voltage to the flashlamp. The rapid multiple lasing pulses generate an elongated plasma in a fluid medium, such as the vitreous fluid body of an eye which makes the laser device extemely efficient for treating glaucoma and other medical treatments.

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: 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: 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: Radiation at the frequency of a preselected absorbing resonance is produced by use of split and recombined interfering optical paths, arranged to produce near white light interference effects, and a preselected absorption medium disposed in one path of the interfering configuration. By association of this configuration with a laser oscillator, the regeneration characteristic of the laser oscillation can be determined by a peak in the reflected or transmitted wave produced by the cooperation of the optical interference system and the absorption medium. Use with standing wave, ring, and gain-switched transient lasers all can produce radiation essentially confined to the narrow absorption profile of a selected gas. Improved methods of laser chemistry and remote and close range gas detection are made possible by the new system.

Abstract: A radioactively biased optical power limiter device is described which comprises first and second lenses disposed along an optical axis with a common focal plane therebetween, the first lens disposed for receiving electromagnetic energy input directed along the optical axis and focusing the input at the focal plane of the first and second lenses, a cell of optically nonlinear material disposed along the optical axis at the focal plane of the lenses, and a radioactive source of ionizing radiation disposed near or in the nonlinear material for selectively controlling the electromagnetic field level necessary to cause optical nonlinear effects in the cell.