Abstract: A high extraction efficiency laser system. The novel laser system includes a master oscillator for providing a laser beam, an amplifier adapted to amplify the laser beam, and an aberrator for aberrating the laser beam to prevent the formation of caustic intensity patterns within the amplifier. In an illustrative embodiment, the laser system also includes a depolarizer disposed between the master oscillator and the amplifier to reduce the contrast of speckle intensity patterns in the amplifier, and a mechanism adapted to rotate or otherwise move the aberrator to time-vary the aberrations in the beam in order to increase the spatial homogenization of saturation and extraction patterns in the amplifier. In a preferred embodiment, the coherence length of the beam is also shortened to reduce interference fringes in the amplifier.

Abstract: A thermal nonlinear cell and method. The cell includes a substantially planar nonlinear medium and a mechanism for removing thermal energy from the medium in a direction substantially orthogonal to said medium. In one embodiment, the mechanism for removing thermal energy is a thermally conductive window mounted adjacent to the medium. Preferably, the mechanism includes plural thermally conductive windows between which the nonlinear medium is disposed. In the best mode, the windows are sapphire and the nonlinear medium is a fluid. The windows and the medium are transmissive with respect to first and second beams that interfere with each other and create an interference pattern in the cell. The interference pattern is sampled by a sampling hologram created within the multiple layers of the medium. The interference pattern is used via a sampling hologram to create a phase conjugate of a signal beam. The windows move thermal energy from the medium in a direction transverse to the longitudinal axis of the medium.

Abstract: A spatial filter adapted to increase the angular spread of non-conjugated energy in a beam and suppress this energy to improve the efficiency of a phase conjugate system. In the illustrative embodiment, the filter includes first and second lenses and an aberrator to increase the angular spread. In the specific embodiment, an opaque plate, with a pinhole aperture therethrough, is sandwiched between the lenses to suppress the non-conjugated energy. The aberrator may be implemented with an amplifier or other suitable mechanism. Likewise, the aperture may be replaced with a highly angle-selective thick Bragg grating or other suitable arrangement. A phase conjugate master oscillator/power amplifier laser architecture is also disclosed.

Abstract: A glaze soldered solid-state laser active medium. The novel laser active medium includes a first section of a first material, a second section of a second material, and a layer of ceramic glaze joining the two sections. The first and second materials may be identical, similar, or dissimilar, and may include crystals or ceramics. The glaze is a multi-oxide eutectic ceramic glaze having a refractivity, light absorption, thermal expansion, and fusion temperature that are compatible with the first material. The sections are joined using a novel glaze soldering process that includes the steps of positioning the sections, applying the ceramic glaze between the sections, and firing the glaze to solder the sections together.

Abstract: An outcoupler having a wavelength selective, angle sensitive element or Bragg grating and an arrangement for maintaining the element in a predetermined orientation relative to an incident beam of electromagnetic energy. The Bragg grating may be reflective or transmissive. The inventive outcoupler may be used to implement a phase conjugate master oscillator power amplifier with an oscillator; a resonator in operational alignment with the oscillator; and an outcoupler in alignment with the oscillator. In the best mode, second and third Bragg gratings are included within the oscillator and the resonator, respectively.

Abstract: An optical arrangement comprising first and second guided structures for providing first and second beams of electromagnetic energy and a node for coherently combining said first and second beams in free space, that is, with an unguided structure. In the illustrative embodiment, the first and second structures are first and second fiber oscillators. The first and second fiber oscillators may be of unequal lengths. The node may be implemented with a polarizing beam splitter or a semi-reflective surface. Beam shaping optics are included in the node to collimate the first and second beams and provide a flat profile mode thereof. The outputs of plural first and second fiber oscillators are combined via plural nodes to provide a single high energy output beam. Amplifying elements may be disposed between nodes. The plural nodes may be disposed in a single integrated structure along with an outcoupler mirror to coherently phase lock the outputs of the plural oscillators.

Abstract: A solid-state suspension laser. The novel laser includes a gain medium comprised of a plurality of solid-state gain particles suspended in a fluid. The laser also includes a pump source for pumping the gain particles and a resonator for amplifying and outputting laser light generated by the gain medium. In an illustrative embodiment, the gain medium is adapted to flow, and the pumping of the gain medium occurs outside of the resonator. The flow velocities and the densities of the gain particles in the gain medium can be optimized for optimal absorption efficiency during the pumping and/or for optimal extraction efficiency in the resonator as well as for overall laser performance optimization, including power, efficiency and beam quality scalability.

Abstract: A self-adjusting interferometric outcoupler. In the most general sense, the invention is an optical system (100) comprising a first mechanism (112) for generating a first beam, a second mechanism (122) for receiving the first beam and returning a second beam, and an interferometer (116) positioned to couple the first beam to the second mechanism (122) and to receive and output the second beam, wherein the interferometer (116) is also shared by the first mechanism (112) and/or the second mechanism (122) to control the frequency of the first beam and/or the second beam, respectively. In the illustrative embodiment, the first mechanism (112) is a master oscillator, the second mechanism (122) is a phase conjugate mirror, and the system (100) further includes a power amplifier (118) positioned to amplify the first beam during a first pass and to amplify the second beam during a second pass.

Abstract: An outcoupler having a wavelength selective, angle sensitive element or Bragg grating and an arrangement for maintaining the element in a predetermined orientation relative to an incident beam of electromagnetic energy. The Bragg grating may be reflective or transmissive. The inventive outcoupler may be used to implement a phase conjugate master oscillator power amplifier with an oscillator; a resonator in operational alignment with the oscillator; and an outcoupler in alignment with the oscillator. In the best mode, second and third Bragg gratings are included within the oscillator and the resonator, respectively.

Abstract: A thermal nonlinear cell and method. The cell includes a substantially planar nonlinear medium and a mechanism for removing thermal energy from the medium in a direction substantially orthogonal to said medium. In one embodiment, the mechanism for removing thermal energy is a thermally conductive window mounted adjacent to the medium. Preferably, the mechanism includes plural thermally conductive windows between which the nonlinear medium is disposed. In the best mode, the windows are sapphire and the nonlinear medium is a fluid. The windows and the medium are transmissive with respect to first and second beams that interfere with each other and create an interference pattern in the cell. The interference pattern is sampled by a sampling hologram created within the multiple layers of the medium. The interference pattern is used via a sampling hologram to create a phase conjugate of a signal beam. The windows move thermal energy from the medium in a direction transverse to the longitudinal axis of the medium.

Abstract: A solid-state laser beam amplifier with integrated reflective surface. A rectangular slab gain medium receives a first portion of an input laser beam along a first zigzag reflection path within the slab. The gain medium also receives a second portion of the input laser beam that has been reflected from an integral reflective surface such that the two portions traverse the gain medium along complementary zigzag paths. The zigzag paths are defined by total internal reflection of the beam portions as they propagate through the gain medium slab. A similar reflective surface may be positioned relative to the exit end of the gain medium slab, which redirects all of the output beam portions in a parallel direction. The gain medium may be Ytterbium or neodymium doped yttrium aluminum garnet. The gain medium may be formed as a high aspect ratio rectangular slab and may be clad with sapphire.

Abstract: A nonreciprocal optical element and method for operating it to effect separate control of intensity and phase (or optical path length) of counter propagating beams over a very wide range. The nonreciprocal optical element includes a circulator for routing a first signal from a first port to a second port and a second signal from the second port to a third port, a third signal from the third port to a fourth port and a fourth signal from the fourth port to the first port; a first mirror for reflecting a signal output by the second port back into the second port; and second mirror for reflecting a signal output by the fourth port back into the fourth port. Polarization rotation elements such as quarter-wave plates are disposed between the mirrors and the second and fourth ports to preserve the polarization of the input beams. Filters are disposed between these ports and mirrors to adjust the transmittance of the input and output signals.

Abstract: A nonreciprocal optical element and method for operating it to effect separate control of intensity and phase (or optical path length) of counter propagating beams over a very wide range. The nonreciprocal optical element includes a circulator for routing a first signal from a first port to a second port and a second signal from the second port to a third port, a third signal from the third port to a fourth port and a fourth signal from the fourth port to the first port; a first mirror for reflecting a signal output by the second port back into the second port; and second mirror for reflecting a signal output by the fourth port back into the fourth port. Polarization rotation elements such as quarter-wave plates are disposed between the mirrors and the second and fourth ports to preserve the polarization of the input beams. Filters are disposed between these ports and mirrors to adjust the transmittance of the input and output signals.

Abstract: A phase conjugate mirror comprising a photonic band gap light guide and a stimulated Brillouin scattering medium disposed in operational relation thereto. In specific embodiments, the light guide is an optical fiber with a high index cladding transparent at a propagation wavelength and a hollow or solid core. The cladding is microstructured silica and supports guide modes through frustrated tunneling photonic band gap guidance or Bragg photonic band gap guidance. The fiber has an array of channels disposed around the core. In one embodiment, the fiber is disposed within a stimulated Brillouin scattering cell. In this embodiment, the medium is gas, gel, or liquid. In an alternative embodiment, the medium is a solid disposed at the core of the fiber. The invention provides a means of guiding light with a gas filled or solid core structure with high guiding efficiency, high reflection back into the medium, without disturbing the polarization state of the light as it propagates.

Abstract: A robust scalable laser. The laser includes plural fiber laser resonators. A cavity that is external to the fiber laser resonators combines plural laser beams output from the plural fiber laser resonators into a single output laser beam. In a specific embodiment, the plural fiber laser resonators are eye-safe double-clad Er:YAG laser resonators that are pumped via laser diode arrays.

Abstract: An optical arrangement (10) comprising a first beam splitter (12) for transmitting light of a first polarization, to provide a first beam, and reflect light of a second polarization; a first spectral filter (16) in optical alignment with the first beam, the filter (16) being adapted to return a second beam thereto; and a first polarization rotator (14) in optical alignment with the beam splitter (12) and the spectral filter (16) for effecting a rotation of the polarization of the second beam relative to the first beam whereby the second beam has the second polarization and is reflected by the beam splitter (12). In a specific implementation, the spectral filter (12) may be a Bragg grating, a quarter-wave plate (22), a Faraday rotator (32) or other suitable device. If a Faraday rotator is used, a polarization adjuster (34) is used in optical alignment therewith. A number of alternative embodiments are disclosed.

Abstract: A solid state waveguided structure a core fabricated of a lasing medium, diffusion-bonded to a cladding fabricated of a laser-inactive material. The medium of the core comprises a lutetium-aluminum-garnet material doped with ions of ytterbium, lutetium-aluminum-garnet material doped with ions of neodymium, and lutetium-aluminum-garnet material doped with ions of thulium, and the laser-inactive material of the cladding comprises an yttrium-aluminum-garnet material. A method of fabricating a solid state waveguided structure with improved characteristics comprising using a combination of a trivalent ions of ytterbium-doped lutetium-aluminum-garnet core and a yttrium-aluminum-garnet cladding.

Abstract: A spatial filter adapted to increase the angular spread of non-conjugated energy in a beam and suppress this energy to improve the efficiency of a phase conjugate system. In the illustrative embodiment, the filter includes first and second lenses and an aberrator to increase the angular spread. In the specific embodiment, an opaque plate, with a pinhole aperture therethrough, is sandwiched between the lenses to suppress the non-conjugated energy. The aberrator may be implemented with an amplifier or other suitable mechanism. Likewise, the aperture may be replaced with a highly angle-selective thick Bragg grating or other suitable arrangement. A phase conjugate master oscillator/power amplifier laser architecture is also disclosed.

Abstract: A system for removing waste energy in the form of sensible heat and fluorescent energy from a solid state laser medium having a broad surface. The system includes a manifold disposed about the laser medium having a plurality of inlet jets interspersed with a plurality of exhaust orifices. Coolant fluid is circulated through the manifold. The fluid is forced through the plurality of inlet jets to impinge the broad face of the laser medium, thereby transferring waste energy by convection from the laser medium to the coolant fluid. The coolant fluid is further circulated to exhaust the pumphead manifold through the plurality of exhaust orifices. The fluorescent energy, which is radiated from the laser medium, is converted to sensible heat by an absorber disposed within the coolant adjacent to the laser medium. The coolant then removes the converted heat by forced convection.

Abstract: A solid-state laser beam amplifier with integrated reflective surface. A rectangular slab gain medium receives a first portion of an input laser beam along a first zigzag reflection path within the slab. The gain medium also receives a second portion of the input laser beam that has been reflected from an integral reflective surface such that the two portions traverse the gain medium along complementary zigzag paths. The zigzag paths are defined by total internal reflection of the beam portions as they propagate through the gain medium slab. A similar reflective surface may be positioned relative to the exit end of the gain medium slab, which redirects all of the output beam portions in a parallel direction. The gain medium may be Ytterbium or neodymium doped yttrium aluminum garnet. The gain medium may be formed as a high aspect ratio rectangular slab and may be clad with sapphire.