Abstract: A method of suppression of Indium carry-over in the MOCVD growth of thin InGaAsP quantum wells, with low Indium content, on top of thick GaInAsP, with high Indium content. These quantum wells are essential in the stimulated emission of 808 to 880 nm phosphorous-based laser structures. The Indium carryover effect is larger in large multi wafer reactors and therefore is this invention focused on large multiwafer MOCVD reactors. This invention improves the quality of the quantum well, as measured by photo-luminescence spectra and uniformity of wavelength radiation.

Abstract: A diode pumped, multi axial mode, intracavity doubled, intracavity tripled laser, includes at least two resonator mirrors defining a resonator cavity. A laser crystal and a doubling crystal are positioned in the resonator cavity. A tripling crystal is also positioned in the resonator cavity. A diode pump source supplies a pump beam to the laser crystal and produces a laser crystal beam with a plurality of axial modes that are incident on the doubling crystal. This produces a frequency doubled output beam. Further, a diode pumped, multi axial mode, intracavity nonlinearly-converted laser is provided and includes at least two resonator mirrors defining a resonator cavity, a laser crystal and a nonlinear conversion apparatus positioned in the resonator cavity. A nonlinear conversion apparatus is also positioned in the resonator cavity.

Abstract: Wavelength stability of an optical oscillator has been enhanced by feedback from an external position-sensing detector to control the position or tilt of an intracavity optical element, such as a mirror. The wavelength stability results from stabilization of the intracavity beam position relative to an aperture in the oscillator. The wavelength selectivity of the aperture results from incorporation of a dispersive element in the oscillator cavity that produces a mapping of wavelength to beam position at the aperture.

Abstract: A diode-pumped solid-state laser has been invented that provides long Q-switched pulses at high repetition rate with high stability. The laser incorporates Nd:YVO4 as the gain medium.

Abstract: A laser bar is soldered to a conventional microchannel copper heat sink whose coefficient of thermal expansion (CTE) is locally modified in the area where the laser bar is soldered to better match the CTE of the laser bar. A strip of ceramic material having a CTE lower than that each of the laser bar and of the copper heat sink is soldered to portions of the metallic heat sink located adjacently to the surface area on which the laser bar is located. The inclusion of the ceramic strips enables a laser bar having a nominal CTE of 6.6×10?6/K, to be soldered directly to a copper heat sink having a nominal CTE of 16.5×10?6/K without incurring thermal distortions at the interface that would limit the useful life of the laser bar.

Abstract: An optical system has a diode pump source, and a gain media made of a material with an anisotropic absorption. The gain media is cut at an angle to produce substantially polarization-independent absorption of a pump beam. An optical coupler is positioned between the diode pump source and the gain media. The optical coupler produces a pump beam that has substantially equal amounts of pump power along any two orthogonal axis that are orthogonal to the pump beam in the gain medium. The wavelength range allowed for the pump source is extended.

Abstract: A method and system are described aimed at substantially increasing the lifetime of sensitive optical elements subjected to high power laser radiation. The lifetime enhancement is accomplished by spatially distributing the laser beam spots both globally and locally according to algorithms that are custom tailored to the subject element as well as the system and application needs. The methods of the invention are particularly well-suited to non-linear crystals used to convert radiation from high repetition rate, diode-pumped laser systems into the UV spectral range, where lifetime requirements are particularly challenging. The methods of the invention further enable effective utilization of available experimental data characterizing the element's performance in combination with a stored library of preferred spot scanning patterns that may be executed on the surface of the element according to the selected algorithm.

Abstract: A wafer that is cleaved to provide a facet for a Fabry-Perot cavity is provided with Bragg gratings whose axes are offset by a small angle from the axis of the Fabry Perot cavity to offset the effect of the randomly uncontrollable location of the cleaved facet on the optical phase of the grating feedback.

Abstract: A laser system includes a pump source that produces a first output. The pump source has a feedback loop with a first summing junction and a first command that has step quantization or digitized set point. An output device is coupled to the pump source to receive the first output and produce a second output. A feedback loop is coupled to the first summing junction. The feedback loop includes a second summing junction coupled to at least a portion of the second output. The second summing junction receives a second command and provides an input to the first summing junction. The feedback loop reduces the step quantization from the first output to provide finer control step of a property of the second output.

Abstract: A laser apparatus includes a modelocked laser system with a high reflector and an output coupler that define an oscillator cavity. An output beam is produced from the oscillator cavity. A gain medium and a modelocking device are positioned in the oscillator cavity. A diode pump source produces a pump beam that is incident on the gain medium. A second harmonic generator is coupled to the oscillator cavity. A third harmonic generator that produces a UV output beam, is coupled to the second harmonic generator. A photonic crystal fiber is provided with a proximal end coupled to the laser system. A delivery device is coupled to a distal portion of the photonic crystal fiber.

Abstract: A method and apparatus are provided for in situ protection of sensitive optical materials from alternation or damage due to exposure to trace atmospheric components, during shipping, storage or operation. The sensitive optical material is disposed within an enclosure adaptable to be substantially sealed against the external atmosphere. A container, enclosing a sink material absorbing trace atmospheric components, is coupled to the enclosure by a gas permeable surface, which allows fast diffusion of the trace atmospheric component inside the enclosure to the sink material.

Abstract: A fiber optic clamp assembly for use with an ultra-precision translation stage to precisely align a fiber optical bundle with a laser diode mounted in a sealable enclosure, comprising a housing for receiving the fiber bundle, a flexible seal positionable between said housing and said enclosure; and a pressure collar for urging the seal against the enclosure, said collar being freely movable within the housing so as not to load the translation stage when the housing is being moved by the translation stage to align said bundle with said laser diode and thereafter being movable to compress the flexible seal without disturbing the alignment.

Abstract: A laser diode bar, solder preform and heat sink are assembled prior to reflowing the solder in a manner to prevent molten solder from being drawn by capillary action over the light emitting end of the diode bar. A recessed pin 30 locates the ends of the laser bar and solder preform with respect to an edge of the heat sink so that the laser bar and solder preform overhang the heat sink edge by respective amounts. When molten, the solder will not be drawn by capillary action to obscure the light emitting end of the laser diode bar.

Abstract: A DBR grating may be created in the cladding of a wafer by defining a non-gain window area, advantageously at the end of the wafer. The non-gain area may be defined either by removing all layers above the cladding layer at the window portion or, preferably, by halting the MOCVD process once the cladding layer has been created and by selectively removing from a portion of the cladding layer a protective coating, advantageously of SiO2, Si3N4, or a metal, to define the window area. A photo resist is applied, and the wafer is exposed to interfering laser beams to create a grating pattern in the photoresist, conveniently without the need for any particular effort to confine either the photoresist or the interfering beams solely to the window area. The photoresist is developed and an etchant used to transfer the pattern into the cladding layer.

Abstract: A laser diode stack includes a serially connected plurality of laser diode bars mounted on heat sinks. Connected in parallel with each laser diode is a respective safety diode which has a higher band gap than its associated laser diode. The safety diode remains nonconductive so long as the associated laser diode is operational. Should the laser diode fail in an open circuit condition, the respective safety diode responds to the open circuit voltage to restore continuity to the serially connected chan of laser diodes.

Abstract: In order to provide an improved heat transfer interface between an solid state device and a heat sink to which it is soldered, one or more “vents” are provided in the interface between the solid state device and the heat sink to prevent the entrapment of gases that could form solder voids. Advantageously, the provision of such vents in the interface surface geometry of the semiconductor may be effected by the use of appropriate masking and etching following the epitaxial regrowth process. Alternatively, the heat sink or a solder preform may be provided with suitable notches. The use of such “die-bond vents” also allows solder, after melting, to be forced under the chip by external gas pressure such that no solder voids are left.

Abstract: A micro-machining apparatus includes a mode-locked, infrared laser system with a high reflector and an output coupler that define an oscillator cavity which produces an output beam. A gain medium and a mode locking device are positioned in the oscillator cavity. A diode pump source produces a pump beam that is incident on the gain medium. A second harmonic generator is coupled to the oscillator cavity. A third harmonic generator is coupled to the second harmonic generator and produces a UV output beam. An output beam directing apparatus directs the output beam to a polymeric surface of an article. At least a portion of the polymeric material is micro-machined by the output beam.

Abstract: A wafer supporting a semiconductor structure having a material gain function that would preferentially support an Fabry-Perot laser mode at an unwanted wavelength &lgr;2 is provided with a second-order dielectric grating located sufficiently remotely from the high intensity optical field of the quantum well and the waveguide layers to receive just enough transverse mode energy to provide feedback to reduce the gain at &lgr;2 and support oscillation at a desired wavelength &lgr;1. More particularly, by locating the grating in an unpumped area not requiring epitaxial overgrowth and so as to provide a gain discrimination factor &Dgr;g≈0.1 cm−1 at the desired wavelength &lgr;1, the fraction of power lost to transverse mode radiation can be held to about 1% which is sufficient to provide stabilizing feedback without sapping too much energy from the longitudinal beam.

Abstract: A laser system includes a high reflector and an output coupler that define a laser oscillator, which produces a fundamental beam. A harmonic generator is positioned to receive at least a portion of the fundamental beam and produce a harmonic beam. The harmonic generator is configured to operate at a temperature selected to provide a least amount of change of a selected parameter of the harmonic beam for the longest period of time. Harmonic beam parameters can include the size and location of the harmonic beam waist, and the divergence of the harmonic beam.

Abstract: An optically pumped laser has a gain medium positioned inside of an optical resonator cavity and disposed about a resonator optical axis. An optical pumping source is positioned outside of the optical resonator cavity. A reflective coupler with a coupler body, and an interior volume passing therethrough is positioned proximal to the optical pumping source. Light from the pumping source passes into an entrance aperture of the reflective coupler to an exit aperture of the reflective coupler positioned distal to the optical pumping source. The interior volume of the reflective coupler is bounded by a reflective surface, an entrance aperture and the exit aperture, and is substantially transparent to radiation from the optical pumping source. The reflective surface has a high reflectivity matched to radiation from the optical pumping source.