Coherent, Inc.

New Focus, Inc.

Gooch and Housego Plc

Murray Keith Reed

Sergei V Govorkov

Luis A Spinelli

Andrea Caprara

Juan L Chilla

R Russel Austin

William Eugene White

Carter F Hand

Guangzhi Z Zhang

John Roderick Lincoln

William K Bischel

Andrei Starodoumov

Daniel K Negus

Alejandro Dario Farinas

H Yang Pang

Andrew C Davidson

Weizhi Wang

Briggs Atherton

Alexander O W Wiessner

Mark Wippich

Robert C Eckardt

David Robinson

A wavelength convertor includes a beam splitter which splits a pulsed laser beam at wavelength &#x3bb;into a first higher power pulse portion and a second low power pulse portion. A fiber super continuum (SC) generator is coupled to receive the second pulse portion which converts the second pulse portion into a SC pulse having a bandwidth of &#x3e;100 nm including a narrow spectral portion at wavelength &#x3bb;. An optical parametric amplifier (OPA) having a periodically poled material is included with domains arranged to provided quasi-phase matching for amplification at &#x3bb;and pumping at &#x3bb;. The arrival of the SC pulse portion at &#x3bb;and the first pulse portion at the OPA is synchronized to overlap in time. The OPA is seeded by the SC pulse portion at &#x3bb;and pumped by the first pulse portion to provide an amplified OPA seed at &#x3bb;.

Pulsed fiber laser wavelength convertor

An original laser-radiation beam having a symmetrical Mbut poor beam quality is sliced in one transverse axis, by a fanned-out stack of parallel transparent plates, into a plurality of beam slices. The beam-slices are also spread by the stack of plates in another transverse axis perpendicular to the first axis. A fanned-out stack of glass blocks aligns the spread beam-slices in the first axis to form what is effectively a single beam having an asymmetric M, with beam quality improved in one axis and degraded in the other compared with the original beam. The effective single beam is projected into a line of radiation by a cylindrical lens, or by a homogenizing projector including spaced apart cylindrical lens arrays followed by a spherical condenser lens.

Laser beam transformer and projector having stacked plates

A projection video display includes a light source including an OPS-laser delivering laser radiation in multiple transverse modes (a multiple-transverse-mode OPS-laser). The display includes a spatial light modulator for spatially modulating the radiation from the multiple-transverse-mode OPS-laser in accordance with a portion of an image to be displayed. Projection optics project the spatially modulated light on a screen on which the image is to be displayed. In one example the OPS-laser is a diode-laser array pumped OPS-laser and is one of three lasers, one delivering red light, one delivering blue light, and the other delivering green light. The lasers are time modulated such that the spatial light modulator receives light from each of the lasers separately. The OPS laser is directly time modulated by periodically turning the diode-laser array on and off.

Laser illuminated projection displays

A projection video display includes at least one laser for delivering a light beam. The display includes a beam homogenizer and a condenser lens. A scanning arrangement is provided for scanning the light in beam in a particular pattern over the condenser lens in a manner that effectively increases the beam divergence. The scanned beam is homogenized by a beam homogenizer and a spatial light modulator is arranged to receive the homogenized scanned light beam and spatially modulate the beam in accordance with a component of an image to be displayed. Projection optics are projecting the homogenized scanned light beam onto a screen. The scanning provides that the homogenized scanned light beam at the screen has a coherence radius less than the original coherence radius of the beam. The reduced coherence radius contributes to minimizing speckle contrast in the image displayed on the screen. The screen includes one or more features providing a further contribution to minimizing speckle contrast in the displayed image. In one example, the screen includes a transparent cell containing a liquid having light scattering particles in suspension.

A fiber laser including doped-core fiber having inner and outer cladding is optically pumped by plurality of diode-lasers. Light emitted by the diode-lasers is coupled into a single multimode optical fiber. Light from the multimode optical fiber is directed to a wavelength selective reflecting device that is partially reflective in a narrow reflection band about a peak reflection wavelength. A portion of the light having the peak reflection wavelength is reflected from the wavelength selective reflecting device back along the multimode optical fiber and back into the plurality of diode-lasers. This locks the emitting wavelength of the light emitted from each of the diode-lasers to the peak reflection wavelength. Light at the emitting wavelength that is not reflected from the wavelength selective reflective device is coupled into the inner cladding of the doped-core fiber for optically pumping the fiber laser.

Wavelength stabilized diode-laser array

An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

Optical pulse duration extender

A laser apparatus and method that provide for suppression of source spontaneous emission (SSE) and amplified spontaneous emission (ASE) light in laser output with minimal intracavity loss. The apparatus comprises a gain medium emitting a light beam, a wavelength element positioned in the light beam, and a non-reciprocal pickoff positioned in the light beam between the gain medium and wavelength element. The non-reciprocal pickoff may comprise a polarization-dependent beam splitter and a non-reciprocal polarization rotator positioned in the light beam before the wavelength selection element. The non-reciprocal pickoff may further comprise a reciprocal polarization rotator positioned in the light beam after the polarization-dependent beam splitter. The method may comprise emitting a light beam from a gain medium outward along an optical path, allowing the outward light beam to interact with a tunable element, returning a spectrally cleaned light beam along the optical path to the gain medium from the tunable element, and non-reciprocally picking off a portion of the returning, spectrally cleaned light beam from the optical path and directing the portion along an output path.

External cavity laser with high spectral purity output

An optically-pumped semiconductor (OPS) laser includes a multilayer structure including a mirror-structure surmounted by a multilayer semiconductor gain-structure. A membrane mirror is spaced apart from the mirror structure to form a laser resonator between the mirror structure and the membrane mirror, with the gain-structure included in the laser resonant cavity. Pump light is transmitted through the membrane mirror into the gain structure. The membrane mirror includes a grating having parameters selected such that the membrane mirror has different reflectivities at the wavelength of the laser in two orthogonally-oriented planes of polarization. The membrane mirror is axially movable along the resonator axis for varying the resonator length to select the wavelength of the single lasing mode.

Tunable optically-pumped semiconductor laser including a polarizing resonator mirror

A laser apparatus and method with compact cavity design that provides suppression of source spontaneous emission (SSE) and amplified spontaneous emission (ASE) light with minimal loss. The laser comprises a gain medium emitting a light beam along an optical path, a tuning element positioned in the optical path and configured feed back light of a selected wavelength to the gain medium and configured to define a first output beam directed along a first output path, a partial reflector located in the optical path and positioned to create a second output beam directed along a second output path substantially parallel to the first output path; and having a spontaneous emission component that is spatially separated from the selected wavelength. The second output beam can be coupled into optical fiber and produce a coherent light source with high spectral purity and tunable wavelengths.

Tunable laser with suppression of spontaneous emission

Apparatus for transporting a laser-pulse from a pulsed-laser to a receiver includes a pulse-expander, an optical-fiber, and a pulse-compressor. The pulse-expander is arranged to receive and temporally-expand the laser-pulse from the pulsed laser. The optical-fiber at its proximal end to receive the laser-pulse from the pulse-expander and transport the laser-pulse to the pulse-compressor. The pulse-compressor is arranged to receive the laser-pulse from the optical-fiber, temporally-compress the laser-pulse, and deliver the laser-pulse to the receiver. The pulse-compressor includes a block of optically-dispersive material, the temporal-compression being effected by an optical arrangement that causes the laser-pulse to follow a zigzag path through the block of optically-dispersive material. The pulse-expander may be arranged to provide variable third-order dispersion of a laser-pulse being expanded. The pulse compressor may be included in a handpiece attached to the distal end of the optical-fiber.

Apparatus for ultrashort pulse transportation and delivery

An ultrafast laser providing short output pulses having a pulse length in the femtosecond range includes a resonant cavity including a plurality folding mirrors for folding the resonant cavity to shorten its overall length. The fold-mirrors each include a plurality of layers deposited by ion-beam sputtering onto a substrate having a surface roughness of less than about 0.5 nanometers RMS. One or more of the folding mirrors may have a negative-group-velocity-dispersion mirror for allowing the laser to operate in a pulsed mode with pulses having a length of less than 500 femtoseconds.

Ultrafast laser with multiply-folded resonant cavity

A system is disclosed for minimizing the depolarization of a laser beam due to thermally induced birefringence in a rod-shaped gain medium over a wide range of excitation levels. After passing through the gain medium, the polarization of the beam is rotated by ninety degrees and either redirected back into the same gain medium or a substantially identical gain medium. By this arrangement, the portion of the beam that was radially polarized during the first pass is tangentially polarized during the second pass so that the original polarization is restored. In order to maximize the compensation, a relay image system is used to generate an image of the beam in the gain medium as it existed during the first pass and project that image into the gain medium during the second pass. The magnification of the relayed image is substantially one to one with respect to the actual image. By using a relayed image with a unity magnification, the size of the beam and the angle and the position of the rays in the beam are preserved at varying thermal loads. In this manner, maximum coincidence of the rays during the two passes is achieved. In the case of asymmetric pumping, performance can be enhanced by inverting the image of the beam prior to the second pass through the gain medium. The subject system is particularly useful for maximizing the fidelity of a phase conjugate reflector used in a solid state amplifier.

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Menlo Park, CA, United States of America

Murray Keith Reed