Coherent, Inc.

Luis A Spinelli

Andrea Caprara

Sergei V Govorkov

Juan L Chilla

R Russel Austin

Murray Keith Reed

Douglas W Anthon

Daniel K Negus

Briggs Atherton

Norman Hodgson

William Eugene White

Jay Michael Ingalls

John D Minelly

Anthony J DeMaria

Vernon A Seguin

Sol Peter DiJaili

Michael Hertwig

Gary Y Wang

Arnaud Lepert

Hailong Zhou

Timothy J Johnston

Bernard J Couillaud

Mark M Gitin

Andrei Staroudoumov

Gilles A Feugnet

An optical parametric oscillator includes one unidirectional enhancement resonator for optical pump-radiation and a second unidirectional resonator at least partially coaxial with the enhancement resonator. An optically nonlinear crystal is located in the coaxial portion of the resonators and converts the optical pump-radiation to signal radiation having a wavelength longer than that of the pump radiation and idler radiation having a wavelength longer than that of the signal radiation. The second resonator resonates the signal-wavelength radiation and delivers a fraction of that radiation as output radiation.

Optical parametric oscillator with embedded resonator

A CW fiber-laser includes a gain fiber having a reflector proximity-coupled to one end, with the other end left uncoated. A laser resonator is defined by the reflector and the uncoated end of the gain-fiber. Pump-radiation from two fast-axis diode-laser bar stacks is combined and focused into the uncoated end of the gain-fiber for energizing the fiber. Laser radiation resulting from the energizing is delivered from the uncoated end of the gain-fiber and separated from the pump-radiation by a dichroic mirror.

High-power CW fiber-laser

A CW ytterbium-doped fiber-laser includes a gain-fiber having a reflector proximity-coupled to one end, with the other end left uncoated. A laser resonator is defined by the reflector and the uncoated end of the gain-fiber. Pump-radiation from fast-axis diode-laser bar-stacks emitting at 915 nm and 976 nm is combined and focused into the uncoated end of the gain-fiber for energizing the fiber. Laser radiation resulting from the energizing is delivered from the uncoated end of the gain-fiber and separated from the pump-radiation by a dichroic mirror.

A gain-module for use in an OPS-laser includes a multilayer semiconductor gain-structure surmounting a multilayer compound mirror-structure. Within the multilayer compound mirror-structure is a relatively thick layer of diamond which serves as a heat-spreader.

Optically-pumped surface-emitting semiconductor laser with heat-spreading compound mirror-structure

A master oscillator power-amplifier stages includes multiple stages of fiber-amplification with a final power amplifier stage in the form of a multi-pass amplifier. With a thin-disk gain medium in one example the thin-disk amplifier includes a common optical arrangement for providing multiple incidences of radiation to be amplified and multiple incidences of a pump-radiation beam on the thin-disk gain medium.

Hybrid fiber-MOPA

In laser engraving apparatus for engraving a gray-scale image on a plastic ID-card, the laser is a modulatable optically pumped semiconductor laser. Focusing optics focus a beam from the laser into a focal spot about 10 micrometers in diameter. The ID-card is mounted on a turntable which is rotated such that the focal spot sweeps over the ID card. The turntable is translated in a direction transverse to the rotation direction and the laser is modulated such that the engraved gray-scale image is formed by a matrix of parallel black lines of various length and spacing.

Laser engraving apparatus

A method of printing labels includes supporting a laser sensitive material on a disc and printing label images on the disc with a modulated focused beam from a diode-laser. The label images may be printed in regions of the medium having pre-cut label boundaries. Alternatively, label boundaries may be cut through the medium using the focused laser beam. The labels are peeled from the disc after printing.

Method for providing a plurality of laser-printed labels from a medium supported on a disc

Laser apparatus is disclosed in which fundamental-wavelength optical pulses delivered from a mode-locked laser resonator at a pulse-repetition frequency (PRF) are converted to harmonic-wavelength pulses in an optical delay loop. One example is disclosed in which the harmonic-wavelength pulses are delivered directly from the delay loop. Another example is disclosed in which the harmonic-wavelength pulses are divided by the delay loop into a number of temporally spaced-apart replicas thereof, and the delay loop delivers bursts of replicas of different one of the harmonic wavelength pulses at a burst-repetition frequency equal to or a multiple of the PRF of the resonator.

Quasi-CW UV laser with low peak pulse-power

Multiple laser resonators share a common acousto-optic Q-switch. The Q-switch is driven by a radio-frequency (RF) transducer that causes an acoustic wave to propagate in the Q-switch. Turning off the RF transducer discontinues propagation of the acoustic wave and causes each of the laser resonators to deliver an optical pulse. The finite velocity of the acoustic wave causes the pulses to be delivered temporally spaced apart.

Multiple pulsed-laser system for silicon crystallization

Arrangements for combination and fast-axis alignment of fast-axes of diode-laser beams are disclosed. Alignment arrangements include providing each diode-laser with a corresponding alignable fast-axis collimating lens, providing individually alignable mirrors for steering an re-orienting beams from each diode-laser, and providing single diode-laser slab-modules in which the diode-laser beams can be pre-aligned to a common propagation-axis direction, and in which edges and surfaces of the slabs can be used to align the fast and slow-axes of the beams. Beam combination methods include combination by dichroic elements, polarization-sensitive elements, and optical fiber bundles.

High power and high brightness diode-laser array for material processing applications

External-cavity optically-pumped semiconductor lasers (OPS-lasers) including an OPS-structure having a mirror-structure surmounted by a surface-emitting, semiconductor multilayer (periodic) gain-structure are disclosed. The gain-structure is pumped by light from diode-lasers. The OPS-lasers can provide fundamental laser output-power of about two Watts (2.0 W) or greater. Intracavity frequency-converted arrangements of the OPS-lasers can provide harmonic laser output-power of about one-hundred milliwatts (100 mW) or greater, even at wavelengths in the ultraviolet region of the electromagnetic spectrum. These high output powers can be provided even in single axial-mode operation. Particular features of the OPS-lasers include a heat sink-assembly for cooling the OPS-structure, a folded resonator concept for providing optimum beam size at optically-nonlinear crystals used for frequency conversion, preferred selection of optically-nonlinear materials for frequency-conversion, and compound resonator designs for amplifying second harmonic-radiation for subsequent conversion to third or fourth harmonic radiation.

High-power external-cavity optically-pumped semiconductor lasers

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

Laser apparatus including two different, pulsed MOPAs, one having a fundamental wavelength of 1064 nm and the other having a fundamental wavelength of 1564 nm, provide trains of optical pulses. The 1064-nm pulses are frequency tripled to 355 nm and the 1564-nm pulses are frequency doubled to 782 nm. The 355-nm and 782-nm pulses are mixed to provide 244-nm pulses. The 244-nm pulses are mixed with residual 1064-nm pulses to provide 198-nm output pulses of the apparatus. The output pulses can be either digitally modulated or amplitude modulated by controlling the phase relationship between the 1064-nm and 1564-nm pulses.

MOPA laser apparatus with two master oscillators for generating ultraviolet radiation

A method of intracavity frequency conversion in a CW laser includes causing fundamental radiation to circulate in a laser resonator. The fundamental radiation makes a first pass through an optically nonlinear crystal where a fraction of the fundamental radiation generates second-harmonic radiation in a forward pass through the crystal. The residual fundamental radiation and the second-harmonic radiation are then sum-frequency mixed in forward and reverse passes through an optically nonlinear crystal such that a fraction of each is converted to third-harmonic radiation. The residual second-harmonic radiation and fundamental radiation from the sum-frequency mixing then make a reverse pass through the second-harmonic generating crystal where the second-harmonic radiation is converted back to fundamental radiation. The third harmonic radiation can be delivered from the resonator as output radiation, or can be used to pump another optically nonlinear crystal in an optical parametric oscillator. Second-harmonic radiation can also be used to pump an optical parametric oscillator.

Intracavity frequency-tripled CW laser

An optically pumped semiconductor pumped optical parametric oscillator (OPS-pumped OPO) includes an OPS laser resonator and an OPO resonator A portion the OPS laser resonator axis and the OPO resonator axis are collinear. An optically nonlinear crystal is located in the coaxial portion of the resonators and arranged to frequency divide fundamental radiation generated in the OPS laser resonator into signal and idler radiations. In one arrangement, the OPO laser resonator is also an OPS resonator and is arranged to generate radiation at the wavelength of the signal radiation, with the idler radiation having the difference-frequency wavelength of the signal and fundamental radiations.

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Sunnyvale, CA, United States of America

Luis A Spinelli