Coherent, Inc.

United Technologies Corporation

United States of America As Represented by the Secretary of the Air Force

Demaria Electrooptics Systems, Inc.

Terabit Communications, L.l.c.

Anthony J DeMaria

John T Kennedy

Leon A Newman

Vernon A Seguin

Richard A Hart

Lanny Laughman

Joel Fontanella

Robert Henschke

R Russel Austin

Thomas W Grudkowski

Thomas M Reeder

Christian J Shackleton

Phillip J Gardner

James F Black

Luis A Spinelli

Peter P Chenausky

Eric R Mueller

Daniel H Grantham

Alexander J Shuskus

Meyer Gilden

Robert J Freiberg

David W Fradin

William F Bridges

Ronald Straayer

Vernon Sequin

A gas includes a housing having a symmetrical arrangement of upper and lower cooling members for removing heat generated in a gas-discharge excited by an electrode assembly. The electrode assembly is clamped between the cooling members and is itself essentially symmetrically arranged. The cooling members and the electrode assembly are mechanically isolated in the housing by a surrounding diaphragm-like arrangement that connects the cooling members to side-walls of the housing. An RF power-supply for supplying the electrode assembly is mounted on one of the sidewalls to avoid disturbing the symmetry of the cooling and electrode arrangements.

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A gas-discharge waveguide COlaser has a Z-shaped folded waveguide formed by three ceramic tubes. Ends of the adjacent tubes are shaped and fitted together to form a common aperture. The tubes are held fitted together by spaced-apart parallel discharge electrodes. Four minors are arranged to form a laser-resonator having a longitudinal axis extending through the tubes.

A gas-discharge waveguide COlaser has a Z-shaped folded waveguide formed by three ceramic tubes. Ends of the adjacent tubes are shaped and fitted together to form a common aperture. The tubes are held fitted together by spaced-apart parallel discharge electrodes. Four mirrors are arranged to form a laser-resonator having a longitudinal axis extending through the tubes.

A COlaser has a resonator mirror that oscillates about an axis perpendicular to the resonator axis through an angular range of oscillation sufficient that the resonator is only able to deliver radiation for a fraction of an oscillation period of the mirror. In one example of the laser, the oscillating mirror is an end-mirror of the resonator. In another example, the oscillating mirror is a fold mirror of the resonator.

A COlaser reference oscillator (RO) can provide injection seeding to a Q-switched (QS) or Q-switched cavity dumped (QSCD) COlaser, where the output frequency of the RO laser is locked to the peak of the laser line by the use of appropriate electronics to dither one of the resonator mirrors of the reference oscillator. This injected radiation seeds the radiation building up within the Q-switched laser cavity, such that the oscillating frequency favors the wavelength of the injected radiation. An electronic feedback control circuit can be used to lock an axial mode of the Q-switched laser to line center. The change in build-up time of the pulses within the QS laser can be used to maintain cavity length at a value that enables oscillating at the peak of the same laser line that is injected into QS laser.

A slab laser includes two elongated electrodes arranged spaced apart and face-to-face. Either one or two slabs of a solid dielectric material extend along the length of the electrodes between the electrodes. A discharge gap is formed either between one of the electrodes and one dielectric slab, or between two dielectric slabs. The discharge gap is filled with lasing gas. A pair of mirrors is configured and arranged to define a laser resonator extending through the gap. An RF potential is applied across the electrodes creating a gas discharge in the gap, and causing laser radiation to circulate in the resonator. Inserting dielectric material between the electrodes increases the resistance-capacitance (RC) time constant of the discharge structure compared with the RC time constant in the absence of dielectric material. This hinders the formation of arcs in the discharge, which enables the laser to operate with higher excitation power, higher lasing gas pressure, and higher output power than would be possible without the dielectric inserts.

An slab CO2 laser includes spaced-apart elongated slab electrodes. A lasing gas fills a discharge gap between the electrodes. An RF power supply is connected across the electrodes and sustains an electrical discharge in the lasing gas in the discharge gap. Either one or two ceramic inserts occupy a portion of width of the electrodes and in contact with the electrodes. A discharge gap is formed between the portions of the width of the electrodes not occupied by the insert or inserts. Provision of the ceramic insert or inserts increases the resistance-capacitance (RC) time constant of the electrode impedance by increasing the capacitive component of the time constant. This hinders the formation of arcs in the discharge, which, in turn enables the inventive laser to operate with higher excitation power or higher lasing-gas pressure than would be possible without the dielectric insert. The ceramic insert also decreases the difference in impedance of the electrodes with and without a discharge. This leads to a better-behaved discharge, and a discharge that is easier to light.

Multiple laser beams, each having a shape such as a Gaussian profile, can be incoherently combined to obtain a shaped, flat top laser beam. The combined laser beams can provide power levels necessary for material processing applications such as annealing, drilling, and cutting, while minimizing the amount of unused power. The lasers can be positioned in an array in order to shape the flat top beam, and can be staggered in position where necessary to give each output beam an equal beam path length. The relative frequencies and/or powers of the lasers can be adjusted to control the flatness and stability of the incoherently combined beam.

Systems and methods for forming a laser beam having a flat top

An electro-optical switch includes an optical assembly arranged to transmit laser-radiation. The optical assembly comprises an active optical crystal. On one of two opposite surfaces of the crystal is an optical window formed from a material having a refractive index lower than the material of the crystal. Heat deposited, as a result of transmission of the laser-radiation, at the surface of the crystal in contact with the widow is transferred to the window, thereby reducing the potential for optical damage to the crystal surface. The window is sufficiently thick that it has an odd integer multiple of quarter-wavelengths optical thickness at a wavelength about equal to a wavelength of the laser-radiation, thereby behaving as an antireflection device for the crystal at that wavelength. In one embodiment of the optical assembly, the active optical crystal is a cadmium telluride crystal and the window is formed from cesium bromide.

This disclosure discusses techniques for obtaining wavelength selected simultaneously super pulsed Q-switched and cavity dumped laser pulses utilizing high optical damage threshold electro-optic modulators, maintaining a zero DC voltage bias on the CdTe electro-optic modulator (EOM) so as to minimize polarization variations depending on the location of the laser beam propagating through the CdSe EOM crystal, as well as the addition of one or more laser amplifiers in a compact package and the use of simultaneous gain switched, Q-switched and cavity dumped operation of COlasers for generating shorter pulses and higher peak power for the hole drilling, engraving and perforation applications.

Q-switched, cavity dumped laser systems for material processing

A laser includes a gain medium located in a laser resonator. The gain medium generates plane polarized radiation plane polarized in a first polarization orientation. An electro-optical switch is located in the resonator. When the switch is activated the polarization plane of the laser radiation is rotated to a second orientation after making a forward and a reverse pass through the optical switch. When the switch is deactivated, the polarization orientation of the forward and reverse transmitted laser radiation remains about the same. A polarization selective device is located in the resonator between the electro-optical switch and the gain medium. The polarization selective device is arranged to permit circulation in the resonator of laser radiation in the first polarization orientation, and to restrict circulation of laser radiation in the second polarization orientation. The Gain medium is energized and the switch activated to allow energy to build in the gain medium. The switch is then deactivated to allow laser radiation to circulate in the resonator and deliver a laser pulse. A method of activating the switch by a sequence of DC pulses is disclosed.

A waveguide gas laser includes an enclosure filled with a lasing gas. A ceramic block is provided with one or more waveguide channels. At least one of the waveguide channels includes an open region which is in fluid communication with a waveguide channel. Lasing gas in the enclosure fills the waveguide channels and the lateral extension. An electric field is applied across the lateral extension of the waveguide channel while simultaneously applying a smaller electric field across the waveguide channel. The electric field across the lateral extension ignites a discharge in the lateral extension that spreads into the lasing gas in the waveguide channel. The electric field across the waveguide channel is sufficient to sustain the discharge in the lasing in the waveguide channel.

A simultaneously super pulsed Q-switched CO laser system for material processing is disclosed. The system comprises sealed-off folded waveguides with folded mirrors that are thin film coated to select the output wavelength of the laser. The system also comprises a plurality of reflective devices defining a cavity; a gain medium positioned within the cavity for generating a laser beam; a cavity loss modulator for modulating the laser beam, generating thereby one or more laser pulses; a pulsed signal generation system connected to the cavity loss modulator for delivering pulsed signals to the cavity loss modulator thereby controlling the state of optical loss within the cavity; a control unit connected to the pulsed signal generation system for controlling the pulsed signal generation system; and a pulse clipping circuit receptive of a portion of the laser beam and connected to the pulsed signal generation system for truncating a part of the laser pulses.

Q-switched CO2 laser for material processing

A folded waveguide CO laser includes a plurality of waveguides arranged in a zigzag pattern with ends thereof overlapping. The laser includes a resonator having an axis extending through the plurality of waveguides. At least a portion of at least one of the waveguides has a uniform minimum width selected cooperative with the height of the waveguide and the laser wavelength such that the resonator can oscillate in only a single mode. At least a portion of one of the waveguides is tapered such that its width increases in one direction along the resonator axis. Tapering one or more of the waveguides provides that the total waveguide area and potential power output of the laser is greater than that of a zigzag arrangement of waveguides having the same total length waveguides each having a uniform width equal to the minimum width of the waveguide in the tapered waveguide arrangement.

Folded tapered-waveguide CO2 laser

The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by a laser of the present invention. In accordance with the present invention the laser comprises a housing defining a plurality of compartments therein, a folded waveguide disposed within the housing, the folded waveguide defining a plurality of channels having a substantially rectangular cross section for guiding a laser beam, a plurality of electrodes disposed in the plurality of compartments and juxtaposed along opposite surfaces of the waveguide and at least one power supply connected to the plurality of electrodes. The channels having a prescribed width to height ratio for a prescribed channel length for a given Fresnel number. At least one optical housing is provided. The optical housing is mounted to the laser housing, the optical housing including a plurality of beam turning mechanisms disposed within a plurality of compartments accessible for adjusting the beam turning mechanisms. The channels are disposed within the waveguide so as to subtend a prescribed angular orientation between adjacent channels. Inductors are provided for suppressing the capacitance of the electrodes.

Growing community of inventors

West Hartford, CT, United States of America

Anthony J DeMaria