David M Cohn

US Patent:

6516008, Feb 4, 2003

Filed:

Aug 9, 2000

Appl. No.:

09/634216

Inventors:

David B. Cohn - Torrance CA

Assignee:

Raytheon Company - Lexington MA

International Classification:

H01S 310

US Classification:

372 22, 372 23, 359 28

Abstract:

A wavelength conversion system and method. The inventive system is adapted to receive a beam of input energy having a first spiked portion with a first wavelength and a first spatial and/or temporal intensity profile and a second tail portion with the first wavelength and a second spatial and/or temporal intensity profile. The inventive system includes an electro-optic switch ( ) and first polarizer ( ) for directing the first portion of the input beam along a first processing path ( ) and a second portion thereof along a second processing path ( ). A first SHG/OPO arrangement ( ) is disposed in the first path ( ) for shifting the wavelength of the first portion of the input energy from the first wavelength to a second wavelength. The first arrangement is optimized for the first spatial and/or temporal intensity profile of the first portion of the energy. A second SHG/OPO arrangement ( ) is disposed in the second path for shifting the wavelength of the second portion of the input energy from the first wavelength to the second wavelength.

US Patent:

8223815, Jul 17, 2012

Filed:

Jul 29, 2010

Appl. No.:

12/846422

Inventors:

David B. Cohn - Torrance CA, US

Assignee:

DBC Technology Corp. - Torrance CA

International Classification:

H01S 3/22
H01S 3/223
H01S 3/097

US Classification:

372 58, 372 55, 372 57, 372 83

Abstract:

A COgas flow laser with multiple discharge modules places acoustic baffles between the discharge modules to suppress shock waves and ions passing between the discharge modules such as may disrupt the optical path of the laser. A catalyst may be placed in a center of a toroidal recirculation chamber of the laser and may have integrated filters to prevent catalyst particulates from coating the chamber optical windows.

US Patent:

8416828, Apr 9, 2013

Filed:

Oct 8, 2010

Appl. No.:

12/901260

Inventors:

David B. Cohn - Torrance CA, US

Assignee:

DBC Technology Corp. - Torrance CA

International Classification:

H01S 3/22

US Classification:

372 59, 372 55

Abstract:

An array of discrete catalyst elements is contained in a heated module external to the main laser vessel with an auxiliary gas flow loop connecting them so as to provide independent control of catalyst temperature and gas flow rate to achieve high CO+1/2Oto COrecombination under high pulse repetition frequency operation for a sealed laser. Catalyst elements in the form of cylinders with holes through their centers are mounted on multiple parallel rods or catalysts in the form of small spherical or cylindrical elements are contained in multiple packets arranged in the module so as to minimize flow impedance and maximize laser gas recycling throughput. The cylindrical catalyst module is constructed so as to allow for rapid heating to operating temperature while withstanding atmospheric differential pressures during laser processing.

US Patent:

20120195342, Aug 2, 2012

Filed:

Jan 31, 2011

Appl. No.:

13/017739

Inventors:

David B. Cohn - Torrance CA, US

International Classification:

H01S 3/03

US Classification:

372 61

Abstract:

Multiple independent electrode sets of a COgas laser are arranged in series within a single optical resonator with each electrode set energized by an independent power source. The total length of the electrode sets together and their maximum power are optimized for output energy at the weakest laser wavelength, and one or several of the independent electrode sets is turned off and/or their power reduced to achieve laser output on strong lines without damage to the laser optics. The total resonator length is chosen to produce an output laser beam with single transverse mode.

US Patent:

47232552, Feb 2, 1988

Filed:

May 20, 1985

Appl. No.:

6/735908

Inventors:

David B. Cohn - San Pedro CA
Peter J. Mendoza - Wilmington CA

Assignee:

Northrop Corporation - Hawthorne CA

International Classification:

H01S 3097

US Classification:

372 87

Abstract:

An improved railgap switch for use with pulse discharge gas lasers. The blade of the prior art railgap switches is replaced by an electrode having an "T" shaped cross section which provides two edges along which arcs are generated. The thickness of the "T" cross section near the edges at which arcs are formed is relatively uniform and oriented at a constant distance from the second electrode so that the thickness and distance remains unchanged despite ablation of the edges of the electrode. As a consequence the electrical properties of the switch are not altered significantly by ablation caused by repetitive operation of the switch.

US Patent:

49907611, Feb 5, 1991

Filed:

Nov 30, 1988

Appl. No.:

7/277814

Inventors:

David B. Cohn - Torrance CA
Michael P. Hasselbeck - Redondo Beach CA
Gregory R. Sasaki - Long Beach CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01J 120

US Classification:

2502021

Abstract:

A radiation protection system is operative within an optical section of a radiation imaging system for protection of an array of detectors of the radiation. The protection system is formed of one or more spark boards arranged in series along a path of radiation propagation, the spark boards having a central window through which the radiation propagates. On a front side of each spark board are arranged a set of electrodes disposed about a periphery of the window. Ground pads are disposed on a back side of each board in registration with the electrodes on the front side to form therewith a set of capacitors. A capacitive-discharge power-supply circuit is connected to a first pair of electrodes in a first one of said boards. In the presence of excessive incident radiation power, a capacitor of the power supply circuit is switched to apply a high voltage across said first pair of electrodes, the voltage being high enough to initiate an arc across the window in said first board. The capacitors and electrodes are connected serially to allow a current of one arc to charge a succeeding capacitor which, upon being charged, initiates a further arc in a process which continues until all arcs have been struck.

US Patent:

46635688, May 5, 1987

Filed:

Mar 28, 1985

Appl. No.:

6/717219

Inventors:

David B. Cohn - San Pedro CA

Assignee:

Northrop Corporation - Hawthorne CA

International Classification:

H05B 3700

US Classification:

315163

Abstract:

An improved electrical gap switch for use with pulsed gas discharge lasers. The closure of a spark gap, railgap, or other multichannel switch is triggered by the application of a second voltage in combination with the primary voltage that is closed by the switch. The second voltage is of opposite polarity and applied to an electrode opposite from that to which the primary voltage is applied. The second voltage has a more rapid rise time than that of the first, and its application to the switch is momentarily isolated from the load by a saturable inductor. Following triggering of the switch by the combination of voltages, the inductor saturates and provides a low impedance path for the voltage and charge from the primary source to the load.

US Patent:

50200690, May 28, 1991

Filed:

Dec 18, 1989

Appl. No.:

7/452141

Inventors:

John A. McNeil - Los Angeles CA
David B. Cohn - Torrance CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H01S 322
B01J 2344

US Classification:

372 59

Abstract:

A catalyst for reacting carbon monoxide and oxygen to form carbon dioxide, comprising platinum black deposited on a platinum wire, and having a moderate activation temperature of about 150. degree. -300. degree. C. A catalytic apparatus includes this catalyst, means for directly heating the catalyst, and electronic means for controlling and monitoring the heating of the catalyst. Carbon dioxide laser systems incorporating this catalytic apparatus are also disclosed.