George T Lockard

US Patent:

57426325, Apr 21, 1998

Filed:

Sep 7, 1995

Appl. No.:

8/524861

Inventors:

Norman P. Barnes - Yorktown VA
Clyde A. Morrison - Wheaton MD
Elizabeth D. Filer - Poquoson VA
Mahendra G. Jani - Poquoson VA
Keith E. Murray - Newport News VA
George E. Lockard - Newport News VA

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

H01S 314

US Classification:

372 68

Abstract:

A laser host material LuLF (LuLiF. sub. 4) is doped with holmium (Ho) and thulium (Tm) to produce a new laser material that is capable of laser light production in the vicinity of 2. mu. m. The material provides an advantage in efficiency over conventional Ho lasers because the LuLF host material allows for decreased threshold and upconversion over such hosts as YAG and YLF. The addition of Tm allows for pumping by commonly available GaAlAs laser diodes. For use with flashlamp pumping, erbium (Er) may be added as an additional dopant. For further upconversion reduction, the Tm can be eliminated and the Ho can be directly pumped.

US Patent:

53553837, Oct 11, 1994

Filed:

Dec 3, 1992

Appl. No.:

7/988082

Inventors:

George E. Lockard - Newport News VA

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

H01S 300

US Classification:

372 38

Abstract:

The present invention detects prelasing in a Q-switch laser and terminates laser operation upon such detection. A detector senses the presence of light beyond a Q-switch and generates an appropriate electrical signal. A comparison stage circuit compares this detector signal with an established threshold value indicative of prelasing and generates a trigger signal if this detector signal exceeds this threshold value. A control stage circuit receives both this trigger value and a sampled Q-switch signal indicative of an opening of the Q-switch. The control stage circuit terminates operation of the laser if the trigger signal from the comparison stage is received while the sampled Q-switch signal is being received to avoid the effects of prelasing. Appropriate delays and timing sequences are established.

US Patent:

20150104193, Apr 16, 2015

Filed:

Nov 21, 2014

Appl. No.:

14/550028

Inventors:

- Washington DC, US
Larry B. Petway - Hampton VA, US
Farzin Amzajerdian - Yorktown VA, US
Bruce W. Barnes - Yorktown VA, US
George E. Lockard - Newport News VA, US
Glenn D. Hines - Yorktown VA, US

International Classification:

H04B 10/556
H04B 10/2575

US Classification:

398187

Abstract:

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

US Patent:

20140334830, Nov 13, 2014

Filed:

Jun 20, 2012

Appl. No.:

13/527638

Inventors:

Diego F. Pierrottet - Poquoson VA, US
Larry B. Petway - Hampton VA, US
Farzin Amzajerdian - Yorktown VA, US
Bruce W. Barnes - Yorktown VA, US
George E. Lockard - Newport News VA, US
Glenn D. Hines - Yorktown VA, US

Assignee:

U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC

International Classification:

H04B 10/548

US Classification:

398187

Abstract:

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.