The United States of America As Represented by the Administrator of the

United States of America As Represented by the Administrator of Nasa

George E Lockard

Farzin Amzajerdian

Diego Fernando Pierrottet

Bruce W Barnes

Glenn D Hines

Larry B Petway

Norman P Barnes

Clyde A Morrison

Mahendra G Jani

Keith E Murray

Elizabeth D Filer

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.

System and method for generating a frequency modulated linear laser waveform

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.

Ho:LuLF and Ho:Tm:LuLF laser materials

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.

Method and apparatus for detection and control of prelasing in a

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Newport News, VA, United States of America

George E Lockard