Raytheon Company

Laser Analytics, Inc.

Richard S Eng

Kenneth W Nill

David L Wall

Arlan W Mantz

Clifford E Morrow

Dudley M Chapman

A laser is provided comprising a laser envelope and a gain medium disposed in the laser envelope. The gain medium comprises a compound subject to dissociation into a plurality of components. Circuitry is included for generating an electrical discharge in the laser envelope, a portion of the electrical discharge passing through the gain medium and disassociating a portion of the compound thereof into the plurality of components. The discharge generating circuitry comprises a cathode, the cathode comprising a first portion for emitting the electrical discharge toward an anode. Such first portion comprises a catalyst for aiding the recombination of the dissociated plurality of components. The first portion of the cathode sputters particulates therefrom during the electrical discharge and a surface is disposed within the laser envelope for collecting the sputtered particulates. Means, including a second portion of said cathode, are additionally provided for spacing the first portion of the cathode sufficiently from the collecting surface to substantially prevent the electrical discharge from being emitted from the first portion to the collected particulate, and thereby constrain the electrical discharge to occur substantially directly between the cathode and the anode. With such arrangement, the sputtered particulates are inhibited from entering the resonant cavity of the laser and adhering to the optics thereof. Thus, the useful operating life of the laser is increased.

Hybrid cathode

A scanning spectrometer incorporating a scanning diode laser powered with a controllable injection current. The injection current control may be set at predetermined discrete levels. These levels may be varied in accordance with signals derived from a servo loop, and may have superimposed upon them a cyclically varying substantially constant amplitude current. The laser output is directed via a beam splitter to both sample and reference cells. The material in the reference cell is so selected as to provide absorption features at each of the desired frequencies. The cyclically varying current is provided with an amplitude sufficient to cause a frequency amplitude at least as great as the maximum breadth of each of these spectral features of interest. The preselected bias currents are selected so as to provide lasing action of the diode at or near each of the selected frequencies. A phase-locked amplifier tuned to the frequency of the cyclically varying current senses the position of the scanned laser output relative to that of the associated absorption feature and provides an error signal to adjust the bias current so as to center the cyclically scanned laser frequency on the selected absorption feature.

Scanning laser spectrometer

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Newton, MA, United States of America

Richard S Eng