Laser for high frequency modulated interferometry

Patent · 31 December 1990

OSTI ID:867920

Mansfield, Dennis K ^[1]; Vocaturo, Michael ^[2]; Guttadora, Lawrence J ^[3]

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1. E. Windsor, NJ
2. Columbus, NJ
3. Iselin, NJ

A Stark-tuned laser operating in the 119 micron line of CH.sub.3 OH has an output power of several tens of milliwatts at 30 Watts of pump power while exhibiting a doublet splitting of about ten MHz with the application of a Stark field on the order of 500 volts/cm. This output power allows for use of the laser in a multi-channel interferometer, while its high operating frequency permits the interferometer to measure rapid electron density changes in a pellet injected or otherwise fueled plasma such as encountered in magnetic fusion devices. The laser includes a long far-infrared (FIR) pyrex resonator tube disposed within a cylindrical water jacket and incorporating charged electrodes for applying the Stark field to a gas confined therein. With the electrodes located within the resonator tube, the resonator tube walls are cooled by a flowing coolant without electrical breakdown in the coolant liquid during application of the Stark field. Wall cooling allows for substantially increased FIR output powers. Provision is made for introducing a buffer gas into the resonator tube for increasing laser output power and its operating bandwidth.

• Research Organization: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ
• DOE Contract Number: AC02-76CH03073
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5034952
• OSTI ID: 867920
• Country of Publication: United States
• Language: English

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119
30
500
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changes
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coolant
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introducing
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