Heat-Pipe Bismuth Laser; Examination of Laser Action at 4722A in Bismuth Vapor
Final rept. 1 May 1973-31 Jan 1975
POLYTECHNIC INST OF NEW YORK BROOKLYN DEPT OF ELECTRICAL ENGINEERING AND ELECTROPHYSICS
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The possibility of producing efficient pulsed laser action at 4722A in the neutral atomic vapor of bismuth has been examined. The presence of a substantial fraction of dimers Bi2 molecules in the vapor of bismuth could prevent laser action by absorption of the 3067A Bi resonance line. This would not only reduce radiation trapping but would also produce dissociation of the dimers leaving one Bi atom in a metastable proposed lower laser level. Heat pipes were used to create a two temperature zone apparatus and thermally dissociate bismuth dimers. Double-pulses were used to produce discharge dissociation of bismuth dimers. The pressure and composition of bismuth vapor has been critically evaluated. A radial discharge was used to reduce the risetime of the excitation current pulse to approx. 25 nsec which is much shorter than the reciprocal of 5300000 sec, the best value for the 4722A transition probability. Absence of laser action at 4722A is believed due to competing processes within the bismuth atom.
- Lasers and Masers