Molecular Hydrogen Laser Pumped by a Relativistic Electron Beam.

The pumping mechanism of stimulated emission of radiation from molecular hydrogen pumped by a high power electron beam was studied. A fast rising, 10 nsec pulse of 10,000 A of 700 keV electrons is guided by a pulsed magnetic field of 2 to 15 kG through the hydrogen gas of pressure from 5 to 200 torr. Intense lasing action is observed in the vacuum ultraviolet region of the molecular hydrogen spectrum, i.e., in the Lyman band and the Werner band transitions similar to the previous molecular hydrogen laser experiments. There exist discrepancies in the pressure dependence of the laser output among the various reports, and it is explained in terms of the energy distribution of plasma electrons produced in the breakdown of the gas due to the high electric field induced by the fast-rising current pulse. Comparison is made between the transverse discharges and e-beam excitations, results favor the plasma electron hypothesis.