Studies of the metastable c³Π_u state of H ₂: Towards a two-photon amplifier

Significant populations in the metastable c3Πu manifold of H2 can be obtained in a pulsed discharge. This manifold potentially could serve as the upper state for two-photon stimulated emission to the autodissociating b3∑u+ level. To evaluate this possibility, studies of the population densities and quenching times of some of these levels have been made using pulsed laser techniques. A peak density of 1012/cm3 in the c3Π u manifold was measured, with observed quenching times of approximately 10 nsec. Similar densities were observed in the a 3∑g+ manifold. This state could potentially be utilized to produce one-photon stimulated emission a→b, tunable from 2 to 7 eV. The spectral dependences of both one- and two-photon cross sections were calculated. It was found that the two-photon cross section c→b peaks at 1.3 eV with a value of ∼10-52 cm4sec while the one-photon cross section a→b peaks at 3 eV with a value ∼3×1018 cm2. © 1978 American Institute of Physics.