Study of opto-galvanic effect in two-photon transition

K. Naveedullah, Athar S. Naqvi

Robert G. W. Brown

Dimo Zhechev, Vasilka Steflekova

The opto-galvanic response of some degenerate states of sputtered atoms to linearly- and circularly polarize light is studied. On the same optical transition both time-resolved- and amplitude opto-galvanic signals are found depending on the polarizations of light absorbed. The latter induces galvanic responses differing in opto-galvanic efficiency, time-evolution and sensitivity to discharge current and laser power. The differences are ascribed to the rate constants of the decay processes, characterizing aligned and oriented atoms.

Munir Hasan Nayfeh, Ali Hasan Nayfeh

Stephen V. Kershaw

Vasilka Steflekova, Dimo Zhechev

The degenerate Zeeman sublevels were found to contribute to the ionization in a gas discharge in accordance with their coherent state. The voltage across the discharge was monitored while the same ensemble of excited atoms was alternately self-aligned ↔ nonaligned or oriented ↔ aligned. In the latter case, the coherence was optically induced; the corresponding opto-galvanic signals, i.e. amplitude- and time-resolved ones, were compared. Each state of the ensemble of degenerate Zeeman sublevels, i.e. (self-) aligned, oriented or disordered was characterized by its own rate of ionization. Various hollow cathode discharge (HCD) media were studied, namely, Ne/As, Ne/Cu, Ne/Ni, Ne/Cd, Ne/Li and Ne/Si in the corresponding commercial HCD spectral lamps.