Vol. 25, issue 02, article # 13

Abstract:

Reports on the search and study of two-photon photoionization channels (TPSI) for bringing the first resonance level of ions alkaline earth (AE) and rare earth (RE) elements directly from the ground states of atoms. To increase the output of TPSI we used quasiresonance of pump with an intermediate level. Lasers were employed with either fixed or tunable wavelength. Installed a quadratic dependence of the generation rate of the ion lines of barium on the pump intensity carried out by XeCl* laser. The irradiation of barium vapor by radiation tuned near the intermediate level 6s7p¹P⁰₁, stimulated emission was observed at 6p²P⁰_3/2 → 5d²D_5/2 ( λ = 614.2 nm) and 6p²P⁰_3/2→6s²S_1/2 ( λ = 455.4 нм) transitions of barium ion. Established that when the pump intensity I_p ≤10⁶ W/cm² can search channels of DFSI with successful. This feature is a consequence of two-photon resonance with the pump autoionization states lying above the first resonant levels of ions. The mechanisms of competition between ionic and atomic lines of generation are discusses in article.

Keywords:

optical pumping, metal vapor lasers, photoionization, shifted state, nonradiative relaxation