Observation of Stark-Induced Electric Dipole Transition in Atomic Samarium with Optical Double Resonance

The Stark-induced electric dipole ( E 1) transition for a high-lying odd-parity level in atomic samarium (Sm) was observed with an optical double-resonance technique as a preliminary study for measuring parity nonconservation (PNC). While a pump laser was locked to an E 1 transition from the 0-cm -1 to 15650.55-cm -1 levels, a probe laser was tuned to the parity forbidden transitions under static electric field. For the probe transition from the 15650.55-cm -1 to 28233.08-cm -1 levels, we have observed the Stark-induced E 1 transition. In order to investigate the contribution of the 28233.08-cm -1 level to the Stark-induced E 1 transition, the tensor polarizability was measured. We have found that the observed Stark-induced E 1 transition is anomalously strong compared with the one estimated from α 2 and an E 1 transition measured as a reference. The transition is one of candidates for improving the precision of the PNC measurements.