11p-M-13 Synchronized Quantum Beat Echoes

Yukio Fukuda, Tuneo HASHI

Tomobumi Mishina, M. Tanigawa, Yukio Fukuda +1 more

正幸 谷川, 行男 福田, 正和 国友 +2 more

M. Tanigawa, Yukio Fukuda, T. Kohmoto +2 more

We report on a new type of sublevel echoes, synchronized-quantum-beat (SQB) echoes, generated by a successive application of two resonant light-pulse trains. The echoes are selectively generated for a sublevel pair whose frequency splitting is equal to an integral multiple of the repetition frequency of the light pulses. By using mode locked laser pulses tuned to the D(1) transition, we observed SQB echoes (and free induction decay) for all Zeeman and hyperfine transitions in the ground state of sodium atoms in low magnetic fields.

正幸 谷川, 行男 福田, 正和 国友 +1 more

M. Tanigawa, Yukio Fukuda, T. Hashi +2 more

We develop a new theoretical treatment that can explain, for the first time to our knowledge, unexpectedly strong synchronized-quantum-beat-echo (SQBE) signals that we previously observed in the ground state of sodium atoms. The SQBE is obtained by successive application of two light-pulse trains tuned to an optical transition under the condition that the pulse repetition frequency or that of one of its harmonics is equal to the separation of a ground-state sublevel pair. The theory is developed for weak optical pumping for which the duration of the light-pulse trains is much longer than the spontaneous decay time of the excited state. We show that the echo is formed effectively as a result of nonuniform depopulation from the sublevel pair to the other levels because of frequency-selective optical pumping during the rapid spontaneous decay of the excited state. Details of the experiment with sodium atoms are described also.