Search for Paired Superradiance Using Metastable State of Atomic Barium

Shigeyuki Ishii, Wolfgang Ohlendorf

Nicolai G. Basov

Chiaki Ohae, Atsushi Fukumi, Susumu Kuma +10 more

We describe in this paper a fast and efficient method of producing a high density of barium (Ba) atoms in the 1D2 metastable state, which is a candidate initial state for a new class of cooperative and coherent optical process called paired superradiance (PSR). In the experiment, Ba atoms are excited first by laser light to the 1P1 state and then brought to the desired state 1D2 via radiative transition in the superradiance (SR) mode. It is found that a production efficiency (from 1S0 to 1D2) of more than ∼30% is achieved within a time interval of a few nanoseconds for a Ba density n > 1019 m−3. Several key features of SR important for future PSR experiments are also studied.

Anatoly A. Isaev, P. I. Ishchenko, Gueorgii G. Petrash

Satoshi Uetake

C. Gabbanini

A DFB diode laser at 1.500 μm has been applied to monitor absorption of the 5d6s 1D2 metastable state of barium in a hollow cathode lamp. The laser has been used to repump barium atoms from the metastable state in a thermal atomic beam. Suitable repumping schemes are discussed in order to implement efficient laser cooling of barium.