Atsushi Fukumi    Department   Kawasaki University of Medical Welfare  ,    Position   Associate Professor
Article types	原著
Language	English
Peer review	Peer reviewed
Title	Production of Ba Metastable State via Superradiance
Journal	Formal name：Journal of the Physical Society of Japan Abbreviation：J. Phys. Soc. Jpn
Volume, Issue, Page	83(4),pp.044301-1-044301-9
Author and coauthor	Chiaki Ohae, Atsushi Fukumi, Susumu Kuma, Yuki Miyamoto, Kyo Nakajima, Itsuo Nakano, Hajime Nanjo, Noboru Sasao, Satoshi Uetake, Tomonari Wakabayashi, Akihiro Yoshimi, Koji Yoshimura, and Motohiko Yoshimura
Publication date	2014/04
Summary	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 > 1019m-3. Several key features of SR important for future PSR experiments are also studied.