Experimental and theoretical studies of Rydberg masers-quantum-electronic devices which produce and employ microwave radiation from highly excited atoms in a cavity-are reviewed. The experimental results are based mainly on studies performed by S. Haroche's group in Paris and H. Walther's group in Munich. In contradistinction to the usual quantum generators the quantum properties of the electromagnetic field itself play an important role in the analysis of the behavioral dynamics of Rydberg masers. The most striking results obtained in this field are the discovery of ``quantum revival'' and the achievement of maser generation on two-photon transitions and Fok states of the electromagnetic field.

RT Journal
T1 Spontaneous and induced emission of a Rydberg atom in a cavity
A1 Beterov,I.M.
A1 Lerner,P.B.
PB Physics-Uspekhi
PY 1989
FD 10 Dec, 1989
JF Physics-Uspekhi
JO Phys. Usp.
VO 32
IS 12
SP 1084-1110
DO 10.1070/PU1989v032n12ABEH002784
LK https://ufn.ru/en/articles/1989/12/c/