One-atom maser

Fig. 9.73 Schematic experimental setup for the one-atom maser with resonance cavity and state-selective detection of the Rydberg atoms [1294]...

Fig. 9.74 Experimental setup for experiments with the one-atom maser with three excitation lasers, cavity resonance microwave generation and a state-selective detection system...

The one-atom maser can be used to investigate the statistical properties of non-classical light [1298, 1299]. If the cavity resonator is cooled down to T < 0.5 K, the number of thermal photons becomes very small and can be neglected. The number of photons induced by the atomic fluorescence can be measured via the fluctuations in the number of atoms leaving the cavity in the lower level n — 1). It turns out that the statistical distribution does not follow Poisson statistics, as in the output of a laser with many photons per mode, but shows a sub-Poisson distribution with photon number fluctuations 70 % below the vacuum-state limit [1300]. In cavities with low losses, pure photon number states of the radiation field (Fock states) can be observed (Fig. 9.77) [1301], with photon lifetimes as high as 0.2 s At very low... 

G. Rempe, H. Walther, The one-atom maser and cavity quantum electrodynamics, in Methods of Laser Spectroscopy, ed. by Y. Prior, A. Ben-Reuven, M. Rosenbluth (Plenum, New York, 1986)... 

H. Walther, One atom maser and other experiments on cavity quantum electrodynamics. Phys. Usp. 39, 727 (1996)... 

In the following we will briefly review the most important properties of Rydberg atoms and then discuss the QED in a cavity and in the last chapter we will describe the present status of our one-atom maser experiment. 

Fig. 14.49. (a) Level diagram of the maser transition in rubidium. The transition frequencies are given in MHz. (b) Measured ion signal, which is proportional to the number of Rydberg atoms in level n), as a function of the cavity resonance frequency. Maser operation of the one-atom maser manifests itself in a decrease in the number of atoms in level n) [14.130]... 

G. Rempe, M.O. Scully, H. Walther The one-atom maser and the generation of nonclassical light . In Proc. ICAP 12, Ann Arbor (1990)... 

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