Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Single-atom experiments and the test of fundamental quantum physics
HERBERT WALTHER
Abstract
The work on the one-atom maser is reviewed. The superconducting maser cavity made of niobium and cooled to 0.5 K to exclude thermal photons has a quality factor of 3 X 1010. Velocity-selected Rydberg atoms pump the maser. The field inside the cavity is investigated by probing the atoms leaving the cavity. The dynamics of the Rabi nutation were investigated. Furthermore, the statistics of the photons in the cavity were determined to be sub-Poissonian corresponding to photon-number fluctuations of 70% below the vacuum-state limit. The one-atom maser is the only maser system which leads to nonclassical radiation even when pumping processes with Poissonian statistics are used. Some applications of the one- atom maser to study the quantum measurement process also are discussed.