Exploration of Radiative Properties of Very Excited Atoms

摘要: Various experiments involving very excited atoms and millimetre-wave photons are described, including high-resolution spectroscopy of Rydberg transitions, Rabi nutation transient maser action between levels. The large number extremely narrow spectral lines observed throughout the spectrum provide a good ' calibration' scale levels Na Cs near ionization limit, which could be used for realization precise infrared frequency markers. observation signals an unusually small absolute reveals great strength atom to radiation coupling is clear indication that these as sensitive detectors. At more fundamental level, study masers provides test superradiance theory. Extrapolation investigation situation where single would exchange photon with resonant cavity considered. atoms, prepared by exciting valence electron state close atomic radiation. These also stable against spontaneous radiative decay, resulting in lines. In this paper, various aspects peculiar properties will described. field spectroscopy, absorption - or multiphoton processes has allowed us achieve mapping energy alkali determination quantum defects, fine a.nd hyperfine structures. Possible application metrology discussed. Another interesting aspect atoms' concerns coherent interaction cavities. Owing electric dipole moments states, atom-radiation strong, possibility observing induced numbers damping system interacting walls. If upper level transition mode, short pulse emitted process quite analogous superradiance. This effect low inversion threshold, about hundred being, at present stage experiment, enough observe emission. Reduction few ultimately unit seems accessible goal allow check laws electrodynamics on unfamiliar scale. All clearly indicate serve detectors amplifiers radiation, range efficient receivers high demand. Some applications detection technology considered conclusion review.