Rydberg atoms and radiation. Report for January-December 1986

The authors achieved their initial goal in the study of basic radioactive processes using Rydberg atoms - the observation of inhibited spontaneous emission. An experiment was carried out demonstrating that spontaneous emission can be effectively turned off. The underlying principle is that spontaneous emission results from the radioactive coupling between matter and a continuum of vacuum states. However, the assumptions underlying the conventional calculation of the density of modes in free space are not always valid. In particular, cavities can dramatically effect spontaneous emission. Such effects are difficult to observe in the optical regime because of the problem of making good fundamental mode cavities at short wavelengths. Excellent cavities can be made at microwave wavelengths, but spontaneous emission is enhanced by a factor of n4 where n is the principal quantum number, allowing such effects to be studied.