Stimulated emission spectroscopy of Rydberg matter: observation of Rydberg orbits in the core ions

Abstract

The short-wavelength bands generated in Rydberg matter (RM) formed by K atoms have been studied both in an operating laser cavity and by amplified emission in the RM, with higher resolution than previously. Transitions down to principal quantum number n′′≥6 in the core ions have been identified previously in the infrared range, while transitions down to n′′=5 and 4 are now observed for transitions of the type n′′=7→4. Efficient down-conversion of emitted wavelengths shorter than 800 nm is found in the RM medium in the cavity by a process similar to two-photon emission. From the good description of the transitions with just one quantum number n′′, it is concluded that the transitions studied are single-electron transitions in the core ions coupled to the conduction band; two-electron processes as proposed previously are not involved in this wavelength range where the change in angular momentum is relatively small.