M. Rosenbluh

Far-infrared-laser magnetic-resonance spectroscopy of 4 He S and P states

A CO(2)-pumped far-infrared (FIR) laser has been used to drive transitions between S and P levels of (4)He Rydberg states with the same principal quantum number (n). The levels are tuned to resonance with the fixed-frequency FIR laser through application of an intense magnetic field. Measurements of such transitions are particularly valuable as they provide high-resolution data for low L states, a previously ill-defined area in the otherwise wellknown energy-level structure of (4)He.

Laser Spectroscopy in Intense Magnetic Fields

Although the behaviour of atoms in intense magnetic fields has been the subject of investigators since the pioneering work of Jenkins et al. (Jen 39, Sch 39), significant new advances have been made only in recent years. Using conventional spectroscopic techniques (Fon 78) and laser-atomic beam techniques (Eco 78) the Landau-level regime has been examined in a number of atoms. Laser-atomic beam techniques have also been used to probe the “n-mixing” region (Zim 78). Our work has been concerned with understanding the behaviour of the thermal distribution of atoms (as opposed to an atomic beam) in an intense magnetic field in the “diamagnetic-perturbation” and “L-mixing” region (Ros 77, Ros 78, Pan 79). Our experimentation and theoretical understanding of our findings is advanced enough to allow us to obtain very precise spectroscopic information from our data. Furthermore, the implications of our results to certain astrophysical spectra and plasma diagnostics seem significant.