Hyperfine Paschen-Back regime realized in Rb nanocell

A simple and efficient scheme based on a one-dimensional nanometric-thin cell filled with Rb and strong permanent ring magnets allows direct observation of the hyperfine Paschen-Back regime on the D-1 line in the 0.5-0.7 T magnetic field. Experimental results are perfectly consistent with the theory. In particular, with sigma(+) laser excitation, the slopes of the B-field dependence of frequency shifts for all 10 individual transitions of Rb-85,Rb-87 are the same and equal to 18.6 MHz/mT. Possible applications for magnetometry with submicron spatial resolution and tunable atomic frequency references are discussed. (C) 2012 Optical Society of America