Hyperfine Physics in Alkali-Metal Vapors

Eric Corsini, Todor S. Karaulanov, M. V. Balabas +1 more

An alkene-based antirelaxation coating for alkali-metal vapor cells exhibiting Zeeman relaxation times up to 77 s was recently identified by Balabas et al. The long relaxation times, two orders of magnitude longer than in paraffin- (alkane-) coated cells, motivate revisiting the question of what the mechanism is underlying wall-collision-induced relaxation and renew interest in applications of alkali-metal vapor cells to secondary frequency standards. We measure the width and frequency shift of the ground-state hyperfine $m{}_{F}=0\ensuremath{\rightarrow}m{}_{F}^{\ensuremath{'}}=0$ transition (clock resonance) in vapor cells with ${}^{85}$Rb and ${}^{87}$Rb atoms, with an alkene antirelaxation coating. We find that the frequency shift is slightly larger than for paraffin-coated cells and that the Zeeman linewidth scales linearly with the hyperfine frequency shift.

Boris Michailovich Smirnov, M. I. Chibisov

Stephen J. Kadlecek

Huining Shang, Sheng Zou, Wei Quan +4 more

The temperature of the alkali metal cell, which affects the density of the alkali-metal vapor and the gas pressure, is usually difficult to measure directly. However, the temperature of the alkali-metal cell and the density of the alkali-metal vapor are important parameters that affect the performance of the atomic sensor. In this paper, a device that can directly measure the internal temperature of an alkali metal cell in real time is designed for the first time to explore the relationship between alkali-metal vapor density and temperature. Alkali-metal vapor density is measured using the absorption spectrum. The pressure broadening model, combined with the transition of four hyperfine levels, was used to fit the absorption line of 87Rb D1 under the action of 700 Torr N2, and a good fitting effect was obtained. The experimental results show that the density of 87Rb is less than the value calculated by the empirical formula. Based on the experimental results, we give the calculation formula of 87Rb density with an uncertainty of only 4% and obtain the temperature dependence index of the line width and linear displacement of 87Rb in N2 by analyzing the absorption spectrum.

James C. Camparo, R. P. Frueholz

A generalized model for the magnetic resonance signal corresponding to the 0-0 hyperfine transition in an optically pumped alkali-metal vapor is presented. Under conditions of microwave power broadening, the model predicts ``anomalous'' light broadening and ``anomalous'' relaxation narrowing of the magnetic resonance linewidth. Good agreement between theory and experiment was obtained in an experiment that confirmed the prediction of anomalous light broadening. These results show that the 0-0 hyperfine transition cannot be described as a simple two-level system; rather, the alkali-atom's nuclear spin plays an important role in determining the magnetic resonance linewidth.

Li-Te Steven Lin