Populations of Magnetic Substates Under the Influence of Optical Pumping in High Buffer Pressures.

Albert R. Young, Stephan Appelt, Andrei Ben-Amar Baranga +2 more

We present detailed images of the Rb polarization in a high-pressure optical pumping cell. Images taken at high magnetic field strengths (≈37 G) yield precise information on the relative occupation probability of the hyperfine Zeeman sublevels. Low-field (⩽4 G) images yield very high resolution (less than 1 mm) maps of the spatial distribution of the Rb polarization. For optical pumping in the presence of high-pressure buffer gases, the measured populations of the hyperfine magnetic sublevels are shown to be well described by a spin temperature, even though the Rb–Rb spin exchange rate is much smaller than the rates of optical pumping or electron-randomizing Rb–Xe collisions in the buffer gas.

Chris J. Bednar

D. Tupa

Ben A. Olsen, Brian Patton, Yuan‐Yu Jau +1 more

We have measured changes in the ground-state populations of Cs vapor induced by optical pumping at high magnetic field. The $2.7$-T field of our experiments is strong enough to decouple the nuclear and electronic spins, allowing us to independently measure each population. The spatial dependence of the Cs populations in small amounts of buffer gas obeys a simple coupled diffusion model and the relative populations reveal the details of relaxation within the vapor cell. Optical pumping can produce high nuclear polarization in the Cs vapor due to perturbations of the hyperfine interaction during collisions with buffer-gas particles and depending on the pumping transition, radiation trapping can strongly influence the electronic and nuclear polarizations in the vapor.

Taro Ito, Koji Kondo, Tsuneo Hashi

Amber Post, Yuan‐Yu Jau, Nicholas N. Kuzma +1 more

Coherent population trapping (CPT) signals can be optimized with amplitude-modulated pumping light. As shown theoretically and experimentally in this paper, the optimum wave forms produce strong CPT signals at both low buffer-gas pressures, where the hyperfine structure (HFS) splitting of the optical absorption lines is well resolved, and also at high buffer-gas pressures, where the HFS is no longer optically resolved due to pressure broadening. On the other hand, CPT resonances from frequency-modulated waves are severely degraded for these high-pressure conditions. High buffer-gas pressures may offer advantages for miniature frequency standards and magnetometers, including suppression of diffusion losses in miniature cells, suppression of light shifts, and less stringent requirements for frequency stability of the pumping light sources.