Double-Resonance Lineshapes in a Cell with Wall Coating and Buffer Gas

Published

June 28, 2010

Author(s)

Svenja A. Knappe, Hugh Robinson

Abstract

Microwave double resonances were measured is a wall-coated Rb vapor cell as a function of additional buffer gas pressure. These data were compared to similar measurements in an uncoated cell. It was found that the linewidth in the coated cell displays a distinct maximum around 0.2 kPa. This agrees well with theoretical solutions of the diffusion equation assuming a complex reflection coefficient at the wall. It was furthermore found that at the intermediate pressures the lineshapes of the microwave resonances become asymmetric with a low-frequency tail. This is in agreement with the explanation that above the pressure where the alkali mean free path is substantially smaller than the average distance between wall collisions at zero pressure, there exist two classes of atoms in the cell. The atoms that get trapped near the walls accumulate much larger phase shifts compared to the ones toward the center of the cell. This effect is not seen in the longitudinal relaxation rate indicating that it is related to a phase-shift effect.

Citation

New Journal of Physics

Volume

12

Pub Type

Journals

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Keywords

alkali vapor cell, buffer gas, wall coating, paraffin, double resonance spectroscopy

Citation

Knappe, S. and Robinson, H. (2010), Double-Resonance Lineshapes in a Cell with Wall Coating and Buffer Gas, New Journal of Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=904448 (Accessed October 16, 2025)