Analysis of Dicke Narrowing in Wall Coated and Buffer Gas Filled Cells with Application to Gas Cell Atomic Clocks

Abstract

Spectral lineshape narrowing of atomic vapor emission in a bufferless, wall-coated absorption cell has been analyzed using the same formalism developed t3 describe sub-Doppler linewidths. Dicke-narrowing, in a buffered cell. Dramatic linewidth reductions in the bufferless cell, compared to the buffered cell, occur because of the high probability that Doppler shifts before and after a particular wall collision will cancel each other. The formalism described allows more physical insight than the classic onedimensional box model previously invoked to explain spectral narrowing in bufferless, wall coated cells. Additionally, this formalism reveals a correlation between post-collision velocities and intercollision times in the buffered cell resulting in modifications of the standard Dicke analysia of these cells. Finally, the computational power of the technique is demonstrated. The effects of varying cell size on Rb and CS hyperfine lineshapes and the results of the presence of an inhomogeneous magnetic field within the cell are analyzed.