Studies of collisional dephasing of two-photon excited atomic sodium

TL;DR

This study investigates how collisions with argon buffer gas affect the coherence relaxation of two-photon excited sodium atoms using femtosecond pump-probe spectroscopy, providing experimental relaxation times and collisional cross-sections.

Contribution

It presents new experimental measurements of coherence relaxation times and collisional cross-sections for Na-Ar collisions using a femtosecond pump-probe approach.

Findings

Measured coherence relaxation times for Na vapor.

Determined collisional cross-sections for Na-Ar collisions.

Analyzed the impact of buffer gas on atomic coherence.

Abstract

Coherence relaxation in Na vapor was studied utilizing a pump-probe method with femtosecond pulses. The coherence was created by the pump pulse, which excited the Na atoms to the 4S state. The atoms were further excited to the 7P state by the probe pulse. As a result a coherent UV radiation was emitted by the atoms. This emission was used to study the relaxation of both the 4S-3S and 7P-3S coherent superpositions. The relaxation is mainly due to collisions with the Ar atoms serving as a buffer gas. Coherence relaxation times and collisional cross-sections for the Na-Ar collision pairs were extracted experimentally.