Multi-state interferometric measurement of nonlinear AC Stark shift

TL;DR

This paper introduces a multi-state atomic interferometer to precisely measure quadratic AC Stark shifts in a Bose-Einstein condensate, demonstrating improved accuracy and control over nonlinear spin dynamics.

Contribution

The work presents a novel multi-state interferometric method for measuring quadratic AC Stark shifts, effectively isolating these shifts from larger state-independent effects.

Findings

Successful measurement of quadratic shifts near the D1 line in $^{87}$Rb

Agreement between experimental results and theoretical predictions

Demonstration of suppression of nonlinear spin evolution using dual-color light pulses

Abstract

We demonstrate measurement of quadratic AC Stark shifts between Zeeman sublevels in an $^{87}$Rb Bose--Einstein condensate using a multi-state atomic interferometer. The interferometer can detect a quadratic shift without being affected by relatively large state-independent shifts, thereby improving the measurement precision. We measure quadratic shifts in the total spin $F = 2$ state due to the light being near-resonant to the D$_1$ line. The agreement between the measured and theoretical detuning dependences of the quadratic shifts confirms the validity of the measurement. We also present results on the suppression of nonlinear spin evolution using near-resonant dual-color light pulses with opposite quadratic shifts.