Femtosecond wavepacket interferometry using the rotational dynamics of a trapped cold molecular ion

TL;DR

This paper proposes a femtosecond wavepacket interferometry method using a cold trapped molecular ion to measure rotational dynamics and polarizability anisotropy with high precision.

Contribution

It introduces a Ramsey-type interferometer utilizing femtosecond laser pulses to probe rotational wavepackets in cold trapped ions, enabling precise polarizability measurements.

Findings

Interferogram visibility exceeds 80% with current experimental setups.

Polarizability anisotropy can be measured with about 2-5% accuracy.

Method effectively links rotational wavepacket dynamics to measurable interferograms.

Abstract

A Ramsey-type interferometer is suggested, employing a cold trapped ion and two time-delayed off-resonant femtosecond laser pulses. The laser light couples to the molecular polarization anisotropy, inducing rotational wavepacket dynamics. An interferogram is obtained from the delay dependent populations of the final field-free rotational states. Current experimental capabilities for cooling and preparation of the initial state are found to yield an interferogram visibility of more than 80\%. The interferograms can be used to determine the polarizability anisotropy with an accuracy of about $\pm 2\%$, respectively $\pm 5\%$, provided the uncertainty in the initial populations and measurement errors are confined to within the same limits.