Nondestructive dispersive imaging of rotationally excited ultracold molecules

TL;DR

This paper proposes a nondestructive, high-fidelity dispersive imaging method for ultracold molecules based on their anisotropic rotational states, enabling polarization-based detection without destroying the molecules.

Contribution

It introduces a theoretical scheme utilizing molecular anisotropy for dispersive imaging, providing a formalism for selecting molecular states and achieving polarization rotations.

Findings

Achieves degree-level polarization rotations in bulk gases.

Provides a formalism for choosing molecular states for imaging.

Outlines requirements for imaging trapped molecules.

Abstract

A barrier to realizing the potential of molecules for quantum information science applications is a lack of high-fidelity, single-molecule imaging techniques. Here, we present and theoretically analyze a general scheme for dispersive imaging of electronic ground-state molecules. Our technique relies on the intrinsic anisotropy of excited molecular rotational states to generate optical birefringence, which can be detected through polarization rotation of an off-resonant probe laser beam. Using \narb and \rbcs as examples, we construct a formalism for choosing the molecular state to be imaged and the excited electronic states involved in off-resonant coupling. Our proposal establishes the relevant parameters for achieving degree-level polarization rotations for bulk molecular gases, thus enabling high-fidelity nondestructive imaging. We additionally outline requirements for the high-fidelity imaging of individually trapped molecules.