Rotational spectroscopy with an optical centrifuge

TL;DR

This paper introduces a novel spectroscopic technique using an optical centrifuge to study electronic transitions in molecules with very high angular momentum, revealing complex rotational spectra beyond thermal levels.

Contribution

The study demonstrates the use of an optical centrifuge to generate high rotational states and record associated spectra, extending the range of accessible molecular rotational levels.

Findings

Successfully created rotational wave packets with N > 120

Recorded multiple ro-vibrational transitions in oxygen molecules

Interpreted complex rotational spectra beyond thermal levels

Abstract

We demonstrate a new spectroscopic method for studying electronic transitions in molecules with extremely broad range of angular momentum. We employ an optical centrifuge to create narrow rotational wave packets in the ground electronic state of $^{16}$O$_2$. Using the technique of resonance-enhanced multi-photon ionization, we record the spectrum of multiple ro-vibrational transitions between $X^3\Sigma_{g}^{-}$ and $C^3\Pi_{g}$ electronic manifolds of oxygen. Direct control of rotational excitation, extending to rotational quantum numbers as high as $N\gtrsim 120$, enables us to interpret the complex structure of rotational spectra of $C^3\Pi_{g}$ beyond thermally accessible levels.