High-resolution spectroscopy on trapped molecular ions in rotating electric fields: A new approach for measuring the electron electric dipole moment

► High-resolution molecular spectroscopy is a sensitive probe of fundamental physics. ► A rotating electric field can be used to polarize trapped molecular ions. ► High-resolution spectroscopy can be performed in the presence of rapidly time-varying fields. ► Spectroscopy on polarized, trapped molecular ions can probe for an electron electric dipole moment.