Cavity electromagnetically induced transparency and all-optical switching using ion Coulomb crystals

TL;DR

This paper demonstrates electromagnetically induced transparency and all-optical switching using ion Coulomb crystals in an optical cavity, achieving narrow resonance features and high-efficiency light control crucial for quantum information applications.

Contribution

First demonstration of EIT and all-optical switching with ion Coulomb crystals in a cavity, showing unprecedented narrow linewidths and effective light modulation.

Findings

Narrow cavity EIT features down to a few kHz

Full transmission to absorption switching within ~100 kHz

Nearly perfect switching of probe field transmission

Abstract

The control of one light field by another, ultimately at the single photon level, is a challenging task which has numerous interesting applications within nonlinear optics and quantum information science. Due to the extremely weak direct interactions between optical photons in vacuum, this type of control can in practice only be achieved through highly nonlinear interactions within a medium. Electromagnetic induced transparency (EIT) constitutes one such means to obtain the extremely strong nonlinear coupling needed to facilitate interactions between two faint light fields. Here, we demonstrate for the first time EIT as well as all-optical EIT-based light switching using ion Coulomb crystals situated in an optical cavity. Unprecedented narrow cavity EIT feature widths down to a few kHz and a change from essentially full transmission to full absorption of the probe field within a window of only ~100 kHz are achieved. By applying a weak switching field, we furthermore demonstrate nearly perfect switching of the transmission of the probe field. These results represent important milestones for future realizations of quantum information processing devices, such as high-efficiency quantum memories, single-photon transistors and single-photon gates.