Selective coupling of quantum dot exciton spin states to a photonic crystal cavity using magnetic field tuning

Abstract

Semiconductor quantum dots (QDs) coupled to high quality optical microcavities provide essential components for solid state cavity quantum electrodynamics systems. Indium Arsenide (InAs) QDs are one of the most promising candidates for quantum emitters due to their discrete density of states and high oscillator strength. When they are combined with small mode volume and high quality microcavities, strong light-matter interaction can be observed. Application of a magnetic field to QDs is necessary for several quantum information applications which require multi-level emitter structures [1–2]. Magnetic field lifts the degeneracy of QD exciton spin states due to the Zeeman effect, providing access to the individual QD spin states. In addition, a magnetic field can be useful as a method to tune QD emission frequency, which can be used to control the interaction between quantum emitters and an optical cavity [3–5]. We apply a magnetic field to photonic crystal cavity devices with embedded InAs QDs, and demonstrate strong coupling between individual QD exciton spin states and a photonic crystal cavity.