Controlling the emission from semiconductor quantum dots using ultra-small tunable optical microcavities

TL;DR

This paper demonstrates the control of quantum dot emission using ultra-small, tunable optical microcavities, achieving significant emission rate enhancement and mode control at room temperature.

Contribution

It introduces novel open-access microcavities with sub-cubic-micrometre mode volumes for controlling quantum dot emission.

Findings

75% increase in emission rate at room temperature

Ability to tune emission spectrum and lifetime

Detection of strong emission from individual nanocrystals

Abstract

We report the control of spontaneous emission from CdSe/ZnS core-shell quantum dots coupled to novel open-access optical microcavities. The cavities are fabricated by focused ion beam milling, and provide mode volumes less than a cubic micrometre. The quantum dot emission spectrum, spatial modes, and lifetime are all modified substantially by the presence of the cavity, and can be tuned by actively varying the cavity length. An increase in emission rate of 75% is achieved at room temperature, attributed to the Purcell effect in the 'bad emitter' regime. We demonstrate a high degree of control over the emission from the dots, including near single-mode operation and the ability to detect strong emission from individual nanocrystals.