A Fully Tunable Microcavity

Monday, February 8, 2010 (All day)
Dr. Russell Barbour

Semiconductor optical microcavities that combine high Q-factors with a small mode volume play a vital role in modifying the interaction between light and matter. Several interesting phenomenon arise when an emitter is introduced into such a cavity. These include enhancement or suppression of the spontaneous emission rate (weak coupling) and normal mode splitting (strong coupling).

The majority of successful microcavity experiments have been performed on self--assembled quantum dots. For quantum dots the work-horse cavity geometries are micropillars, photonic crystals and whispering gallery devices. However these devices lack in situ spatial tuning and offer only very limited spectral tuning. Over coming these challenges is crucial for maximizing the interaction between light and matter.

In this seminar I will present the development of a miniaturized, fully tunable Fabry-Perot type microcavity for quantum dot microcavity experiments. The cavity has demonstrated high Q-factor modes (Q ~ 104), presently limited only by the quality of the coatings. The relatively high Q-factor is obtained by using a miniaturized spherical mirror which laterally confines the optical mode. We have demonstrated unprecedented in situ control over a single quantum dot within the cavity, spatially positioning the dot at the exact anti-node of the cavity electric field, hence maximizing the interaction between light and matter. Spectral and spatial tuning of a single dot Purcell effect has been demonstrated.