Coupling an epitaxial quantum dot to a fiber-based external-mirror microcavity

We report the coupling of individual InAs quantum dots (QDs) to an external-mirror microcavity. The external mirror is bonded to a fiber and positioned above a semiconductor sample consisting of a QD-containing GaAs layer on top of a distributed Bragg reflector. This open cavity can be rapidly tuned with a piezo-electric actuator without negatively affecting the QD linewidth. A mirror radius of curvature of 42 μm and a cavity length of 10 μm enable good mode matching and thus high collection efficiency directly into the fiber. With an improved finesse, this system may enter the strong coupling regime.