We review recent studies of cavity switching induced by the optical injection of free carriers in micropillar cavities containing quantum dots. Using the quantum dots as a broadband internal light source and a streak camera as detector, we track the resonance frequencies for a large set of modes with ps time resolution. We report a record-fast switch-on time constant (1.5 ps) and observe major transient modifications of the modal structure of the micropillar on the 10-ps time scale : mode crossings are induced by a focused symmetric injection of free carriers, while a lifting of several mode degeneracies is observed when off-axis injection breaks the rotational symmetry of the micropillar. We show theoretically and experimentally that cavity switching can be used to tailor the dynamic properties of the coupled QD-cavity system. We report the generation of ultrashort spontaneous emission pulses (as short as 5 ps duration) by a collection of frequency-selected QDs in a switched pillar microcavity. These pulses display a very small coherence length, attractive for ultrafast speckle-free imaging. Moreover, the control of QD-mode coupling on the 10 ps-time scale establishes cavity switching as an appealing resource for quantum photonics.

https://www.nature.com/articles/s41377-021-00654-y

E. Peinke, T. Sattler, G. M. Torelly, P. L. Souza, S. Perret, J. Bleuse, J. Claudon, W. L. Vos, and J.-M. Gérard

2021

10/2021

Light Sci. Appl.

10

215: 1-15

10.1038/s41377-021-00654-y

all-optical switching, quantum dots, quantum optics, speckle, ultrafast optics