摘要
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 picosecond 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 6 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.
基金
the Laboratoire d’Excellence LANEF in Grenoble(ANR-10-LABX-51-01)for a PhD grant.G.M.T.and P.L.S.acknowledge funding from CAPES(PDSE 88881.187056/2018.1)
CNPq.This work was also partly funded by the FOM“Zap!”project
which is financially supported by NWO,NWO-Nano,and STW,as well as by NOMOS project,which is financed by ANR(ANR-18CE24-0026).
