Design and Control of Mode Interaction in Coupled ZnTe Optical Microcavities

The photonics involving II–VI epitaxial layers was limited so far to structures based on a single planar microcavity. Here, we present double vertically coupled ZnTe optical microcavities in planar and 3-D photonic molecule geometry. We design the structures with the help of transfer matrix method calculations and we establish their fabrication technology using molecular beam epitaxy. We characterize the samples by reflectivity spatial mapping and study them by angle-integrated and angle-resolved photoluminescence and reflectivity. We efficiently tailor the interaction strength of the optical cavities modes by adjusting the spatial separation between the microcavities, their thickness ratio, and the size of the micropillars etched out of the planar structure. Coupling constants extracted from our measurements agree with those determined in calculations in the frame of a tight-binding approach applied to one-dimensional photonic structures

Magneto-optical induced supermode switching in quantum fluids of light

The insensitivity of photons towards external magnetic fields forms one of the hardest barriers against efficient magneto-optical control, aiming at modulating the polarization state of light. However, there is even scarcer evidence of magneto-optical effects that can spatially modulate light. Here, we demonstrate the latter by exploiting strongly coupled states of semimagnetic matter and light in planar semiconductor microcavities. We nonresonantly excite two spatially adjacent exciton-polariton condensates which, through inherent ballistic near field coupling mechanism, spontaneously synchronise into a dissipative quantum fluidic supermode of definite parity. Applying a magnetic field along the optical axis, we continuously adjust the light-matter composition of the condensate exciton-polaritons, inducing a supermode switch into a higher order mode of opposite parity. Our findings set the ground towards magnetic spatial modulation of nonlinear light

Inhibition and Enhancement of the Spontaneous Emission of Quantum Dots in Micropillar Cavities with Radial-Distributed Bragg Reflectors

We present a micropillar cavity where nondesired radial emission is inhibited. The photonic confinement in such a structure is improved by implementation of an additional concentric radial-distributed Bragg reflector. Such a reflector increases the reflectivity in all directions perpendicular to the micropillar axis from a typical value of 15–31% to above 98%. An inhibition of the spontaneous emission of off-resonant excitonic states of quantum dots embedded in the microcavity is revealed by time-resolved experiments. It proves a decreased density of photonic states related to unwanted radial leakage of photons out of the micropillar. For on-resonance conditions, we find that the dot emission rate is increased, evidencing the Purcell enhancement of spontaneous emission. The proposed design can increase the efficiency of single-photon sources and bring to micropillar cavities the functionalities based on lengthened decay times