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.

Coupling of quantum emitters in a semiconductor relies, generally, on short-range dipole-dipole or electronic exchange type interactions. Consistently, energy transfer between exciton states, that is, electron-hole pairs bound by Coulomb interaction, is limited to distances of the order of 10 nm. Here, we demonstrate polariton-mediated coupling and energy transfer between excitonic states over a distance exceeding 2 μm. We accomplish this by coupling quantum well-confined excitons through the delocalized mode of two coupled optical microcavities. Use of magnetically doped quantum wells enables us to tune the confined exciton energy by the magnetic field and in this way to control the spatial direction of the transfer. Such controlled, long-distance interaction between coherently coupled quantum emitters opens possibilities of a scalable implementation of quantum networks and quantum simulators based on solid-state, multi-cavity systems.

In this work, we present three groups of microcavities: based on selenium compounds only, based on tellurium compounds only, and structures based on mixed selenium and tellurium compounds. We focus on their possible applications in the field of optoelectronic devices and fundamental physics (VCSELs, narrow range light sources, studies of cavity-polariton electrodynamics) in a range of wavelength from 540 to 760 nm.

We report on a two-step etching of ZnTe based micropillars. We demonstrate applicability of the technology and we analyze the optical properties of obtained structures. Microphotoluminescence spectra of individual micropillars show a typical mode pattern that confirms a successful growth of photonic structures. The reflectivity and photoluminescence spectra of a planar microcavity measured for various incident angles show that additional side distributed Bragg reflectors will be important for the further enhancement of photon confinement in micropillar cavity.

Lasing relies on light amplification in the active medium of an optical resonator. There are three lasing regimes in the emission from a quantum well coupled to a semiconductor microcavity. Polariton lasing in the strong light-matter coupling regime arises from the stimulated scattering of exciton-polaritons. Photon lasing in the weak coupling regime relies on either of two mechanisms: the stimulated recombination of excitons, or of an electron-hole plasma. So far, only one or two out of these three regimes have been reported for a given structure, independently of the material system studied. Here, we report on all three lasing regimes and provide evidence for a three-threshold behavior in the emission from a photonic trap in a Se/Te-based planar microcavity comprising a single CdSe/(Cd,Mg)Se quantum well. Our work establishes the so far unsettled relation between lasing regimes that differ by their light-matter coupling strength and degree of electron-hole Coulomb correlation.