Vertical microcavities with highQand strong lateral mode confinement

We show that strong lateral photon confinement in a vertical Fabry-P\'erot microcavity can be achieved without sacrificing the quality factor Q or the need for pillar structures. A submicrometer Gaussian-shaped defect inserted between two distributed Bragg reflectors confines the photons on resonance in a small modal volume V on the order of (λ/n)³ while maintaining a Q up to 10⁵. This design minimizes light scattering induced by lateral dielectric discontinuities, and therefore our simulations demonstrate that the $Q/V$ is increased by nearly two orders of magnitude relative to cavities with an embedded mesa defect. We further discuss possible fabrication strategies for such devices, which are well suited for the study of cavity quantum electrodynamics with either organic or inorganic quantum emitters, and hold promise for the implementation of scalable quantum photonic networks.