Monolithically integrated photonic crystal surface emitters on silicon with a vortex beam by using bound states in the continuum

Optical resonant cavities with high quality factor (Q-factor) are widely used in science and technology for their capabili-ties of strong confinement of light and enhanced light-matter interaction. The 2D photonic crystal structure with bound states in the continuum (BICs) is a novel concept for res-onators with ultra-compact device size, which can be used to generate surface emitting vortex beams based on symmetry -protected BICs at the Gamma point. Here, to the best of our knowledge, we demonstrate the first photonic crystal surface emitter with a vortex beam by using BICs monolithically grown on CMOS-compatible silicon substrate. The fabri-cated quantum-dot BICs-based surface emitter operates at 1.3 mu m under room temperature (RT) with a low continuous wave (CW) optically pumped condition. We also reveal the BIC's amplified spontaneous emission with the property of a polarization vortex beam, which is promising to provide a novel degree of freedom in classical and quantum realms. (c) 2023 Optica Publishing Group