High‐Purity Polarization Lasing From Bound States in the Continuum Enabled by Interface Engineering

ABSTRACT The applications of lasers demand the precision selection of appropriate polarization modes and robust polarization emission properties. Recently, the bound state in the continuum (BIC) laser has emerged with advantages such as an ultra‐high quality factor, vortex beam emission, and planar architecture that facilitates integration. However, BIC lasers based on all‐dielectric structures typically exhibit multiple polarization modes and are highly susceptible to environmental perturbations. Herein, we design a semiconductor‐insulator‐metal BIC laser that employs a surface plasmon‐assisted approach to achieve mode selection and high‐stability of emission. The lasing operation is predominantly governed by a symmetry‐protected transverse electric mode, exhibiting vertically‐emitting vortex beam. The as‐designed BIC laser demonstrates stable output performance even under asymmetric excitation. This semiconductor‐insulator‐metal BIC laser platform holds great promises for applications such as on‐chip photonics, secure communications, and high‐precision sensors.