Multimode Vortex Lasing from Dye–TiO 2 Lattices via Bound States in the Continuum

作者：Zhenshan Zhai, Zhuang Li, Yixuan Du, Xin Gan, Linye He, Xiaotian Zhang, Yufeng Zhou, Jun Guan, Yangjian Cai, Xianyu Ao · 发表于：ACS Photonics · 年份：2023 · DOI：10.1021/acsphotonics.2c01496 · 被引用次数：41 · 研究领域：Orbital Angular Momentum in Optics、Plasmonic and Surface Plasmon Research、Metamaterials and Metasurfaces Applications

Spatially extended bound states in the continuum (BICs) can provide high-quality optical feedback for vortex lasing. This work reports that three out of the four supported BIC modes in 2D square lattices of dye-covered TiO 2 nanoparticles can lase simultaneously under pulsed pumping, while the remaining one can be tuned into the gain bandwidth by adjusting the nanoparticle size. All the BIC modes in the in-plane symmetric lattices exhibited doughnut-shaped lasing patterns, regardless of the pump polarization, but with a polarization-dependent threshold. Multiple vortex beams can be generated by illuminating with multiple pump spots. When changing the nanoparticle shape from square to trapezoidal, the symmetry breaking resulted in predominantly single-lobed lasing at symmetry-breaking-induced band edges and dramatically suppressed two-lobe lasing at BIC modes. Such on-chip multimode lasing with different polarization patterns thus enables multiplexing in not only wavelength, but also polarization.