Nearfield Vortex Dynamics of Supercell Bloch Modes

TL;DR

This paper introduces a novel paired-rotation design in supercell photonic crystals to control nearfield vortex dynamics, enabling tailored light-matter interactions and enhanced nonlinear effects like second harmonic generation.

Contribution

The study demonstrates a new paired-rotation approach to manipulate vortex configurations and mode transitions in supercell photonic crystals, expanding control over optical properties.

Findings

Achieved high-Q Bloch mode transitions with paired rotations.

Observed diverse vortex distributions and physical behaviors.

Enhanced second harmonic generation due to asymmetric vortex modes.

Abstract

Densely arranged optical vortices are natural solutions of high-symmetry Bloch modes in photonic crystals. However, strict symmetry constraints limit the potential spatial configurations of nearfield vortices, restricting the control over light-matter interaction. Here, we demonstrate a nearfield vortex dynamic within a supercell photonic crystal. By introducing paired rotations of triangular structures, we achieve high-quality-factor Bloch mode transition from evanescent valley modes, to quasi-bound states in the continuum, frustrated modes, and quasi-valleys. Each stage exhibits distinct nearfield vortex distributions, nonlinear overlap properties, and quality factors, revealing diverse physical behaviors for tailoring light-matter interaction. Notably, the asymmetric vortex configuration of frustrated modes enhances second harmonic generation, driven by an optimized nonlinear overlap factor. Our paired-rotation strategy offers a versatile design framework for creating supercell photonic crystals with unique nearfield vortex properties, presenting promising applications in lasing, nonlinear optics and optical forces.