Reconfigurable Momentum-space vectorial lasing enabled by Quasi-BIC

TL;DR

This paper presents a reconfigurable momentum-space vectorial laser using a 2D photonic crystal that can switch between multiple lasing patterns by adjusting pump energy, enabling versatile applications.

Contribution

It introduces a novel reconfigurable vectorial laser platform based on quasi-BIC modes in 2D photonic crystals, allowing dynamic pattern switching.

Findings

Achieved reversible switching between single donut and BDL patterns.

Identified geometric asymmetry factors for different BIC modes.

Demonstrated versatile momentum-space lasing patterns.

Abstract

Bound states in the continuum (BICs) have enabled lasers with rich momentum-space textures. However, the output patterns of quasi-BIC lasers remain largely static and confined to a few geometries. Here, a reconfigurable momentum-space vectorial laser was proposed based on two-dimensional photonic crystal. By selectively exciting quasi-BIC modes, we identify the geometric asymmetry factors favoring single BIC, dual-BIC, and radiative mode with BIC operation. This approach yields vectorial lasing with characteristic patterns lasing in momentum space of bidirectional double lobes (BDL), radially polarized ring with BDL, azimuthally polarized ring with BDL, and linearly polarized spot with BDL. Importantly, reversible switching between a single donut and a donut with BDL was achieved in the same device by varying the pump energy density. Our work establishes a compact, versatile platform for reconfigurable vectorial lasers, with potential applications in tunable optical tweezers, super-resolution imaging, and on-chip optical interconnects.