Absorption modulation of quasi-BIC in Si–VO<sub>2</sub> composite metasurface at near-infrared wavelength
Hongxiang Dai, Jukun Liu, Jiaqi Ju, K. L. Cheng
Abstract
Abstract Bound states in the continuum (BIC) have attracted great attention in nanophotonics in the past few years. The metasurface with inverted symmetry breaking exhibits high Q resonance through quasi-BIC (Q-BIC), which realizes light modulation, sensing and nonlinear generation. In this work, a symmetry-broken Si–VO 2 composite metasurface is studied and modulate near-infrared light absorption in Q-BIC mode. First, a L-shaped Si metasurface with broken C 4v symmetry is designed, which realizes the transition from BIC to Q-BIC and shows strong circular dichroism. Later, phase-change material VO 2 is integrated into the L-shaped Si metasurface. By changing the ambient temperature, the Si–VO 2 composite metasurface shows distinct light absorption characteristics, including insensitivity to incident angle and a maximum absorption modulation of up to 210%. The results show that VO 2 can effectively modified Q-BIC resonator to realize the modulation absorption of near-infrared light.