All-Optical Tuning of Fano Resonance for Quasi-BIC and Terahertz Sensing Applications

The bound states in the continuum (BIC) support anomalous resonances optical or terahertz band with a theoretically infinite quality factor. Therefore, it has great application prospects field of sensors. However, current regulation BIC mainly relies on asymmetry material structure, which requires high processing technology. structure can hardly be effectively adjusted once is formed. In this work, we propose new metasurface consisting an array rectangular hole combined aluminum and photosensitive silicon, supports quasi-BIC to achieve ultrasensitive sensing range. By introducing efficiently controlled by light field, thus realizing bidirectional continuous control from BIC-like states. Through optimization class highly sensitive based tuning finally proposed. narrow-band resonance medium thickness refractive index, compared pure metal sensitivity dynamic range increased 2.60 times 2.63 times, respectively. Due slope Fano lineshape, reach 9.41 GHz/RIU 0.65 GHz/μm, Furthermore, feasible practical provides ideal platform for sensing.