Bound states in the continuum (BICs) with infinite quality factor (Q-factor) and significant field enhancement pave the way for realizing highly sensitive optical sensors with enhanced light-matter interactions on the nanoscale. However, current optical sensing methods are difficult to discriminate between isotropic and anisotropic media from resonance spectral lines, resulting in optical sensing methods still being limited to isotropic media. In this work, we demonstrate that BICs can be realized by modulating the period of structural units to convert BICs to QBICs without changing their space group symmetry, and propose a polarization-independent metasurfaces-based realization of highly sensitive refractive index sensors for isotropic and anisotropic media as well as discrimination.
View Article and Find Full Text PDFThis study optimizes a surface plasmon resonance (SPR) sensor based on - periodic grating using graphene and a hybrid structure to enhance sensitivity. The sensing performance was analyzed by wavelength modulation. By optimizing the structural parameters, we can obtain the quality factor and sensitivity of 90.
View Article and Find Full Text PDFIn order to overcome the limitations in range of traditional prism structure surface plasmon resonance (SPR) single-point sensor measurement, a symmetric bimetallic film SPR multi-sensor structure is proposed. Based on this, the dual-channel sensing attenuation mechanism of SPR in gold and silver composite film and the improvement of sensing characteristics were studied. By optimizing the characteristics such as material and thickness, a wider range of dual-channel distributed sensing is realized.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
March 2017