Actively tunable plasmon-induced transparency in terahertz based on Dirac semimetal metamaterials.

We numerically investigate a tunable plasmon-induced transparency based on bulk Dirac semimetal (BDS) metamaterial in the terahertz band. In the unit cell, the prominent transparent peak appears to be due to the interference between the cut wires (CWs) and split-ring resonators (SRRs). An active modulation via near-field coupling is obtained by varying the Fermi level of the BDS.

Polarization-independent and ultra-sensitive biosensor with a one-dimensional topological photonic crystal.

Optical biosensor, which perceptively captures the variety of refractive index (RI) of the surrounding environment, has great potential applications in detecting property changes and types of analytes. However, the disequilibrium of light-matter interaction in different polarizations lead to the polarization-dependence and low sensitivity. Here, we propose a polarization-independent and ultrasensitive biosensor by introducing a one-dimensional topological photonic crystal (1D TPhC), where two N-period 1D photonic crystals (PhC1 and PhC2) with different topological invariants are designed for compressing the interaction region of the optical fields, and enhancing the interaction between the light and analyte.