Handedness-Switchable Optical Chirality in One-Dimensional Periodic Plasmonic-Grooves for Circular Dichroism and Simultaneous Refractive Index Sensing

Through a numerical study, we proposed and demonstrated that the one-dimensional periodic plasmonic-grooves (1D-PPG) can give rise to a super chiral field inside grooves under normal illumination with off-groove linear polarization. The handedness of the optical chirality of chiral field can be reversed by modifying the incident polarization angle from + 45° relative to groove's period direction to its mirror-symmetrical angle -45°. This makes possible a novel sensing scheme that utilize this polarization-dependent local chiral field for circular dichroism detecting; meanwhile, the dielectric environment-sensitive plasmonic resonance of 1D-PPG can be employed for refractive index sensing. This dual-sensing strategy offers great potential for low-cost chirality sensing for chiral molecules.