Design and Theoretical Investigation of an on Chip Two-Dimensional Newton’s Ring-like Plasmonic Sensor for Differentiating the Chirality of Circularly Polarized Lights

Abstract

In this paper, an on chip two-dimensional Newton’s ring-like plasmonic sensor is designed for differentiating the chirality of circularly polarized lights (CPLS). The structure of the plasmonic sensor consists of a circular arc slit and an array of periodic rectangular nano-grooves that are etched into a silver film. When the sensor is illuminated by CPLS with a given chirality, the surface plasmon polariton waves generated by the slit and nano-groove array will selectively interfere with each other in the near field, which results in two different transmitted light intensity distributions in the far field. The generated far-field light intensity distributions are utilized as criteria to qualitatively differentiate the concrete chirality of the incident CPLS. The finite difference time domain method is utilized to theoretically investigate the function of the designed plasmonic sensor. The simulated results indicated that the proposed sensor has the ability to visually display the chirality information in the far field, and can provide a tool to conveniently and qualitatively differentiate the chirality of CPLS in the far field.