The Mechanism of Circular Dichroism in Twisted Arch nanostructures analyzed by Finite-difference Time-Domain method

Abstract

Metamaterials are artificial materials with special geometry design so that we can create many unique physical properties which do not exist in nature Due to its size is much smaller than operating wavelength metamaterials allow the possibility to control electromagnetic wave Chiral metamaterials are metamaterials with chirality which means polarizes light of opposite handedness namely left-handed and right-handed circularly polarized (LCP and RCP) interact differently with its’ non-mirror symmetry structures Optical activity stemming from chirality include circular dichroism (CD) which measures the different optical activity of two opposite handedness circularly polarized waves Twisted arch nanostructures are chiral metamaterials composed by two metal arch with height difference The coupling between two metal arch and the phase delay caused by height different will trigger circular dichroism With Finite Difference Time Domain (FDTD) simulations we can analyze the mechanism of circular dichroism in twisted arch nanostructures Base on experiment data we discover that with appropriate design twisted arch structure can produce enormously strong circular dichroism

Date of Award	2019
Original language	English
Supervisor	Shih-hui Chang (Supervisor)