Numerical simulation and characterization of photonic/plasmonic devices

Abstract

Nano-scale optical materials are often difficult to fabricate for experimental characterization and too complex for analytical analysis. Numerical simulation is a more cost effective way to characterize nano-scale optical materials due to increasingly cost effective computers and the availability of commercial electromagnetic-simulation software. One of the electromagnetic simulation methods that become increasingly favorable due to the ability to simulate a wide variety of problems is the Finite-Difference Time-Domain (FDTD) method. However, FDTD is not an unconditionally stable numerical simulation method. To facilitate the use of FDTD to characterize nano-scale optical materials, knowing the conditions for a numerically stable simulation is necessary. The main focus of this project is to quantify the ability of FDTD to characterize thin films using simulations which mimics ellipsometry measurements using a chosen commercial FDTD software. Simulating polarization states of light reflected by thin films is chosen due to the availability of analytical solutions to the problem. In the second part, planar chiral metamaterials (PCM), a material with periodic structure and unit cell in the shape of(left-, or right- hand) gammadions which are shown to support surface plasmon resonance with the ability to excite circularly polarized light into super-chiral light is characterized. These structures are of interest as recently, PCM have been shown to enhance the detection of biomolecules using Circular Dichroism by up to six orders of magnitudes as compared to conventional chirality detection schemes.