Innovative implementation of RCWA for modelling gratings and metamaterials

OmniSim's RCWA engine (Rigorous Coupled-Wave Analysis) can be used to perform two-dimensional and three-dimensional calculations to simulate the propagation of light incident on 1D- or 2D-periodic structures such as: 

• Diffraction gratings

• Periodic metamaterials

• Diffractive optical elements 

The user can define the angle of incidence using two degrees of freedom for both 1D-periodic (2D RCWA) and 2D-periodic (3D RCWA) simulations. 

The RCWA engine supports metal and dielectric materials and arbitrary geometries in the grating plane. 

Improved convergence compared with standard RCWA

Standard RCWA can result in unphysical oscillations, numerical artefacts and it fails to correctly predict the discontinuity of the electric field at the metal-dielectric interface. OmniSim’s RCWA reduces the oscillations and calculates the discontinuity accurately, as shown below.

Near field around cylindrical gold nano-rods: with OmniSim's RCWA (left) 
the fields exhibit clear discontinuity as expected, whilst with a standard implementation (right) 
the fields suffer from unphysical oscillations due to the Gibbs phenomenon

Features

• RCWA calculations for 1D-periodic and 2D-periodic gratings

• Arbitrary angle of illumination with two degrees of freedom for both 2D and 3D simulations

• Arbitrary polarisation: linear, circular, elliptical

• Support for metal and dielectric materials

• Support for slanted walls in 1D-periodic and 2D-periodic gratings

• Innovative formulation for the modelling of the electric near-field

• Improved formulation for 1D-periodic slanted gratings compared with standard RCWA

• Built-in scanner to generate spectra, parameter scans or convergence tests

• Calculation inspector allows you to inspect modes (profiles and excitation) and discretised refractive index profile

• Plot near-field and calculate power in the different diffraction orders for the far-field (reflection and transmission)

Computational data for a 3D simulation of a 2D array of holes in a silicon slab