FDTD simulation of PAAO with gold nanoparticles: varying refractive index of surrounding medium, s-polarization

FDTD software: Lumerical (Ansys, version 2021 R2.3).

Structure: aluminum (Palik) substrate; 290 nm thick aluminum oxide (Palik) layer with 35 nm diameter cylindrical pores with 100 nm distance between the pore centers (representing porous anodized aluminum oxide - PAAO); 60 nm diameter gold (Johnson and Christy) nanoparticles placed directly above each pore.

Refractive index of the surrounding medium: 1; 1.1; 1.2.

Simulation region: from 300 nm below the substrate/PAAO interface to 1.3 µm above PAAO surface; x and y spans are equal to one period of the structure.

Mesh override region: from 50 nm below the PAAO to 50 nm above the nanoparticles; 2 nm step size in each direction.

Light source: BFAST plane wave light source; 500 nm above PAAO; 45° angle of incidence; 300 nm – 1000 nm wavelength range; s-polarization.

Monitors: frequency domain field and power monitor; 1 µm above PAAO; T result from the monitor.

Information in the file name: h - thickness of PAAO; pol - polarization; RNP - diameter of gold nanoparticles; RPo - diameter of pores; D - distance between pore centers; ang - angle of incidence; n - refractive index of surrounding medium.

Information inside the file: lambda(nm) (first column) - wavelength in nanometers; Y (second column) - T data from the monitor.