FDTD simulation of 230 nm thickness PAAO with Au NPs in different mediums (AoI 60 deg., s- and p-polarizations)

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

Structure: aluminum (Palik) substrate; 230 nm thickness (h) aluminum oxide (Palik) layer with 35 nm diameter (RPo) cylindrical pores with 100 nm distance (D) between the pore centers (representing porous anodized aluminum oxide - PAAO); 60 nm diameter (RNP) gold (Johnson and Christy) nanoparticles (Au NPs) placed directly above each pore.

Refractive index of the surrounding medium (n): 1.0; 1.1.

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; 60° angle of incidence (ang); 300 nm – 1000 nm wavelength range; s- and p-polarizations (pol).

Monitors (frequency domain field and power): (1) 2D Z-normal; 1 µm above PAAO; results are in "_reflection.txt" files. (2) 2D Y-normal; centered to the structure; starts 50 nm below PAAO and ends 50 nm above nanoparticles; results are in ".fsp" files. (3) 2D X-normal; centered to the structure; starts 50 nm below PAAO and ends 50 nm above nanoparticles; results are in ".fsp" files.

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.

Files: (1) "_reflection.txt" - lambda(nm) (first column) - wavelength in nanometers; Y (second column) - T data from the monitor above the structure. (2) "_p0.log" - log file produced by the software while running the simulation. (3) ".fsp" - Lumerical software file containing the simulation project; it can be used to extract data from Y- and X-normal monitors (license required to open these files). (4) "Lumerical_Screenshots.pdf" - shows software screenshots for every object and its every property; red text is added to show which values are different for different simulations. (5) "Structure_Illustration.png" - a schematic of modeled structure. (6) "h230.jpg" - a preview of data from "_reflection.txt" files.