Example results and CAD download

Sphere_Mie_diameter400nm_metal.zip

https://drive.google.com/open?id=15m0DXK2uKcpYmsZJEdFhIf5WDoU47Sw3

Analytical Solution download :

bhmie_analytical.zip

https://drive.google.com/open?id=1TdyHFRQGLTOWf20DCmPLQbdFijPZmb3x

Theoretical Solution refer to these web

http://scatterlib.wikidot.com/mie

http://juluribk.com/2013/01/22/electric-field-at-localized-plasmon-resonance-using-meep/

Field pattern analysis examples download:

Sphere_Mie_diameter400nm_metal_1095.zip

https://drive.google.com/open?id=1Rpq971Boki000_BefQF4mu8IJOHxOGY5

Sphere_Mie_diameter400nm_metal_625.zip

https://drive.google.com/open?id=1i-Ro2IgD1dr_zx8dzbTmcmYjN-d6rVyW

Sphere_Mie_diameter400nm_metal_300.zip

https://drive.google.com/open?id=10jZ1VEmXmdH6e499n4AFMbJd69ojlZII

*.FCstd is the save file of FreeCAD

Add the boundary of the CAD files (FreeCAD)

Reference : 3D-CAD Simulation & Examples

Define Parameters

A.Main-Setup

1. Selected the simulation dimension.

2. Define total x, y, z length that equal to CAD, and then set a appropriate resolution.

3. Import CAD files.

4. Define the material of each CAD.

5. Press【建立網格 Cad to Grids (Create)】button to create simulation grids.

Due to FreeCAD default unit is mm, and in this case the sphere unit is nm. If use nm unit in FreeCAD, the resolution of output STL file will not enough. So, at here express

"the unit can directly transform between any unit, nm <=> um <=> mm "

setup the dielectric constant of metal gold (using Electrical Model 1)

instruction webpage : Electric & Magnetic Models

B.Boundary Conditions

A. Define the boundary conditions

B. Press the【創建 (Create)】button => Create the total grid size (Include the boundary condition & add space)

C.Wave & Observation

To simulate the Scattering-Absorption spectrum, select the (TFSF-RCS) radar cross section source

D. Probe & Lumped

None, press 【創建(Create)】 button

E. Geometries. Design

Checked out the simulation geometries, and then press 【輸出 Output】button to output the geometries files

Data_Materials.csv // (simulation index of structures)

F.Spectrum & Field Pattern

1. Set the Spectrum Analysis & Wavelength range

2. Check out the source

G.Calculation

1. Set the simulation time setp

2. Save parameters

3. Calculation

H.Result Analysis

★(Result Analysis)：

頻譜 (Spectrum) : Analysis the spectrum

Theoretical Solution refer to this web

bhmie_analytical.zip

https://drive.google.com/open?id=1TdyHFRQGLTOWf20DCmPLQbdFijPZmb3x

Theoretical Solution refer to these web

http://scatterlib.wikidot.com/mie

http://juluribk.com/2013/01/22/electric-field-at-localized-plasmon-resonance-using-meep/

Code :

clear all

a=100 ; %The normalization unit used in the simulation

rad=2; % radius of the sphere in normalized units, If a=100 then radius =2*100 nm

resl=10 ; % Normalized Resolution of the simulation domain if resl = 10 and a=100 then the actual resolution in nm is a/resl=100 nm/10=10 nm

fcen=0.3 ; % Central frequency of the source in normalized units if fcen =0.3 then the actual central wavelength is a/fcen =100/0.3=333 nm

df=0.3 ; % Frequency span of the source in normalized units

nfreq=60; % Number of wavelengths in the wavelenth spectrum to calculate the electric field, extinction

sample=10; %

decayby=1e-8 ; % This determines the accuracy. Smaller this value, longer the simation time, but more accurate calculations.

mpirun_bool=1 ; % controls whether computation is on parallel (uses multiple processors on a computer) or serial.

rad=a*rad; % Should be in nanometers.

lam=[200:2:2000]; % Should be in nanometers

[epsr,epsi,N]=LD(lam*1e-9,'Ag','LD');

for k=1:1:length(lam)

x=2*pi*rad/lam(k);

[s1,s2,qext,qsca,qback,gsca]=mie(x,N(k),2);

temp(:,k)=[qsca,qext,qext-qsca];

end

temp=temp';

plot(lam,temp)

xlabel('Wavelength (nm)')

ylabel('Efficiencies')

legend('Scattering','Extinction','Absorption')

temp2=[lam',temp(:,1),temp(:,2),temp(:,3)];

save('analytical.dat','temp2','-ascii')

print('silver_analytical.png','-dpng','-r100') 

Field pattern analysis

The simulation results show the first order resonance is at about wavelength 1095 nm,

the second order resonance wavelength at about 625nm,

the maximum absorption peak at about 300 nm

Method 1, Using the 【Geometries Sweep】function to sweep the frequencies

refer to the instruction web-page:

Geometries Sweep-Frequencies

Method 2, press 【saveas project】, and use the continue wave input

F.Spectrum & Field Pattern

1. Set the Spectrum Analysis & Wavelength range

2. Check out the source

(Wavelength) = 1095 nm

G.Calculation

1. Set the simulation time setp

2. Save parameters

3. Calculation

H.Result Analysis

★(Result Analysis)：

頻譜 (Spectrum) : Analysis the Field pattern

(Wavelength) = 1095 nm

Localized Surface Plasmon Resonance - Dipole

the same can obtain

(Wavelength) = 625 nm

Localized Surface Plasmon Resonance - Quadrupole

(Wavelength) = 300 nm for Absorption

Temporary fields analysis

instruction webpage : Temporary Field Analysis - Make a gif file