中文/English
目的 : 模擬半徑 200nm (直徑 400 nm)奈米金屬圓球其散射吸收頻譜,並與理論解析解比較。
Dipole
波長 (Wavelength) = 1095 nm
局域表面電漿共振
Localized Surface Plasmon Resonance
Quadrupole
波長 (Wavelength) = 625 nm
局域表面電漿共振 Localized Surface Plasmon Resonance - Quadrupole
範例結果與CAD下載:
Sphere_Mie_diameter400nm_metal.zip
https://drive.google.com/open?id=15m0DXK2uKcpYmsZJEdFhIf5WDoU47Sw3
解析解 Analytical Solution :
bhmie_analytical.zip
https://drive.google.com/open?id=1TdyHFRQGLTOWf20DCmPLQbdFijPZmb3x
http://scatterlib.wikidot.com/mie
http://juluribk.com/2013/01/22/electric-field-at-localized-plasmon-resonance-using-meep/
場圖分析結果範例下載:
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
其中*.FCstd是FreeCAD的存檔
結構檔案加上邊界(使用FreeCAD)
參考 : 3D-CAD 範例 (流程簡介)
1. 選取模擬的維度
2. 定義總x,y,z長度相等於模型檔案,然後調整適當的各軸解析度
3. 匯入模型檔案
4. 確定模擬材料定義
5. 按【建立網格 Cad to Grids (Create)】按鈕建立模擬網格
* 材料使用 Electric Model1, 這裡注意: 在CAD裡結構的單位是mm,然而載入風行後單位為nm,由於FreeCAD的預設長度為 mm,如果使用nm、FreeCAD輸出的 STL網格數會不足。因此這邊也展示
單位是可以轉換的 nm <=> um <=> mm
計算散色吸收頻譜、選擇 雷達截面場
沒有使用探測與元件,直接按 【創建(Create)】
最後檢查結構,按 輸出Output
理論解析解 (Analytical Solution) :
bhmie_analytical.zip
https://drive.google.com/open?id=1TdyHFRQGLTOWf20DCmPLQbdFijPZmb3x
http://scatterlib.wikidot.com/mie
http://juluribk.com/2013/01/22/electric-field-at-localized-plasmon-resonance-using-meep/
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')
場圖分析
由模擬結果頻譜得知第一階共振峰約在波長 1095 nm、第二階共振峰約在波長625 nm、吸收頻譜最大值約在 波長 300 nm。
(方法1) 使用【參數結構掃描】功能進行批次頻率運算
連結教學
(方法2) 另存專案,重新計算使用連續波(CW wave)輸入
1.設定頻譜分析 & 觀測波長範圍
2.檢察波源
設定連續波輸入,波長 (Wavelength) = 1095 nm
波長 (Wavelength) = 1095 nm
局域表面電漿共振 Localized Surface Plasmon Resonance - Dipole
同樣的可得
波長 (Wavelength) = 625 nm
局域表面電漿共振 Localized Surface Plasmon Resonance - Quadrupole
波長 (Wavelength) = 300 nm
金屬吸收
結果 :
Dipole
波長 (Wavelength) = 1095 nm
局域表面電漿共振
Localized Surface Plasmon Resonance
Quadrupole
波長 (Wavelength) = 625 nm
局域表面電漿共振 Localized Surface Plasmon Resonance - Quadrupole
建議參考資料與模擬:
Localized Surface Plasmon Resonance Spectroscopy and Sensing, Katherine A. Willets and Richard P. Van Duyne
https://pdfs.semanticscholar.org/8101/b9e4d794020a8924ef7fec815f3628c47290.pdf
Lumerical FDTD Solution:
Methodology - Fluorescence Enhancement
https://kb.lumerical.com/en/sp_methodology_fluorescence_enhancement.html
Mie Scattering 3D (FDTD)
https://kb.lumerical.com/en/particle_scattering_mie_3d.html