patpat~ 不要哭。

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%不知道对不对，妹妹先试试看

clear;

close;

clc;

n1 = 1.445;

n2 = 3.445;

n3 = 0.1453 + i*11.3587;

n4 = 1;

h = 100*10^-9;

lamada = 1550*10^-9;

k0 = 2*pi/lamada;

b = 70*10^-9;

n = 1;

N0 = 0.1453 + i*11.3587;

syms N1

delta3=(1+((N1^2-n4^2)^(1/2)-(N1^2-n3^2)^(1/2))/((N1^2-n4^2)^(1/2)+(N1^2-n3^2)^(1/2))*exp(-2*k0*(N1^2-n3^2)^(1/2)*h)) ...

/(1-((N1^2-n4^2)^(1/2)-(N1^2-n3^2)^(1/2))/((N1^2-n4^2)^(1/2)+(N1^2-n3^2)^(1/2))*exp(-2*k0*(N1^2-n3^2)^(1/2)*h));

f=-k0*(n1^2-N1^2)^(1/2)+n*pi+atan((N1^2-n2^2)^(1/2)/(n1^2-N1^2)^(1/2))-atan((N1^2-n2^2)^(1/2)/(n1^2-N1^2)^(1/2)*delta3);

ezplot(f);

solve(f,'N1')