反射系数和透射系数随入射角的变化曲线

已知界面两侧的折射率n2,n1和入射角θ，绘出n1<n2（由光疏介质射向光密介质）和n1>n2（由光密介质射向光疏介质）两种情况下，反射系数和透射系数随入射角的变化曲线

// An highlighted block

clear;
disp('请输入介质折射率n1和n2');
n1=input('n1=');
n2=input('n2=');
theta=0:0.1:90;
a=theta*pi/180;
rp=(n2*cos(a)-n1*sqrt(1-(n1/n2*sin(a)).^2))./(n2*cos(a)+n1*sqrt(1-(n1/n2*sin(a)).^2));
tp=(2*n1*cos(a))./(n2*cos(a)+n1*sqrt(1-(n1/n2*sin(a)).^2));
rs=(n1*cos(a)-n2*sqrt(1-(n1/n2*sin(a)).^2))./(n1*cos(a)+n2*sqrt(1-(n1/n2*sin(a)).^2));
ts=(2*n1*cos(a))./(n1*cos(a)+n2*sqrt(1-(n1/n2*sin(a)).^2));
figure(1);
subplot(121);
plot(theta,rp,'-',theta,rs,'--',theta,abs(rp),'-.',theta,abs(rs),':','LineWidth',2);
legend('rp','rs','|rp|','|rs|');
xlabel('入射角\theta_i');
ylabel('振幅');
title(['n_1=',num2str(n1),'n_2=',num2str(n2),'时反射系数随入射角的变化曲线']);
axis([0 90 -1 1]);
grid on;
subplot(122);
plot(theta,tp,'-',theta,ts,'--',theta,abs(tp),'-.',theta,abs(ts),':','LineWidth',2);
legend('tp','ts','|tp|','|ts|');
xlabel('入射角\theta_i');
ylabel('振幅');
title(['n_1=',num2str(n1),'n_2=',num2str(n2),'时透射系数随入射角的变化曲线']);
if n1<n2
    axis([0 90 0 1]);
else
    axis([0 90 0 3.5]);
end
grid on;