clear
clc

% simulation parameters
c=299792458;            % light speed in vacuum
Frep=160.3084e6;        % laser repetition rate
D=0.07;                 % side distance between "output" windows of the vessel
DR=0.12;                % side distance between "input" windows of the vessel
L0=1.02;                % cavity box length
L3=0.505;               % distance between spherical mirrors

theta1=linspace(0.115,0.120,1e3);

% calculated parameters
Lrt=c/Frep;
theta2=2*atan(1./((Lrt/D)-1./tan(theta1/2)));
L2=D./sin(theta2);
L4=D./sin(theta1);
L1=Lrt-L2-L3-L4;

LM3=(DR-D)./tan(theta2);
LM2=L0-DR./tan(theta2);
LM1=L0-L1-LM2;
LM4=L0-L3-LM3;

id=LM1>0.15 & LM2>0.15 & LM3>0.15 & LM4>0.15 & abs(LM1-LM3)>0.08 & abs(LM2-LM4)>0.08;
L1(~id)=0;
L2(~id)=0;
L4(~id)=0;
LM1(~id)=0;
LM2(~id)=0;
LM3(~id)=0;
LM4(~id)=0;

figure(1)
clf
plot(theta1*1e3,L1)
hold on
plot(theta1*1e3,L2)
plot(theta1*1e3,L4)
plot(theta1*1e3,LM1)
plot(theta1*1e3,LM2)
plot(theta1*1e3,LM3)
plot(theta1*1e3,LM4)
grid on
legend('L1','L2','L4','LM1','LM2','LM3','LM4','location','best')
xlabel('theta1 angle (mrad)')
ylabel('length parameters (m)')

id=find(id~=0);
id=id(1);

disp(['LRT = ' num2str(Lrt) ' m'])
disp(['D = ' num2str(D*1e3) ' mm'])
disp(['theta1 = ' num2str(theta1(id)*1e3) ' mrad'])
disp(['theta2 = ' num2str(theta2(id)*1e3) ' mrad'])
disp(['L1 = ' num2str(L1(id)*1e3) ' mm'])
disp(['L2 = ' num2str(L2(id)*1e3) ' mm'])
disp(['L3 = ' num2str(L3*1e3) ' mm'])
disp(['L4 = ' num2str(L4(id)*1e3) ' mm'])
disp(' ')
disp(['L0 = ' num2str(L0) ' m'])
disp(['DR = ' num2str(DR*1e3) ' mm'])
disp(['LM1 = ' num2str(LM1(id)*1e3) ' mm'])
disp(['LM2 = ' num2str(LM2(id)*1e3) ' mm'])
disp(['LM3 = ' num2str(LM3(id)*1e3) ' mm'])
disp(['LM4 = ' num2str(LM4(id)*1e3) ' mm'])
disp(['LM3-LM1 = ' num2str((LM3(id)-LM1(id))*1e3) ' mm'])
disp(['LM2-LM4 = ' num2str((LM2(id)-LM4(id))*1e3) ' mm'])