% FP Cavity HOM Frequencies Estimate
% Alberto Stochino, October 2008

R1 = 7280;      % Mirror1 radius of curvature
R2 = 57.57;     % Mirror2 radius of curvature
L = 38.458;     % Length of the FP Cavity
n = 1;          % X Order of the Mode
m = 0;          % Y Order of the Mode

c = 299792458;  % Speed of Light

g1 = 1 - L/R1;  % g1 factor
g2 = 1 - L/R2;  % g2 factor

fsr = c/2/L

f_plus = (1+(m+n+1)*acos(sqrt(g1*g2))/pi)*c/2/L

% f_minus = (1+(m+n+1)*acos(-sqrt(g1*g2))/pi)*c/2/L