HOME SBOX THOMX MINICAV Utilities
SBOX orders SBOX installation SBOX commissioning SBOX control command
  Status of commissioning, report also here plots are reports.  Not logged in ELOG logo
Entry   Finesse vs power by difference between main and second resonance, posted by Loïc Amoudry at Optical room about lasers and optics CrossSecondaryResonance.mGetCavity.m
    Reply   Finesse vs power by difference between main and second resonance, posted by Loïc Amoudry at Optical room about lasers and optics 
    Reply   Finesse vs power by difference between main and second resonance, posted by Loïc Amoudry at Optical room about lasers and optics 
Message ID: 12     Entry time: Wed Oct 31 11:36:30 2018     Reply to this: 15   16
 Author: Loïc Amoudry 
 Status: Fixed 
 Type: report 
 Category: lasers and optics 
 Location: Optical room 
 Title: Finesse vs power by difference between main and second resonance 

Measurements show that ratio decrease versus power. BUT, the second resonance measurement induce lower power in the cavity so the ratio is not directly true.

Also, simulation of the main/second resonance power by Pierre's simulation has shown ratio ~50, ~47.6 and 43.5 respectively for 0A, 2A and 4A.

I (A) Main resonance (mW) Second resonance (mW) Ratio
0 8.07 0.416 19.4
2 121 6.77 17.9
4 324 20.2 16

 

Attachment 1: CrossSecondaryResonance.m  2 kB  | Show | Hide all | Show all
Attachment 2: GetCavity.m  1 kB  | Hide | Hide all | Show all
function [TAS,r,r_prod] = GetCavity(cav_name,varargin)
% Return T and r coefficient of a given cavity
% TAS vector contains the 4 T coeffs, then 4 A coeffs, then 4 S coeffs

if strcmp(cav_name,'SBOX_ULE')==1
    TAS(1) = 180e-6;   % T
    TAS(2) = 2e-6;
    TAS(3) = 2e-6;
    TAS(4) = 2e-6;
    TAS(5) = 1.15e-6;  % A
    TAS(6) = 1.27e-6;
    TAS(7) = 1.2e-6;
    TAS(8) = 1e-6;
    TAS(9) =  7e-6;     % S
    TAS(10) = 4.5e-6;
    TAS(11) = 3.6e-6;
    TAS(12) = 9e-6;
%     TAS(1) = 180e-6;   % T
%     TAS(2) = 3.2e-6;
%     TAS(3) = 2.8e-6;
%     TAS(4) = 2.85e-6;
%     TAS(5) = 30e-6;  % A
%     TAS(6) = 30e-6;
%     TAS(7) = 30e-6;
%     TAS(8) = 30e-6;
%     TAS(9) = 20e-6;     % S
%     TAS(10) = 20e-6;
%     TAS(11) = 20e-6;
%     TAS(12) = 20e-6;
    
elseif strcmp(cav_name,'ThomX')==1
    TAS(1) = 120e-6;   % T
    TAS(2) = 1.5e-6;
    TAS(3) = 1.5e-6;
    TAS(4) = 1.5e-6;
    TAS(5) = 0.4e-6;  % A
    TAS(6) = 0.24e-6;
    TAS(7) = 0.24e-6;
    TAS(8) = 0.27e-6;
    TAS(9) = 4e-6;     % S
    TAS(10) = 4.5e-6;
    TAS(11) = 10e-6;
    TAS(12) = 4.5e-6;
    
elseif strcmp(cav_name,'MIGHTY_low')==1
    TAS(1) = 1060e-6;
    TAS(2) = 330e-6;
    TAS(3) = 330e-6;
    TAS(4) = 330e-6;
    TAS(5:12) = 0;

elseif strcmp(cav_name,'Fab_cav')==1
    TAS(1) = 100e-6;
    TAS(2) = 10e-6;
    TAS(3) = 10e-6;
    TAS(4) = 10e-6;
    TAS(5:12) = 0;
end

switch nargin
    case 2
        TAS = repmat(TAS,numel(varargin{1}),1);
        TAS(:,1) = varargin{1};
    case 3
        TAS = repmat(TAS,numel(varargin{1}),1);
        TAS(:,1) = varargin{1};
        TAS(:,2) = varargin{2};
end
    
% Field reflection coeffs
rr = @(TAS) (1-sum(TAS,2)).^(1/2);
for ii = 1:4
    r(:,ii) = rr(TAS(:,ii:4:12));
end
r_prod = prod(r,2);
end
ELOG V3.1.4-395e101