| ID |
Date |
Author |
Status |
Type |
Category |
Location |
Title |
|
5
|
Tue Oct 9 10:15:17 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Polarization optimization |
Optimization of the polarization has been made the 03/10/18. Checked in reflection of the cavity in reflection&transmission of a PBS, locked and unlocked. Only with 2nd stage.
Ratio values are reflection of PBS divided by transmission or the opposite.
| |
Unlock value |
Ratio min/max |
Lock value |
Ratio min/max |
| No optimization |
|
|
|
|
| Reflection |
1.21 |
X |
3.89 |
X |
| Transmission |
14.3 |
8.5 % |
3.1 |
80 % |
| Only Lambda/2 |
|
|
|
|
| Reflection |
4.4 |
X |
2.91 |
X |
| Transmission |
11 |
40 % |
2.79 |
96 % |
| 2xLambda/2 + 1Lambda/4 |
|
|
|
|
| Reflection |
8.3 |
X |
3.4 |
X |
| Transmission |
6.8 |
82 % |
2.2 |
65 % |
| Same + PID optimization |
|
|
|
|
| Reflection |
9 |
X |
3.35 |
X |
| Transmission |
5.76 |
64 % |
2 |
60 % |
|
|
6
|
Tue Oct 9 10:19:29 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Record power-up |
Measurement made on 03/10/18 (nothing has been done since there).
Stable power in the cavity of 225 kW.
| 3rd stage current |
Transmission (mW) |
Pin (W) |
| 0 |
8 |
0.37 |
| 2 |
|
5.3 |
| 2.2 |
145 |
6.4 |
| 3 |
|
10.7 |
| 4 |
350 |
16.1 |
| 5 |
|
21.8 |
| 6 |
|
27.3 |
| 7 |
|
32 |
| 8 |
|
36.7 |
| 8.5 |
640 |
39.1 |
|
|
7
|
Thu Oct 18 09:42:39 2018 |
Loïc Amoudry | Fixed | report | mechanics | lasers and optics | Optical room | Motors for D-shaped mirrors |
Motors have been installed on 16/10/18. No problem with them.
Effect of the motors tested on 17/10/18. No improvement. But they give the possibility to perfectly cut HOM or let them go through as show the following picture of a 2.2 mode at ~340 mW in trans and 70% coupling @4A. |
| Attachment 1: tek00000.png
|
 |
| Attachment 2: tek0000CH1.isf
|
| Attachment 3: tek0000CH2.isf
|
| Attachment 4: tek0000CH3.isf
|
| Attachment 5: tek0000CH4.isf
|
|
8
|
Fri Oct 19 11:13:40 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Transmission vs D-shape position at different powe |
Measurements have been done on 18/10/18.
Datas are on excel file, also matlab file. |
| Attachment 1: Plot_matlab.JPG
|
 |
| Attachment 2: motors.xlsx
|
| Attachment 3: Power_stored_vs_Dshape_mirrors_position.m
|
clear all
close all
P0A_V = [9.34 9.25 9 8.5 7.3 5.2 3.5 1.9 0.7 0.2];
Step0A_V = [0:0.1:0.9];
P0A_H = [9.15 9.1 9 8.75 8.4 7.9 6.6 4.45 2 0.6 0.15];
Step0A_H = [0:0.1:1];
P2A_V = [116 113 111 99 80 53 35 19 6 1.8];
Step2A_V = [0:0.1:0.9];
P2A_H = [113 112.7 112.5 112 110.5 107 101 93.5 78 53 24 7.8 1.9];
Step2A_H = [0:0.1:1.2];
P4A_V = [325 311 288 240 178 116 73 40 13];
Step4A_V = [0:0.1:0.8];
P4A_H = [323 320 318 310 290 254 224 172 104 45 12];
Step4A_H = [0:0.1:1];
subplot(3,1,1)
xlabel('Déplacement des D-shape, o = vertical et * = horizontal')
ylabel('Puissance stockée')
title('Mesures à 0A')
hold on
plot (Step0A_V,P0A_V/9.34,'o-')
plot (Step0A_H,P0A_H/9.15,'*-')
hold off
subplot(3,1,2)
xlabel('Déplacement des D-shape, o = vertical et * = horizontal')
ylabel('Puissance stockée')
title('Mesures à 2A')
hold on
plot (Step2A_V,P2A_V/116,'o-')
plot (Step2A_H,P2A_H/113,'*-')
hold off
subplot(3,1,3)
xlabel('Déplacement des D-shape, o = vertical et * = horizontal')
ylabel('Puissance stockée')
title('Mesures à 4A')
hold on
plot (Step4A_V,P4A_V/325,'o-')
plot (Step4A_H,P4A_H/323,'*-')
hold off
|
|
9
|
Fri Oct 19 11:23:27 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Beam size vs D-shape position |
Measurement done on 18/10/18.
At high power, the shape of the 0.0 mode does not change. The D-shape only generate losses in the cavity. Then the power stored in the cavity decrease. As with this configuration, the cavity beam size decrease when power increase, the beam size decreased.
Measurements done @4A on 3rd stage.
| x (um) |
y (um) |
Picomotors displacement (um) |
Transmission power (mW) |
| 1820 |
2013 |
0 |
337 |
| 1820 |
2013 |
200 |
330 |
| 1925 |
2029 |
400 |
306 |
| 1936 |
2090 |
600 |
245 |
| 2117 |
2249 |
800 |
125 |
| 2260 |
2392 |
1000 |
17 |
Then we get the D-shape away from the beam to not cut it and decreased the amplifier power to validate the beam size at a known value. So the power as been decreased to 2A (= 125 mW in trans) and the beam size was x=2079 y=2255, similar to the 125 mW with D-shape mirrors values. |
| Attachment 1: 181018_4A_no_cut.PNG
|
 |
|
10
|
Fri Oct 19 11:46:21 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Beam size vs D-shape position |
Matlab code for size vs position and power :
clear all
close all
x = [1820 1820 1925 1936 2117 2260];
y = [2013 2013 2029 2090 2249 2392];
Position = [0 0.2 0.4 0.6 0.8 1];
Trans = [337 330 306 245 128 17]
hold on
[ax,h1,h2] = plotyy(Position,x,Position,Trans)
set(get(ax(1), 'Ylabel'), 'String', 'Beam diameter (um)');
set(get(ax(2), 'Ylabel'), 'String', 'Transmitted power (mW)');
xlabel('Position of the D-shape (mm)')
plot(Position,y,'g')
hold off
| Loïc Amoudry wrote: |
|
Measurement done on 18/10/18.
At high power, the shape of the 0.0 mode does not change. The D-shape only generate losses in the cavity. Then the power stored in the cavity decrease. As with this configuration, the cavity beam size decrease when power increase, the beam size decreased.
Measurements done @4A on 3rd stage.
| x (um) |
y (um) |
Picomotors displacement (um) |
Transmission power (mW) |
| 1820 |
2013 |
0 |
337 |
| 1820 |
2013 |
200 |
330 |
| 1925 |
2029 |
400 |
306 |
| 1936 |
2090 |
600 |
245 |
| 2117 |
2249 |
800 |
125 |
| 2260 |
2392 |
1000 |
17 |
Then we get the D-shape away from the beam to not cut it and decreased the amplifier power to validate the beam size at a known value. So the power as been decreased to 2A (= 125 mW in trans) and the beam size was x=2079 y=2255, similar to the 125 mW with D-shape mirrors values.
|
|
| Attachment 1: size_vs_position_and_power.JPG
|
 |
|
11
|
Wed Oct 31 11:27:49 2018 |
Loïc Amoudry | Fixed | report | mechanics | lasers and optics | Optical room | Power measurement with D-shape |
Measurements of lot of points with D-shape mirrors well positionned.
Power not optimized to the best but almost. (@4A could have 350 mW).
| I (A) |
Ptrans (mW) |
Coupling (%) |
|
0
|
8 |
62 |
| 1 |
18 |
67 |
| 1.3 |
43 |
72 |
| 1.6 |
76 |
72 |
| 1.9 |
112 |
72 |
| 2.2 |
145 |
72 |
| 2.5 |
177 |
72 |
| 2.8 |
217 |
72 |
| 3.1 |
253 |
72 |
| 3.4 |
281 |
72 |
| 3.7 |
300 |
72 |
| 4 |
323 |
71 |
| 4.3 |
249 |
71 |
| 4.6 |
379 |
68 |
| 4.9 |
402 |
68 |
| 5.2 |
417 |
67 |
| 5.5 |
435 |
67 |
| 5.8 |
441 |
65 |
|
|
12
|
Wed Oct 31 11:36:30 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | 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
|
clear all; close all;
tic
addpath(genpath('C:\Users\amoudry\desktop\Fichiers Labo\Fichiers Pierre\Simulation\Personal codes\Various'))
[TAS,~,r] = GetCavity('SBOX_ULE');
[F,~] = Get_info(TAS(1:4),TAS(5:8),TAS(9:12));
lambda = 1030e-9;
c = 299792458;
FSR = 133.33e6;
w0 = 2*pi*c/lambda;
tau = 1e-12; % FWHM duration
a = 4*log(2)/tau^2;
E0 = 1;%(pi/2/a)^(1/2); % Energy to normalize gaussian spectrum (Input beam power = 1)
DeltaPhiCE = 0; % CEP
N = 1e5;
dk = 0:(N-1);
Aa = (r.^dk-r.^(2.*N-dk));
Bb = E0*TAS(1)./(1-r.^2);
Cc = (1-r.^(2.*N));
Nn = 5e2; % Increase Nn <-> increase resolution
dtt = -Nn:Nn;
dtt = dtt*lambda/c/(0.1*Nn); %1e6
Ecn = zeros(numel(dtt),1);
for ii = 1:numel(dtt)
for ll = 0:3
% ll = 0;
dt = dtt(ii)+ll*lambda/c;
Phid = DeltaPhiCE + w0.*dt;
temp_vect = Aa.*cos(dk.*Phid).*exp(-a.*dk.^2.*dt.^2./2);
Ecn(ii,ll+1) = Bb.*(2*sum(temp_vect)-Cc);
disp([num2str(ii)]);
end
end
toc
%% Time plots
% figure
% semilogy(dtt/lambda*c,Ecn/max(Ecn),'LineWidth',2)
% hold on
% semilogy(dtt/lambda*c,Ecn2/max(Ecn),'LineWidth',2)
% hold on
% semilogy(dtt/lambda*c,Ecn3/max(Ecn),'LineWidth',2)
% hold on
% semilogy(dtt/lambda*c,Ecn4/max(Ecn),'LineWidth',2)
% set(gca,'FontSize',15)
% xlabel('\DeltaT (\lambda/c)')
% ylabel('Energy (A.U.)')
% grid on
% legend('\DeltaT = 0','\DeltaT = \lambda/c','\DeltaT = 2\lambda/c','\DeltaT = 3\lambda/c')
% axis square
% figure
% semilogy(dtt/lambda*c,Ecn/max(Ecn),'LineWidth',2)
% grid on
% set(gca,'FontSize',25)
% % set(gca,'YLim',[1e-9 1e0])
% xlabel('\DeltaT (\lambda_0/c)')
% ylabel('log(Energie (u.a.))')
%% Frequency
nu0 = w0/2/pi;
frep = (1/FSR-nu0/FSR*dtt).^(-1); % Infinity in dtt = 1/nu0
fprintf('\nFinesse : %g\n\n',F);
% Get linewidth
figure
for jj = 1:4
% Find the 2 minimas of Ecn_half. Take the corresponding frep and
% substract them
Ecn_half = abs(Ecn(:,jj)-max(Ecn(:,jj))/2);
Ecn_half2 = sort(Ecn_half);
[row1,~] = find(Ecn_half==Ecn_half2(1),1);
[row2,~] = find(Ecn_half==Ecn_half2(2),2);
if numel(row2)>1 % Sometimes row can be a vector
row2 = row2(2);
end
dnu = abs(frep(row2)-frep(row1));
fprintf('RES %g\nMax gain : %g. Linewidth : %g kHz\n\n',jj-1,max(Ecn(:,jj)),dnu/1e3);
% plot((frep-FSR)/FSR,Ecn(:,jj)/max(Ecn(:,1)),'LineWidth',2)
% hold on
semilogy((frep-FSR)/FSR,Ecn(:,jj)/max(Ecn(:,1)),'LineWidth',2)
xlim([-0.05 0.05])
hold on
end
set(gca,'FontSize',15)
xlabel('(f_r_e_p-FSR)/FSR')
% ylabel('Energy (A.U.)')
ylabel('log(Energie (u.a.))')
grid on
legend('\DeltaT = 0','\DeltaT = \lambda/c','\DeltaT = 2\lambda/c','\DeltaT = 3\lambda/c')
axis square
% axis([-0.01 0.01 10^-6 1])
|
| Attachment 2: GetCavity.m
|
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
|
|
13
|
Wed Oct 31 13:42:22 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Polarization frequency |
Check of the frequency of the onefive locked on each polarization of the cavity (tilt a waveplate by 45°).
Frequency repetition rate : 133.335 MHz on spectrum analyzer for both polarization locked. |
|
14
|
Wed Oct 31 13:43:03 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Polarization frequency |
Measurement on 30/10/18.
| Loïc Amoudry wrote: |
|
Check of the frequency of the onefive locked on each polarization of the cavity (tilt a waveplate by 45°).
Frequency repetition rate : 133.335 MHz on spectrum analyzer for both polarization locked.
|
|
|
15
|
Wed Oct 31 13:43:28 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Finesse vs power by difference between main and second resonance |
Measurement on 24/10/18
| Loïc Amoudry wrote: |
|
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 |
|
|
|
16
|
Wed Oct 31 13:44:22 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Finesse vs power by difference between main and second resonance |
Measurement on 25/10/2018
| Loïc Amoudry wrote: |
|
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 |
|
|
|
17
|
Wed Oct 31 13:48:58 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | M1 transmission measurement |
Center of M1:
| I (A) |
Input power (mW) |
Transmitted power (mW) |
Transmission (ppm) |
| 0 |
78 |
0.01477 |
189 |
| 4 |
16500 |
3.2 |
194 |
|
|
18
|
Wed Oct 31 13:51:17 2018 |
Loïc Amoudry | Fixed | info | lasers and optics | Optical room | Change of the 3 ULE mirrors by 3 spare ULE mirrors |
First finesse measurement 20 266, FSR 133.351 MHz under vacuum |
| Attachment 1: Miroirs_à_1031_nm-ThomX_-_décembre2017.pdf
|
| Attachment 2: vacuum.isf
|
|
19
|
Wed Oct 31 14:03:22 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | M4 transmission measurement |
The kept transmission for M4 is 2.17 ppm. Which is the value measured after alignement (center of the mirror).
These measurements have been taken before alignement.
| I (A) |
Input power (mW) |
Transmitted power after window (mW) |
Transmission (ppm) |
| 0 |
74.3 |
195.2e-6 |
2.63 |
| 0 |
73.5 |
212.8e-6 |
2.89 |
| 0 |
52.4 |
151e-6 |
2.88 |
| 6 |
28 400 |
72e-3 |
2.54 |
High dependence against the position. Few measurement several mm away from the center each one at different position give 194, 193, 208, 200 ppm. |
|
20
|
Wed Oct 31 14:04:50 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | M4 transmission measurement |
| Loïc Amoudry wrote: |
|
The kept transmission for M4 is 2.17 ppm. Which is the value measured after alignement (center of the mirror).
These measurements have been taken before alignement.
| I (A) |
Input power (mW) |
Transmitted power after window (mW) |
Transmission (ppm) |
| 0 |
74.3 |
195.2e-6 |
2.63 |
| 0 |
73.5 |
212.8e-6 |
2.89 |
| 0 |
52.4 |
151e-6 |
2.88 |
| 6 |
28 400 |
72e-3 |
2.54 |
High dependence against the position. Few measurement several mm away from the center each one at different position give 2.86, 2.68, 2.93, 3.01, 3.06, 3.35 ppm.
|
|
|
21
|
Wed Oct 31 14:06:17 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | M1 transmission measurement |
At different positions, transmission give 194, 193, 208, 200 ppm?
| Loïc Amoudry wrote: |
|
Center of M1:
| I (A) |
Input power (mW) |
Transmitted power (mW) |
Transmission (ppm) |
| 0 |
78 |
0.01477 |
189 |
| 4 |
16500 |
3.2 |
194 |
|
|
|
22
|
Mon Nov 5 13:11:08 2018 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | First run with spare mirrors |
| I (A) |
Trans (mW) |
Coupling (%) |
Pin (W) |
Gain |
| 0 |
4 |
70 |
0.37 |
4982 |
| 2 |
58 |
80 |
5.2 |
5140 |
| 4 |
180 |
75 |
16.1 |
5152 |
| 6 |
270 |
63 |
27.3 |
4558 |
| 8 |
340 |
60 |
36.7 |
4269 |
|
| Attachment 1: Plot_power_and_gain_vs_all.JPG
|
 |
| Attachment 2: powerup.xlsx
|
|
23
|
Thu Nov 15 13:02:44 2018 |
Loïc Amoudry | Fixed | info | lasers and optics | Optical room | Mirrors cleaning |
The new mirrors didn't give expected results. Then the 4 old mirrors have been sent to LMA on 12/11/18 for a cleaning and caracterization before and after cleaning. Also asked for a diffusion/absorption map on the mirrors if possible. They didn't really answered on what will they do.
Received on 13/11/18 by LMA. |
|
24
|
Fri Dec 21 13:42:43 2018 |
Loïc Amoudry | Fixed | info | lasers and optics | Optical room | Mirrors features, come back from LMA |
Mirrors arrived today from LMA. Their features are damaged.
Photos avant ou après nettoyage, pas clair dans le mail de Laurent :
"J'ai commencé à nettoyer M1 et M2 avec notr methode habituelle et je me suis aperçu que sur la partie centrale (en gros taille de ton faisceau j'ai l'impression) que des choses apparaissaient (voir photo)
Si bien que la diffusion n'a pas évolué dans le bon sens (diminution) voir empiré pour M1. J'ai donc arrêter de les nettoyer !!!
J'ai regardé les faces arrières des miroirs avant nettoyage et j'ai pu voir ce que tu vois sur la photo même au centre. Je sais pas de quoi cela peut venir.
Une chose est sûre le coating IBS a été altéré par je ne sais quoi dans ta manip provoquant cette dégradation dès qu'on y touche. L'interaction avec les faisceaux d'eélectrons n'avait jamais altéré les miroirs sur l'expértience DESY par exemple!!
Pour me rassurer, j'ai pris un miroir fait sur un micropoli qu'on a en stock et aucun pb lors du nettoyage (on peut penser à tout)"
|
| Attachment 1: 181201_caracteristiques_miroirs.PNG
|
 |
| Attachment 2: 20181207_155704_resized.jpg
|
 |
| Attachment 3: 20181207_155726_resized.jpg
|
 |