| ID |
Date |
Author |
Status |
Type |
Category |
Location |
Title |
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14
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Fri Feb 1 13:39:21 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Mirrors checked with binocular microscope |
29/01/19 - ThomX mirrors have also been checked with binocular microscope. They shown the same spots as S-BOX mirrors.
1st image shows reflective face of a spherical mirror.
2nd image shows reflective face of M1 (sapphire). |
| Attachment 1: 41_THOMX_SphericalZoom1x.jpg
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| Attachment 2: 49_THOMX_M1ReflectiveZoom4x.jpg
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15
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Fri Feb 1 14:10:25 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Other | Mirrors sent to LMA |
30/01/19 - As LMA people came, we discussed about the spots on ThomX mirrors which should be clean. As mentionned in "SBOX commissioning", these spots are normal.
An other question appeared during the conversation about the storage time and location of these mirrors. They have been stored for more than two years in plastic boxes. LMA people explained that some company do not let anything more than 6 months in these boxes for pollution issues.
We merged into the same conclusion, clean the mirrors in case of pollution. Finally, they took the mirrors and we will go to LMA to recover them between 11/02 and 14/02. |
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18
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Tue Mar 19 16:35:32 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Beam size and finesse |
FSR initiale : 33.34 MHz (S3 = -825000 et S4 = -825000)
Beam size initiale : wx=2.05mm et wy=2.15mm
Finesse initiale : 3400
FSR après éloignement des miroirs sphériques : 33.29 MHz (S3 ~= -1496000 et S4 ~= -1496000)
Beam size : wx=1.7mm et wy=1.85mm
Finesse : 3600
FSR après rapprochement des miroirs sphériques : 33.39 MHz (S3 ~= -250000 et S4 ~= -500000)
Beam size : wx = 2.1mm et wy=2.4mm
Fit de la caméra jamais au dessus de 90%. ~~80%. |
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21
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Tue Mar 26 18:26:32 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Check of mirrors and coating directions |
Direction of HR face of P1 and P4 have been checked, there was no problem. The mirrors are in the good direction and the coating is on the good face.
Once P1 and P4 outside of the cavity, we checked the coating position by sending the HeNe laser with an angle. There was two reflections and the most intense was the one closer to the normal to the mirror.
On P4 we noticed a spot which seems to be in the coating (does not move while sending nitrogen). |
| Attachment 1: ThomX_P4.jpg
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25
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Tue Apr 2 17:59:18 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Finesse after removing wires |
19/04/01: We removed the wires from the beam path in the cavity. Finesse stayed at 3400. FSR: 33.342 MHz.
When locked:
Input Power: ~4mW
Through S2: ~0.950uW
Through S3: ~0.930uW
Through P4: ~0.850uW |
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26
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Tue Apr 2 18:03:31 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Transmission of the mirrors |
We openned the cavity, removed S2 and measured trans of P1 and same for S2.
Pin ~= 3.91 mW
PS2 ~= 20 nW --> ~~ 5 ppm !!!
PP1 ~= 5.23 uW --> ~~ 1337 ppm !?!?!
P1 is the Sapphire mirror. 3mm thick. Tomorrow we'll measure its trans again, being out of the mount for constraint issues. |
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27
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Tue Apr 2 18:05:46 2019 |
Loïc Amoudry | Fixed | info | lasers and optics | Optical room | Beam size at closest spherical mirrors position |
S3 and S2 @ +1 640 000 and P1 and P4 @ -825 000
Diameter in x: 4.7mm
Diameter in y: 4.7mm |
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28
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Thu Apr 4 09:42:12 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Transmission of the mirrors |
After verification, transmission of P1 correspond to ~150ppm.
The 1337ppm come from a beam leakage. Reflection from P1 goes to the input window which reflects again a part of the beam directly into the cavity between P1 and S3 then between P4 and S2.
| Loïc Amoudry wrote: |
|
We openned the cavity, removed S2 and measured trans of P1 and same for S2.
Pin ~= 3.91 mW
PS2 ~= 20 nW --> ~~ 5 ppm !!!
PP1 ~= 5.23 uW --> ~~ 1337 ppm !?!?!
P1 is the Sapphire mirror. 3mm thick. Tomorrow we'll measure its trans again, being out of the mount for constraint issues.
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29
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Fri Apr 5 11:18:47 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Transmission of the mirrors |
P1 transmission out of the mount (means angle of the mirror is not the real angle):
Pin = 3.2 mW
Pout = 545 nW
Offset = 68 nW
Transmission = (545-68)/3.2e6 = 149 ppm
| Loïc Amoudry wrote: |
|
After verification, transmission of P1 correspond to ~150ppm.
The 1337ppm come from a beam leakage. Reflection from P1 goes to the input window which reflects again a part of the beam directly into the cavity between P1 and S3 then between P4 and S2.
| Loïc Amoudry wrote: |
|
We openned the cavity, removed S2 and measured trans of P1 and same for S2.
Pin ~= 3.91 mW
PS2 ~= 20 nW --> ~~ 5 ppm !!!
PP1 ~= 5.23 uW --> ~~ 1337 ppm !?!?!
P1 is the Sapphire mirror. 3mm thick. Tomorrow we'll measure its trans again, being out of the mount for constraint issues.
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30
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Fri Apr 5 11:28:39 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Finesse with P1 SUPRASIL |
P1 SUPRASIL has been installed instead of P1 Sapphire. It has been cleaned 3 times on each face with wipe+isopropanol before to be installed.
Finesse ~= 10 000 - 11 000 (EOM Sweep of 100 kHz in 10sec, see last image.)
Coupling ~= 45%
Motors position:
P1 = -825 000
S2 = +825 000
S3 = +825 000
P4 = -825 000 |
| Attachment 1: 190404_mode_size_with_P1_SUPRASIL.PNG
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| Attachment 2: 190404_mode_fit_with_P1_SUPRASIL.PNG
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| Attachment 3: tek00000.png
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| Attachment 4: tek00002.png
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31
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Mon Apr 8 10:18:31 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Finesse after 2days |
Finesse measured this morning after P1 SUPRASIL being into the cavity for two days. In order to check if it's getting dirty.
Finesse still ~= 11 000 |
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32
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Mon Apr 8 11:55:40 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | P4 cleaned and finesse measurement |
P4 cleaned with isopropanol.
Finesse measured afterward: ~=13 000 (clear increase) |
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33
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Wed Apr 10 13:11:46 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Mirror's cleaning and finesse |
Summary of what have been cleaned the last week:
P1 with isopropanol, finesse 11000
P4 with isopropanol, finesse 13000
S2 with isopropanol, finesse 13000
S3 with isopropanol, finesse 14000
S2 with isopropanol, finesse 14000
P4 with isopropanol, finesse 12500
P4 with isopropanol, finesse 12500
Finesse decreased with last steps which probably means our cleaning technique is at its maximum. We will probably try a cavity axis change with the mirror's motors to increase the finesse to the maximum like that.
Next step is to clean P1 with acetone + pur ethanol, then install the Onefive. |
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34
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Thu Apr 18 16:07:23 2019 |
Loïc Amoudry | Fixed | info | lasers and optics | Optical room | Injection of 33MHz Onefive through fiber |
Output power of the Onefive, and power after injection and different components have been measured.
Coupling ~= 90%
Each of our two EOM roughly have the same loses ~3dB |
| Attachment 1: power_ouput_Onefive.PNG
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| Attachment 2: power_after_injection_and_point9dB_blue_fiber.PNG
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| Attachment 3: power_after_halfwaveplate_and_injection_and_point9dB_blue_fiber.PNG
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| Attachment 4: power_after_halfwaveplate_and_injection_and_point9dB_blue_fiber_and_EOM_NIR-MPX-LN-0dot1.PNG
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| Attachment 5: power_after_halfwaveplate_and_injection_and_point9dB_blue_fiber_and_EOM_NIR-MPX-LN-02.PNG
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35
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Thu Apr 18 16:17:53 2019 |
Loïc Amoudry | Fixed | issue | lasers and optics | Optical room | 33MHz Onefive power overtime decrease |
Power of the 33MHz Onfive decreases over time. Have to pay attention to that.
Note that air dryers have never been stopped.
10th april 2018: ~40mW (first picture, 10dB filter)
25th september 2018: ~36mW (second picture, 10dB filter)
16th april 2019: ~29mW (third picture, no filter)
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| Attachment 1: 180410_power_33mhz_1jours.PNG
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| Attachment 2: 180925_Power.JPG
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| Attachment 3: 190416_power_ouput_Onefive.PNG
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36
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Tue May 21 17:44:46 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | New Suprasil mirror from LMA |
14/05/19:
New Suprasil mirror received. It will replace the S-BOX suprasil mirror on ThomX which was already replacing the sapphire mirror.
First finesse measurement: 14000
Features sent by Christophe Michel:
"- Transmission mesurée (1064 nm)= 172 ppm ; Transmission estimée (1031 nm)= 140 ppm
- Réflexion (1064 nm)= 1025 ppm; doit être inférieure à 1031 nm
L'AR n'est pas bon alors que l'on obtenu 170 ppm pour le run de calage!
J'espère que vous pourrez néanmoins l'utiliser.
- Diffusion moyenne sur diamètre 12 mm: 2.6 ppm"
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37
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Tue May 21 17:49:30 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Finesse after cleaning (new suprasil mirror) |
15/05/19-20/05/19:
Cleaning of the mirrors:
Initial finesse 14000 @air
S2 with isopropanol, finesse 17000 @air
P4 with isopropanol, finesse 17000 @air
S3 with isopropanol, finesse 17000 @air
S3 with first contact, finesse 17000 @air
S2 with first contact, finesse 17000 @air |
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38
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Thu May 23 10:10:56 2019 |
Ronic Chiche | Fixed | report | lasers and optics | Optical room | Finesse measurement by decay time technique |
5 Files attached:
- Note on the technique and results for the present cavity on 2019, May 21th : F ~ 18 000
- 2Tektronix scope raw data
- 2 matlab files to fit the scope raw data and extract the Finesse |
| Attachment 1: 2019-05-21_-_Finesse_measurement_by_decay_time_technique.docx
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| Attachment 2: tek0005CH1.isf
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| Attachment 3: tek0006CH1.isf
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| Attachment 4: plotdata.m
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clear
clc
global datacut tcut Trt
[h,data]=myisfread('tek0005CH1.isf');
dt=h.Xincr;
Nt=h.Npoints;
t=0:dt:(Nt-1)*dt;
t=t';
% offset removing
offset=mean(data(0.9*Nt:Nt));
data=data-offset;
% magnitude calculation
datamax=mean(data(1:0.1*Nt));
% cuting data to remove constant part at the beginning of the signal
% and where log(data) becomes complex (signal close to zero is sometime negative)
id1=find(data<0.967*datamax);
id2=find(imag(log(data))~=0);
tcut=t(id1(1):id2(1)-1);
datacut=data(id1(1):id2(1)-1);
%fit
L=9;
c=3e8;
Trt=L/c;
rho=1-1.5e-4;
k=1-15e-4;
pc0=0.14;
t0=2e-3;
x0=[rho k pc0 t0];
options = optimset('Display','iter','PlotFcns',@optimplotfval,'TolX',1e-7,'TolFun',1e-7);
x=fminsearch('myerror',x0,options);
rho=x(1);
k=x(2);
pc0=x(3);
t0=x(4);
datafit=pc0/(rho-k)^2*((1-k)*rho.^((tcut-t0)/Trt)-(1-rho)*k.^((tcut-t0)/Trt)).^2;
%%
figure(1)
clf
plot(t*1e3,data)
grid on
xlabel('Time (ms)')
ylabel('Transmited power (A.U)')
figure(2)
clf
plot(tcut*1e3,log(datacut))
hold on
plot(tcut*1e3,log(datafit),'.')
grid on
xlabel('Time (ms)')
ylabel('Log(Transmited power) (A.U)')
legend('data','fit')
Tpin=Trt/2/abs(log(k));
Tcav=Trt/2/abs(log(rho));
F=2*pi*Tcav/Trt;
disp(['Finesse : ' num2str(F)])
disp(['Cavity decay time : ' num2str(Tcav*1e6) ' µs'])
disp(['Pin sw decay time : ' num2str(Tpin*1e6) ' µs'])
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| Attachment 5: myerror.m
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function [ output ] = myerror( x )
%MYERROR Summary of this function goes here
% Detailed explanation goes here
global tcut datacut Trt
rho=x(1);
k=x(2);
pc0=x(3);
t0=x(4);
mydata=pc0/(rho-k)^2*((1-k)*rho.^((tcut-t0)/Trt)-(1-rho)*k.^((tcut-t0)/Trt)).^2;
output=sum((mydata-datacut).^2);
end
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39
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Thu May 23 17:30:03 2019 |
Loïc Amoudry | Fixed | report | lasers and optics | Optical room | Transmission of Sapphire mirror |
See image. |
| Attachment 1: Sapphire_transmission.PNG
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42
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Wed Jun 12 17:49:20 2019 |
Loïc Amoudry | Fixed | info | lasers and optics | Optical room | Polarization |
Polariztion measured with Input vertically/horizontally polarized (~100% DOLP)
- Transmission (P4) locked on cavity horizontal polarization is ~50% linearly polarized and ~50% unpolarized ?
- Transmission (P4) locked on cavity vertical polarization is ~50% linearly polarized and ~50% unpolarized ? |
| Attachment 1: Polar_horiz_trans_P4.PNG
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| Attachment 2: Polar_vert_trans_P4.PNG
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| Attachment 3: Polar_vert_input.PNG
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