ELOG THOMX commissioning

Soudure des fibres des diodes de pompe 3^ème étage avec les fibres du recirculateur.
Câblage entre les 2 boitiers et fixation des fibres dans le boitier du 3^ème étage.

3^ème jour (26°) :

Connexion refroidissement à eau du recirculateur (chiller).
Soudure fibre CFBG avant 1^er étage (temporaire pour faire des mesure).
Mise en place des éléments 1^er et 2^ème étage sur le support de l’ampli.
Montée en puissance 35W.

4^ème jour :

Adaptation du mode de sortie en contrôlant la position de la fibre avant le collimateur.
Mesure de M².

Attachment 1: Ampli_ThomX.PNG

Attachment 2: M2_ThomX.png

Tue Jun 11 18:03:10 2019

Loďc Amoudry

Fixed

report

mechanics | lasers and optics

Other

Amplifier mission Bordeaux

Voyage Bordeaux au CELIA avec Jérôme LHERMITE (Loïc et Titoutan)

1^er jour (34°) :

Mesure du spectre et de la puissance des 4 diodes de pompe 3^ème étage jusqu’à ~60W (12A).
Mécanique et câblage ampli.

2^ème jour (30°) :

Soudure des fibres des diodes de pompe 3^ème étage avec les fibres du recirculateur.
Câblage entre les 2 boitiers et fixation des fibres dans le boitier du 3^ème étage.

3^ème jour (26°) :

4^ème jour :

Adaptation du mode de sortie en contrôlant la position de la fibre avant le collimateur.
Mesure de M².

Attachment 1: 1st_and_2nd_stage.jpg

Attachment 2: 3rd_stage_pumps.jpg

Attachment 3: 3rd_stage_signal.jpg

Thu May 23 17:30:03 2019

Transmission of Sapphire mirror

See image.

Attachment 1: Sapphire_transmission.PNG

Thu May 23 10:10:56 2019

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

Attachment 2: tek0005CH1.isf

Attachment 3: tek0006CH1.isf

Attachment 4: plotdata.m

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) ' ľs'])
disp(['Pin sw decay time : ' num2str(Tpin*1e6) ' ľs'])

Attachment 5: myerror.m

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

Tue May 21 17:49:30 2019

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

Tue May 21 17:44:46 2019

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"

Thu Apr 18 16:17:53 2019

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)

Attachment 1: 180410_power_33mhz_1jours.PNG

Attachment 2: 180925_Power.JPG

Attachment 3: 190416_power_ouput_Onefive.PNG

Thu Apr 18 16:07:23 2019

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

Attachment 2: power_after_injection_and_point9dB_blue_fiber.PNG

Attachment 3: power_after_halfwaveplate_and_injection_and_point9dB_blue_fiber.PNG

Attachment 4: power_after_halfwaveplate_and_injection_and_point9dB_blue_fiber_and_EOM_NIR-MPX-LN-0dot1.PNG

Attachment 5: power_after_halfwaveplate_and_injection_and_point9dB_blue_fiber_and_EOM_NIR-MPX-LN-02.PNG

Wed Apr 10 13:11:46 2019

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.

Mon Apr 8 11:55:40 2019

P4 cleaned and finesse measurement

P4 cleaned with isopropanol.

Finesse measured afterward: ~=13 000 (clear increase)

Mon Apr 8 10:18:31 2019

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

Fri Apr 5 11:28:39 2019

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

Attachment 2: 190404_mode_fit_with_P1_SUPRASIL.PNG

Attachment 3: tek00000.png

Attachment 4: tek00002.png

Fri Apr 5 11:18:47 2019

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.

Thu Apr 4 09:42:12 2019

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.

Tue Apr 2 18:05:46 2019

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

Tue Apr 2 18:03:31 2019

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.

Tue Apr 2 17:59:18 2019

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

Fri Mar 29 18:33:15 2019

Ronic Chiche

Fixed

issue

mechanics | lasers and optics

Optical room

Alignment procedure

we did again the complete alignment procedure starting with iris and optimizing injection motors Ma and Mb, then installing mirror S2, S3, P4 and P1, optimizing thetaX and thetaY axis for each motor.

everything was fine until we installed P1. we tried to optimize thetaX and thetaY of P1 and we clearly observed a strange motion when doing that :
- for thetaX axis, steps in one direction seem to have a different length from steps in reverse direction.
- for thetaY axis, trying to move in one direction, makes sometime a motion in the reverse direction.
at this moment, it is difficult to say if the problem comes from the controller, the mirror mount or the motor itself.
if both axis are concerned on the same mirror (P1), maybe the problem comes from the mount... to be continued on Monday.

Thu Mar 28 09:25:58 2019

Motors Z axis reversed

All Z motors (for P1, S2, S3 and P4) have been initialized again with a proper HOME command with their own controller with the "superviser" software (which means they all moved to the +1650000 position).
Thus, they have been moved to their default position : +825000 for spherical mirrors (S2 and S3) and -825000 for plan mirrors (P1 and P4).

reminder : lower values on the motors makes the motor tip going inside which makes the cavity length larger.
thus spherical mirrors are in default position with a possible big range to put inside the motor tip (for thermal effects compensation).
by complementarity, plan mirrors are in default position with a possible big range to put outside the motor tip.

the Labwindows CVI was buggy about the proper representation of the motors motion in Z direction (wrong direction and wrong default position).
the software is now fixed.

Loïc Amoudry wrote:

S2 and S3 z-axis are initially at 1/4 (5mm/20mm) of there range over ~20mm range. This is meant to be able to spread them up to ~15mm in case of thermal effect.

Actually, they are in an opposite position. Means that they can only be spread of 5mm from the initial position.

Tue Mar 26 18:32:40 2019

Loďc Amoudry

Fixed

report

mechanics | lasers and optics | cabling

Optical room

Wires in laser path

There was some ceramic wires close to the beem path right before P4. We moved them away (we can imagine they could move again with vibration).

Attachment 1: before.jpg

Attachment 2: after_wire_displaced.jpg

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