New mirrors batch informations, posted by Ronic Chiche at ThomX igloo about lasers and optics 
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the 2 files describe the specfications for the 16 mirrors ordered (4 for ThomX + spare, 4 for SBOX + spare) and the measurements made by the LMA.
I add also a 3rd file in which all the "special' mirrors are referenced. |
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AFM performed on S-BOX mirrors, posted by Loïc Amoudry at Other about lasers and optics
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| 29/02/19 - AFM has shown that spots on mirror's surfaces are bumps and not holes. |
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Meeting with LMA people, AFM, posted by Loïc Amoudry at Other about lasers and optics
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30/01/19 - The following powerpoint shows the results discussed with LMA people.
What came out from the discussion is:
- Their cleaning method uses demineralized water drop on a spinner. It is probably the explanation of the circular traces on the mirror's |
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AFM+ InfraRed spectroscopy (IR spectro) has been performed, posted by Loïc Amoudry at Other about lasers and optics
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AFM+ InfraRed spectroscopy (IR spectro) has been performed on 400kW S-BOX mirrors.
Seems that XPS made M3 and M4 dirty, but M1 have also ome dust. M2 seems clean, further AFM experiment should show that it is as clean as M1. |
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Cavity polarization states (Koheras), Finesse of 2 polarization states, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurments of Finesse with the 2 polarization states, let's call them H (higher) and L (lower): 24500 for the H and 23500 for the L.
We checked the polarization states in transmission of the FP cavity after a PBS. The H was stronger in PBS trans and the L stronger in PBS ref.
We measured the power in reflection of the PBS and added a half WP that we aligned with the PBS polarization. Then, to get the maximum power |
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Phase measurement with HASO, posted by Loïc Amoudry at Optical room about lasers and optics
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2 measurement.
First one locked, in transmission of M2 with 2nd stage 0A.Total 89 cm from the big waist (planar mirrors). 2 wedges used.
Second one at input beam with the same power. Datas taken at the same equivalent position than the first one. 3 wedges used. |
Phase measurement with HASO, posted by Loïc Amoudry at Optical room about lasers and optics 8x
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* Loic has to fix the number of files (3) regarding the number of measurements (2)
* splitted Intensity and phase HASO files
* image for each file |
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Phase measurement with HASO, posted by Loïc Amoudry at Optical room about lasers and optics
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with just intensity, the coupling is 98%, and with phase, x direction coupling is 95%, y direction 97%, so the telescope is good.
Loïc
Amoudry wrote:
* Loic has to fix the number of files (3) regarding the number of |
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Polarization optimization, posted by Loïc Amoudry at Optical room about lasers and optics
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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. |
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Record power-up, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement made on 03/10/18 (nothing has been done since there).
Stable power in the cavity of 225 kW.
3rd stage current
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Motors for D-shaped mirrors, posted by Loïc Amoudry at Optical room about mechanics | lasers and optics
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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. |
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Transmission vs D-shape position at different powe, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurements have been done on 18/10/18.
Datas are on excel file, also matlab file. |
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Beam size vs D-shape position, posted by Loïc Amoudry at Optical room about lasers and optics
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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. |
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Beam size vs D-shape position, posted by Loïc Amoudry at Optical room about lasers and optics
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Matlab code for size vs position and power :
clear all
close all |
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Power measurement with D-shape, posted by Loïc Amoudry at Optical room about mechanics | lasers and optics
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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 |
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Finesse vs power by difference between main and second resonance, posted by Loïc Amoudry at Optical room about lasers and optics
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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 |
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Polarization frequency, posted by Loïc Amoudry at Optical room about lasers and optics
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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. |
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Polarization frequency, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement on 30/10/18.
Loïc
Amoudry wrote:
Check of the frequency of the onefive locked on each polarization |
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Finesse vs power by difference between main and second resonance, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement on 24/10/18
Loïc
Amoudry wrote:
Measurements show that ratio decrease versus power. BUT, the second |
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Finesse vs power by difference between main and second resonance, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement on 25/10/2018
Loïc
Amoudry wrote:
Measurements show that ratio decrease versus power. BUT, the second |