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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Mirror's cleaning, posted by Loïc Amoudry at Optical room about lasers and optics
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XPS has been proceeded on the 400kW SBOX mirrors M3 and M4 (the initial cavity spherical mirrors) in frebruary 2019. Deposited a lot of particles on
these mirrors.
All the mirrors received a Infrared spectroscopy the 12th of november 2019. Deposited glue on the non-reflective face (was used to hold them). |
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Mirror's installed, posted by Loïc Amoudry at Optical room about lasers and optics
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| The initial 400kW SBOX mirrors which have been cleaned ont 28th of november have been installed this morning on the SBOX. |
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Microscope and cleaning of SBOX mirrors, posted by Loïc Amoudry at Optical room about lasers and optics
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The mirrors went in the cavity the 28th of november (We did several power up to 30kW stored and only one to 40kW then the power went down to 2kW
during the run).
Microscope study shows that mirrors get some dust during the handling [travel from microscope to SBOX --> installation --> |
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AFM analysis of M1, posted by Loïc Amoudry at Optical room about lasers and optics
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AFM has been proceeded on M1 and M2.
The pdf shows the first images taken with the PLIC room Leica microscope (zoom x10 and x80).
Then the hole has been studied with a handmade microscope. It brought a better resolution. We can now see the hole has an edge, a center structure |
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AFM analysis of M2, posted by Loïc Amoudry at Optical room about lasers and optics
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We had enough time to proceed a quick scan of M2 which has also a hole but not centered on the mirror.
The hole is larger and higher than the one on M1. But the vertical range was to high for the AFM. Then we cannot see if there are sparkles or
not on this image. Further study with microscope would be welcome. |
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CFBG removed from ThomX CELIA amplifier, posted by Loïc Amoudry at Optical room about lasers and optics
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The CFBG has been removed successfully and the amplifier is closed now.
The soldering machine had a calibration trouble and was sent to the company for review during holidays.
The output power has been checked and is the same as before (tested until 30W ouput power). |
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Glow discharge cleaner on SBOX mirrors, posted by Loïc Amoudry at Optical room about lasers and optics
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The glow discharge cleaner has been tested on the SBOX mirrors.
I've put them 1 by 1. Each run was 15min long at 15mA. The mirrors HR face was always away from the electrode and ~35° angle
with the support. These values have been choosen thanks to the reference: |
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SBOX mirrors cleaned, posted by Loïc Amoudry at Optical room about lasers and optics
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Today, SBOX mirrors have been cleaned with spin coater on HR face and isoprop on back face. They show similar spots as before.
They also have been installed in the SBOX. The M1 mount has been displaced so the beam doesn't go in its center (spot). |
SBOX mirrors cleaned, posted by Loïc Amoudry at Optical room about lasers and optics
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Yesterday, after installation and alignment of mirrors and cavity, the Finesse has been measured with cavity at air pressure, with Koheras and modulation
technique.
the measurement has been done 7 times with quite different fits for the Finesse : 21.5k, 21.5k, 23.7k, 21.3k, 22.3k, 22k, 21.5k |
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SBOX mirrors cleaned, posted by Loïc Amoudry at Optical room about lasers and optics
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Today we put the cavity to vacuum (~ 0.1 mBar) and we measured again the Finesse with Koheras and modulation technique.
the measurement has been done 3 times with Finesse of 23.2k, 23.8k, 23k
Loïc |
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Power up to 48kW crater effect again, posted by Loïc Amoudry at Optical room about lasers and optics
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As we said, after glow discharge and spin coater we recovered a low power finesse ~23000 (aligning away from the M1 crater).
Today, we have made some power up to 48kW (3A on 3rd stage). At this power, there was no important effect on the transmission which can be compared
with the coupling (see image "3A_136mWtrans"). We waited ~20min without aligning and the power dropped slowly (misalignment) to 39kW. |
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Mirror's cleaning and microscope imaging, posted by Loïc Amoudry at Optical room about lasers and optics 14x
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On 10th of december 2020 we cleaned the SBOX mirrors and took microscope images (the name of the images indicates what they are).
There are 7 mirror, the initial M1 (spot in the center), M2 (spot on the edge), M3 and M4 which made the 200-400kW and the M2, M3 and M4 SPARE.
The difference we make between M3 and M4 SPARE is the number on the box (11 or 13). |
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amplifier, posted by Huan Wang at Optical room about lasers and optics
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Onefive output power is 24mW now, and 2.41mW(after EOM) injected into fiber,
a injection power monitor added, 99% (2.06mW) injected into amplifier, 1% (16.1uW) monitored with photodiode DET36A/M, which
gives ~500mV DC signal on oscilloscope with 1Mohm impedanc; |
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amplifier, posted by Huan Wang at Optical room about lasers and optics
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I just had a phone call with Jérome and he told me 2 things :
* Be carefull ! the MightyLaser amplifier is not designed to work with 33MHz laser : the streching level is not sufficient !
One could worsen the phase noise by self-modulation due to peak power or even distroy the amplifier ! |
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chiller for CELIA amplifier, posted by Aurélien Martens at Optical room about utilities
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The chiller of CELIA amplifier has been moved from the corridor to the changing room in front of PLIC.
It was not functionning well (quick drop of flow below 0.9l/min). After several cleanings of the filter, shorting the water circuit a stable
2.1l/min flow was obtained. Then the water circuit was elongated to go close to the amplifier but not into it. Allowing to get about 1.3l/min stable. Now |
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chiller for CELIA amplifier, posted by Aurélien Martens at Optical room about utilities
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today, temperature of the chiller has been set to 23°C.
measured temperature in the chiller reaches 23°C after approximatively 10 minutes
Aurélien |
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Menhir 160MHz laser, posted by Alice Renaux at Optical room about lasers and optics
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The Menhir 160MHz has been put back in place on the CELIA amplifier setup. Its output power is measured to be 150-160mW with an attenuator as expected.
Its spectrum is available in "spectre_avant_cvbg.xlsx" and "spectre_avant_cvbg.png".
The pulses are stretched by means of a CVBG. Their spectrum is available in "spectre_apres_cvbg.xlsx" and "spectre_apres_cvbg.png". |
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Menhir 216MHz laser, posted by Alice Renaux at Optical room about lasers and optics
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The Menhir 216MHz laser has been put back in place on the cavity table. Its output power is measured to be 160mW with an attenuator. Its spectrum is
available in "spectre.xlsx" and "spectre.png". The main wavelength is a bit shorter (1028.75nm) and the spectrum a bit narrower (4.73nm)
than expected. |