Alphanov amplifier compressor's CVBG thermal images, posted by Ronic Chiche at ThomX igloo about lasers and optics 
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last Friday with Manar, we took some thermal images of the Alpnavov compressor box.
I post a small document to summarize some points :
- the 2 mirrors used to make the CVBG injection are polarized thin-film mirrors... thus sensitive to the beam polarization. |
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Alphanov amplifier compressor's CVBG thermal images, posted by Ronic Chiche at ThomX igloo about lasers and optics
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last Friday with Manar, we took some thermal images of the Alpnavov compressor box.
I post a small document to summarize some points :
- the 2 mirrors used to make the CVBG injection are polarized thin-film mirrors... thus sensitive to the beam polarization. |
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Vessels vacuum at ambiant pressure, posted by Ronic Chiche at ThomX igloo about vacuum
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Last Friday and this morning, with Bruno, we close the ring/cavity valves and put some dry air in the two vessels through a filter to avoid turbulences.
Now, the two vessels are at ambient pressure and ready for opening (to remove the mirrors).
One can let the ambient pressure in the vessels as long as we want, the ring/cavity valves have been chosen to be compatible with the high vacuum |
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mirrors removing, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Viktor, we opened the 2 vessels and removed the 4 FP-cavity mirrors.
all the mirrors have been put in plastic boxes with labels to indicate which mirror it is,
and with all the HR coatings face down. |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Today, after laser was modelocked, we checked the power inside the fiber coming from the Alphanov Strecher box.
it was almost zero, at the nW level.
after doing some very rough alignment, we clearly saw some power (with the powermeter) correlated with the position of mirrors, when turning |
Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Viktor, we started the alignment of the CVBG and fiber.
we did a better alignment of the 2-pass CVBG.
we are able to the see a spot after PBS (after the 2 CVBG pass) which means the alignment is OK even if it can be improved. |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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In preparation for tomorrow morning, I did a test with a 45° mount to have a power pickup inside the injection box.
I used the 133MHz laser.
output power measured with the powermeter : 45mW |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Manar, we measured the power at different points:
- direct measurement at the output of the 33MHz laser : 35 mW
inside the injection box : |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Ronic, using a pickup mirror, we measured the power in different locations along the path of the stretcher box
Output power from oscillator : ~35mW
After the isolator : ~ 35 mW |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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I used the 33MHz spectrum measurement : https://elog.lal.in2p3.fr/FPC/THOMX+commissioning/153
fitted by P=P0*sech²((f-f0)/df)
f0 = c/1030m |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Manar + Victor, today in the morning we aligned the CVBG of the stretcher.
The double path using the mirror mounts, reached up to 5.4 mW just before the injection into the fibers
then we rotated the quarter wave plate and the power increased by a factor of ~ 2 to 10.3 mW |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Manar, we continued the strecher CVBG alignment and fiber injection procedure :
- we checked the power at the output of the laser and confirmed the measurement after the Isolator : ~ 36 mW
- we tried to improve the power after the strecher CVBG by rotating the quarter-wave plate but it seems we were already at the maximum : ~ 10.5 |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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this morning : still 6.2 mW at the output of the fiber.
the powermeter has been removed and the fiber connected to amplifier input fiber (no EOM connected in between).
Ronic |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Monday 7/11 morning, the power in the fiber was still 6.2 mW
Ronic
Chiche wrote:
this morning : still 6.2 mW at the output of the fiber. |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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on Monday morning 7/11, we tried to restart the Alphanov amplifier which was not turned on since end of april 2022, but it didn't start.
we did a standard "turn ON" procedure :
- check the safety button on the front panel (which has to be released). |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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I just tested the fuse inside the black ON/OFF switch on the rear panel => it is OK ! :-(
Ronic
Chiche wrote:
on Monday morning 7/11, we tried to restart the Alphanov amplifier |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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The laser amplifier controller has been sent yesterday and received today by Alphannov.
they should do the assessment quickly...
Ronic |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Today, I did a Teams meeting with Guillaume.
He didn't see any problem with the controller.
normally, the controller will be shipped to the lab tomorrow. |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Yesterday, we received the controller back from Alphanov
and I tested it immediately in the optical room.
if the software is properly talking to the controller, everything works normally. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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today with Manar, we brought everything to make the profile measurement.
the chiller was in error because of the water level : we filled it in.
! warning ! there is no alarm signal, only a message on the screen. |