Incoming laser beam power issue, posted by Ronic Chiche at ThomX igloo about lasers and optics 
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today, we observed on the photodiode used in reflexion of the cavity, that its voltage level stops increasing after 50% of power for the laser amplifier
when the cavity is not locked (the FP-cavity is just a reflective mirror).
the photodiode itself is not saturated (low power sent after a wedge and an absorbing filter) and the reading is done on 50 ohms. |
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First X rays and FP-cavity mode and electron beam waists size @ IP, posted by Ronic Chiche at ThomX igloo about lasers and optics
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on friday 23/06 afternoon, after scanning the hexapod z-axis, we observed a cut of the power stored in the FP-cavity (with constant input power/coupling)
at both ends of the scan, due to the losses of the beam-pipe aperture.
we placed the hexapod exactly in the middle of this range ~ z=-1.68 mm (which is not the middle of the maximum range of the hexapod), we opened |
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PW laser Injection into cavity , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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Yesterday,
we installed the second high power reflecting mirrors at the output of the amplifier.
We aligned and installed a telescope
that has adjustable distance between the 2 lenses of -100 mm, and + 200 mm, with approximate diameter at the injection window of ~ 4.5 mm.
Amplifier |
PW laser Injection into cavity , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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On Monday with Daniele,
we did full characterization of amplifier beam @ 10% amplification, adjusted the telescope accordingly
and injected into the cavity aligned and improved on the fundamental mode.
On Tuesday with Daniele and Kevin
I
added a low pass filter between 1 - 1.9 MHz on the reflected signal, to reject the oscillator signal (33.33 MHz)
removed the external resistors |
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PW laser Injection into cavity , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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Added Note: the coupling we get is at low power, only preamplifier is on (~ 300 mW)
was done at the end due to excitation of higher order modes.
Wanted to improve the fundamental first, then increase the power. |
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PW laser Injection into cavity , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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Today with Ronic and Daniele we attempted to lock the cavity, but the alphanov amplifier did not turn on because of an error in MMD3 (related to the
third stage)
the new error is having the MMD3 error show on the alarm window of the LAL software, and having the Alarms on the line 3 of the alphanov software |
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Cavity Lock - Alphanov Amplifier , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics | cabling | software
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This morning, while trying Guillaume solution of disconnecting the 24 V necessary to the second and third stage and raise the threshold of Temp preamp
1 (to only operate the ampli with first stage only)
Ronic disconnected the 24 volt connection, turned on amplifier LAL software but no MMD3 error or a big temp on Temp preamp 1 , software worked |
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Cavity Lock - Alphanov Amplifier , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics | cabling | software 13x
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Yesterday, with Ronic we locked ThomX cavity on the second resonance
Laser : 33.36 MHz , Amplifier : 0 % (worked with no errors all day)
adding image for the lock on the second resonance (locked), 00 Mode image, fit, Beam measurements |
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Cavity Lock - Alphanov Amplifier , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics | cabling | software
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Today, I installed a power meter at the transmission point of the 1st spherical mirror , transmission 3 ppm (direct from cavity window beam profiler,
no filter)
We locked the cavity at 2 different resonances of the fundamental mode, the lock in both cases was stable for a round 1 minute. |
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Cavity Lock - Alphanov Amplifier , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics | cabling | software
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Today with Ronic,
starting with major events that happened (Water circulation + ThomX valves )
Early in the morning a company worked on the water network, it seemed it was not restarted properly so there was no water circulation |
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Cavity Lock - Alphanov Amplifier , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics | cabling | software
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In the morning, we locked on the first resonance. With an increase on the amplifier power @ 20-25% and 30%, which reduced the noise
we manage to get a coupling when improving the CEP up to 55 - 60 % coupling : put there is still a drift on the CEP
The controller for the oscillator frep and CEP produces a lot of noise, even if it is disconnected. we need to switch it off to remove its effect |
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Cavity Lock - Alphanov Amplifier , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics | cabling | software
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The computer is possible to connect from the control room,
we are able to run remotely the amplifier, cavity motors, oscillator motors, lase lock (note: there is an issue with the keyboard, we are not
able to use it with remote access!!!!!!!!) |
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Cavity Alighnment , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics 9x
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Last week, with Ronic and Victor we aligned the cavity using CW laser (Koheras)
we have also installed 4 mirrors in the cavity with the best theoretical qualities (serial number and images included)
The
Plan ULE mirror P4 thickness was not compatible with the piezoelectric mount. We had to install a metal spacer behind the mirror |
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Cavity Alighnment , posted by Manar Amer at ThomX igloo about lasers and optics | vacuum | detectors and electronics
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Today, we prepared lenses for a telescope for the CW laser injection into the cavity, yet to be installed
Image of the transmission at P4 attached, an estimation of the beam size of the mode see is ~ 5.5 mm
The vacuum in the 2 optical cavities is decreasing but slowly. today it is 2.6 - 2.4 * 10^-7 mbar |
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CW FP Cavit lock , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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Yesterday morning we locked the cavity on a strange mode in the cavity (we call it mode, but not sure what it is ??)
we also managed to lock on a higher order mode 02
we get an estimated 30% coupling (expected value), and note that we have not installed a telescope yet. |
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CW FP Cavit lock , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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This morning with Daniele and Viktor,
- we confirmed the "potato" mode was well centered on the injected beam and was not due to some misalignment of the injected beam compared
to the cavity axis. |
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FP Finesse measurement using CW, posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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This morning, with Ronic and Daniele, we locked the cavity again (The lock was relatively easy and stable during the reading of the finesse)
We took 2 reading of finesse
1st : @ 33.2808 MHz (what the cavity length was at) : Finesse = |
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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. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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yesterday morning with Manar,
1) we fixed the threshold level of the laser input signal which makes the measurement of the repetition rate.
(if the rep rate is not measured properly, the amplifier safety interlock stops immediately the amplification). |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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this morning with Manar,
- we checked first the chiller problem.
the fluctations of +/-2° around 25°C are still there. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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Today with Ronic
For the Temperature fluctuation :
we checked the valves of the tubes bumping water into the chiller from ThomX main water supply, they were |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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this morning with Manar,
- we fixed the chiller problem (+/-2°C fluctuation around the set temperature value = 25°C).
we opened and closed several times the water valve of the primary circuit to remove air bubles => no effect on the temperature variations. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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Ronic on Friday operated the Amplifier from the Alphanov software, switched it off then turned on the LAL software,
and it worked for 40 min without issues or error appearing,
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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the laser amplifier worked for some days but it ended to a "watchdog" alarm which switches off the amplifier... investigation is ongoing
Ronic
Chiche wrote:
Ronic on Friday operated the Amplifier from the Alphanov software, |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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we have had this new issue (watchdog alarm switching off the amplifier) for several days.
Alphanov mentionned it could come from the input oscillator stability (modelock loss for example).
Today, |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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With Daniele after, we took a readings of the beam with a lens of 750 mm.
From the observed data, we can state that the beam is not completely Gaussian M2 > 1, due to the variation of the ellipticity of the beam
along the focused path |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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This morning,
- with the "Alphanov" software => Central panel => "system" button => Watchdog "Period Max" was at 100ns
and has been set to 200ns. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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This morning with Daniele, we did a second measurement of the beam profile using a different lens of focal 400 mm.
at a power amplification of 20%
the amplifier stayed on for around one hour and a half with no errors. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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On Monday 20th of February, Daniele and Viktor took some beam profile measurement data @ 50% of power amplification.
data and analysis can be found in the attached file.
Ronic |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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Yesterday, Guillaume Machinet and Vincent Clet from Alphanov came to fixe some issues with the laser amplifier:
- 1) they fixed the "rep. rate" measurement issue.
previously, the voltage range in which it was possible to detect the correct rep rate (33MHz) was very narrow ~ 50mV. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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This morning with Victor we took a reading of the beam profile using a 400 mm lens at 70 % and 100 % amplification.
Will process the data and add after
Note : after an hour and half of amplifier on at 70% we increased the power to 100%, and after ~ 10 minutes the amplifier turned off and showed |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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this morning with Manar,
we checked the Alphanov amplifier issue : "The laser has been stopped because its power is too far from the nominal power".
the photodiode voltage measuring the output power has drifted again and then, the estimated output power was wrong, triggering an alarm issue. |
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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We took reading of the beam profile of the amplifier without a lens @ 30 cm from the 2nd wedge for amplification percentages
20-30-40-50-60-70-80-90-100 % another additional 3 readings will be taken at different locations for all amplification percentages.
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Alphanov amplifier beam profile measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | software
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due to several "case temperature" issues, I change the "Max case temperature" in the "general config" of the "Alphanov
Software" from 50°C to 55°C.
=> validated by Alphanov. |
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Power shut down on Saturday the 18th, posted by Ronic Chiche at ThomX igloo about utilities
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All the equipments have been switched off on Friday 17th due to a power shut down on Saturday 18th :
CW and Onefive oscillators, computers, laser amplifier, cavity mirror motors, chiller, etc... |
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Power shut down on Saturday the 18th, posted by Ronic Chiche at ThomX igloo about utilities
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Today, I restarted all the equipements :
Chiller
: ok, temperature converged quickly to the set temperature : 25°C |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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On the 8th of July, the SN2439 33MHz laser was returned from NKT to our lab, being repaired.
it stayed all the weekend to warm up in the optical room and has been turned on on Monday.
the mode-locking was not working (28mW output power and a CW line for the optical spectrum), thus I "kicked" the laser with 100µm |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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This morning, with Aurélien and Daniele, we did the swap between the 33MHz and 133MHz oscillators.
now, the 33MHz oscillator is on ThomX inside the casemate.
it has been restarted and some laser is going out. |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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Yesterday with Aurélien, we try to make the laser modelock using the Smaract translation stages embedded inside the laser head.
unfortunately, we got some errors when we try to do the "calibration" and "reference" of both Smaract stages !
we contacted by email M. Nicoul to help us on this topic |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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Today, we used an "ELI-NP" Smaract controller made with these 2 references :
MCS-3CC-ETH-TAB (SN 2271) => main controller
MCS-3S-EP-SDS15-TAB (SN 2472) => sensor module |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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Yesterday, we put back the 33MHz oscillator into the casemate with the new Smaract controller.
after switching ON the laser controller, we saw some power at the output but we have to check if the laser is modelock or not.
Ronic |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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Today, we succeded to make the laser modelock.
the ouptut power is above 35mW (the powermeter was saturated)
here is a screenshot of the signal on the scope. |
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33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
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As the general local network for the FP-cavity devices is 192.168.xxx.xxx, I changed the IP adress of the smaract laser motors (Frep and CEP) controller.
For that, I used the embedded web server as described in the manual in attached file.
the new adresses are : |
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New Mirrors from LMA _ Images, posted by Manar Amer at Optical room about lasers and optics
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Today we tested a mirror from one patch
image is for the front face of the mirror
PowerPoint has more details about the images |
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Amplifier Beam Profile over time , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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This morning, with Ronic, we opened the compressor box to observe if there is any misalignment of the mounts or the CVBG's
a comparison slide between the Beam Profile over time and measurements we have taken, is included.
we noticed
today that the images need a rotation, and I took the assumption we did not rotate last year and did the rotation of the previous images.
Comparing |
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Amplifier Beam Profile over time , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics 10x
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This morning we took data of the beam profile at 4 different points to see the evolution of
the beam shape
divergence
over distance for all amplification percentages
Data plotted for the distance vs radius for all and divergence in rad is extracted and plotted as a variation of amplification power. |
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Amplifier Beam Profile over time , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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Information about today's work is added to logBook !!
Manar
Amer wrote:
This morning we took data of the beam profile at 4 different points |
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CW laser installation and cleaning, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Manar, in order to prepare the installation of the news FP cavity mirrors,
- we installed the Koheras below the optical table
- we put a fiber prolongator at the end of the Koheras fiber and we put a mounted collimator at the end of the fiber. |
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CW laser installation and cleaning, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Ronic , in preparation for the mirror installation, we removed additional mechanics and cables from the table.
We organized and cleaned the permanently installed cables on the table away from the area of the cavity opening.
We opened the two top vents and left the shutters open to circulate clean air , (note the shutters surrounding the laser and amplifier are half |
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Alphanov amplifier beam profile Data , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics 8x
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Adding the schematic of the measurements.,
the 4° Beam Deviation, AR Coating ( B coating)
The 3 data points taken of the beam profile are fitted in Gaussian Beam with taking the beam waist at the output of the compressor box. |
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Alphanov amplifier beam profile Data , posted by Manar Amer at ThomX igloo about lasers and optics | detectors and electronics
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This Morning with Victor the amplifier was turned on @ 20% amplification (output ~ 9 W ) for approximately 3 hours and no error appeared.
I took data of the beam profile at different points without a lens after the 2 wedges
@ 0% (only pump beam), output ~ 300 mW (taken from previous data) , output after 2 wedges 2.2 uW |
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Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
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The ouput power of the ThomX amplifier has been measured as a function of the 3rd stage pumps current (0A is 1st and 2nd stage turned on).
We measured the total power, the total power without the "donuts" pump signal dumped by an iris and the transmission of a dichroic
mirror (for ref see image). |
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Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
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Loïc
Amoudry wrote:
The ouput power of the ThomX amplifier has been measured as a function |
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Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
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We checked the Dichroic mirror we have : it is a DMSP1000 shortpass dichroic mirror as specified in this post.
The Arrow engraved on the edge of the mirror points on the AR surface !
not on the HR surface... |
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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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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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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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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 8x
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Today: Manar, Ronic and Aurlien started the study of the beam profile of the alphanov amplifier at high power.
The setup shown in the image shows how the power is reduced by using Anti-reflective mirrors,
pick up 1 : Anti-reflective coating on both sides , pick up 2 : Anti-reflective coating on one side and High |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics
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Manar
Amer wrote:
Today: Manar, Ronic and Aurlien started the study of the beam profile |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 6x
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Adding the fitted beam in 1D in Horizontal and vertical axis.
for 10% to 60%
Manar |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics
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Today a second reading of the beam profile was done , with Victor ,Ronic, Aurlien and Manar
an additional set-up was made using two 4 deg wedges instead of High reflecting (HR) and Anti-reflecting (AR) mirrors.
Two reading were taken: |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 9x
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Readings of the beam shape and horizontal (upper plot) and vertical (lower plot) axis fit at the direct output of the amplifier.
The beam shape relatively shaped like an egg.
Manar |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics
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Readings of the beam shape and fit at the output of the compressor
differance from previous reading is that here we used wedges instead of HR mirrors.
Similar to previous readings, the beam shape deforms and the Gaussian fit is bad after 50% amplification |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 6x
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Adding the readings 20% , 30% , 40% for output of amplifier after the compressor
Manar |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 12x
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This Morning, another reading was taken for the output of the amplifier after the compressor using 2 wedge mirrors.
In addition, a start of the calibration of a PulseCheck "Autocorrelator" to measure the pulse duration.
note, the pulsed laser used is OneFive 133.33 MHz |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 20x
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Victor, Ronic, Manar
Today was dedicated to the study of the CVBG, and it's effect on the beam profile
we opened the box containing the 2 CVBGs : The 2CVBG are glued from the bottom on a copper surface . |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 8x
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For better comparison ,
the measurements done previously with 2 CVBGs was done at ~ 30 cm and the one done on Friday was for 1 CVBG is at 1 m
so we did additional measurement for 2 CVBGs at 1 m, for 20 , 50 and 70 % amplification |
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Alphanov amplifier Beam Pulse Duration, posted by Manar Amer at ThomX igloo about lasers and optics
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The pulse duration from the amplifier compressor output will be measured using PulseCheck autocorelator
a first alignment of the device was done, continuation in the afternoon.
YouTube link attached of the general operation of pulse check < 5 min : https://www.youtube.com/watch?v=J1pNHYySSYg |
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Alphanov amplifier Beam Pulse Duration, posted by Manar Amer at ThomX igloo about lasers and optics
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Measurement of the pulse was done at the end of the afternoon, Pulse Duration FWHM = 12.9 ps
After a long process of adjusting the alignment and angle of the crystal inside the device
The power input on the PulseCheck device should be above the sensitivity, in our case we had 1 mW input. |
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Alphanov amplifier Beam Pulse Duration, posted by Manar Amer at ThomX igloo about lasers and optics
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Pulse Duration FWHM = 12.9 ps
Manar
Amer wrote:
Measurement of the pulse was done at the end of the afternoon, Pulse |
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First hands on the Alphanov amplifier & software, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Aurélien, Manar, and I spent more than 2h trying to start the software communicating with the Alphanov amplifier controller.
each time, we had a problem with the software, asking to switch OFF and ON the controller before being able to switch the amplifier diodes ON.
we switched OFF and ON many times without any success. |
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First hands on the Alphanov amplifier & software, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Additional information related to the injected power into the amplifier fibers.
power = 4.45 mW (as shown from the software)
the minimum to inject into amplifier is 2 mW |
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First hands on the Alphanov amplifier & software, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Software Works well and is operational.
Just closing the log series!!!
Ronic |
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Alphanov amplifier power measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning, with Manar and Aurélien, we measure the power directly at the output of the Alphanov amplifier with the 2 compressors CVBG
(seeding laser at Frep = 133MHz)
(we had to remove the base plate where the deflector mirrors were mounted to put the large powermeter). |
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Alphanov amplifier power measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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answers from Guillaume:
- the chiller temperature has to be set to 25°C
- the power measured with the software can change a little from what Alphanov measured with their laser. |