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 |
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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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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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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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 |
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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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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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33MHz oscillator + Alphanov amplifier lock, posted by Ronic Chiche at ThomX igloo about lasers and optics
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the last tries to lock the 33MHz + amplifier to the 30k Finesse FP-cavity were unsuccessful.
during a laser Frep scan using the Laselock, one observes that the main cavity resonance is not able to stay inside the PZT scan range from one
scan to another (500ms-1s period) |
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33MHz oscillator + Alphanov amplifier lock, posted by Ronic Chiche at ThomX igloo about lasers and optics
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finding the right modulation/demodulation PDH phase is very difficult on the main resonance because the we get non stationnary signals with a lot of
oscillations.
changing the phase, in this condition, does not really change the error signal. |
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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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33MHz oscillator + Alphanov amplifier lock, posted by Ronic Chiche at ThomX igloo about lasers and optics
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today with Daniele, we locked easily (but with a noisy lock) on the secundary resonance and we tried to lock on the main resonance (with very low coupling
~10% which mean a CEP ~Pi)
the lock was possible but was very noisy. |