OEwaves lock and Finesse measurement, posted by Ronic Chiche at Optical room about lasers and optics
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this morning, I locked the FP cavity with the OEwaves CW laser and the "Fred fiber amplifier" used at 500mA of pump current.
the lock was much more easy than with the Koheras.
I had to change the 10GHz EOM which seems damaged as the modulation depth is very low and does not allow a Finesse measurement by modulation |
OEwaves CW Laser - Phase Noise , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics 
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We started measuring the phase noise on the OEwaves CW laser.
Class 3b
wavelength 1.5 um
The
procedure is done using self coupling of the laser
splitter 50%-50%\
delay line 100 m
all fibers are PM type
(polarity maintained)
Photodetector is "lab buddy", very fast diode.
Note: différance from schematic (we did not |
OEwaves CW Laser - Phase Noise , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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a correction on the wavelength of the laser it is 1030 um
Manar
Amer wrote:
We started measuring the phase noise on the OEwaves CW laser.
Class |
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OEwaves CW Laser - Phase Noise , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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correction on unit 1030 nm
Manar
Amer wrote:
a correction on the wavelength of the laser it is 1030 um |
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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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Mounts installation and cavity alignment, posted by Xinyi Lu at Optical room about lasers and optics
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Over the last two days, Viktor, Ronic and I have started to install the mirror mounts and try to align the cavity.
- We used the Menhir laser @ 160MHz for alignment.
- To make it easier to operate, we removed some lenses and waveplates, and kept only a few necessary reflective mirrors. |
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Mounts installation and cavity alignment, posted by Xinyi Lu at Optical room about lasers and optics
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Over the past few days, Viktor, Ronic and I have continued to align the cavity. We installed 4 mirrors and monitored the transmitted laser with
a CCD and photodiode. By adjusting the motors of the cavity mirror stages and the injector mirrors, we obtained resonances and less symmetric TEM20-like
patterns. Possible reasons for this are a mismatch between the beam sizes of the laser and the cavity mode, and the mounts are installed in rough |
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Mounts installation and cavity alignment, posted by Xinyi Lu at Optical room about lasers and optics
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- Over the last few days, Viktor, Ronic and I have reinstalled the mounts and realigned the cavity with CW laser and old mirrors. By optimizing the injector
mirrors, we got the fundamental mode at the transmission. We measured the beam size in the M2 window with a diameter of 2.5 mm.
- The current coupling efficiency is low. There is a need to increase the coupling in order to lock the cavity and measure FSR and finesse. |
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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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Mirrors features, come back from LMA, posted by Loïc Amoudry at Optical room about lasers and optics
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Mirrors arrived today from LMA. Their features are damaged.
Photos avant ou après nettoyage, pas clair dans le mail de Laurent :
"J'ai commencé à nettoyer M1 et M2 avec notr methode habituelle et je me suis aperçu que sur la partie centrale |
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Mirrors cleaning, posted by Loïc Amoudry at Optical room about lasers and optics
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The new mirrors didn't give expected results. Then the 4 old mirrors have been sent to LMA on 12/11/18 for a cleaning and caracterization before
and after cleaning. Also asked for a diffusion/absorption map on the mirrors if possible. They didn't really answered on what will they do.
Received on 13/11/18 by LMA. |
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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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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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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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Mightylaser Amplifier , posted by Manar Amer at Optical room about lasers and optics | cabling
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Migthylaser amplifier has been moved from the SBox table to the PLIC table.
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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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Menhir pulsed laser locking, posted by Xinyi Lu at Optical room about lasers and optics
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These days, Ronic, Daniele and I achieved stable cavity locking with the menhir pulsed laser.
- After vacuuming, the current cavity finesse is now about 23,000. The diameter of the cavity mode is w_x=2.2mm, w_y=2.7mm.
- We had to compensate for frequency drift by manually adjusting the cavity length to keep locking. |
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Menhir pulsed laser locking, posted by Xinyi Lu at Optical room about lasers and optics
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Here is a simulation of the relative FP-cavity gain vs the CEP for a Finesse of 23000 and taking into account the Menhir laser optical spectrum and several
CVBG parameters.
I added the commented Matlab code to produce this plot. |
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Menhir pulsed laser locking, posted by Xinyi Lu at Optical room about lasers and optics
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Last week, Ronic and I focused on CEP measurements of the menhir laser.
Measurements without Cavity Locking:
Direct measurement of repetition rate (Frep) with a spectrum analyzer.
Altering the laser pump current from 950mA to 850mA, Frep changed by +28Hz.
Measurement of the variation of carrier-envelope frequency |
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Menhir pulsed laser locking, posted by Xinyi Lu at Optical room about lasers and optics
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here is the code to get this last curve
Xinyi
Lu wrote:
Last week, Ronic and I focused on CEP measurements of |