Mode observed and cavity Lock , posted by Manar Amer at Other about lasers and optics 
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** Following up from yesterday an observation about the TM00 mode : it has been seen with similar dimensions and its position is the same, this was before
restarting the temperature regulator.
--> after restarting the temp. regulator |
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Mode observed and cavity Lock , posted by Manar Amer at Other about lasers and optics
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New configuration is made. The new mode observed in NF_Trans is the following :
Manar
Amer wrote:
** Following up from yesterday an observation about the TM00 mode : |
Mirrors Mottors Connections , posted by Manar Amer at Other about mechanics
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* The connections to control the motors of the mirrors are connected in the order stated :
M1
- M2 - M3 - |
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Mirrors Mottors Connections , posted by Manar Amer at Other about mechanics | cabling
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Added the cabling to the categories
Manar
Amer wrote:
* The connections to control the motors of the mirrors are connected |
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Mesures de Polarisation Lockline et Tangor, posted by Blanc at Optical room about lasers and optics 11x
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Vérification des polarisations après le combiner pour le Tangor et la Lockline.
On remarque certains paramètres de Stokes ont des valeurs étranges, comme S1 de la lockline.
De plus le polariseur voit la lockline comme non-polarisé. |
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Mesures de Polarisation, posted by Blanc at Optical room about lasers and optics
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En récupérant la transmission du miroir M3 sphérique sortant de la cavité, on a pu faire une mesure de polarisation de la
cavité. (Cf courbes ci-dessous)
La moyenne pour chaque courbe donne : |
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Mesures de Polarisation, posted by Blanc at Optical room about lasers and optics
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Correction su l'orientation de l'ellipse.
Blanc
wrote:
En récupérant la transmission du miroir M3 sphérique |
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Mesure polarisation voie de réflexion, posted by Blanc at Optical room about lasers and optics 18x
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J'ai fait les mesures de polarisation sur la voie de réflexion pour voir la polarisation avant le glan et après le glan du Tangor et
de la lockline.
Dans l'ordre : |
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Mesure de finesse, posted by Blanc at Optical room about lasers and optics
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Fréquence centrale : 879.48 MHz
FWHM mesurée à la main sans sweep : 120 / 130 KHz
=> Finesse = FSR/FWHM = ~7000 |
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Mesure de finesse, posted by Blanc at Optical room about lasers and optics
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Blanc
wrote:
Fréquence centrale : 879.48 MHz |
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Manip 17 12 2021 reprise réf nouvelle injection pour polarisation, posted by Kevin Dupraz at Optical room about lasers and optics
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Tangor : 4.2W
* Réalignement de l'injection suite aux modifications :
- Changement de l'ordre des waveplate maintenant : lambda/4, puis lambda/2 |
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Manip 16 12 2021 montée en puissance, posted by Kevin Dupraz at Optical room about lasers and optics
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Matin:
* Redémarrage Tangor 4W
- couplage 15% |
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Manip 16 12 2021 montée en puissance, posted by Kevin Dupraz at Optical room about lasers and optics
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Kevin
Dupraz wrote:
Matin: |
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Manip 14 12 2021 injection optimization (and calibration), posted by Kevin Dupraz at Optical room about lasers and optics
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Matin :
moteurs :
M1, M2 (plans): 5.110500m |
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Manip 14 12 2021 injection optimization (and calibration), posted by Kevin Dupraz at Optical room about lasers and optics
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Après-midi :
* Optimisation de l'alignement en injection pour avoir le plus de puissance en transmission
* Optimisation (vérification) de la polarisation pour avoir le plus de couplage. |
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Manip 10 12 2021 (optimization injection Burst), posted by Kevin Dupraz at Optical room about lasers and optics
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Manip 10/12/2021
Après recherche de la résonnance principale
- MCS miroirs plan à 5.110250mm (en derive vers les negatifs) |
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Locking with fast analog loop on AOM, posted by Ronic Chiche at Optical room about lasers and optics
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in addition to the standard locking scheme with the GHz laser PZT,
we added an AOM after the PDH modulation EOM and we drove it with an FM modulated signal generator (FMDev = 2.4MHz) seeded by the error signal.
(we didn't put a 50ohm plug to adapt the error signal coming from the PDH box, otherwise, it is too much smaller) |
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Locking of the cavity and setup changing, posted by Blanc at Optical room about lasers and optics | detectors and electronics
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We change the setup a bit to have the same polarization on the photodiode and the PDH (in reflexion of the cavity). CF: schematics (futur).
Thanks to that, the symetry between reflexion and transmission is better now (as you can see on the plot).
We also put more power on PHD to have a better SNR by changing splitters. (We had 100 µW and now we have more than 1 mW, at the expense |
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Lock, cavity length and finesse estimate, posted by Aurélien Martens at Optical room about lasers and optics | detectors and electronics
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Ronic just suceeded in obtaining a reasonably good lock on the cavity. Air flow is switched off.
We stopped all movements (closed loop, click STOP in the PTC interface) and saw immediately a fair but not excellent lock.
We then switched off the smaract motors and the obtained lock was good. Switching on again the smaract means tthat the references are lost. |
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Lock, cavity length and finesse estimate, posted by Aurélien Martens at Optical room about lasers and optics | detectors and electronics
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we observed that the transmitted light coming from the cavity is made of the cavity mode light and the scattered light on the borders of the mirrors.
the scattered light on the borders of the mirrors is triggered by the cavity mode itself when the cavity is locked.
we didn't put an iris to cut this scattered light coming from the cavity. |