Presentations, posted by Blanc at Other about utilities 
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| Here the first part of all the presentations since the beginning of the project. |
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Presentations, posted by Blanc at Other about utilities
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| Here the second part of all the presentations since the beginning of the project. |
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Presentations, posted by Blanc at Other about utilities
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| Here the last part of all the presentations since the beginning of the project. |
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Distances between mirrors , posted by Manar Amer at Other about mechanics | software
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At the reference zero the distance between the mirrors is (taken from a reference presentation "status9nov2020" attached):
M1-M2 = 88.029 mm
M3-M4 = 84.6895 mm |
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new smaract positions, posted by Aurélien Martens at Optical room about mechanics | software
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| M1 and M2 at 5.1085mm and M3 and M4 at -2.9mm |
Distances between mirrors , posted by Manar Amer at Other about mechanics | lasers and optics | software
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New update on the position of the Motors for the cavity
***** we moved the motors to set the cavity at 876MHz, and checked it right after with the RF modulation at FSR.
So compared to the expected setting we had to move inwards the two planar mirrors by 0.9 mm each. |
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1GHz oscillator Frep measurement, posted by Blanc at Optical room about mechanics | lasers and optics | detectors and electronics
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a previous cavity FSR measurement was giving a center frequency around 867.5MHz.
the present 1GHz oscillator Frep measurement is about 879.888MHz.
the
present shift is about 12.4MHz which is equivalent to move one cavity lenght by 4.3mm which is HUGE !!!
as the 1GHz oscillator does not have any motor,
one has to move the FP cavity mirrors instead.
the PZT inside the 1GHz oscillator (Thorlabs PC4QR) has a dynamic range of (20µm for 150V... we will |
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PZT resonant frequencies, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics
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we have excited the PZT with a swept sinus wave from 1kHz to 10kHz and from 10kHz to 100kHz.
here are the 2 different spectrums:
- the 1kHz-10kHz is a standard spectrum where we see the impedance behavior of the PZT: Zpzt ~ 1/jCw |
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1GHz oscillator Frep measurement, posted by Blanc at Optical room about mechanics | lasers and optics | detectors and electronics
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The optical spectrum of the GHz oscillator: FWHM ~ 4nm
Blanc
wrote:
a previous cavity FSR measurement was giving a center frequency around 867.5MHz. |
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new position of smaract motors, posted by Aurélien Martens at Optical room about mechanics | detectors and electronics | software
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following the measuremetn at 879.9 MHZ of the laser theoptical cavity length has been adjusted to that value from 876MHz setting of the 5th of may 21.
new motor positions:
M3/M4 : -2.9mm |
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Setting up the Motors, posted by Manar Amer at Other about mechanics | cabling | software
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A document attached that describes the procedure needed to:
- connect the motors
- configure the Ethernet connection |
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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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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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Phase noise measurement of the Amplitude MIKAN, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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Installation of the MIKAN.
powermeter (with OD1) just after the oscillator shows 440mW for 4A of the MIKAN pump current.
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Phase noise measurement of the Amplitude MIKAN, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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Coupling into a 50-50% fiber coupler using the Thorlabs XYZ table NanoMax TS.
We reached 117mW after the 50% arm which means we coupled about 230mW (the coupling better than 50%).
Ronic |
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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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Cameras Calibration, posted by Kevin Dupraz at Optical room about lasers and optics | detectors and electronics
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After installing cameras the actual calibration are :
NF_Refl: acA1920-40gm
pixel size (real): 5.86um |
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Cavity lock and references, posted by Kevin Dupraz at Optical room about lasers and optics | detectors and electronics
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Cavity is lock and optimized with the NKT. Input power is maximized (10mW).
Cavity mode is in attachement. The reference on camera with BeamProfiler Matlab code is the following:
FF_refl: [2.0883 1.1606] |
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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. |
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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 |