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. |
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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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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Alignment using Koheras , posted by Manar Amer at Other about lasers and optics 6x
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Following the Helium Neon Alignment + change in the distance between the mirrors to be; M3-M4 = 90.5 mm , M1-M2 = 80.2 mm -→ The alignment
using the Koheras CW laser is done.
Additional components used:
for monitoring beam : Photodiode (power of beam), Beam Profiler (shape, position, power |
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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 : |
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Theoretical Finesse, Gain and Coupling, posted by Ronic Chiche at Optical room about lasers and optics
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For spherical mirrors M3 and M4 (batch C117I054) the reflectance (R) is around 99.9987% (if T+R=1 => T=13ppm)
For plan mirror M2 (batch C217G054) the reflectance (R) is around 99.9977% (if T+R=1 => T=23ppm)
(1) => For plan mirror M1 (batch C217H023) the reflectance (R) is around 98.96% and transmittance (T) is around 1.14% (T=11400 ppm) |
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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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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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Alignment using Helium Neon Laser , posted by Manar Amer at Other about lasers and optics
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| 05 April 2021 : A rough alignment of the cavity was done using the Helium Neon Laser. |
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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
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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 |