SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 
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Yesterday, to find the source of why the mode is deformed, I tried to rotate the mirrors to see if there is a change.
I started with M2 and rotated it by ~ 90 degrees, there is a change in the shape of the beam.(image attached)
Will see if changing M2 to the spare M2 from SBox can fix the issue. |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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Following the observation that when rotating M2 plan mirror of SBox the deformation position of the mode changes.
M2 was replaced with M2 spare of SBox
images of the mirror front side attached before and after cleaning, no spots at the center, but there seems to be 2 spots far from the center |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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M2 Sbox changed to spare. Alignment of M2 was redone.
With the help of Ronic , We observe fundamental mode of the cavity with higher order modes. A frequency scan on the piezo was done to find the
beating frequency , the shape is elliptical with no clear deformation. |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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While repeating the alignment, the mirrors were cleaned using the spin-coater and placed again.
The current mirrors placed in the SBox are
M1 plane injection from Gamma factory |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 7x
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The external and internal alignment was redone.
External Alignment : the collimator position moved so in order to have a good start I placed 2 metallic mirrors and did a rough retrace of it's
line through the cavity box. |
Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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The current setup for the SBox has a beam viewer and 2 photodiodes placed at reflection and transmission.
The CW laser piezoelectric crystal was driven using the lase lock system to observe the 00 mode.
Mode Observed and has no reflection (from what was previously seen) |
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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Adding images from the transmission after the spherical mirrors M3 and M4 window for a resonating mode inside the cavity.
There appears to be some misalignment from the center of the mirror ???
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Closing Series for Alignment.
Beating observed, beam is in the locking stages
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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Images of the Transmitted beam at M2 mirror at different days.
The first one was from last week, the second from yesterday.
There is misalignment (drift due to temperature) from the position where the beam was initially. ( reference taken between centers of mode and |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Start with the cavity lock images attached, taken from last week, at start we have a coupling ~ 5% and started improving on the
alignment .
The image of 00 modes attached corresponds to the coupling seen on the oscilloscope. |
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Telescope - Spacial Matching , posted by Manar Amer at Optical room about lasers and optics
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Divergence of the CW beam out of the collimator measured after 1 meter to be
2 x = 0.7425 mrad --> x = 0.37125 mrad
2 |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Current setup at SBox for locking the cavity
After spacial matching, the coupling increased to ~ 15 - 20 %
The locking was done for the fundamental mode, tried to improve the coupling with the motors, but the lock is very unstable to be investigated. |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Cavity locked today under vacuum and no airflow, it is stable over a long time
the alignment was improved and an increase of the transmission by 20 % from its original value
unfortunately, data from the oscilloscope was saved, but it was not in the correct format (image) to show. |
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Menhir Pulsed Laser, posted by Manar Amer at Optical room about mechanics | lasers and optics | detectors and electronics
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The SBox Length (FSR), was changed to match the repetition rate of the Menhir pulsed laser Frep = 216.6625 MHz
It was changed by removing the 2 D-shaped mirrors placed between M1 and M2, distance between M1-M2 ~= 169 mm
it was still needed to be adjusted with M1 motor to reach the correct FSR. |
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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The Sbox currently has the injection from ThomX installed T ~ 120 ppm , M2 planar from Sbox spare and M3 / M4 spherical mirrors from Sbox installed.
The last finesse measurement that was done gave a Finesse of ~ 19300 (After cleaning M2 using ethanol + aceton + pure water)
on Friday the whole optical table was cleaned again and the inside of the box was cleaned (even with a lot of dust inside the box the Finesse |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Closing the series for the setup
The cavity was only locked @ 133.33 MHz but the Finesse was not measured
The FSR was changed to match the new laser MENHIR 216.6625 MHz |
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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Closing series of 00 mode for FSR @ 133.33 MHz
Manar |
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Divergence of the CW beam after collimator , posted by Manar Amer at Optical room about lasers and optics
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Closing the series of the telescope for the beam @ 133.33 MHz
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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Max Finesse obtained @ 4 mirror setup was ~ 19 300
With M1 from ThomX , M2/M3/M4 from SBox
Manar |
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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Manar
Amer wrote:
Max Finesse obtained @ 4 mirror setup was ~ 19 300 |