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 |
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 |
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2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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The SBox cavity setup was changed to have only 2 mirrors M1 plane and M2 spherical, both from ThomX
Distance between the mirror ~ 72 cm , increased from 70 cm to take into account the thickness of the ThomX mirrors
Two lenses (300 mm @ 50 cm , 200 @ 104 cm) were placed to have the beam radius ~ 0.55 mm. |
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Images of ThomX mirrors , posted by Manar Amer at Optical room about lasers and optics
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Under the microscope,
the spherical mirrors show the deposit of metal dots on the reflecting surface and not on the back of the mirrors
The mirror with fewer spots near the center was used in the setup. |
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Images of ThomX mirrors , posted by Manar Amer at Optical room about lasers and optics
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Mirror images in the previous log showing the metal deposit of the coating of the spherical mirrors
(not sent by mail due to large size of images)
Manar |
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2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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The cavity was realigned using irises instead of pinholes, gave a better alignment.
The inside of the box, the spherical and the injection mirror were cleaned and placed back inside the box.
we see beating of fundamental mode, previously at the transmission point we placed a wedge to split the beam which resulted in an elliptical |
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2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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Update for Finesse measurement, The cavity was put under vacuum ~ 1.1*10^-1 mbar
and the alignment and coupling improved.
FSR = 210.1 MHz |
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FSR change & Finesse Measurements , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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The FSR of the 2 mirror (plan-spherical) Cavity was adjusted from 210 MHz to reach 216.643 MHz
it was done by having two reference irises, one at the injection point and one at the reflection
then changing the position of injection plan mirror to slightly closer distance and monitoring the reflection on the oscilloscope to be max. |
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FSR change & Finesse Measurements , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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Yesterday evening the cavity was Vacuum pumped up to pressure of 5.5*10^-2 and locked
changed FSR to be 216.662 MHz and alignment a little and measured the Finesse
in Vacuum we have average Finesse = 30341.6265 |
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FSR change & Finesse Measurements , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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a Finesse of 30k with the present mirrors :
T1=120 ppm ;A1=(2.6+1) ppm;
T2=1.5 ppm ;A2=(4.5+0.27) ppm; |