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 |
SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 6x
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SBox alignment, using CW laser Koheras power 1 mW
Finished M1 and M2 alignment using the diffraction patterns seen on the beam profiler,
the beam fit is not very good ?? (image taken)
Positions of Ma1 and Ma2 motors are |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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After pointers and Advice from Aurélien,
improvement of the beam alignment through M1 and M2 irises was done.
To improve the image on the beam profiler, I cleaned the alignment mirrors and the windows using pure ethanol and optical lens cleaning tissue, |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Remember to update the position of the reference Irises tomorrow !!!!
Manar
Amer wrote:
After pointers and Advice from Aurélien, |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 9x
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Adjust the placement of the Irises (done at the start of the day, adjusted at the end
when M1 mirror was placed)
Improvement on the
Ma1 and Ma2 (The Alignment Mirrors)
Improves the alignment a bit. There is an observation where there |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Finished the alignment of the SBox with M1 of SBox placed, to be changed to gamma factory mirror later
Observed what seems to be transmission through M2 mirror, to be confirmed. image attached shows it
a PowerPoint attached showing the details of today's work. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Last week In FP cavity we had all SBox mirrors including the damaged M1 mirror.
The beating was observed with just a slight adjustment on M4 alignment.
In addition, it was also observed while driving the piezo of the CW laser. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Today; replaced the M1 SBox mirror with M1 from gamma factory , following the previous alignment.
Removed all mirrors and cleaned them one by one.
Started with no M1, placed M2 did its alignment through M3 pinhole, then placed M3 aligned it through M4 pinhole, then placed M4 aligned it through |
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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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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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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. |
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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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SBOX mirrors cleaned, posted by Loïc Amoudry at Optical room about lasers and optics
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Today, SBOX mirrors have been cleaned with spin coater on HR face and isoprop on back face. They show similar spots as before.
They also have been installed in the SBOX. The M1 mount has been displaced so the beam doesn't go in its center (spot). |
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SBOX mirrors cleaned, posted by Loïc Amoudry at Optical room about lasers and optics
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Yesterday, after installation and alignment of mirrors and cavity, the Finesse has been measured with cavity at air pressure, with Koheras and modulation
technique.
the measurement has been done 7 times with quite different fits for the Finesse : 21.5k, 21.5k, 23.7k, 21.3k, 22.3k, 22k, 21.5k |
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SBOX mirrors cleaned, posted by Loïc Amoudry at Optical room about lasers and optics
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Today we put the cavity to vacuum (~ 0.1 mBar) and we measured again the Finesse with Koheras and modulation technique.
the measurement has been done 3 times with Finesse of 23.2k, 23.8k, 23k
Loïc |
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Record power-up, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement made on 03/10/18 (nothing has been done since there).
Stable power in the cavity of 225 kW.
3rd stage current
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Pulse duration measurement before and after CVBG (as a strecher), posted by Ronic Chiche at Optical room about lasers and optics
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I recorded the pulse shape of the MENHIR 216MHz in its fiber injection setup.
the fiber is then connected to the Labbuddy photodiode (~ 15GHz BW) and then to the R&S RTO2000 4GHz scope (~ 100ps rise time).
1) I put a mirror just before the CVBG. |
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Power up to 48kW crater effect again, posted by Loïc Amoudry at Optical room about lasers and optics
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As we said, after glow discharge and spin coater we recovered a low power finesse ~23000 (aligning away from the M1 crater).
Today, we have made some power up to 48kW (3A on 3rd stage). At this power, there was no important effect on the transmission which can be compared
with the coupling (see image "3A_136mWtrans"). We waited ~20min without aligning and the power dropped slowly (misalignment) to 39kW. |
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Power storage In Cavity, posted by Manar Amer at Optical room about lasers and optics
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We start of power output from amplifier of 1W with only the first and second stage on then we start with the third stage power increase,
Note: when changing the current on the third stage 4 diodes, better to do it step by step for each one with a step of ~ 0.5 A
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