First hands on the Alphanov amplifier & software, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Additional information related to the injected power into the amplifier fibers.
power = 4.45 mW (as shown from the software)
the minimum to inject into amplifier is 2 mW |
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First hands on the Alphanov amplifier & software, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Software Works well and is operational.
Just closing the log series!!!
Ronic |
First X rays and FP-cavity mode and electron beam waists size @ IP, posted by Ronic Chiche at ThomX igloo about lasers and optics 
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on friday 23/06 afternoon, after scanning the hexapod z-axis, we observed a cut of the power stored in the FP-cavity (with constant input power/coupling)
at both ends of the scan, due to the losses of the beam-pipe aperture.
we placed the hexapod exactly in the middle of this range ~ z=-1.68 mm (which is not the middle of the maximum range of the hexapod), we opened |
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First Lock with 2nd satge of amplifier : Motor issue ? , posted by Ronic Chiche at Optical room about mechanics
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Global locking almost clean : tranmission and reflection are quite noiseless except the peaks at every 500ms.
During the amplifier 2nd stage lock, we experienced 2 strange behaviors :
- short "unlocks" every 500ms exactly all the time, during the whole lock process |
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First Lock with 2nd satge of amplifier : Motor issue ? , posted by Ronic Chiche at Optical room about mechanics
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The 500 ms noise disapeared. We had to disable the "power save" mode of the smaract translation stage. AND turn OFF and ON the controler box.
Ronic
Chiche wrote:
Global locking almost clean : tranmission and reflection are quite |
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First Lock with 2nd satge of amplifier : Finesse issue ?, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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1st lock today with the second stage of the amplifier.
~ 300mW of injected power (but which proportion of the pump and of the signal ? => One must use a spectrometer to determine this proportion)
MAYBE the real injected power of the signal is lower => maybe the Finesse is higher ! |
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First Lock with 2nd satge of amplifier : Finesse issue ?, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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First of all, we used and optical spectrometer to determine which proportion of pump and signal is in the injected beam.
the wavelength is THE SAME for the 2nd stage for the beam coming from the core or coming from the clad !
thus, it is impossible to use a spectrometer to obtain this proportion. |
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Finesse with P1 SUPRASIL, posted by Loïc Amoudry at Optical room about lasers and optics
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P1 SUPRASIL has been installed instead of P1 Sapphire. It has been cleaned 3 times on each face with wipe+isopropanol before to be installed.
Finesse ~= 10 000 - 11 000 (EOM Sweep of 100 kHz in 10sec, see last image.)
Coupling ~= 45% |
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Finesse measurement by decay time technique, posted by Ronic Chiche at Optical room about lasers and optics
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5 Files attached:
- Note on the technique and results for the present cavity on 2019, May 21th : F ~ 18 000
- 2Tektronix scope raw data |
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Finesse measurement after the Edge installation, posted by Ronic Chiche at Optical room about lasers and optics
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After the Edge installation inside the cavity, the Finesse has been measured several times by modulation technique with an average around 16000:
(the scan speed is 50kHz in 10 seconds.)
So, it hasn't changed since the last measurement in June, just before the Edge installation. |
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Finesse measurement after mirror cleaning using the spin coater, posted by Ronic Chiche at Optical room about lasers and optics
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Last Finesse measurement in air : ~ 17 000 the 20th of may (see logbook)
28th and 29th of august, we cleanned, with Loïc, mirrors S3 then P1 successively using only ultra pure water with the spin coater.
we measured the finesse after each cleaning by modulation technique and in both cases, F ~ 12 500 !!! |
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Finesse measurement after mirror cleaning using the spin coater, posted by Ronic Chiche at Optical room about lasers and optics
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today I cleaned S3 with isopropanol and then with pure water on spin coater.
Finesse is only 10 700.(coupling 50% ? => to be confirmed...)
maybe we have to redo the procedure with a different way of cleanig (pushing less on the mirror ... ?) |
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Finesse measurement after mirror cleaning using the spin coater, posted by Ronic Chiche at Optical room about lasers and optics
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Following finesse measurements (start @10700):
Clean P1 with SC (water) + isoprop (wipe) finesse @15000
Clean S2 with SC (water) + isoprop (wipe) finesse @13000 |
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Finesse measurement after confinement, posted by Loïc Amoudry at Optical room about lasers and optics
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After 3 months without human presence, finesse has been measured 3 times with average optimization:
- 16150
- 16067 |
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Finesse measurement, posted by Ronic Chiche at Optical room about lasers and optics
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After mirrors were going back from LMA for cleaning and thermal anealing, they have been installed in FP cavity for Finesse measurement.
after getting strange results when the cavity is closed (very low Finesse...maybe too much ethanol inside cavity procucing some lineic losses),
we get 12k-12k5 Finesse with primary vacuum (~4 mbar) and a clean lock (very flat transmission signal and quite noiseless reflection signal) |
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Finesse measurement, posted by Ronic Chiche at Optical room about lasers and optics
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To complete these observations:
Finesse has been measured on thursday, right after cleaning the cavity with ethanol @6000.
Finesse has been measured on friday, after opening the cavity for few tens of minutes @12000-12500. The cavity was openned while |
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Finesse after removing wires, posted by Loïc Amoudry at Optical room about lasers and optics
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19/04/01: We removed the wires from the beam path in the cavity. Finesse stayed at 3400. FSR: 33.342 MHz.
When locked:
Input Power: ~4mW |
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Finesse after cleaning (new suprasil mirror), posted by Loïc Amoudry at Optical room about lasers and optics
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15/05/19-20/05/19:
Cleaning of the mirrors:
Initial finesse 14000 @air |
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Finesse after 2days, posted by Loïc Amoudry at Optical room about lasers and optics
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Finesse measured this morning after P1 SUPRASIL being into the cavity for two days. In order to check if it's getting dirty.
Finesse still ~= 11 000 |
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Finding correct motors position and parameters to keep the lock during a move, posted by Ronic Chiche at ThomX igloo about mechanics
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this morning, I try to find a new region for MOT.03 and MOT.06 where we can move them without unlocking the cavity.
I started from the position:
MOT06 : ~ -785 000 |