Power storage In Cavity, posted by Manar Amer at Optical room about lasers and optics 
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At transmission power of 42 mW, coupling 60%, we see fundamental mode with a degeneracy
The D-shape motors were moved to a position 2 000 000 steps (in theory they should be the max position)
but no change appeared on the 00 mode or the higher order mode. |
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Power storage In Cavity, posted by Manar Amer at Optical room about lasers and optics
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Power increased in the amplifier
reflective filters added at the transmission point to be able to have signal on the Beam Profiler, Transmission diode and power meter
Amplifier output current |
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Power storage In Cavity, posted by Manar Amer at Optical room about lasers and optics
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at max stage we reached at 2.5 A on the diodes we have
8000 gain , coupling ~ 60% , with power inside the cavity 50 kW
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Power storage In Cavity, posted by Manar Amer at Optical room about lasers and optics
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The cavity was locked under vacuum, coupling is approximately < 10%
The lock was relatively easy and the usual sign (oscillations on the transmission tail) of high finesse on the transmission signal was not seen.
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Power storage In Cavity, posted by Manar Amer at Optical room about lasers and optics
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We improved the lock using the alignment, polarization and CEP , the maximum we got was ~ 12% coupling
only the second stage is on !
Decision : this is the maximum we can obtain using the M1 from mighty laser |
Power measurement with D-shape, posted by Loïc Amoudry at Optical room about mechanics | lasers and optics
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Measurements of lot of points with D-shape mirrors well positionned.
Power not optimized to the best but almost. (@4A could have 350 mW).
I (A)
Ptrans (mW)
Coupling |
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Polarization optimization, posted by Loïc Amoudry at Optical room about lasers and optics
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Optimization of the polarization has been made the 03/10/18. Checked in reflection of the cavity in reflection&transmission of a PBS, locked and
unlocked. Only with 2nd stage.
Ratio values are reflection of PBS divided by transmission or the opposite. |
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Polarization issue & 50kW with 22W injection, posted by Xinyi Lu at Optical room about lasers and optics
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Today, Ronic and I lock the cavity on the other polarization and achieved 50kW with 22W injection.
- After we optimize and lock the cavity in vertical polarization, we rotate the waveplate at the transmission to minimize the signal, then rotate
the waveplate at the injection laser to maximize the signal. We lock the cavity in this horizontal polarization and optimize CEP and alignment. |
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Polarization issue, posted by Xinyi Lu at Optical room about lasers and optics
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These days, Ronic, Aurélien, Fatematuj and I have been doing some tests on polarization issue, trying to see if it is possible to obtain higher
gain under other polarization conditions.
We installed an additional half-wave plate + PBS + PD at the transmission. By rotating the waveplate of the injection laser, we can compare |
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Polarization issue, posted by Xinyi Lu at Optical room about lasers and optics
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just to add some details :
about the S and P polarization frequency shift:
the PZT scan is 10Vpp at 3.1Hz => the slope is 62 V/s because of the triangle shape of the PZT scan. |
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Polarization frequency, posted by Loïc Amoudry at Optical room about lasers and optics
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Check of the frequency of the onefive locked on each polarization of the cavity (tilt a waveplate by 45°).
Frequency repetition rate : 133.335 MHz on spectrum analyzer for both polarization locked. |
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Polarization frequency, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement on 30/10/18.
Loïc
Amoudry wrote:
Check of the frequency of the onefive locked on each polarization |
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Phase measurement with HASO, posted by Loïc Amoudry at Optical room about lasers and optics
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2 measurement.
First one locked, in transmission of M2 with 2nd stage 0A.Total 89 cm from the big waist (planar mirrors). 2 wedges used.
Second one at input beam with the same power. Datas taken at the same equivalent position than the first one. 3 wedges used. |
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Phase measurement with HASO, posted by Loïc Amoudry at Optical room about lasers and optics 8x
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* Loic has to fix the number of files (3) regarding the number of measurements (2)
* splitted Intensity and phase HASO files
* image for each file |
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Phase measurement with HASO, posted by Loïc Amoudry at Optical room about lasers and optics
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with just intensity, the coupling is 98%, and with phase, x direction coupling is 95%, y direction 97%, so the telescope is good.
Loïc
Amoudry wrote:
* Loic has to fix the number of files (3) regarding the number of |
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Origami SN2440 133MHz laser tests, posted by Ronic Chiche at Optical room about lasers and optics
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Today, we received the Origami SN2440 133MHz oscillator from repair (NKT mentioned a defective wire inside the controller....)
We immediately installed it behind an isolator (Faraday rotator+PBS+halfwave plate).
the output power is around 60mW. |
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Origami SN2440 133MHz laser power measurment... and failure, posted by Ronic Chiche at Optical room about lasers and optics
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we received from NKT the Origami SN2440 133MHz oscillator from repair on 2020/12/17
and we measured the power trend from 2020/12/21 until the whole winter Hollyday, during 14 days and 17h (1 273 334 s).
the power was quite constant, about 58mW (the measurement has been done with the OD2 filter and using a (x20) factor in the software to compensate |
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Optical amplifier polarization state, posted by Ronic Chiche at Optical room about lasers and optics
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We placed a PBS + 2 photodiodes (PhD1, PhD2) at the output of the amplifier to check how the polarization of the amplifier changes with power.
example with 2nd stage @ 6A :
PhD1 = 24.7 mV |
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Optical amplifier polarization state, posted by Ronic Chiche at Optical room about lasers and optics
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The polarimeter was giving a strange 50% of DOP of the light coming from the cavity.
we had to calibrate (LONG calibration process with care) the polarimeter to get a proper 100% of DOP !
the polarimeter needs also a good alignment with 2 mirrors, a colimated beam and a max power on photodiode between 0.7 and 0.8 (use electronic gain |
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Optical amplifier polarization state, posted by Ronic Chiche at Optical room about lasers and optics
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polarization state of the cavity at higher power : 20kW, 30kW and 33kW (slight CEP and alignment optimization) :
the polarization state changes only a little to ~ 87° and is almost linear.
Ronic |