First mode degeneracy on ThomX, posted by Loïc Amoudry at Optical room about lasers and optics 
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Yesterday, we've observed the first degeneracy on ThomX cavity at ~115 kW stored. The shape of the stored power on the oscilloscope is really close
to what has been published in the D-shape mirror's paper ("tek0000" transmission in yellow, piezoelectric activator in green, error
signal in blue). |
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Spherical mirrors at closest position. FSR, finesse and beam size., posted by Loïc Amoudry at Optical room about lasers and optics
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The spherical mirrors are at the closest position to get a FSR ~=33.3435 MHz. Planar mirrors are at the largest position.
The finesse has been measured about 17 000.
Beam diameter (2*w) is ~= 4.6 mm x and y. |
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Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
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The ouput power of the ThomX amplifier has been measured as a function of the 3rd stage pumps current (0A is 1st and 2nd stage turned on).
We measured the total power, the total power without the "donuts" pump signal dumped by an iris and the transmission of a dichroic
mirror (for ref see image). |
Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
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Loïc
Amoudry wrote:
The ouput power of the ThomX amplifier has been measured as a function |
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Onefive Origami 33MHz specs, posted by Loïc Amoudry at Optical room about lasers and optics
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Beam Size Onefive added
Loïc
Amoudry wrote:
Power during ~20h, power after turn on, spectrum image and excel |
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Pneumatic valves, posted by Loïc Amoudry at Optical room about vacuum
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The pneumatic valves are now plugged on the university air network.
The air valve is fully openned for the moment.
We still have to check if there is some minor leakage close to the pneumatic valve to improve the setup. |
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Onefive output power, posted by Loïc Amoudry at Optical room about lasers and optics
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The pump voltage has been increased few days ago when looking for a modlock of the laser.
The 33MHz Onefive output power is now 3.58mW with OD1 filter ==> ~36mW.
There are 2µW @ 1% coupling fiber with OD1 filter ==> ~20µW ==> 2mW @99% coupling fiber (2mW to the amplifier). |
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CVBG reference and Eric Cormier calculation, posted by Loïc Amoudry at Optical room about lasers and optics
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The Stretcher is the "D 24-02-II", it must be used in double path before the amplifier injection.
There are two compressors in single path, "D 25-14-I" and "D 25-14-II".
Eric calculations are attached below. |
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Onefive output power, posted by Loïc Amoudry at Optical room about lasers and optics
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Onefive output power measured today. 3.52 mW with OD1 filter ==> ~35mW.
Loïc
Amoudry wrote:
The pump voltage has been increased few days ago when looking for |
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Telescope for compressors and ThomX, posted by Loïc Amoudry at Optical room about lasers and optics
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CVBGs telescope is done with w ~= 1mm.
ThomX telescope is done with w ~= 2.3mm in x and y.
Newt step is to lock with these short pulses (measured ~2.5ps with FWHM standard deviation interference method). |
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ThomX Locked with CVBGs, posted by Loïc Amoudry at Optical room about lasers and optics
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ThomX has been locked with a new telescope while using compression CVBGs.
Coupling is ~50-55% and lock is stable.
Power up to ~50kW should follow up soon (stop when HOM are observed). We'll not go over ~100kW to not risk any breakdown due to the |
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Powerup with 2.5ps pulses, posted by Loïc Amoudry at Optical room about lasers and optics
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A power up has been performed on ThomX until 65kW intracavity power. We didn't see any modes but stored power was really unstable since ~60kW (see
image tek00004.png).
Measurement report is shown in the table below. Gain seems to decrease against intracavity power. |
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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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Coating reflectivity, posted by Loïc Amoudry at Optical room about lasers and optics 6x
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| Coatings reflectivity curves and datas for HR Saphir, HR Suprasil and HR ULE. |
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Beam size and finesse, posted by Loïc Amoudry at Optical room about lasers and optics
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Measurement behind P4 (planar mirror)
Loïc
Amoudry wrote:
FSR initiale : 33.34 MHz (S3 = -825000 et S4 = -825000) |
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Onefive ouput power and spectrum, posted by Loïc Amoudry at Optical room about lasers and optics
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After turning on, one can see the 133.33MHz Onefive output power for ~40min with OD2 filter (~/20). So the real output power is ~57mW. A measurment over
several days (15?) should come in few weeks.
The spectrum here has been taken one day after turning on the Onefive (see Fig. 133_spectrum_full and 133_spectrum). One can see the central |
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Onefive ouput power and spectrum, posted by Loïc Amoudry at Optical room about lasers and optics
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1) Note: The OneFive laser used for experimenting is the one for the SBox
but, for now only this laser arrived from the company so we are doing tests (measuring the spectrometer and power ) on it inside the ThomX cavity
clean room. |
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Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
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We checked the Dichroic mirror we have : it is a DMSP1000 shortpass dichroic mirror as specified in this post.
The Arrow engraved on the edge of the mirror points on the AR surface !
not on the HR surface... |
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telescope for Koheras, posted by Huan Wang at Optical room about lasers and optics
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telescope of Koheras is removed, information record here:
- distance between collimator edge and -50 lens mount edge is 14.7cm,
- distance between another edge of -50 lens mount and +250 lens mount edge is 14.3cm, |
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Characterizing Focus Tunable Lens, posted by Fatematuj Johora at Optical room about lasers and optics
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Yesterday Ronic and I worked on the high laser power measurements with the Vertical set-up of the Focus Tunable Lens. We went upto 38W@4 dpt at the begining
and then also changed the focal power at 38W.
Observation: |