analysis of stored and reflected power, posted by Ronic Chiche at Optical room about lasers and optics 
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with this Finesse around 22-23k, the technique comparing TRANSMISSION and REFLECTION signals doesn't work, even in taking into account individual
photodiode time responses.
It seems that the cavity is not completely stationnary and the shapes are not comparable easily with just a Low Pass Filter related to the Finesse. |
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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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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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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"ThomX" CELIA Amplifier commissionning, posted by Ronic Chiche at Optical room about lasers and optics
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The "ThomX" CELIA amplifier is installed on the optical table.
I added all the rubber pieces available between the 2 racks to isolate as best as possible the top rack, which embeds some fans, from the bottom
rack from which the laser beam is going out to the FP cavity. |
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"ThomX" CELIA Amplifier commissionning, posted by Ronic Chiche at Optical room about lasers and optics
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Beam size at the amplifier output:
to make this measurement, I switched ON only 1st and 2nd stage.
the dichroïc mirror seems to work the best in reflection at normal AOI !!! |
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Koheras CW laser lock on FP cavity, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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I locked the Koheras CW on the FP cavity but the lock was pretty noisy and very difficult to acquire.
I tried to produce some modulation sidebands close to 216MHz to measure the Finesse but the power loss was very small so, the signal to extract
the Finesse would be unreadable ! |
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OEwaves lock and Finesse measurement, posted by Ronic Chiche at Optical room about lasers and optics
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this morning, I locked the FP cavity with the OEwaves CW laser and the "Fred fiber amplifier" used at 500mA of pump current.
the lock was much more easy than with the Koheras.
I had to change the 10GHz EOM which seems damaged as the modulation depth is very low and does not allow a Finesse measurement by modulation |
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"ThomX" CELIA Amplifier commissionning, posted by Ronic Chiche at Optical room about lasers and optics
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this afternoon, with Fabian, we did some measurements on the 3rd stage.
finally we used the Dichroïc mirror at AOI=45°C as first mirror and a Thorlabs BB1-E03 as 2nd mirror to send the
beam to the powermeter. |
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2nd stage CELIA amplifier, posted by Ronic Chiche at Optical room about lasers and optics
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| today, we measured the 2nd stage CELIA amplifier pump wavelength : 970-990 nm |
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2nd stage CELIA amplifier, posted by Ronic Chiche at Optical room about lasers and optics
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today we did several test with the Dichroic shortpass mirror (Thorlabs DMSP1000) and with a 10nm optical filter around 1030nm (which works in tranmission
at AOI=0).
one used the dichroic mirror in reflection: one should cut the pump @970-990nm and we should keep only the signal @1030nm. |
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unsuccessful telescope design :-(, posted by Ronic Chiche at Optical room about lasers and optics
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we wanted to calculate the right telescope with 2 spherical lenses.
1) we have the FP cavity mode size which is 0.58mm at the input mirror and 0.7mm at the output mirror.
2) we planned to measure the laser beam at the output of the amplifier working at P=1W (2nd stage ON only). |
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D-shape mirrors positionning status, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics
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This afternoon we opened the cavity and put the D-shape mirrors at their correct place, close to the beam.
we checked the relative position of the mirrors to the beam using the 2nd stage of the amplifier (<1W) and with the sensitive (and cleaned) orange
optical card. |
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D-shape mirrors positionning status, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics
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The cavity box is vacuum pumped at 6*10^-2 mbar.
Ronic
Chiche wrote:
This afternoon we opened the cavity and put the D-shape mirrors at |
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Laser Menhir reinstallation + CVBG + fiber injection, posted by Ronic Chiche at Optical room about lasers and optics
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The lab purchased the Menhir laser @ 216MHz.
it has been sent back to Menhir photonics for inspection, and then is now at lab.
it has been reinstalled to the SBOX setup with injection in a CVBG for pulse stretching before amplification. |
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New mirrors batch informations, posted by Ronic Chiche at ThomX igloo about lasers and optics
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the 2 files describe the specfications for the 16 mirrors ordered (4 for ThomX + spare, 4 for SBOX + spare) and the measurements made by the LMA.
I add also a 3rd file in which all the "special' mirrors are referenced. |
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new setup for the 160MHz Menhir oscillator, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics | software
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from the begining of the week, Xinyi, Aurélien, Viktor and myself started to install a new setup for the Menhir 160MHz oscillator.
the goal is to rich a record power in the FP-cavity.
- the 160MHz Menhir oscillator has been injected in a fiber. |
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100W CELIA laser amplifier "how's to" document, posted by Ronic Chiche at Optical room about lasers and optics | software
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1st version of the document.
if some information is not correct or missing, give any comment by replying to this post. |
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100W CELIA laser amplifier "Power vs Pump current" curve, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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We measured again the 100W CELIA laser amplifier with a pump current until 8A.
as the first current pump of the amplifier has a Peltier issue, we don't exceeded 6A on this stage and we compensated with the 3 other stages.
7A average current is obtained with 6A / 7.3A / 7.3A / 7.4A |
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D-shape mirrors positionning status, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics
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summary:
- the motors used to move the D-shape are the Newport Picomotors 8303-V
the sensitivity is roughly 30nm/step |