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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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. |
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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FP cavity alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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as the iris used to locate the FP-cavity axis have been removed before moving the table inside the Igloo, we have to find again this FP-cavity axis.
this morning with Viktor, we started to make the alignment of the FP-cavity with a red laser using only the "input window" iris mount
built by Yann. |
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FP cavity alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This afternoon, we continued the alignment of the red laser.
we did it using the 2 final injection mirrors.
we still see a clear transmission after M2, a weak transmission after M3, and almost nothing after M4 due to the power loss going through the dielectric |
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FP cavity alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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A continuation of the alignment process was done, there was change in it due to variation in temperature,
it was done using the semiconducting laser, and we were able to obtain an output at M2.
2 references were placed before the alignment mirrors Ma and Mb , to fix the line when changing from semiconducting laser to CW "koheras" |
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FP cavity alignment , posted by Manar Amer at ThomX igloo about lasers and optics
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Note the direction of injection is M1 - M2 - M3 - M4
P1 - S2 - S3 - P4 |
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FP cavity alignment , posted by Manar Amer at ThomX igloo about lasers and optics
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The alignment is on hold until next week 17th - 18th Jan
an Alignment attempt will be done when the ring part close to the FP cavity is opened.
Manar |
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FP cavity alignment , posted by Manar Amer at ThomX igloo about lasers and optics
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***** Continuation of the alignment ---- FP Cavity Open --- ****
The cavity was put under outer pressure and was opened for the alignment
The alignment was done using CW koheras infrared laser and the inside mirrors irises |
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FP cavity alignment , posted by Manar Amer at ThomX igloo about lasers and optics
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Yesterday, we did the alignment again using Iris and beam profilers to obtain a more precise result.
at the end of the alignment procedure, we successfully obtained the beating modes.
the geometrical alignment seems good (weak odd modes) but we could need to put a telescope on the Koheras line as the beam size seems quite different |
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FP cavity mode axis change and Finesse measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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this morning with Manar, we did a cavity mode axis change.
we checked the cavity mode centroid position on the beam profiler (placed behind P4) and changed it by roughly 1mm on the X-axis and by 500µm
on the Y-axis. |
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Cavity beam Image , posted by Manar Amer at ThomX igloo about lasers and optics
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Updated beam image after change on the mode axis.
Taken after P4. |
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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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Aurélien, Manar, and I spent more than 2h trying to start the software communicating with the Alphanov amplifier controller.
each time, we had a problem with the software, asking to switch OFF and ON the controller before being able to switch the amplifier diodes ON.
we switched OFF and ON many times without any success. |
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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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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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Alphanov amplifier power measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning, with Manar and Aurélien, we measure the power directly at the output of the Alphanov amplifier with the 2 compressors CVBG
(seeding laser at Frep = 133MHz)
(we had to remove the base plate where the deflector mirrors were mounted to put the large powermeter). |
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Alphanov amplifier power measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics
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answers from Guillaume:
- the chiller temperature has to be set to 25°C
- the power measured with the software can change a little from what Alphanov measured with their laser. |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics 8x
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Today: Manar, Ronic and Aurlien started the study of the beam profile of the alphanov amplifier at high power.
The setup shown in the image shows how the power is reduced by using Anti-reflective mirrors,
pick up 1 : Anti-reflective coating on both sides , pick up 2 : Anti-reflective coating on one side and High |
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Alphanov amplifier Beam Profile, posted by Manar Amer at ThomX igloo about lasers and optics
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Manar
Amer wrote:
Today: Manar, Ronic and Aurlien started the study of the beam profile |