amplifier, posted by Huan Wang at Optical room about lasers and optics
|
I just had a phone call with Jérome and he told me 2 things :
* Be carefull ! the MightyLaser amplifier is not designed to work with 33MHz laser : the streching level is not sufficient !
One could worsen the phase noise by self-modulation due to peak power or even distroy the amplifier !
One should use it only at low power !!!
* He thinks we should more or less find back the same DC levels than before even with lower seeding power and lower repetition rate.
He thinks we should look at the optical spectrum to check if we don't have some ASE in the 1st stage and 2nd stage signal !
We can send him plots or call him to discuss these points.
| Huan Wang wrote: |
|
Onefive output power is 24mW now, and 2.41mW(after EOM) injected into fiber,
a injection power monitor added, 99% (2.06mW) injected into amplifier, 1% (16.1uW) monitored with photodiode DET36A/M, which gives ~500mV DC signal on oscilloscope with 1Mohm impedanc;
First stage amplifier works good, monitoring phtodiode gives more than 200mV DC signal with 50ohm impedance on oscilloscope (as attached photo);
Second stage, the old monitoring photodiode is broken, a new monitoring photodiode is connected, which we don't have reference data for it,
on the optical output port of the monitoring signal, it's written 150mW, but at where we measured 40mW.
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Transmission vs D-shape position at different powe, posted by Loïc Amoudry at Optical room about lasers and optics 
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Measurements have been done on 18/10/18.
Datas are on excel file, also matlab file. |
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Transmission Measurements for the Mirrors. , posted by Manar Amer at Optical room about lasers and optics 6x
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- Thursday 10 December 2020: First Test Measurement - Inside Box
- The transmission ( T ) for the mirrors of SBOX and ThomX was measured over a range from the center of the mirror up to 5mm.
-
- The first setup was initially done while the mirrorr is installed inside the metal box, when measuring T we observe that there is an erregular change in the power measured as we move azay from the center of the mirror, this was due to reflection of light inside the box. The reflection from the mirror was reflected on the metal inside the box and it was measured by the power meter.
(so for this setup we only took measrements for T along the center of the mirror)
The file stating the measurements is : Test Cavity _ Mirrors transmission _ Inside box
=======================================================================
- Tuesday 15 December 2020 : Second Test - Outside Box
- The setup for T test was moved outside the metal box with the same distances between the injection beam and mirror ~ 50 cm. and the distance between the injection laser and the mirror next to it ~ 9 cm.
-
- Observation for T is done at full angle and at half angle of reflection ( the mirror was tilted to achive this )
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- we observed that after each change in the distance from the center the power meter needed to be aligned to have the max power.
- after doing all the measurements for the range from the center we made it again for the center only and the consistance of the transmission was good.
The file stating the measurements is : Test Cavity _ Mirrors transmission _ outside box
note: the laser used for the test is the Koheras
details on the pwer used, mirrors, power meter, filters, ....etc are shown in the Excel data sheets
Done By : Loic , Manar and Ahmed |
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
|
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
|
I placed a periscope to adjust the high of the beam from the amplifier output from ~ 10 cm from the table to ~ 15 cm
a dichroic mirror placed after it to reject the pump laser, all the mirrors on the path to the cavity were replaced with dielectric mirrors BB01-E03
the length of the path from the amplifier output to the cavity coupling mirror ~ 2 meters
setup defines the different optics placed in the path
Note: the beam goes all the way to the cavity, put it is not yet optimized to the irises.
| Manar Amer wrote: |
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
|
Here is a view of beam propagation in the optical software : GaussianBeam
the red filled shape is the model of the CELIA amplifier beam propagation with a divergence of 4.46 mrad
(the 2 black dots is the measurement of the beam size without any lens to change the beam propagation).
the 2 black lines have been put at the input and output cavity mirrors position relative to the CELIA amplifier position, respectively 2m and 2.7m roughly.
the cavity mode radius should be 0.55mm and 0.7mm respectively.
the cavity mode shape is represented by the 2 red lines (very close to the red filled shape which is the beam).
the most simple working telescope could be a +250 lens at 280mm from the CELIA amplifier.
it gives a beam radius of 0.53mm at the input mirror and 0.64mm at the output mirror.
the overlapping is more than 99%
the 2nd file is the GaussianBeam file.
| Manar Amer wrote: |
|
I placed a periscope to adjust the high of the beam from the amplifier output from ~ 10 cm from the table to ~ 15 cm
a dichroic mirror placed after it to reject the pump laser, all the mirrors on the path to the cavity were replaced with dielectric mirrors BB01-E03
the length of the path from the amplifier output to the cavity coupling mirror ~ 2 meters
setup defines the different optics placed in the path
Note: the beam goes all the way to the cavity, put it is not yet optimized to the irises.
| Manar Amer wrote: |
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
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removing the reading which is not correct (wrong use of software)
redone a reading similar using a lens of focal 250 mm got a FWHM-X = 0.64 mm , FWHM-Y = 0.84 mm
using the vertical to calculate the divergence, we get divergence ~ 2.17 mrad which is closer to fit obtained for the beam profile by taking data points along the path
attached is also the amplifier beam data taken at different points and their fit using Gaussian beam software
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad
| Manar Amer wrote: |
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
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Note the correct beam divergence is approximately ~ 2.3 mrad
M2 = 1.1 in this fit, but it is not yet optimized !!!!! could be reason for not accurate telescope reading.
Have tInstalled a new telescope with lenses
250 mm @ 86.8 cm from amplifier ,
-150 mm @109 cm (~ 22 cm between lenses)
the beam waist measured at a point on the reflection which is relatively the same distance to the injection mirror and the beam was much smaller than before
@ ~ 2 meters from amplifier + telescope , FWHM = 1.2 mm , waist = 0.85 * FWHM = 1.02 mm
| Manar Amer wrote: |
|
Here is a view of beam propagation in the optical software : GaussianBeam
the red filled shape is the model of the CELIA amplifier beam propagation with a divergence of 4.46 mrad
(the 2 black dots is the measurement of the beam size without any lens to change the beam propagation).
the 2 black lines have been put at the input and output cavity mirrors position relative to the CELIA amplifier position, respectively 2m and 2.7m roughly.
the cavity mode radius should be 0.55mm and 0.7mm respectively.
the cavity mode shape is represented by the 2 red lines (very close to the red filled shape which is the beam).
the most simple working telescope could be a +250 lens at 280mm from the CELIA amplifier.
it gives a beam radius of 0.53mm at the input mirror and 0.64mm at the output mirror.
the overlapping is more than 99%
the 2nd file is the GaussianBeam file.
| Manar Amer wrote: |
|
I placed a periscope to adjust the high of the beam from the amplifier output from ~ 10 cm from the table to ~ 15 cm
a dichroic mirror placed after it to reject the pump laser, all the mirrors on the path to the cavity were replaced with dielectric mirrors BB01-E03
the length of the path from the amplifier output to the cavity coupling mirror ~ 2 meters
setup defines the different optics placed in the path
Note: the beam goes all the way to the cavity, put it is not yet optimized to the irises.
| Manar Amer wrote: |
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
|
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
|
Am adjustment on the lenses position to have a smaller waist.
+ 250 mm @ 88 cm from amplifier
-150 mm @ 111 cm from amplifier
the overlap with this placement is ~ 91%
the measured beam FWHM at the injection point M1 estimated to be ~ 0.94 mm
waist = 0.85*0.94 = 0.79 mm , it is still much larger than the needed 0.58 mm radius waist.
There is an improvement in reducing higher order modes, but the fundamental is still too weak to see, we observe higher order even modes 11 , 44 , ...
| Manar Amer wrote: |
|
Note the correct beam divergence is approximately ~ 2.3 mrad
M2 = 1.1 in this fit, but it is not yet optimized !!!!! could be reason for not accurate telescope reading.
Have tInstalled a new telescope with lenses
250 mm @ 86.8 cm from amplifier ,
-150 mm @109 cm (~ 22 cm between lenses)
the beam waist measured at a point on the reflection which is relatively the same distance to the injection mirror and the beam was much smaller than before
@ ~ 2 meters from amplifier + telescope , FWHM = 1.2 mm , waist = 0.85 * FWHM = 1.02 mm
| Manar Amer wrote: |
|
Here is a view of beam propagation in the optical software : GaussianBeam
the red filled shape is the model of the CELIA amplifier beam propagation with a divergence of 4.46 mrad
(the 2 black dots is the measurement of the beam size without any lens to change the beam propagation).
the 2 black lines have been put at the input and output cavity mirrors position relative to the CELIA amplifier position, respectively 2m and 2.7m roughly.
the cavity mode radius should be 0.55mm and 0.7mm respectively.
the cavity mode shape is represented by the 2 red lines (very close to the red filled shape which is the beam).
the most simple working telescope could be a +250 lens at 280mm from the CELIA amplifier.
it gives a beam radius of 0.53mm at the input mirror and 0.64mm at the output mirror.
the overlapping is more than 99%
the 2nd file is the GaussianBeam file.
| Manar Amer wrote: |
|
I placed a periscope to adjust the high of the beam from the amplifier output from ~ 10 cm from the table to ~ 15 cm
a dichroic mirror placed after it to reject the pump laser, all the mirrors on the path to the cavity were replaced with dielectric mirrors BB01-E03
the length of the path from the amplifier output to the cavity coupling mirror ~ 2 meters
setup defines the different optics placed in the path
Note: the beam goes all the way to the cavity, put it is not yet optimized to the irises.
| Manar Amer wrote: |
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
|
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Telescope / amplifier output, posted by Manar Amer at Optical room about lasers and optics
|
We increased the power of the amplifier up to 10 W to see if there is a change in the beam shape at the injection point or the transmission.
There was no change in the shape of both of them from the reading at 1 W (with only the 2nd stage on)
Only saw an increase in the transmission power, which is expected.
| Manar Amer wrote: |
|
Am adjustment on the lenses position to have a smaller waist.
+ 250 mm @ 88 cm from amplifier
-150 mm @ 111 cm from amplifier
the overlap with this placement is ~ 91%
the measured beam FWHM at the injection point M1 estimated to be ~ 0.94 mm
waist = 0.85*0.94 = 0.79 mm , it is still much larger than the needed 0.58 mm radius waist.
There is an improvement in reducing higher order modes, but the fundamental is still too weak to see, we observe higher order even modes 11 , 44 , ...
| Manar Amer wrote: |
|
Note the correct beam divergence is approximately ~ 2.3 mrad
M2 = 1.1 in this fit, but it is not yet optimized !!!!! could be reason for not accurate telescope reading.
Have tInstalled a new telescope with lenses
250 mm @ 86.8 cm from amplifier ,
-150 mm @109 cm (~ 22 cm between lenses)
the beam waist measured at a point on the reflection which is relatively the same distance to the injection mirror and the beam was much smaller than before
@ ~ 2 meters from amplifier + telescope , FWHM = 1.2 mm , waist = 0.85 * FWHM = 1.02 mm
| Manar Amer wrote: |
|
Here is a view of beam propagation in the optical software : GaussianBeam
the red filled shape is the model of the CELIA amplifier beam propagation with a divergence of 4.46 mrad
(the 2 black dots is the measurement of the beam size without any lens to change the beam propagation).
the 2 black lines have been put at the input and output cavity mirrors position relative to the CELIA amplifier position, respectively 2m and 2.7m roughly.
the cavity mode radius should be 0.55mm and 0.7mm respectively.
the cavity mode shape is represented by the 2 red lines (very close to the red filled shape which is the beam).
the most simple working telescope could be a +250 lens at 280mm from the CELIA amplifier.
it gives a beam radius of 0.53mm at the input mirror and 0.64mm at the output mirror.
the overlapping is more than 99%
the 2nd file is the GaussianBeam file.
| Manar Amer wrote: |
|
I placed a periscope to adjust the high of the beam from the amplifier output from ~ 10 cm from the table to ~ 15 cm
a dichroic mirror placed after it to reject the pump laser, all the mirrors on the path to the cavity were replaced with dielectric mirrors BB01-E03
the length of the path from the amplifier output to the cavity coupling mirror ~ 2 meters
setup defines the different optics placed in the path
Note: the beam goes all the way to the cavity, put it is not yet optimized to the irises.
| Manar Amer wrote: |
|
Beam divergence was measured using a method called "Focal Length Divergence Measurement Method"
Where a lens of a known focal length is placed on the beam path and the beam waist is measured at the focal distance using a beam profiler.
We ramped the power up to 10 W
for a focal length = 400 mm,
we measured a FWHM = 2.1 mm,
corresponding to a divergence = 4.45 mrad (edit : wrong software use)
for comparison, we measured the FWHM 8.1 mm @ 1.55 m and extracted the divergence directly 4.46 mrad (edit : this measurement is wrong - wrong use of the software)
Note: better to use a lens of a focal lens higher than 100 mm (to reduce the error in the distance measured)
| Manar Amer wrote: |
|
The previous Sbox telescope was dismantled and the mechanical components cleaned.
its lenses are still in the mounts, it looks that two of them are spherical and two are cylindrical
2 are -100 mm and 2 are +150 mm, there is also a box containing fused silica lenses that could be used.
Note: at high power use only fused silica lenses not BK7 type
|
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Telescope - Spacial Matching , posted by Manar Amer at Optical room about lasers and optics
|
Divergence of the CW beam out of the collimator measured after 1 meter to be
- 2
 x = 0.7425 mrad --> x = 0.37125 mrad
- 2 y = 0.7115 mrad --> y = 0.3575 mrad
two lenses were placed to decrease the diameter of the injected beam |
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Successful lock (finally !), posted by Alice Renaux at Optical room about lasers and optics
|
Today, with Ronic, we managed to get a successful lock with the NKT laser by setting up a new PDH box from scratch (photodiode + amplifer + mixer).
Me measured the injected power (5.4mW) and the transmitted power (33µW) after a wedge (92% transmission) and a 7ppm transmission mirror, so the intracavity power was 5.1W. We have a 950 enhancement factor for a 3100 finesse cavity, so a nominal enhancement factor of 2500. The lock was very stable, as shown in the attached picture (yellow signal is the transmitted power, orange signal is the error signal and green signal is the voltage sent from the Laselock module to the pizeoelectric actuator of the NKT laser cavity).
Then, we added a second EOM in order to perform a finesse measurement, but we weren't able to inject more than 3mW at full laser power in the cavity or to lock the laser onto the cavity. |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about utilities
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In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available.
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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Used the spincoater and pure water to clean dielectric mirrors which will be installed inside the SBox for directing the reflection line.
The method : place pure alchole on mirror - wipe it using white sterile tissue (in one direction) - clean with pure water in spincoater suing cotton swap .
After multible rounds, the result in the images was obtained. there is still a significant amount of dust particles (not all could be dust!!).
Not sure if the reason is the cleaning method ?? will invistegate it more !!!
| Manar Amer wrote: |
|
In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available.
|
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
|
Images of the SBox mirrors cleaned at the same time when the cavity was aligned.
Directly from the spincoater to the SBox directly.
PowerPoint attached shows details
| Manar Amer wrote: |
|
Used the spincoater and pure water to clean dielectric mirrors which will be installed inside the SBox for directing the reflection line.
The method : place pure alchole on mirror - wipe it using white sterile tissue (in one direction) - clean with pure water in spincoater suing cotton swap .
After multible rounds, the result in the images was obtained. there is still a significant amount of dust particles (not all could be dust!!).
Not sure if the reason is the cleaning method ?? will invistegate it more !!!
| Manar Amer wrote: |
|
In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available.
|
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
|
PowerPoint shows the detailed images of all the mirrors before and after cleaning.
Images of SBox mirrors and M1 from Gamma factory attached only for the front after cleaning
the lines showing are on the back of the mirrors, they come from the spinning mount the mirrors are fixed on in the spin-coater.
Naming code :
M#BB - M# mirror Back Before cleaning
M#BA - M# mirror Back After cleaning
M#FB - M# mirror Front Before cleaning
M#FA - M# mirror Front After cleaning
G : Gamma factory
| Manar Amer wrote: |
|
Images of the SBox mirrors cleaned at the same time when the cavity was aligned.
Directly from the spincoater to the SBox directly.
PowerPoint attached shows details
| Manar Amer wrote: |
|
Used the spincoater and pure water to clean dielectric mirrors which will be installed inside the SBox for directing the reflection line.
The method : place pure alchole on mirror - wipe it using white sterile tissue (in one direction) - clean with pure water in spincoater suing cotton swap .
After multible rounds, the result in the images was obtained. there is still a significant amount of dust particles (not all could be dust!!).
Not sure if the reason is the cleaning method ?? will invistegate it more !!!
| Manar Amer wrote: |
|
In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available.
|
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|
|
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
|
Following the observation that when rotating M2 plan mirror of SBox the deformation position of the mode changes.
M2 was replaced with M2 spare of SBox
images of the mirror front side attached before and after cleaning, no spots at the center, but there seems to be 2 spots far from the center of the mirror.
After comparing with old images of M2 SBox spare, they do not appear to be damages, but dust !! (old image attached, taken on 10/12/2020, was never opened after)
| Manar Amer wrote: |
|
PowerPoint shows the detailed images of all the mirrors before and after cleaning.
Images of SBox mirrors and M1 from Gamma factory attached only for the front after cleaning
the lines showing are on the back of the mirrors, they come from the spinning mount the mirrors are fixed on in the spin-coater.
Naming code :
M#BB - M# mirror Back Before cleaning
M#BA - M# mirror Back After cleaning
M#FB - M# mirror Front Before cleaning
M#FA - M# mirror Front After cleaning
G : Gamma factory
| Manar Amer wrote: |
|
Images of the SBox mirrors cleaned at the same time when the cavity was aligned.
Directly from the spincoater to the SBox directly.
PowerPoint attached shows details
| Manar Amer wrote: |
|
Used the spincoater and pure water to clean dielectric mirrors which will be installed inside the SBox for directing the reflection line.
The method : place pure alchole on mirror - wipe it using white sterile tissue (in one direction) - clean with pure water in spincoater suing cotton swap .
After multible rounds, the result in the images was obtained. there is still a significant amount of dust particles (not all could be dust!!).
Not sure if the reason is the cleaning method ?? will invistegate it more !!!
| Manar Amer wrote: |
|
In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available.
|
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|
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
|
While repeating the alignment, the mirrors were cleaned using the spin-coater and placed again.
The current mirrors placed in the SBox are
M1 plane injection from Gamma factory
M2 plane from SBox spare
M3/M4 spherical from SBox main set
no visible damage seen on the mirrors with the microscope
no images of the surfaces were taken due to time constraint.
| Manar Amer wrote: |
|
Following the observation that when rotating M2 plan mirror of SBox the deformation position of the mode changes.
M2 was replaced with M2 spare of SBox
images of the mirror front side attached before and after cleaning, no spots at the center, but there seems to be 2 spots far from the center of the mirror.
After comparing with old images of M2 SBox spare, they do not appear to be damages, but dust !! (old image attached, taken on 10/12/2020, was never opened after)
| Manar Amer wrote: |
|
PowerPoint shows the detailed images of all the mirrors before and after cleaning.
Images of SBox mirrors and M1 from Gamma factory attached only for the front after cleaning
the lines showing are on the back of the mirrors, they come from the spinning mount the mirrors are fixed on in the spin-coater.
Naming code :
M#BB - M# mirror Back Before cleaning
M#BA - M# mirror Back After cleaning
M#FB - M# mirror Front Before cleaning
M#FA - M# mirror Front After cleaning
G : Gamma factory
| Manar Amer wrote: |
|
Images of the SBox mirrors cleaned at the same time when the cavity was aligned.
Directly from the spincoater to the SBox directly.
PowerPoint attached shows details
| Manar Amer wrote: |
|
Used the spincoater and pure water to clean dielectric mirrors which will be installed inside the SBox for directing the reflection line.
The method : place pure alchole on mirror - wipe it using white sterile tissue (in one direction) - clean with pure water in spincoater suing cotton swap .
After multible rounds, the result in the images was obtained. there is still a significant amount of dust particles (not all could be dust!!).
Not sure if the reason is the cleaning method ?? will invistegate it more !!!
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In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available.
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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The Sbox currently has the injection from ThomX installed T ~ 120 ppm , M2 planar from Sbox spare and M3 / M4 spherical mirrors from Sbox installed.
The last finesse measurement that was done gave a Finesse of ~ 19300 (After cleaning M2 using ethanol + aceton + pure water)
on Friday the whole optical table was cleaned again and the inside of the box was cleaned (even with a lot of dust inside the box the Finesse was 19300 )
all the mirrors were cleaned after using the three steps, M3 and M4 had clear visible dust on them.
D-shaped mirrors were installed again between M1 and M2
The alignment was redone and the beating observed , There is still a need for alignment improvement.
the cavity is under vacuum ~ 4.8*10^-2 mbar on Friday evening (~ 19h00) , The cavity is yet to be locked and to measure its Finesse
A PowerPoint showing the last finesse measurement and the error signal of the menhir laser lock
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