Amplifier power and mirror transmission, posted by Xinyi Lu at Optical room about lasers and optics 
|
Today, Ronic, Daniele, Aurélien and I measured the amplifier power and mirror transmission.
Current (A)
0 (2rd stage)
1
2
3
4
5
6
7
7.5
8
Power
(W)
1
1.8
11.8
23.5
35.5
47
57.5
66.9
70.7
74.9
For |
Amplifier output Beam Profile, posted by Manar Amer at Optical room about lasers and optics
|
In preparation to measure the output beam profile from the amplifier at high power, I have placed two wedge mirrors just before the beam dump to be able
to extract the beam.
One of the wedges was taken from ThomX bunker, also the HR and AR mirrors were taken to plic room in case we might need them |
|
Amplifier output Beam Profile, posted by Manar Amer at Optical room about lasers and optics
|
Beam divergence after amplifier 4.46 mrad
Manar |
|
Amplified laser injection, posted by Xinyi Lu at Optical room about lasers and optics
|
In the last two days, Ronic and I connected the amplifier and locked the cavity.
- We installed an iris on the output to remove a part of the pump.
- We turned on the second stage of the amplifier. When locking, the injected power is 220 mW and the transmitted power after M2 is 26 uW. |
|
Alignment of a 2-mirror FP cavity, posted by Ronic Chiche at Optical room about mechanics | lasers and optics
|
today with Alice,
- we measured the height of the SBOX windows center : 140mm from the optical table.
- we set the laser fiber colimator exactly at this height. |
|
Alignment / Table setup , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
|
The current setup of the optical table attached.
The cavity is aligned and the lock of the fundamental mode has been attempted, but the mode is drifting too quickly to be able to follow.
I have placed the cavity under vacuum for a better stability. |
|
Alignment / Table setup , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
|
closing series
Manar
Amer wrote:
The current setup of the optical table attached. |
|
AFM+ InfraRed spectroscopy (IR spectro) has been performed, posted by Loïc Amoudry at Other about lasers and optics
|
AFM+ InfraRed spectroscopy (IR spectro) has been performed on 400kW S-BOX mirrors.
Seems that XPS made M3 and M4 dirty, but M1 have also ome dust. M2 seems clean, further AFM experiment should show that it is as clean as M1. |
|
AFM performed on S-BOX mirrors, posted by Loïc Amoudry at Other about lasers and optics
|
| 29/02/19 - AFM has shown that spots on mirror's surfaces are bumps and not holes. |
|
AFM analysis of M2, posted by Loïc Amoudry at Optical room about lasers and optics
|
We had enough time to proceed a quick scan of M2 which has also a hole but not centered on the mirror.
The hole is larger and higher than the one on M1. But the vertical range was to high for the AFM. Then we cannot see if there are sparkles or
not on this image. Further study with microscope would be welcome. |
|
AFM analysis of M1, posted by Loïc Amoudry at Optical room about lasers and optics
|
AFM has been proceeded on M1 and M2.
The pdf shows the first images taken with the PLIC room Leica microscope (zoom x10 and x80).
Then the hole has been studied with a handmade microscope. It brought a better resolution. We can now see the hole has an edge, a center structure |
|
2nd stage amplifier issue, posted by Ronic Chiche at Optical room about lasers and optics
|
the 2nd stage amplifier needed several hours (4-5h) to reach its nominal power (we look at photodiode level on a scope), instead of the awaited 30 minutes.
could it come from the probable spectrum shifting of the OneFive laser ?
(the power coming from the CVBG, coupled to the fiber, is lower than expected). |
|
2nd stage amplifier issue, posted by Ronic Chiche at Optical room about lasers and optics
|
Last time, we switched ON directly the 2nd stage at 6A without increasing/decrinsing slowly the current.
today, we switched ON the chiller, switched ON the 1st stage, switch ON the power supply of the 2nd stage at 0A and then we increased slowly the
current until 6A... and the problem disappeared. |
|
2nd stage amplifier issue, posted by Ronic Chiche at Optical room about lasers and optics
|
2nd stage output power was going down. We checked the pump diode technical data sheet and the operating temperature is [25°C:35°C].
We increased the chiller temperature setpoint from 19°C to 23°C.
Then the output power increased (93mW on 2nd stage photodiode). |
|
2nd stage CELIA amplifier, posted by Ronic Chiche at Optical room about lasers and optics
|
| today, we measured the 2nd stage CELIA amplifier pump wavelength : 970-990 nm |
|
2nd stage CELIA amplifier, posted by Ronic Chiche at Optical room about lasers and optics
|
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. |
|
2-mirror cavity locking, posted by Alice Renaux at Optical room about lasers and optics
|
In June, we encountered some problems regarding the transmission and error signals (see images here),
looking as if the laser was switched off before the cavity was filled.
|
|
2-mirror cavity full setup, posted by Alice Renaux at Optical room about lasers and optics
|
Today with Ronic, we changed the FP cavity's mirrors to Layertek (Gamma Factory) mirrors :
- M1 : n°161186 --> fused silica, unknown absorption, unknown diffusion, T1=2500ppm transmission planar mirror ;
- M2 : n°161182 --> fused silica, unknown absorption, unknown diffusion, T2=10ppm transmission, 5m ROC mirror. |
|
2-mirror cavity alignment, posted by Alice Renaux at Optical room about mechanics | lasers and optics
|
At the beginning of the week, I installed a half-wave plate, a beamsplitter cube and a quarter-wave plate, as well as the end-of-cavity mirror, which
I unsuccessfully tried to align.
I removed the end-of-cavity mirror and started the laser injection over again with the two motorized mirrors placed in front of the vacuum chamber |
|
2-mirror cavity alignment, posted by Alice Renaux at Optical room about lasers and optics
|
Yesterday and today, I replaced the OEWaves CW laser with the NKT CW laser. Its screen does not display anything, so it has to be operated through the
GraphiK software.
I then re-aligned the cavity with a new adjustment adaptation tool between the mirror mounts and the irises. |