at max stage we reached at 2.5 A on the diodes we have
8000 gain , coupling ~ 60% , with power inside the cavity 50 kW
The higer order mode that was observed today,
it was also observed on Friday along the other higher order mode recorded on the logbook.
after cutting it with the D-shaped mirror we recorded the shape (image attached)
| Manar Amer wrote: |
|
Power increased in the amplifier
reflective filters added at the transmission point to be able to have signal on the Beam Profiler, Transmission diode and power meter
|
Amplifier output current (A)
diode 1
|
Amplifier output current (A)
diode 2
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Amplifier output current (A)
diode 3
|
Amplifier output current (A)
diode 4
|
Power Output (W) |
Transmitted power (mW) |
note |
| 0.5 |
0.5 |
0.5 |
0.5 |
|
|
no change in the beam shape |
| 1 |
1 |
1 |
1 |
|
|
|
| 1.5 |
1 |
1 |
1 |
|
|
Appearance of higher order mode (vertical), suppressed using D-shaped mirror (vertical only) by (-23000), image recorded. |
| 1.5 |
1.5 |
1.5 |
1.5 |
|
|
no change |
| 2 |
1.8 |
1.5
|
1.5 |
|
52 mA |
52 mA after CEP adjustment , power measured after 2 reflective fillers NDUV30A and NDUV20 |
| 2 |
2 |
2 |
2 |
|
70 mA |
|
| 2.5 |
2.5 |
2 |
2 |
|
95 |
|
| 2.5 |
2.5 |
2.5 |
2.5 |
|
|
sudden drop in power, cavity lock lost, lock system looks ok (maybe something in the cavity)
mode shape is the same
coupling is large, transmission is very low
change the CEP, mo effect in changing it (we have no gain in the cavity, No Finesse) could be something happened to the mirrors !!!!!!
|
| Manar Amer wrote: |
|
At transmission power of 42 mW, coupling 60%, we see fundamental mode with a degeneracy
The D-shape motors were moved to a position 2 000 000 steps (in theory they should be the max position)
but no change appeared on the 00 mode or the higher order mode.
We will break the vacuum and check the position of the D-shaped mirrors.
| Manar Amer wrote: |
|
We start of power output from amplifier of 1W with only the first and second stage on then we start with the third stage power increase,
Note: when changing the current on the third stage 4 diodes, better to do it step by step for each one with a step of ~ 0.5 A
|
Amplifier output current (A)
for four diodes
|
Power Output (W) |
Transmitted power (MW)
|
| 0 , 0 , 0 , 0 |
~ 1 |
2.3 |
| 1 , 1 , 1 , 1 |
/ |
11.0 |
| 1.5 , 1.3, 1 , 1 |
/ |
35 |
| 1.5 , 1.5 , 1 , 1 |
/ |
42.16 |
| |
|
- we placed at the transmission point a splitter the transmitted power before was 35 mW after placing it we had 26 mW
- 97 % transmission , 3% reflected which goes to the beam profiler
- We see degeneracy modes at the last step of 42.16 mW , so we started to test the D-shaped mirrors
- the full range of the motors is 50.8 mm
- each step = 30 nm , 30 000 steps = 1 mm
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