Measurement done on 18/10/18.
At high power, the shape of the 0.0 mode does not change. The D-shape only generate losses in the cavity. Then the power stored in the cavity decrease. As with this configuration, the cavity beam size decrease when power increase, the beam size decreased.
Measurements done @4A on 3rd stage.
| x (um) |
y (um) |
Picomotors displacement (um) |
Transmission power (mW) |
| 1820 |
2013 |
0 |
337 |
| 1820 |
2013 |
200 |
330 |
| 1925 |
2029 |
400 |
306 |
| 1936 |
2090 |
600 |
245 |
| 2117 |
2249 |
800 |
125 |
| 2260 |
2392 |
1000 |
17 |
Then we get the D-shape away from the beam to not cut it and decreased the amplifier power to validate the beam size at a known value. So the power as been decreased to 2A (= 125 mW in trans) and the beam size was x=2079 y=2255, similar to the 125 mW with D-shape mirrors values. |