I ran another measurement with same experimental conditions as the ones in (entry 279), and made the same analysis of (entry 280) and (entry 281)
2016-07-25. Tama-size , 1h, rate: 100ms.
|
DATE 2016-07-25 |
DC | X/DC*1e6 |
X/DC*1e6 gauss.fit |
Y/DC*1e6 |
Y/DC*1e6 gauss.fit |
sqrt(meanX/DC^2+meanY/DC^2)*1e6 |
Absorption ppm/cm |
phase | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pump | mean | std | mean | std | fit_mean | fit_std |
mean |
std | fit_mean | fit_std | mean | precision | mean | std | |
| 0W | 6.5 V | 0.11% | -0.98 | 11.3 | -1.1 | 11.2 | 0.58 | 11.2 | 0.8 | 11.1 | 1.1 | 6.6 | 7.8 | -154° | 128° |
| 9W | 6.6 V | 0.15% | -9.0 | 13.0 | -9.1 | 10.8 | -3.2 | 13.5 | -3.3 | 10.9 |
8.9 |
||||
after filtering
|
DATE 2016-07-25 |
DC | X/DC*1e6 |
X/DC*1e6 gauss.fit |
Y/DC*1e6 |
Y/DC*1e6 gauss.fit |
sqrt(meanX/DC^2+meanY/DC^2)*1e6 |
Absorption ppm/cm |
phase | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pump | mean | std | mean | std | fit_mean | fit_std |
mean |
std | fit_mean | fit_std | mean | precision | mean | std | |
| 0W | 6.5 V | 0.11% | -1 | 1.1 | -0.9 | 1.1 | 0.6 | 1.2 | 0.7 | 1.2 | 1.1 | 6.5 | 1.6 | -154° | 108° |
| 9W | 6.6 V | 0.15% | -8.9 | 2.2 | -9.2 | 1.8 | -3.2 | 3.2 | -3.4 | 3.8 | 8.8 | ||||
I did the same measurement for the 4th time but this time I covered better the pump path so that the scattered light is less.
The absorption value now is 4ppm/cm with a precision of 0.8 ppm/cm (after filtering).
This means that the pump stray light (1064nm) from outside the box gives a contribution of at least 2ppm/cm on the measure.
I couldn't cover the sample, but also the scattered light from the sample could give a significant contribution. So I would like to put a filter in front of the photodetector, to make only the probe light (633 nm) pass.