X-Arm electronics:
All chassis have been tested mounted in the rack. All that is left is to replace the variable power supplies currently being used for the visible laser, fan and flipper with 5V, 12V and 15V DIN mounted power supplies respectively.
X-Arm beam profiling:
X-arm is not behaving as predicted by the model especially in the horizontal axis.
The beam was profiled using the nano scan along a 55cm length after the second lens and a q-parameter was fit using this data.
This is compared to the model and a Jammt model using the measured QCL q and assuming a linear optical system with the lens at the same distances as in the physical set up.
For the fit q-parameter the w at the ITM was found by propagating the q at L2 to the ITM.
Additionally, during the trouble shooting process a wedge was found on the first telescope lens (L1) which isnt in the optical system and was compensating for some of the astigmatism of the QCL. The effect of this is that in the data below the beam size at the ITM is too large and astigmatic.
Discussion and solutions of this effect will be the subject of its own log.
Vertical
| Measurement/model | w0 [ µm] | z [mm] | w at ITM [mm] |
| Fit from data |
978.9±22.7 |
-1063.1±33.8 |
50.09 |
| Fintrace |
857.11 |
-500.64 | 61.38 |
| Jammt | 874.53 | -572 | 62.1 |
Horizontal
| Measurement/model | w0 [ µm] | z [mm] | w at ITM [mm] |
| Fit from data | 1280.3+/-54.9 |
-1813.3±83.5 |
38.01 |
| Fintrace |
979.42 |
-653.71 | 54.38 |
| Jammt | 1013 | -256 | 53.1 |
None of the values agree within the measurement uncertainty bounds, especially in the horizontal direction. We are also observing non-gaussian beam profiles on the nano-scan, plots attached, but this is predominately in the vertical direction. This structure isnt new and appeared when matt and I were initially profiling the lens and were able to see good agreement.
The fintrace and Jammt are close but not identical which would be expected as the Jammt does not include any additional optics outside the QCL and L1 and L2. We are currently working on determining the source of this discrepancy.
