Shalika
This elog report covers two aspects:
1. Measurement of the beam size and fitting of the beam to find the minimum waist position.
2. Optimizing the position of AOM to observe maximum power in the first-order beam.
(Details below) 1. Yesterday we (Mitsuhashi-san, and Shalika) observed that the unclean lens was causing issues with the beam after AOM. So, we cleaned the lens and had to perform beam fitting again. Today, I performed beam fitting. When I measured the beam size, I used ND(2.0) filter with the beam profiler. The result of it as follows and attached. The width of the error bar is 4σ.
| position(mm) | Radius Major(mm) | Radius Minor(mm |
| 50 | 0.22795±0.0018240 | 0.21812±0.0018659 |
| 70 | 0.16254±0.0011663 | 0.15547±0.0017116 |
| 100 | 0.11734±0.0016665 | 0.11409±0.0012195 |
| 120 | 0.14136±0.0017934 | 0.13829±0.00085817 |
| 150 | 0.19957±0.0018980 | 0.19486±0.0013230 |
| 170 | 0.25669±0.0026610 | 0.2463±0.00242734 |
2. The AOM was placed at the position obtained from beam fitting. The power of the beam observed before AOM was 11.44mW. The RF driver was tuned with 9.85V of supply for 80MHz output. The power of the beam after AOM was 11.26mW. The power of the 1st-order beam was found to be 3.81mW (33.83% of beam after AOM).
Next Step:
We will perform beam fitting for lens position after AOM and see if it agrees with our design.
