Yuefan and Yuhang
We found the beam height of the green beam between SHG and filter cavity has very large beam height change after the work of beam center on each lens.
We measured the beam height at several points. (The beam height at Faraday isolator is a very important parameter. We may send a tilted beam if the beam height is wrong. Also, Astigmatism beam could be cut if the beam is not center in this FI.)
| position(holes) | height(mm) | height(mm) after adjustment |
| 4.5 before lens2 | 77.5 | |
| 1.5 before lens2 | 77 | |
| 3 before EOM | 76 | |
| 2 after EOM | 74 | |
| between two steering mirrors after EOM | 74.5 | |
| 2 after lens3 | 76 | 75.5 |
| 3 after lens3 | 76.5 | 75.5 |
| 2 after AOM | 78 | 76 |
| 5.5 after lens4 | 76 | 76.5 |
| 6.5after lens 4 | 76 | 76.5 |
| 10.5 after lens 4 | 73 | 76.5 |
| 1 after lens 5 | 74 | 76.5 |
| 1 after FI | 74.5 | 76 |
| 1 before last steering | 74 | 75.5 |
| 2 after last steering | 76 | 75.5 |
Note: Lens1~5 is the lens in the sequance from SHG to PR chamber. (Details are also shown in the attached figure 1)
We also checked the beam shape. Attached picture 2: beam shape after AOM. Attached picture 3: beam shape before injection to PR chamber (magnified by a 50mm lens). Attached picture 4: beam shape seen at the end camera. Attached picture 5: reflected beam shape seen before FI.
We measured the beam parameter and fit with basic Gaussian beam function before and after today's work. The comparison is attached in the last two figures.
