Michael and Yuhang

We found the new way of fixing lens causes the problem of BAB OPO transmission to drift. This is the second lens we have in the transmission of OPO along the FIS measurement path. So we need to find a new way to fix this lens.

Now we put it on a pedestal pillar. After doing so, a large portion of p-polarization appears. Before removing this p-pol, it composes of ~5% of total power. However, we found that we could convert p-polarization completely to s-polarization by tilting HWP.