During the last week and today, we did a lot of investigation about how to put lens to achieve many limitations. Today, we finally found it really diffcult to design telescope with all the condition we have now. We talked with Matteo, we got an important conclusion. It is we can decrease laser low to 30mW.

However, after measured the beam dimension, we found the beam is not like the simulation result of Jammt. We guess this comes from that the inital beam is not very collimated. We decided to decrease power further more. So we decrease power to 18mW. Then we characterize beam again. The beam is really similar with before. See Fig.1

Then we put the EOM, the position is decided as shown in attached Fig.2. After put EOM, we characterized beam again. The Fig.2 is the characterization result.

According to this result. We tried to put another lens. We can recover the beam to beam waist as 940um. See attached Fig.3. This is a little different from what we need. By putting more lens, we can have good dimension of 1000um of waist. However, more lenses cost too much space.