Marc and Michael

We measured the beam profile after the mode matching telescope simulated in 2486 and placed as shown in 2501. The measurements are plotted in figures 1 and 2. Figure 2 includes an outlier, perhaps the distance was recorded incorrectly? Figure 1 shows the result without the outlier. Either way, it seems the beam size and position is close enough to the prediction that fine tuning can be done using the lens rails of the mode matching telescope. Note that in the OPO replacement measurement, the beam will be shifted by a periscope after the f=75mm and then the OPO will be mounted on a rotation stage.

Before this measurement, we checked the alignment of the beam path. It is well centered on the steering mirror before the f=75mm. Without the lens, the beam goes along the screw holes on the table. However, when the lens is placed, the beam diverts about 1cm towards the edge of the table over a distance of about 25-30 holes. It diverts in the same direction when the lens is flipped.

Also I made a slight bump on the EOM rotation stage adjustment knob when handling the beam profiler cable, but it doesn't seem to have affected the beam path.