I'm trying to re-align the beams to the cavities. Due to the new RTV springs for the seismic stack, the cavities' natural axes shift by ~1/4 " with respect to the previous position.

     I had to adjusted the height of the top mirror of the periscope before I could align and lock RCAV (visibility ~ 95%) again. The pictures below show the position of the current beam. With the previous setup, the beam position was almost at the center of the holes. Now, for RCAV, the axis shifts closer to the edge. RCAV might yaw with respect to the previous position. Left picture shows the incoming beam position, Right picture shows the outgoing beam position.

      For ACAV, however, it seems that the position changes a lot and the beam clips on the outer edge of the top mirror before I can even find TEM00. I think I'll have to add a spacer between the mirror mount and the vertical plate in order to re align the beam.

     I think we can keep the stack position as it is for now, if I can lock both cavities and the transmitted beams can be adjusted on the breadboard for beat path. We might also have to increase the hole size on the insulation cap as well depending on where the beam position of ACAV will be.