Images I took yesterday show that the 2nd reflection from IO_MB_L1 is clipping on the output aperture of the EOM.  The beam is clearly seen on the housing on the +Y side of the output aperture.  The beam should be going cleanly back through the EOM and be easily identified and dumped on or near the EOM steering mirror mount, such that there's no possible path for the beam to re-enter the optical system.   The images also show that the beam is not centered on IO_MB_L2, and should be centered, and the beam is currently mis-centered to the -Y side of the lens.  Both the clipping and mis-alignment show that the beam line from the EOM through the IMC mode matching lenses has not been restored to an alignment that satisfies the original design of the optical system.

Attached is document, T1800243-v1, that shows my IR images taken yesterday.  

• page 1: the alignment fiducials that I installed, and are used to identify and evaluate the current input pointing into the IMC
• page 2: my images of the EOM output aperture, from 3 different angles, which all show the 2nd reflection from IO_MB_L1 clipping on the +Y side of the aperture
• page 3: my image of the beam path from the EOM through IO_MB_L1, IO_MB_WG1, and IO_MB_L2, and my close up of IO_MB_L2, which shows the mis-centered beam

Being mi-centered through the IMC mode matching lenses has the potential to modify the shape of the IMC input beam, as well as increasing the effects of any small beam mis-alignment through the lenses, compared to having the beam better centered.