Alignment and tolerancing of a mirror relay system for a newly upgraded LGS system on Subaru Telescope

Subaru telescope is currently in the process of upgrading its laser guide star (LGS) system. The newest upgrade will have a TOPTICA SodiumStar laser source (operates at ~22W and 589nm) which is then sent to a laser launch telescope (LLT) just behind the secondary mirror of the telescope. In order to send the laser light to the LLT, a system of 6 mirrors has been designed to relay the laser light. Since the distances between these mirrors are quite large (the largest is ~9m), it was necessary to model the system in order to determine the correct placement and proper alignment procedure of each of these mirrors. For simplicity, the complete mirror relay system (including parts of the LLT up to the beam expander lens) has been modeled as an 8 mirror system in order to complete a tolerance analysis. The results of this analysis suggest that alignment of the system should be possible to do with a simple pinhole alignment procedure.