Coaxial Multiple Laser Beam Combiner for the LHD Thomson Scattering System

Abstract

We developed a polarization-based beam-combining method for multiple lasers to improve the time resolution and accuracy of a large helical device (LHD) Thomson scattering system. We combined two or more beams from different apertures of the laser heads in series into a coaxial beam line with the use of polarization optics. We have implemented this beam-combining method in an LHD Thomson scattering system from the 15th experimental campaign. We also propose a method of combining three or more laser beams by the use of a Pockels cell.