Preliminary design of the spatial filters used in the multi-pass amplification system of TIL

The spatial filters are used in Technique Integration Line (TIL),which has a multi-pass amplifier, not only to suppress parasitic high spatial frequency modes but also to provide places for inserting a light isolator and injecting the seed beam, and to relay image while the beam passes through the amplifiers several times. To fulfill these functions, the parameters of the spatial filters are optimized by calculations and analyses with the consideration of avoiding the plasma blow-off effect and components damaging by ghost beam focus. The "ghost beams" are calculated by ray tracing. A software was developed to evaluate the tolerance of the spatial filters and their components, and to align the whole system on computer simulantly.