Improvement of target area for 3ω shot experiments in SG-Ⅱ facility

The paper concerns the improvement of two primary technologies for 3ω(351nm) shot experiment in SG-Ⅱfacility target area , which are 3ω target alignment laser and optical viewing system .The 1ω (1 053nm) laser is exported form the Nd:YLF laser and passes the KTP+BBO system to acquire the 3ωlaser. And the 3ω laser is couplingout with main laser. In order to improve the laser accurately position on the target, the reflection optical system is replaced by the transmission optical system, which avoids the effect of chromatic aberration.