All Solid-State UV lasers are efficient, clean and semipermanent light sources for various applications, such as eye surgery, semiconductor lithography. $CsLiB_6O_10 (CLBO)$ is the most promising crystal for UV generation, because of its small walk-off, high effective nonlinear susceptibility in UV region and high damage threshold.
We obtained fourth (266 nm) and fifth (213 nm) harmonic generation of Nd:YAG laser using $LiB_3O_5(LBO)$ as a second harmonic generation medium, CLBO as fourth harmonic and fifth harmonic medium. Temperature tuning curve of the LBO noncritical phase matching was calculated. 4.7mJ of 2ω output from 30mJ of fundamental input energy. 1.12mJ of 4ω output at 266nm with conversion efficiency of 25.8% from the second harmonic input was generated. 5ω output at 213nm of 1.03mJ was obtained by sum-frequency generation of the 266- and 1064-nm beams, corresponding to a 3.43% conversion efficiency of the initial fundamental input energy. Fifth harmonic output was measured as a function of pump intensity and angle for two different length crystal. When using L=11.9mm CLBO crystal, conversion was more efficient than when using L=6.9 mm CLBO.
