Noncollinear noncritically phase-matched generation of tunable far-UV radiation in an LB4 crystal

Tunable far-UV laser radiation is generated in the 204.7–205.5-nm region in a 3.4-cm long LB4 crystal by using noncritical noncollinear sum frequency mixing of the Nd:YAG laser radiation and the second harmonic of a tunable dye laser. A large value of phase-matching angular acceptance of 0.50 mrad is measured at noncritical phase-matching, which is 1.8 times larger than the critically phase-matched value. A conversion efficiency of 2.1% is obtained for the generation of far-UV at 205 nm. Tunable UV radiation is also generated in the range from 246 to 255 nm using collinear second harmonic of tunable dye laser radiation in an LB4 crystal.