Generation of femtosecond laser pulses at 263 nm by K₃B₆O₁₀Cl crystal

The third harmonic generation (THG) of a linear cavity Ti:sapphire regenerative amplifier by use of a K₃B₆O₁₀Cl (KBOC) crystal is studied for the first time. Output power up to 5.9 mW is obtained at a central wavelength of 263 nm, corresponding to a conversion efficiency of 4.5% to the second harmonic power. Our results show a tremendous potential for nonlinear frequency conversion into the deep ultraviolet range with the new crystal and the output laser power can be further improved.