We show that, in the case of sum-frequency mixing, one can alleviate group-velocity mismatch between IR and UV pulses by choosing different pulse widths, thus extending the interaction length of ultrashort pulses within nonlinear crystals. By fifth-harmonic generation with a Nd:glass laser, we demonstrate efficient frequency upconversion of 195-fs 264-nm pulses under the envelope of 0.9-ps 1055-nm pulses in β-barium borate crystal, yielding <270-fs pulses with energy of up to 110μJ at 211 nm.
© 2000 Optical Society of America
(190.0190) Nonlinear optics : Nonlinear optics
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.7220) Nonlinear optics : Upconversion
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
A. Dubietis, G. Tamošauskas, A. Varanavičius, G. Valiulis, and R. Danielius, "Generation of femtosecond radiation at 211 nm by femtosecond pulse upconversion in the field of a picosecond pulse," Opt. Lett. 25, 1116-1118 (2000)