We present a technique for efficient generation of the second-harmonic signal at several points of a nonlinear crystal simultaneously. Multispot operation is performed by using a diffractive optical element that splits the near-infrared light of a mode-locked Ti:sapphire laser into an arbitrary array of beams that are transformed into an array of foci at the nonlinear crystal. We show that, for pulse temporal durations under 100 fs, spatiotemporal shaping of the pulse is mandatory to overcome chromatic dispersion effects that spread both in space and time the foci showing a reduced peak intensity that prevents nonlinear phenomena. We experimentally demonstrate arbitrary irradiance patterns for the second-harmonic signal consisting of more than 100 spots with a multipass amplifier delivering 28 fs, 0.8 mJ pulses at 1 kHz repetition rate.
© 2012 Optical Society of America
Original Manuscript: October 20, 2011
Revised Manuscript: December 22, 2011
Manuscript Accepted: December 29, 2011
Published: February 29, 2012
Raúl Martínez-Cuenca, Omel Mendoza-Yero, Benjamín Alonso, Íñigo Juan Sola, Gladys Mínguez-Vega, and Jesús Lancis, "Multibeam second-harmonic generation by spatiotemporal shaping of femtosecond pulses," Opt. Lett. 37, 957-959 (2012)