Second harmonic generation (SHG) of modelocked near-infrared lasers is useful, both as a source of visible ultrafast pulses, and as a means for increasing single-pass conversion efficiency. While LBO has proven to be efficient for SHG of femtosecond Ti:S lasers, crystals of sufficient length for picosecond applications are not available. Hence, alternative materials are of interest. Previously, 0.3-mm-thick samples of periodically-poled lithium niobate (PPLN) produced 52%-efficient SHG of green light when pumped by cw-modelocked picosecond pulses. Recently, we reported on backswitch-poling, an electric-field poling technique for ferroelectrics which utilizes spontaneous flip-back for obtaining domain patterning with high resolution and high yield. Here we demonstrate cw-modelocked second harmonic generation of blue light in 0.5-mm-thick backswitched PPLN.
展开▼
