Abstract: We report over 20 W, 6 ps, 170 MHz, passive mode-locking of a Nd:YVO 4 laser using χ Among laser materials, neodymium-doped vanadate Nd:YVO 4 has been the most extensively studied and widely used in diode-pumped high average power continuous-wave (CW) and mode-locked lasers for the past two decades. Nd:YVO 4 has large emission cross-section and polarized emission attributed to its natural birefringence as well as capacity for being pumped efficiently by laser diodes. The major drawback which limits the output power of Nd:YVO 4 lasers is the poorer thermo-mechanical properties of the crystal in comparison with that of Nd:YAG. Typically, multi-Watt operation of picosecond Nd:YVO 4 lasers has been demonstrated mainly using a modelocking technique based on semiconductor saturable absorber mirrors (SESAMs) In this work we report χ (2) -lens mode-locking of a Nd:YVO 4 laser using a LBO SHG crystal. The laser generates 6 ps transform-limited pulses at 170 MHz with output power of 20.1 W. To our knowledge, it is the maximum output power achieved by a χ (2) -lens mode-locked laser. The design of the mode-locked laser is based on a 810 mm long linear cavity
