Multicolor broadband tunable pulses generation from a Yb:KGW ultrafast laser

Abstract

We demonstrate the simultaneous generation of multicolor femtosecond laser pulses in a 0.5 mm Type I BBO crystal from 1028 nm fundamental and weak near-IR supercontinuum of a Yb:KGW ultrafast Yb based laser. The multicolor broadband laser pulses observed are attributed to cascaded four-wave mixing (CFWM) processes. A set of spatially separated CFWM sideband signals with second harmonic-generation and sum-frequency-generation pulses are arose from the interaction between the two pulses intersect at a certain angle. The CFWM sideband signals can be changed by rotating the BBO crystal to achieve the phase matching condition and adjusting the time delay between the two incident pulses to change the time overlapping.