High-power widely tunable sub-20fs Gaussian laser pulses for ultrafast nonlinear spectroscopy

We demonstrate the generation of widely tunable sub-20fs Gaussian-shaped laser pulses using a grating-based 4-f pulse shaper and a liquid crystal spatial light modulator. Our pump source is an Yb:KGW solitary mode-locked oscillator at 44MHz repetition rate which is coupled into a large mode area microstructured fiber to generate a broad spectrum from below 900nm to above 1150nm. These pulses are precompressed by a prism sequence and subsequently sent into the pulse shaper. We use the multiphoton intrapulse interference phase scan (MIIPS) for phase shaping and iterative amplitude optimization to achieve Gaussian-like tunable sub-20fs pulses with output powers of up to 142mW as well as nontunable pulses with 310mW output power as short as 11.5fs. ©2011 Optical Society of America

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