A tilted pulse-front setup for femtosecond extreme ultraviolet transient grating spectroscopy in highly non-collinear geometries
We demonstrate a tilted pulse-front transient grating technique that allows to optimally utilize time-resolution as well as transient grating line density while probing under grazing incidence as typically done in extreme ultraviolet (EUV) or soft x-ray (SXR) experiments. Our optical setup adapts the pulse front tilt of the two pulses that create the transient grating to the relative tilt grazing incident pulse. We demonstrate the technique using all 800 nm femtosecond laser pulses for transient grating generation on a vanadium dioxide film. We probe that grating via diffraction of a third 800 nm pulse. The time resolution of 100 fs is an improvement by a factor 30 compared to our previous experiments on the same system (1,2). The scheme paves the way for EUV and SXR probing of optically induced transient gratings on any material.