Two-color pump-probe interferometry of ultra-fast light-matter interaction

Two-color side-view probing of light-matter interaction from minute focal volume of a tightly focused fs-laser pump pulse reveals charge dynamics with high 0.9 μ m optical resolution and approximately ~45fs temporal resolution defined by pulse duration. Use of two colors is advantageous for probing optically excited plasma regions with different density. Holographical digital focusing and spatial filtering were implemented to obtain the same resolution images for subsequent Fourier analysis. Fast plasma density decay with time constant ~150 fs was resolved and is consistent with self-trapping. Potential applications of an optical control over light-induced defects with deep-sub-wavelength resolution is discussed.