Abstract

We demonstrate a delay-programmable two-color femtosecond source based on a chirped-seed noncollinear optical parametric amplifier. Introducing controlled dispersion into the seed enables spectral selection through pump–seed delay, allowing flexible generation of two independently tunable pulse components with adjustable relative timing at high repetition rate. The source provides tunable output across the 660–950 nm spectral range with pulse energies of up to 1.5 μJ per spectral component and typical pulse durations of 40–60 fs. The temporal and spectral properties are characterized using nonlinear optical cross-correlation and dispersion-scan measurements. As a benchmark application, the source is employed in a COLTRIMS-based multiphoton ionization experiment on trapped Li atoms, revealing delay-dependent ionization pathways and demonstrating its suitability for bichromatic ultrafast spectroscopy.

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