Generation of 7-fs pulses at 800 nm from a blue-pumped optical parametric amplifier at degeneracy

In this work we report on a two-stage approach for the generation of few-optical-cycle pulses at 800 nm; (i) a FF- pumped near-IR OPA produces pulses at 1.3 mum, which are used to generate a WLC with smooth spectral amplitude and phase characteristics around 800 nm; (ii) this WLC is amplified in a broadband second harmonic-pumped OPA around degeneracy. The pulses are compressed to nearly transform-limited 6.8 fs duration by chirped mirrors