Generation of femtosecond tunable radiation from 380 nm to 450 nm via cascaded wave-mixing in a seeded 405-nm pumped type-I BBO noncollinear optical parametric amplifier

We report the generation of femtosecond tunable radiation from 380-nm to 450-nm in a 405-nm pumped BBO noncollinear optical parametric amplifier (NOPA). The generation is attributed to the cascaded sum-frequency-generation between the OPA and the fundamental of the lasers near its degenerate point of the OPA. The pulse duration of the SFG is about 80-fs. The energy conversion efficiency from the pump to the SFG output is more than 10%.