High-energy, sub-30 fs near-IR pulses from a broadband optical parametric amplifier based on collinear interaction in...

We report efficient generation of tunable femtosecond pulses in the near IR using a two stage, white-light seeded, collinear, femtosecond optical parametric amplifier (OPA). The OPA, based on BiB(3)O(6) crystal in both stages and pumped at 807 nm by a 1 kHz Ti:sapphire laser amplifier, provides sub-30 fs signal pulses after compression with energies exceeding 200 microJ, which corresponds to fivefold pulse shortening and approximately 30% internal conversion efficiency in the second stage considering 150 fs pump pulses with 1.5 mJ energy. The corresponding idler pulses with more than 100 microJ have sub-60 fs duration without compression. The first stage alone is capable of producing sub-20 fs pulses near 1400 nm at the microjoule level without using any compression.