Generation of 16-fs pulses at 425 nm by extracavity frequency doubling of a mode-locked Ti:sapphire laser

Summary form only given. We report the generation of 16 fs pulses at 425 nm by second-harmonic generation using 15 fs pulses at 850 nm and a 100 /spl mu/m BBO crystal. The average fundamental power at the crystal was 550 mW and the second-harmonic power generated was 40 mW. Having expanded the fundamental beam from a self-mode-locked Ti:sapphire laser in a 31 mirror telescope it was then focused into a BBO crystal with a f=75 mm lens. The second harmonic was recollimated, compressed in a double-pass quartz prism compressor and the autocorrelation measured. Maximum output power was achieved when the fundamental at the doubling crystal had a minimum pulse length.