Abstract

Tunable ultraviolet (UV) pulses shorter than 10 fs are generated by achromatic frequency doubling the output of a noncollinear optical parametric amplifier. We achieve first and second order achromatic phase matching with a suitable two-prism sequence and thereby increase the natural bandwidth of the nonlinear crystal by a factor of 80. Extremely broad UV spectra with a Fourier limit of 2.9 fs are generated in a 360 µm thick BBO crystal at a conversion efficiency of 20 %. The angular dispersion and the first order chirp of the highly stable UV pulses is compensated with a second prism sequence. The full characterization of the UV pulses is performed with zero-additional-phase SPIDER at the point of a possible experimental interaction. By controlling the higher order chirp with a deformable mirror we generate pulses as short as 7.1 fs.

© 2004 Optical Society of America