Generation of sub-10 fs UV light by up-conversion of visible pulses

Ultrashort light pulses in the ultraviolet (UV) spectral range (λ<;400 nm) are required to study fundamental chemical and biological processes in biomolecules, which exhibit absorption in this region and ultrafast dynamics after photoexcitation. The generation of sub-10 fs UV pulses poses serious challenges in terms of: (i) broad bandwidth generation; (ii) pulse energy; (iii) spectral phase handling; (iv) pulse measurement. To address these issues, we introduce a scheme for the generation of ultrashort UV pulses based on collinear sum-frequency generation (SFG) between broadband visible pulses and narrowband pulses at 800 nm, and use a novel technique for the measurement of the UV-pulse duration.