High-energy ultraviolet dispersive-wave emission in compact hollow capillary systems.

We demonstrate high-energy resonant dispersive-wave emission in the deep ultraviolet (218 to 375 nm) from optical solitons in short (15 to 34 cm) hollow capillary fibers. This down-scaling in length compared to previous results in capillaries is achieved by using small core diameters (100 and 150 μm) and pumping with 6.3 fs pulses at 800 nm. We generate pulses with energies of 4 to 6 μJ across the deep ultraviolet in a 100 μm capillary and up to 11 μJ in a 150 μm capillary. From comparisons to simulations we estimate the ultraviolet pulse to be 2 to 2.5 fs in duration. We also numerically study the influence of pump duration on the bandwidth of the dispersive wave.