Tunable ultraviolet dispersive-wave emission driven directly by 40-fs Ti: sapphire laser pulses in hollow capillary fiber

By adjusting the gas type and pressure inside the HCF, the central wavelength of the UV DW can be continuously tuned from 185 nm to ~450 nm. In the experiment, we found that for ~320 to ~450 nm DW generation, Raman-active gas filled in the HCF can efficiently suppress the pulse fission effect of the high-order soliton due to the Raman-induced pulse energy dissipation, leading to the high-quality DW generation at these wavelengths with smooth, single-peak spectra.

These results provide some useful insights for designing compact, wavelength-tunable ultrafast UV light sources with microjoule-level pulse energies.