  We investigate soliton self-compression and ultraviolet resonant dispersive
wave emission in the higher-order modes of a gas-filled hollow capillary fibre.
Our simple analytical scaling rules predict shorter required waveguides and
different energy scales when moving from the fundamental to higher-order modes.
Experimentally, we demonstrate soliton self-compression and ultraviolet
dispersive wave emission in the double-lobe LP$_{11}$ mode of an argon-filled
hollow capillary fibre, which we excite by coupling into the fibre at oblique
incidence. We observe the generation of ultraviolet dispersive waves which are
frequency-shifted and more narrowband as compared to fundamental-mode
generation due to the stronger modal dispersion, and a suppression of the
supercontinuum between the dispersive wave and the pump pulse. With numerical
simulations, we confirm the predictions of our scaling rules and find that the
use of higher-order modes can suppress photoionisation and plasma effects even
while allowing for much higher pulse energy to be used in the self-compression
process. Our results add another degree of freedom for the design of
hollow-waveguide systems to generate sub-cycle field transients and tuneable
ultrashort laser pulses.
