Soliton self-compression and resonant dispersive wave emission in higher-order modes of a hollow capillary fibre

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