Vacuum-ultraviolet to infrared supercontinuum in hydrogen-filled photonic crystal fibre

01.01.2016, 00:00

Newsletter 9

Although supercontinuum sources are readily available for the visible and near infrared, and recently also for the mid-IR to deep-UV, many areas of biology, chemistry, and physics would benefit greatly from the availability of compact, stable, and spectrally bright deep-UV and vacuum-UV supercontinuum sources. Recently we have succeeded in generating a bright supercontinuum, spanning more than three octaves from 124 nm to beyond 1200 nm (see the inset), in a hydrogen-filled kagomé-style hollow-core photonic crystal fibre. Few-microjoule, 30 fs pump pulses at wavelength of 805 nm are launched into the fibre, where they undergo self-compression via the Raman-enhanced Kerr effect. Modelling indicates that before reaching a minimum subcycle pulse duration of ~ 1  fs, much less than one period of molecular vibration (8 fs), nonlinear reshaping of the pulse envelope, accentuated by self-steepening and shock formation, creates an ultrashort feature that causes impulsive excitation of long-lived coherent molecular vibrations. These phase modulate a strong VUV dispersive wave (at 182 nm or 6.8 eV) on the trailing edge of the pulse, further broadening the spectrum into the VUV.

Contact: amir.abdolvand(at)mpl.mpg(dot)de
Group: Russell Division
Reference: F. Belli et al., Optica 2, 292-300 (2015).