Simple route toward efficient frequency conversion for generation of fully coherent supercontinua in the mid-IR and UV range

摘要

Optical fibers containing two zero-dispersion wavelengths can be efficient generators of broad-spectrum laser light, predicts a new study. Supercontinuum light that spans several octaves is valuable for spectroscopic studies, but it is challenging to compress this bright, white radiation into short pulses for time-resolved studies. Ayhan Demircan from Leibniz Universität Hannover and colleagues have used simulations to discover a new regime where the concept of solitary light waves (or solitons) starts to break down. Propagation in photonic-crystal fibers having two wavelengths with vanishing second-order dispersion revealed that solitons with few-femtosecond duration rapidly annihilate after propagating just a few micrometers and nearly completely convert into a disparate wavelength range. The converted radiation can then directly be compressed into a short pulse, which can reach sub-femtosecond pulse duration.