Gaafar, Mahmoud A.Mahmoud A.GaafarJalas, DirkDirkJalasO'Faolain, LiamLiamO'FaolainLi, JuntaoJuntaoLiKrauss, Thomas F.Thomas F.KraussPetrov, AlexanderAlexanderPetrovEich, ManfredManfredEich2019-08-272018-06-082019-08-272018-04-13Nature communications 1 (9): 1447 (2018)http://hdl.handle.net/11420/1679.3The reflection of light from moving boundaries is of interest both fundamentally and for applications in frequency conversion, but typically requires high pump power. By using a dispersion-engineered silicon photonic crystal waveguide, we are able to achieve a propagating free carrier front with only a moderate on-chip peak power of 6 W in a 6 ps-long pump pulse. We employ an intraband indirect photonic transition of a co-propagating probe, whereby the probe practically escapes from the front in the forward direction. This forward reflection has up to 35% efficiency and it is accompanied by a strong frequency upshift, which significantly exceeds that expected from the refractive index change and which is a function of group velocity, waveguide dispersion and pump power. Pump, probe and shifted probe all are around 1.5 µm wavelength which opens new possibilities for "on-chip" frequency manipulation and all-optical switching in optical telecommunications.en2041-172320181art. no.1447Nature Publishing Group UKhttps://creativecommons.org/licenses/by/4.0/optical materials and structuresoptics and photonicsslow lightNaturwissenschaftenPhysikIngenieurwissenschaftenJournal Articleurn:nbn:de:gbv:830-882.04688110.15480/882.1676.311420/167910.1038/s41467-018-03862-010.15480/882.1676.310.15480/882.1769Other