%0 Journal Article
%T Frequency comb generation at terahertz frequencies by coherent phonon excitation in silicon
%A Hase, Muneaki
%A Katsuragawa, Masayuki
%A Constantinescu, Anca Monia
%A Petek, Hrvoje
%J Nature Photonics
%D 2012
%V 6
%F Hase_etal2012
%O exported from refbase (https://db.rplab.ru/refbase/show.php?record=794), last updated on Wed, 09 May 2012 11:30:28 -0500
%X High-order nonlinear light–matter interactions in gases enable the generation of X-ray and attosecond light pulses, metrology and spectroscopy1. Optical nonlinearities in solid-state materials are particularly interesting for combining optical and electronic functions for high-bandwidth information processing2. Third-order nonlinear optical processes in silicon have been used to process optical signals with bandwidths greater than 1 GHz (ref. 2). However, fundamental physical processes for a silicon-based optical modulator in the terahertz bandwidth range have not yet been explored. Here, we demonstrate ultrafast phononic modulation of the optical index of silicon by irradiation with intense few-cycle femtosecond pulses. The anisotropic reflectivity modulation by the resonant Raman susceptibility at the fundamental frequency of the longitudinal optical phonon of silicon (15.6 THz) generates a frequency comb up to seventh order. All-optical >100 THz frequency comb generation is realized by harnessing the coherent atomic motion of the silicon crystalline lattice at its highest mechanical frequency.
%K fromIPMRAS
%P 243–247