Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Non-linear materials are cornerstones of modern optics and electronics. Strong dependence on the intrinsic properties of
particular materials, however, inhibits the at-will extension of demanding non-linear effects, especially those second-order
ones, to widely adopted centrosymmetric materials (for example, silicon) and technologically important burgeoning spectral
domains (for example, terahertz frequencies). Here we introduce a universal route to efficient non-linear responses enabled
by exciting non-linear Thomson scattering, a fundamental process in electrodynamics that was known to occur only in
relativistic electrons in metamaterial composed of linear materials. Such a mechanism modulates the trajectory of charges,
either intrinsically or extrinsically provided in solids, at twice the driving frequency, allowing second-harmonic generation at
terahertz frequencies on crystalline silicon with extremely large non-linear susceptibility in our proof-of-concept experiments.
By offering a substantially material-and frequency-independent platform, our approach opens new possibilities in the fields of
on-demand non-linear optics, terahertz sources, strong field light-solid interactions and integrated photonic circuits