A universal route to efficient non-linear response via Thomson scattering in linear solids

• Published in: National science review 2023-07, Vol.10 (7), p.nwad136-nwad136
• Main Authors: Wen, Yongzheng, Giorgianni, Flavio, Ilyakov, Igor, Quan, Baogang, Kovalev, Sergey, Wang, Chen, Vicario, Carlo, Deinert, Jan-Christoph, Xiong, Xiaoyu, Bailey, Joe, Chen, Min, Ponomaryov, Alexey, Awari, Nilesh, Rovere, Andrea, Sun, Jingbo, Morandotti, Roberto, Razzari, Luca, Aeppli, Gabriel, Li, Junjie, Zhou, Ji
• Format: Article
• Language: English
• ISSN: 2095-5138; 2053-714X
• DOI: 10.1093/nsr/nwad136

ABSTRACT 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. Metamaterials featuring locally enhanced non-linear Thomson scattering offer a practical and universal method for efficiently stimulating non-linear responses in linear solid materials.