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

Area of Science:

• Optics and Photonics
• Materials Science
• Quantum Electrodynamics

Background:

• Non-linear materials are crucial for optics and electronics, but second-order non-linear effects are limited in centrosymmetric materials like silicon and in spectral domains like terahertz (THz) frequencies.
• Existing limitations hinder the widespread application of advanced non-linear optical phenomena in technologically relevant materials and frequencies.

Purpose of the Study:

• To introduce a universal method for achieving efficient non-linear optical responses, specifically second-harmonic generation (SHG).
• To overcome material and spectral limitations in current non-linear optics applications.
• To enable efficient THz-frequency non-linear optics in centrosymmetric materials.

Main Methods:

• Excitation of non-linear Thomson scattering, a process previously observed only in relativistic electrons, in metamaterials composed of linear materials.
• Modulation of charge trajectories at twice the driving frequency within solid-state materials.
• Experimental demonstration of SHG at THz frequencies in crystalline silicon.

Main Results:

• Achieved efficient non-linear responses through non-linear Thomson scattering in a solid-state system.
• Demonstrated second-harmonic generation at terahertz frequencies in crystalline silicon with exceptionally high non-linear susceptibility.
• Established a proof-of-concept for a material- and frequency-independent platform for non-linear optics.

Conclusions:

• The developed approach offers a universal route to efficient non-linear optical effects, overcoming previous material and frequency constraints.
• This breakthrough opens avenues for on-demand non-linear optics, novel terahertz sources, and advanced integrated photonic circuits.
• The findings have significant implications for strong-field light-solid interactions and future optoelectronic devices.