Nonreciprocal scattering and unidirectional cloaking in nonlinear nanoantennas

Area of Science:

• Nanophotonics
• Nonlinear Optics
• Metamaterials

Background:

• Reciprocal scatterers absorb equal power regardless of excitation direction, limiting asymmetric devices.
• Overcoming this requires breaking time-reversal symmetry, often with complex external biases.
• Existing limitations hinder advancements in nanophotonic circuits and asymmetric imaging.

Purpose of the Study:

• To explore nonlinearities and geometric asymmetries for nonreciprocal scattering in nanoantennas.
• To demonstrate directional cloaking and scattering using tailored resonant structures.
• To overcome fundamental reciprocity constraints in light-matter interactions.

Main Methods:

• Designing resonant nanoantennas with tailored nonlinear optical properties.
• Incorporating geometric asymmetries into the nanoantenna structures.
• Simulating and analyzing the scattering behavior under bidirectional excitation.

Main Results:

• Demonstrated a nonlinear scatterer that can be rendered invisible from one direction.
• Showcased strong scattering from the opposite direction at the same frequency and intensity.
• Achieved directional control over light scattering, breaking conventional reciprocity.

Conclusions:

• Nonlinearities combined with geometric asymmetry enable nonreciprocal scattering.
• This approach offers practical solutions for asymmetric nanophotonic devices.
• Opens new avenues for nonlinear nanophotonics, all-optical signal processing, and directional sensing.