Controlling Mie scattering response to refractive index variations via light field manipulation

Area of Science:

• Nanophotonics and Light-Matter Interactions
• Computational Electromagnetics
• Optical Metrology

Background:

• The T-matrix method is crucial for understanding light scattering by particles.
• Vector spherical harmonics (VSHs) are essential for describing electromagnetic fields.
• Controlling refractive index sensitivity is key for optical sensing.

Purpose of the Study:

• To present an efficient method for T-matrix determination of axisymmetric particles.
• To enable tailored nanoparticle responses to complex optical fields.
• To introduce new degrees of freedom for controlling light-matter interactions.

Main Methods:

• Finite element method (FEM) combined with analytical VSH expansion for T-matrix calculation.
• Designing incident fields based on the T-matrix for tailored nanoparticle response.
• Utilizing principal modes (PMs) and anti-principal modes (anti-PMs) to control refractive index sensitivity.
• Employing inverse design for light field generation and focusing.

Main Results:

• An efficient FEM-based method for T-matrix calculation.
• Demonstrated control over scattering field sensitivity to environmental refractive index.
• Successful design of incident fields to generate specific PMs and anti-PMs.
• New capabilities for manipulating light-matter interactions.

Conclusions:

• The developed method offers precise control over nanoparticle optical properties.
• This approach provides a powerful tool for optical sensing and measurement.
• It opens new avenues for designing advanced photonic devices and systems.