Nanowerk December 12, 2023
The canonical studies on Mie scattering unravel strong electric/magnetic optical responses in nanostructures, laying foundation for emerging meta-photonic applications. Conventionally, the morphology-sensitive resonances hinge on the normalized frequency, i.e. particle size over wavelength, but non-paraxial incidence symmetry is overlooked. Through confocal reflection microscopy with a tight focus scanning over silicon nanostructures, an international team of researchers (Taiwan, Japan, China) showed the scattering point spread functions’ distinctive spatial patterns featuring linear scattering efficiency was maximal when the focus was misaligned. The underlying physical mechanism was the excitation of higher-order multipolar modes, not accessible by plane wave irradiation, via displacement resonance, which showcases a significant reduction of nonlinear response threshold, sign flip in all-optical switching, and spatial resolution enhancement. According to the researchers their result fundamentally extends the century-old light scattering theory, and suggests new dimensions to tailor Mie resonances… read more. Open Access TECHNICAL ARTICLE
Concept of displacement resonance. Credit: Nature Communications volume 14, Article number: 7213 (2023)Â