Manipulation of Scattering Spectra with Topology of Light and Matter

• Published in: Laser & photonics reviews Vol. 17; no. 3
• Main Authors: Barati Sedeh, Hooman, Pires, Danilo G., Chandra, Nitish, Gao, Jiannan, Tsvetkov, Dmitrii, Terekhov, Pavel, Kravchenko, Ivan, Litchinitser, Natalia
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.03.2023
• Subjects: Aspect ratio; Excitation; Fluid flow; Gaussian beams (optics); high‐index nanoparticles; Incident light; Light; Metamaterials; Micromanipulation; Mie resonances; multipole decomposition; Optical materials; Optics; Phase distribution; Remote sensing; Scattering; Spectrum analysis; structured light; Topology; Wave fronts
• ISSN: 1863-8880; 1863-8899
• DOI: 10.1002/lpor.202200472

Structured lights, including beams carrying spin and orbital angular momenta, radially and azimuthally polarized vector beams, as well as spatiotemporal optical vortices, have attracted significant interest due to their unique amplitude, phase front, polarization, and temporal structures, enabling a variety of applications in optical and quantum communications, micromanipulation, and super‐resolution imaging. In parallel, structured optical materials, metamaterials, and metasurfaces consisting of engineered unit cells—meta‐atoms, opened new avenues for manipulating the flow of light and optical sensing. While several studies explored structured light effects on the individual meta‐atoms, their shapes are largely limited to simple spherical geometries. However, the synergy of the structured light and complex‐shaped meta‐atoms has not been fully explored. In this paper, the role of the helical wavefront of Laguerre–Gaussian beams in the excitation and suppression of higher‐order resonant modes inside all‐dielectric meta‐atoms of various shapes, aspect ratios, and orientations, is demonstrated and the excitation of various multipolar moments that are not accessible via unstructured light illumination is predicted. The presented study elucidates the role of the complex phase distribution of the incident light in shape‐dependent resonant scattering, which is of utmost importance in a wide spectrum of applications ranging from remote sensing to spectroscopy. Mie resonance manipulation using structured light beams carrying orbital angular momentum (OAM) is described. By utilizing an SLM to change the structural features of the incoming light beam, the excited multipole moments within the polycrystalline silicon meta‐atom can be manipulated and “turned on and off” on demand.