Publication

2026

• 374. Kana Kondo, Mojtaba Karimi Habil, Yongan Hu, Hiroshi Sugimoto, Minoru Fujii, "Thermo-Optic Tuning of Mie Resonances in Silicon Nanospheres in the Visible Range", ACS Applied Optical Materials, Vol. , Issue , pp.(2026). (First published:March 1, 2026).

  

  The thermo-optical behavior of crystalline silicon nanospheres (Si NSs) exhibiting Mie resonances in the visible range was investigated. The temperature rise of a Si NS exhibited a nonlinear dependence on the input laser power, arising from the temperature-dependent absorption efficiency due to the thermo-optical effect on the complex refractive index. By employing this effect, active modulation of the scattering spectra was achieved through optical heating, with modulation depths reaching up to 69% at 650 nm and stable performance maintained over 50 switching cycles. The optical properties of the Si NSs remained unchanged even at temperatures of >600 °C, demonstrating their excellent thermal stability. Based on the properties, simulations were performed for Si NS square arrays, which demonstrated significant transmittance modulation by temperature-dependent shifts in the lattice resonances. These findings establish a foundation for thermally reconfigurable all-dielectric metasurfaces for their potential applications in optical modulation, sensing, and adaptive photonic systems.

• 373. Mojtaba Karimi Habil, Hiroshi Sugimoto, Daisuke Shima, Hiroto Shinomiya, Minoru Fujii, "Tailoring the Helicity-Resolved Raman Response of MoS2 Coupled to Mie-Resonant Silicon Nanospheres ", ACS Photonics, Vol. , Issue , pp.(2026). (First published:February 23, 2026).

  

  High-index all-dielectric nanoantennas supporting Mie resonances provide a versatile platform for tailoring light–matter interactions. However, their effect on the helicity of emission from nearby emitters is poorly understood. Here, we investigate the Raman intensity and degree of circular polarization (DOCP) in few-layer MoS2 coupled to the Mie resonances of silicon nanospheres (Si NSs). Theoretical analysis shows that a circularly polarized (CP) emitter near a Si NS exhibits strong radiative enhancement at the magnetic dipole (MD) and magnetic quadrupole (MQ) modes while largely preserving the ellipticity. In contrast, Au NSs provide no considerable enhancement and significantly degrade the ellipticity in their near field. Experimentally, the helicity of the out-of-plane vibration of chalcogen atoms in Si NS/MoS2 structures is well preserved at ED, MD, and MQ resonances. These results reveal Mie-mode-selective control of Raman intensity and helicity, highlighting the advantages of Si NSs for valleytronics, helicity-resolved Raman spectroscopy, and chiral nanophotonics.

• 372. María Sanz-Paz, Nicole Siegel, Guillermo Serrera, Javier González-Colsa, Fangjia Zhu, Karol Kołątaj, Minoru Fujii, Hiroshi Sugimoto, Pablo Albella, Guillermo P. Acuna, "Color Routing and Beam Steering of Single-Molecule Emission with a Spherical Silicon Nanoantenna", Advanced Functional Materials, Vol. , Issue , pp.(2026).(First published: January 26, 2026)

  

  Single-photon emitters radiate as electric dipoles, which limits light collection efficiency and complicates integration into flat photonic devices. Developing nanophotonic structures capable of directing photon emission with tunable angular distributions in the visible spectrum has been pursued for applications ranging from integrated optical systems to discrimination of molecular species. To date, such directional control has been achieved using components whose overall footprint is larger than the emission wavelength and often rely on lossy plasmonic components. Here, we employ the DNA origami technique for deterministic nanoscale assembly, positioning single fluorophores in nanometric proximity to a single silicon spherical nanoparticle (SiNP) and demonstrate unidirectional emission with forward-to-backward intensity ratios up to ∼7 dB. Furthermore, we show that a single silicon nanosphere antenna can function as a color router or a beam steerer depending on its size, emitter spectral range and emitter-nanoparticle distance, enabling the use of these structures as versatile functional components in photonic devices.

• 371. Jiancheng Xu, Yuheng Mao, Yeshun Guo, Ruizhao Yao, Shulei Li, Hiroshi Sugimoto, Minoru Fujii, Fu Deng, Guangcan Li, and Sheng Lan, "Greatly enhanced photoluminescence of an integrated WSe₂ monolayer by exploiting the pure magnetic resonance and localized strain induced by a hybrid Si/Si₃N₄/Au nanoantenna",Optics Express, Vol. 34, Issue 2, pp.1369-1382 (2026).(First published: January 12, 2026)

  

  Exploiting the optical resonances inherent to dielectric nanoparticles offers an effective approach for modulating light-matter interactions at the nanoscale while maintaining minimal optical losses. In this study, we introduce a hybrid nanoantenna platform composed of Si/Si₃N₄/Au layers, which facilitates the tuning of resonant multipolar modes and their application in enhancing the photoluminescence (PL) of WSe₂ monolayer. By systematically varying the thickness of the Si₃N₄ spacer, we achieve modulation of both the spectral positions and spatial field distributions of the resonances associated with Si nanospheres, thereby enabling precise control over near-field confinement and far-field scattering characteristics. Optimal performance is observed with an 80 nm spacer thickness, where a distinct magnetic dipole resonance emerges near 750 nm. Additionally, fine-tuning the nanoparticle radius allows for controlled red- and blue-shifting of the resonant modes. These deliberately engineered resonances lead to a substantial enhancement of the PL emission from WSe₂ integrated onto the hybrid structure, with an enhancement factor approximating 1609. The observed enhancement is attributed to a combination of intensified local electromagnetic fields and strain-induced exciton funneling, presenting a promising methodology for the active manipulation of light emission within integrated nanophotonic devices.