When light is scattered by anisotropic plasmonic nanoparticles, its polarization can be partially altered, giving rise to depolarized light scattering (dPLS). Compared to dielectric nanoparticles, plasmonic nanoparticles exhibit significantly stronger dPLS for a given degree of anisotropy due to differences in their localized surface plasmon resonance (LSPR) wavelengths along different axes. This enhanced sensitivity to plasmonic anisotropy makes dPLS a powerful tool for quantifying spectrally unresolved anisotropy and detecting nanoscale symmetry breaking in nanoparticles and their local environments. We explore the potential applications of dPLS in highly sensitive bio/chemical sensing and optical metrology.

Nanoporous plasmonic nanostructures consist of interconnected networks of nanoscale gold or silver ligaments and pores. Their large surface area, abundance of low-coordination metal atoms, and numerous electromagnetic hot spots arising from LSPRs make them highly attractive for a wide range of optical and catalytic applications. 

We develop innovative fabrication techniques for nanoporous plasmonic nanostructures, including hollow porous gold nanoshells (HPAuNSs) and wrinkled nanoporous silver films (w-npAgFs), using dry plasma etching. Our approach allows flexible control over structural parameters such as overall size, ligament and pore dimensions, and the sharpness of ligament junctions. By tailoring these structural features, we can effectively tune their LSPR properties to optimize performance for specific applications. Moreover, our plasma-based approach offers a more environmentally friendly alternative to conventional chemical dealloying methods that rely on corrosive chemicals. We explore their potential applications in surface-enhanced sensing, particularly surface-enhanced Raman scattering (SERS), as well as plasmonic catalysis.

Semiconductor-based photocatalysts absorb light to generate electron–hole pairs that drive oxidation and reduction reactions at their surfaces. Among various photocatalytic materials, TiO₂ has been extensively studied owing to its abundance, low cost, low toxicity, high chemical stability, and excellent photocatalytic activity. However, a major limitation of TiO₂ is its wide bandgap, which restricts its light absorption primarily to the UV region, accounting for only a small fraction of the solar spectrum. 

Plasmonic photocatalysts combine semiconductors such as TiO₂ with plasmonic metal nanoparticles that strongly absorb visible light through LSPR. The plasmonic excitation can enhance photocatalytic activity through hot-electron generation, local electromagnetic field enhancement, and other mechanisms, enabling efficient utilization of visible light. We develop metal–oxide hybrid nanoparticles as plasmonic photocatalysts for visible-light-driven chemical reactions.

Optical microscopy is a powerful tool for investigating microscopic structures and dynamic processes in a wide range of materials and biological systems. However, conventional imaging techniques often suffer from limited contrast and sensitivity, making it difficult to visualize subtle structural features and dynamic changes at micro- and nanoscales. Our research focuses on developing and improving optical microscopy techniques by exploiting various light–matter interactions, including scattering, reflection, and interference. Through these approaches, we aim to achieve high-contrast, label-free visualization and real-time monitoring of microscopic structures and dynamic phenomena. These techniques have been applied to a variety of systems, ranging from colloidal particle assemblies and nanostructured materials to biological interfaces, providing new insights into their structural and dynamic properties.