Plasmonic nanomaterials have attracted significant attention in recent years due to their exceptional near-field enhancement, photothermal, and photomechanical effects, resulting in remarkable progress in fields such as energy, catalysis, optics, and biomedicine. Particularly in biomedicine, their applications have played a crucial role in developing ultrasensitive biosensing strategies and effective therapeutic approaches. In this paper, we explore plasmonic nanomaterials from three key perspectives: near-field enhancement, photothermal effect, and photomechanical effect. We summarize the latest advancements in their applications in biomedical fields such as sensing, imaging, and therapy, and provide insights into future development directions in this field.

The topological properties of photonic bands are directly influenced by the magnitude and spatial distribution of the Dirac mass term. By engineering mass-term lattices with spatial inhomogeneity on topological metasurfaces, the optical bound state can be precisely controlled, enabling the realization of configurable optical Dirac cavities. In this paper, we investigate how the trapped light and quality factor for Dirac cavities based on topological metasurfaces can be manipulated through varying mass-term lattice arrangements. The results show that incorporating spatially distributed mass terms into metasurfaces significantly enhances the localization of light fields under topological protection. In addition, discrete and smooth mass-term distributions correspond to different regulation mechanisms. By systematically optimizing the design of the mass term, the localized intensity and spatial extent of topological Dirac cavities can be flexibly tuned, facilitating the development of high-quality, directionally enhanced laser systems.

Liquid?liquid diffusion, an ancient yet fundamental scientific problem, has not been fully described by theory due to the complex interactions between liquid molecules. As a result, precise experimental measurements are crucial for advancing our understanding of this phenomenon. Since the introduction of Fick's laws in 1855, various methods have been developed to measure the liquid?liquid diffusion coefficient. Among these, optical methods are particularly valuable for monitoring the diffusion process, offering more accuracy than non-optical techniques. In this paper, we begin by discussing the Fickian diffusion model and the commonly used methods for measuring liquid?liquid diffusion. We then present two types of non-Fickian phenomena observed in experiments, highlighting the limitations of current optical methods in monitoring diffusion. Finally, we introduce a new optical micro-sensor scanning method proposed by our research group, which offers a promising approach for studying and uncovering new principles of liquid?liquid diffusion.