亚波长光栅是光子学中至关重要的一种基本元件，其制备和应用均是当前微纳光子学领域的研究重点。本项目中，申请人拟基于非对称金属包覆介质波导结构，实现周期可调的大面积亚波长光栅刻写并将其应用于SERS研究。理论上，通过数值模拟和理论分析手段，研究波导结构中存在的导波模式、表面等离子体模式及其刻写的亚波长光栅的周期与光刻胶薄膜厚度之间的关系。实验上，用442nm、325nm激光激发波导结构中的导模、表面等离子体干涉场，刻写制备各种周期的金属薄膜/亚波长介质光栅结构。在此基础上，将金属薄膜/亚波长介质光栅与金属纳米颗粒的耦合结构作SERS基底。通过理论分析与数值模拟，研究该耦合结构中表面等离子体、局域表面等离子体的激发及其强共振耦合条件和诱导的电场增强，揭示耦合结构提高SERS信号强度的物理机理，进而发展成本低廉、操作简单的高灵敏度SERS检测技术。

Sub-wavelength gratings is a critical element in photonics. So its fabrication and application has attracted a great deal of research attention. In this proposal, we plan to realize an adjustable period and large area sub-wavelength gratings inscribing based on asymmetric metal-cladding dielectric waveguiding structure and to apply the gratings in SERS research. Numerical simulation and theoretical analysis will be used to investigate the dependency of the waveguide modes, the surface plasmons modes existing in the waveguiding structure and the period of the sub-wavelength gratings inscribed to the thickness of the resist in detail. The 442nm and 325nm laser will be used to excite interference field of the waveguide modes or surface plasmons in the waveguiding structure, which will be used to fabricate the metal film/sub-wavelength dielectric gratings structure with various period. On this basis，the coupling structure of the metal film/sub-wavelength dielectric grating and metal nanoparticles will be used as SERS substrates. Theoretical analysis and numerical simulation will be used to investigate the excitation of surface plasmons and localized surface plasmons, the condition of high resonant coupling and its field enhancement, which may reveal the physical mechanism of high SERS signal enhancement within the coupling structure. Further more, the SERS detecting techniques with low cost, simple operation and high sensitive will be developed.