等离激元纳米结构光热一体化建模与仿真方法研究

Photothermal effect of plasmonic nanostructures is an emerging research field developed in recent years. On the one hand the photothermal effect seriously affects the integration level and performance of photonic devices, on the other hand it plays an important role in many fields as an excellent nano heat source. Since the nanoscale manufacturing and testing are complex, the numerical simulation becomes an important tool to guide the analysis of the photothermal effect. This project focuses on the difficult points and key problems in the field of photothermal simulation, and researchs a fast and accurate method for the transient photothermal integrated modeling and simulation. Based on the finite-element time-domain method in computational electromagnetics, a transient nonlinear photothermal coupled algorithm will be developed to solve the problem of photothermal co-simulation caused by the frequency-dispersive and temperature-dependent parameters of nanomaterials. Moreover, a multifrontal based nested data-sparse formatted fast algorithm with linear computational complexity will be developed to deal with the problem of the ill-conditioned matrices caused by the multiscale meshes in photothermal simulation. Finally, a multilevel direct finite element tearting and interconnecting method, which is not dependent on any iterative solution mechanism, will be developed to handle the low efficiency of photothermal simulation cause by the large-scale and nolinear problems. The research of this project will break a new path for the nanoscale transient photothermal integrated modeling and simulation, which has significant theoretical and application value.

等离激元纳米结构的光热效应是近期发展起来的一个新兴研究领域。光热效应一方面作为负面效应严重影响着光子器件的集成度和性能，另一方面作为绝好的纳米热源在诸多领域发挥了重要作用。纳米制造工艺和测试的复杂性，让数值仿真方法成为指导光热效应分析的重要手段。本项目聚焦光热效应仿真领域的难点和关键问题，研究实现一种快速精确的瞬态光热一体化建模与仿真方法。方法从计算电磁学时域有限元方法出发，研究一种瞬态光热非线性耦合算法，解决材料参数的光学色散特性和温变特性带来的光热耦合困难的问题；研究一种具有线性计算复杂度的多波前嵌套数据稀疏格式快速算法，解决光热仿真中多尺度网格导致的病态矩阵求解的问题；研究一种不依赖于任何迭代求解机制的多层直接撕裂对接法，解决大规模和非线性导致的光热仿真效率低的问题。项目将为纳米尺度瞬态光热一体化建模与仿真开辟新的思路，具有重要的理论意义和应用价值。

表面等离激元是纳米光子学领域的研究热点。表面等离激元光热效应的数值分析方法在光学器件设计中发挥着重要作用。本项目针对等离激元光热效应的应用需求，研究了金属纳米材料的光热一体化仿真方法，为光频率下局域表面等离激元共振和传播型的表面等离激元极化的光热效应均提供了高效的数值预测方案，能够快速获得目标的光场和瞬态温度分布；研究了石墨烯等离激元波导的光热一体化分析方法，探索了石墨烯混合等离激元波导器件的光热建模和仿真，为实际中石墨烯光互连器件的设计和分析提供了支撑；研究了一种基于数据稀疏格式的无迭代型有限元区域分解算法，为现有计算电磁学有限元区域分解法开辟了新的思路，尤其适合于多右边向量问题的分析；研究了光热一体化撕裂对接算法，实现了电磁部分和热力学部分的同时撕裂对接，并搭建了光热一体化并行计算平台，为大规模光热问题提供了有效方案；研究了有限元-边界积分方法的直接解法，避免了传统迭代型有限元-边界积分解法的收敛速度的问题以及多右边向量冗余计算的问题。研究成果在等离激元光热疗法、光通信互连器件设计、天线及其阵列分析、电磁散射和微波器件设计等多个领域具有广阔应用前景。