光梯度力驱动微机械谐振器的能量耗散机理与复杂动力学特性研究

The waveguides resonator driven by optical gradient force has numerous unique properties and attracts a lot of attention. In this project, the physical mechanism and its inherent nonlinear characteristics of optical gradient force are studied. The enhanced optical forces in integrated hybrid plasmonic waveguides are discussed. The dynamic models and theoretic analyzing approaches for the coupled systems at micro-scale under multi-physical fields (light, machine, thermal, electricity and magnetism) are presented. The stiffness softening effect of optical gradient force is revealed. The research mainly investigates the effects of the inherent nonlinear characteristics (including pull-in effect, spring softening and hardening, jumping and delay) of the opto-waveguide resonator on the system modelling, stability and nonlinear vibration. With considering the bolometric effect of injected optical power, the theory model of thermoelastic damping in the opto-waveguide resonator is derived through solving the heat diffusion equation. The effects of the injected optical power, representative temperatures, waveguide material and geometries on the thermoelastic damping are revealed. In addition, the effects of axial thermal stress on the resonance frequency shift and nonlinear dynamic characteristics are explored. The research in this project will provide a theoretical basis and technical guarantee on the research of the complex dynamic behavior of optical gradient force actuated micromechanical resonator, has important academic significance and value on promoting the development and application of micromechanical resonant system.

本项目以光梯度力驱动微机械谐振器为研究对象，研究光梯度力的物理发生机理及其固有非线性特性，探讨复合“超”材料中光梯度力的强化本质，提出微尺度下光、机、热、电磁等多场域耦合系统的动力学建模与理论分析方法，重点研究光梯度力驱动下微机械谐振器的弹簧硬化或软化等非线性动力学特性对系统建模、稳定性及非线性振动的影响。研究光的热辐射效应，提出热弹性耦合波导梁谐振器中温度场的建模与分析方法，揭示光的热辐射效应对光梯度力驱动微谐振器的热弹性阻尼的影响规律，探讨波导梁轴向热应力对系统非线性动力学特性及谐振频率偏移等的影响规律。本项目的研究将为解决光梯度力驱动微机械谐振器的复杂动力学问题提供理论基础和技术保证。

本课题在国家自然科学基金资助下，较为全面地研究了光梯度力激励作用下微纳谐振器的耦合非线性振动特性和能量耗散机理，包括光梯度力的物理发生机理及其固有非线性特性，复合“超”材料中光梯度力的强化本质，以及热弹性阻尼这一重要的能量耗散机理。重点对对光梯度力驱动微纳谐振器的非线性谐振特性、可调式光梯度力作用下超材料波导谐振器的振动特性、边界效应对微悬臂梁谐振器的动力学特性影响、以及光梯度力驱动微纳谐振器在光热效应下的热弹性阻尼进行了深入研究。鉴于品质因子对高灵敏度微机械谐振器的重要性，项目研究过程中还进一步对光梯度力驱动微梁谐振器中尺度效应下的热弹性阻尼、微流体管道谐振器中的热弹性阻尼、功能梯度材料微梁谐振器中的热弹性阻尼等方面进行了积极的探索和研究，取得了一系列有益的研究成果。