低损耗硅基狭缝混合等离激元波导光传输特性及其应用研究

Micro/nano structures based on surface plasmon polaritons are capable of breaking the fundamental diffraction limit and achieving light transport at the truly sub-wavelength scale, which have been regarded as one of the key solutions to realize highly-integrated photonic chips. However, most of the existing metallic micro/nano waveguides that could realize deep-subwavelength optical confinement have large propagation losses, which greatly hinders their further applications in integrated photonic devices. Based on the coupling of silicon slot and metal nanostructures, this program proposes a novel type of hybrid plasmon polariton waveguide. By leveraging the efficient hybridization between the guided modes supported by the silicon slot and the metallic nanowire, a hybridized slot mode with ultra-low propagation loss, deep-subwavelength mode size and significant field enhancement could be achieved. Through theoretical analysis and numerical simulations of the fundamental issues including the hybridization mechanism and modal characteristics, combined with the comprehensive consideration of practical issues such as fabrication technologies and photonic integrations, design and optimization of the waveguiding structures will be carried out. By further employing the novel features of the hybrid slot mode, passive and active micro/nano photonic devices will also be explored, along with the investigations on their applications in the related areas. On the other hand, waveguides and components will be fabricated by ultilizing microfabrication techniques. Experiments will be then carried out to further investigate their guiding properties. The above work in this program is expected to provide novel approaches in overcoming some of the technical bottlenecks in integrated photonics.

表面等离激元微纳结构可突破衍射极限的束缚，实现对传输光场的亚波长限制，因而被视为实现超高密度集成光子芯片的关键技术发展方向。然而，现有大多数能实现深亚波长光场束缚的金属基微纳波导均有较高的传输损耗,这极大的制约了其在集成光子器件中的广泛应用。本项目提出基于硅基狭缝与金属纳米结构耦合的新型混合等离激元波导，利用介质狭缝导波模式与金属纳米线模式的高效杂化，实现兼具超低损耗、深亚波长模场尺寸、显著场增强效应等优势的混合狭缝模式。通过对杂化机理、模式特性等基础问题的理论分析和数值计算模拟，并结合波导加工工艺、集成等实际问题的综合考虑实现对结构的设计和优化，在此基础上进一步利用混合模式的新颖特性开发无源及有源微纳光子器件，探讨在相关领域应用的可行性。同时，采用微加工工艺技术实现波导器件的加工制备，并对器件的传输特性进行实验测量。相关研究有望为克服集成光学领域的若干技术瓶颈提供全新的解决思路。

表面等离激元微纳结构可突破衍射极限的束缚，实现对传输光场的亚波长限制，因而被视为实现超高密度集成光子芯片的关键技术发展方向。然而，现有大多数能实现深亚波长光场束缚的金属基微纳波导均具有较高的传输损耗,这极大的制约了其在集成光子器件中的广泛应用。本项目从表面等离激元和硅基导波模式的耦合机制等核心问题出发，提出并研究了一系列具有新颖光学特性的低损耗硅基混合等离激元介观光子波导。项目具体在深亚波长硅基混合等离激元光波导以及长程硅基混合等离激元光波导这两个方面开展了系统的研究工作。首先，通过在传统杂化结构中引入具备强光场限制能力的二维等离激元模式或硅基狭缝导波模式，我们在保持长程传输特性的前提下进一步提升了杂化等离激元的模场束缚水平。其次，利用具备空间对称性的硅基导波结构与各类金属纳米结构之间的耦合效应，我们有效降低了传统杂化等离激元模式的传输损耗，将其在通信波段的传输距离提升至厘米量级，且仍保持了亚波长的光场限制能力。针对以上波导，我们通过对其杂化机理、模式特性等基础问题的理论分析和数值计算模拟，并结合波导加工工艺、集成等实际问题的综合考虑实现对其结构的系统设计和优化。同时，在此基础上进一步利用杂化模式的新颖特性开发了无源及有源微纳光子器件，探讨了其在相关领域应用的可行性。在本项目资助下，课题组在各类高水平期刊上发表SCI论文14篇，其中4篇被选为期刊封面。有关获得国内外同行引用共计132次。本研究为构建高性能集成光子芯片和集成光路奠定了坚实的工作基础，同时为克服集成光学领域的若干技术瓶颈提供了全新的解决思路。