石墨烯等离激元体系光学双稳、调制不稳定性和二次谐波效应的研究

Due to its unique electronic and energy band characteristics, graphene has novel surface nonlinear optical properties. We aim at the investigations of the optical bistability, nonlinear spatiotemporal evolution dynamics, and second (third) harmonic generations in grphene plasmonics. Firstly, we adopt the full-wave electromagnetic scattering theory and self-consistent field approximation to study the optical bistability and multi-stability in nonlinear graphene systems with different nano-structures. Secondly, with the aid of dispersion relation method and numerical simulations, we study the subwavelength modulational instability and nonlinear spatiotemporal evolution dynamics in one-dimensional arrays and two-dimensional lattices composed of graphene nanostructures with the surface third-order nonlinear conductivity. By taking into account the surface nolocality and magnetic-optical effects under the applied magnetic field, we take one step forward to establish the nonlinear full-wave electromagnetic theory to study the second harmonic generations, and the second induced third harmonic generations in graphene nanostructures. Finally, we shall develop the theory and provide series numerical programs to supplement the relevant electromagnetic simulation softwares on the nonlinear graphene plasmonics. Our theoretical analyses and numerical simulations will help us to have a deep understanding on the interactions between light and two-dimensional condensed matter, to promote the design of novel and ultrathin optical and electronic components, and lead to the development of multi-disciplinary researches among the graphene condensed matter, nano-optics, and nonlinear science etc.

由于独特的电子及能带特征，石墨烯具有新颖的非线性光学性质。我们开展石墨烯等离激元体系的非线性光学双稳、非线性时空演化动力学和二（三）次谐波效应研究。首先结合全波电磁散射理论和自洽场近似开展石墨烯包裹不同纳米结构体系的光学双（多）稳研究。其次，利用色散关系方法和数值模拟，研究克尔非线性石墨烯等离激元纳米结构阵列的电磁波调制不稳定性和时空动力学演化行为。综合考虑表面非局域性和外磁场下的磁光响应，进一步研究非线性石墨烯等离激元体系的二次谐波产生和二次诱导三次谐波产生的规律。将发展理论和数值方法，以弥补电磁仿真软件对非线性石墨烯等离激元纳米体系研究的不足。研究有助于加深光与凝聚态二维体系相互作用本质的理解，推动新型超薄光电元器件的设计，并促进低维凝聚态体系、纳米光学和非线性科学等领域交叉与发展等。

在该基金的资助下，我们的科研工作按照申请书计划顺利开展。我们在石墨烯包裹的等离激元纳米颗粒、非局域颗粒的光力与光操控、非线性等离激元体系的光学性质、超材料/超表面、等离激元体系的光自旋霍尔效应、表面等离子体纳米天线和光学传感器设计等方面取得较好进展，顺利完成并超过预期成果目标。重点建立非线性电磁波理论，研究克尔非线性石墨烯包裹纳米球颗粒（纳米圆柱线）体系的光学双稳。特别是对非线性石墨烯纳米结构体系的光学双稳和二（三）次谐波转换的本质理解进一步深化，为将石墨烯等离激元材料应用到非线性纳米光学领域提供重要的理论支撑。研究结果为利用石墨烯来设计超薄和可调控的新型纳米光电元器件如：光学纳米雷达、光信息处理器、光存贮器、光开关等提供重要理论依据。