双层金属环形阵列的太赫兹表面等离子体研究

研究了太赫兹波垂直通过具有周期性亚波长环形空气槽阵列的金属-介质-金属三层结构的透射谱特性,以及与表面等离子体谐振的关系。共振模式电场分布与色散曲线分别表明:表面等离子体具有束缚性,表面电磁波的传输机制与能量流动过程,透射谱的两个共振峰与传播性的表面等离子体模式、局域化的表面等离子体模式及其耦合有关。改变结构的几何参数,其共振峰变化趋势进一步印证了以上观点,并且空气环中激发的准波导效应也影响了太赫兹波的传输。

Research on surface plasmon modes for terahertz transmission through double-layer metal loop arrays

When a metal-dielectric-metal structure is illuminated by vertical incidence of terahertz wave,the characteristic of transmission spectra and the relationship with surface plasmon resonance are studied.The electric field distributions of the resonance modes in transmission spectra confirms the confinement of surface plasmon and the propagation mechanism of surface electromagnetic waves and process of energy flow.Based on dispersion curve of the structure,propagating surface plasmon and localized surface plasmon principally dominated the lower and higher resonances,respectively.By changing the parameters of the structure,further studies show that besides the two SP modes mentioned above,coupling of SP modes as well as quasi-rectangular waveguide effect generated in the air loop significantly modifies the terahertz transmission.