研究了金属板上下两个表面内侧都周期性地嵌入电介质小球体系的透射和吸收性质.结果显示:对于嵌入深度很小的电介质小球,电磁波可通过隧穿效应进入到电介质小球内,并以腔体本征模式的形式存在.当嵌入深度很小时,周期排列的电介质小球会对金属表面做有效的周期性调制,使体系在特定的频率出现金属表面等离子激元.当腔体本征模式与金属表面等离子激元模式的频率相近时,它们之间的耦合将使两种电磁模式大幅度地增强,从而使上层的电介质小球内具有非常强的电磁场.这些高强度的电磁场有相当一部分可通过隧穿效应进入到下层的电介质小球内,并通过与上表面类似的方式将电磁场引导至金属板外,形成强烈的透射平面电磁波,最终导致体系的透射率大幅度增高.
Transmission properties of the system of dielectric spheres periodically mounted in a metal slab are investigated. The electromagnetic wave can enter the dielectric spheres by tunneling effect and exists as a cavity mode. The surface plasmon polaritons can occur at certain frequency because of the periodically mounted dielectric spheres,which effectively modulate the metal surface to a periodical structure. When the frequencies of the cavity mode and that of the surface plasmon polaritons are close to each other,the coupling between them can greatly enhance both the electromagnetic modes,which results in a very strong electric field in the dielectric spheres of the upper layer. This strong electric field can further enter partially the dielectric spheres at the lower layer by tunneling effect,and can propagate out of the metal slab by the similar mechanism at the upper side of the metal slab,which causes additional increment in the transmission.