微型腔单一亚波长金属狭缝的光波透射

摘要

Optical wave transmission through a subwavelength slit grooved with cavity in internal wall is investigated in a thick metallic plate by two-dimensional finite-difference time-domain method, and enhanced transmissions are found at some wavelengths in transmission spectra. Using Maxwell equations and waveguide resonance theory, the mechanism of the enhanced transmission is explored with amplitude distributions. It is considered that waveguide resonance modes play an important role in the transmission. The longitudinal modes forming in the subwavelength slit can lead to transmission peaks, and so can the cavity modes.%利用时域有限差分法模拟了厚金属层上单一亚波长狭缝内壁刻有一微型腔结构光波传输,结果发现在特定波长发生异常的增强透射.结合透射峰值对应波长近场分布,利用麦克斯韦方程组和波导理论对增强透射进行解释,认为光波在微型腔和狭缝中形成共振腔模起了重要作用:在狭缝内形成纵模,可以形成透射峰;在腔内形成不同的腔模也可以形成透射模.