金属光子晶体平板的超强透射及其表面等离子体共振

用全矢量的三维有限差分时域(finite-difference time-domain，简称FDTD)方法，研究了正方形单元结构金属光子晶体平板的增强传输效应以及局域性表面等离子体共振现象.这种增强效应来自于两个不同的等离子体共振机制：由长方形空气孔形成的局域波导共振以及由周期性结构引起的光子晶体共振效应.对于由长方形空气孔形成的局域波导共振模式，其等离子体波全部局域在整个长方形空气孔区域中.而由周期性引起的共振模式，其频率随着金属平板表面周期性的变化而变化，相应的等离子体波分布在长方形空气孔区域的两端.产生的表面等离子体都局域在长方形空气孔区域中，电场强度得到了显著的增强.关键词：光子晶体金属平板超强透射表面等离子体

Enhanced transmission through metal-film hole arrays and the surface plasmon resonance

In this paper，we show that the enhanced transmission and the surface plasmon distribution through a thin gold film with a periodic array of subwavelength holes with the finite-difference time-domain (FDTD) method. The transmission spectra exhibit two different surface plasmon resonance features: the localized waveguide resonance and the well-recognized photonic crystal resonance. For the localized waveguide resonance，the tangential electric field component Ey is seen to be concentrated entirely in the rectangular air hole region. And for the photonic crystal resonance，the tangential electric field components Ey is nonzero only on the two sides of the rectangular hole region. With the aid of the SP，light can form a strong focal spot at the bottom of the metal.