提出一种利用表面等离子体耦合的金属光栅结构, 该光栅结构因入射光的方向和耦合表面等离子体的条件不同, 从不同方向入射时会有不同的透射率。周期为500 nm、填充因子为0.7的Au-SiO2光栅结构在565~589 nm波段具有单向透射性。当填充因子为0.662时, 最大透射对比率达3×104。当光栅厚度为60 nm时, 入射波长在570~630 nm之间的透射对比率均可达到5以上, 最高透射率为43%。当光栅周期为1 100 nm时, 1 530~1 590 nm波段的透射对比率均大于5, 可以满足中红外波段的应用。

A kind of metal gratings based on surface plasmon coupling was presented in this paper. The metal grating has different transmission rate according to incident direction because of different surface plasmon coupling conditions. The unsymmetrical transmission phenomenon appears for the Au-SiO2 grating when the periodic is 500 nm and the filling factor is 0.7, particularly for wavelength from 565 to 589 nm. A maximum transmission contrast of more than 3×104 is found at filling factor 0.662. When the thickness of Au is 60 nm, the transmission contrast is more than 5 during 570～630 nm, and the maximum transmission is 43%. When the periodic is 1 100 nm, the transmission contrast is more than 5 during 1 530～1 590 nm, which satisfies for the mid-infrared applications.