摘要
We present a design for tunable directional beaming through a subwavelength metallic double slit sur- rounded by dielectric surface-relief gratings. On-axis and off-axis beaming can be switched by controlling the incident angle to asymmetrically excite surface plasmon polaritons （SPPs） that are subsequently cou- pled out to propagating beams by the two gratings on the left and the right sides of the double slit. Furthermore, the division of optical power into two off-axis beaming directions can be tuned smoothly by varying the incident angle while keeping the total power almost unchanged. The mechanism of this effect is analyzed theoretically and verified using rigorous numerical simulations.
We present a design for tunable directional beaming through a subwavelength metallic double slit sur- rounded by dielectric surface-relief gratings. On-axis and off-axis beaming can be switched by controlling the incident angle to asymmetrically excite surface plasmon polaritons （SPPs） that are subsequently cou- pled out to propagating beams by the two gratings on the left and the right sides of the double slit. Furthermore, the division of optical power into two off-axis beaming directions can be tuned smoothly by varying the incident angle while keeping the total power almost unchanged. The mechanism of this effect is analyzed theoretically and verified using rigorous numerical simulations.
基金
supported by the National Basic Research Program of China (No. 2007CB935303)
the National Natural Science Foundation of China (No.11004119)
the Academy of Finland (No. 128420)
