Tuning the polarization of transmitted light through a double-layered gold film of U-shaped apertures by changing the chiral configuration

We propose a double-layered gold film structured with U-shaped aperture in chiral configuration to manipulate the polarization of transmitted light. Two U-shaped aperture arrays are fabricated on both gold films separated by a spacing film, where each face-to-face pair of apertures is arranged perpendicularly to each other in counterclockwise or clockwise. Due to the coupling of the pairs, surface plasmon polariton resonances in the double-layered films in phase and out of phase at two frequencies, respectively. The polarization of transmitted light is rotated 90° by switching the chiral configuration of the doubled-layered gold film between counterclockwise and clockwise. The double-layered gold film structured with apertures tailors the polarization state of the transmitted light at their resonance peaks relative to their complementary structures. These results provide us an effective way to realize an extraordinary transmission and manipulate the polarization state of a double-layered films in chiral configuration.