Single-layer micro-nano structure enhancing asymmetric transmission and preparation method thereof

The invention provides a single-layer micro-nano structure enhancing asymmetric transmission. The structure is formed by connecting a plurality of periodic units in the same structure up, down, left and right. All periodic units are located in the same plane. According to each periodic unit, a rectangular hole and a semicircular hole are processed in the periodic unit body; the long side of the rectangular hole is parallel to the diameter of the semicircular hole, and the arc of the semicircular hole is separated from or tangent to the long side of the rectangular hole; and the angle alpha between the long side of the rectangular hole and the Px direction is 0 to 45 degrees. Due to different charge gathering ability of crevices between rectangular holes and semicircular holes, a formant pattern shows on a polarization conversion spectrum, and two large AT signals appear in a long wavelength band. An AT signal is added in a short wavelength, which improves the detection accuracy of chiral molecules. According