Method for realizing unidirectional enhanced photon spin Hall effect displacement

Abstract

The invention discloses a method for realizing unidirectional enhanced photon spin Hall effect displacement. A metasurface with S4 symmetry is constructed, the metasurface comprises outer-layer glass with the dielectric constant being 2.25 and two embedded silver crosses with the dielectric constant meeting a Dyde model, the front-end silver cross is provided with a long arm and a short arm, the size of the rear-end silver cross is the same as that of the front-end silver cross, the rear-end silver cross is obtained by performing C4 rotation on the front-end silver cross and performing mirror symmetry on the central plane of the glass, and a Fabry-Perot cavity is formed between the two silver crosses. Based on the S4 symmetry, the Brewster angle phenomenon of p and s linearly polarized light occurring on different sides of the metasurface is achieved, and then a one-way enhanced SHE effect is achieved. A formula for calculating SHE displacement is analyzed, the metasurface is used for regulating and controlling a Fresnel reflection coefficient, a high order term of the Fresnel coefficient is eliminated, and the displacement is increased. According to the invention, the limitation of the enhanced SHE effect on the polarization state is broken, and the unidirectional enhanced photon SHE effect of the two ports at the front and back sides is realized; and the transverse displacement of the photon spin Hall effect is enhanced.

Description

technical field [0001] The invention belongs to the field of optical microstructures, and in particular relates to a method for realizing unidirectionally enhanced photon spin Hall effect (spin Hall effect, SHE) displacement. Background technique [0002] As an analog of the electron spin Hall effect in a photonic field, the photonic spin Hall effect is attributed to the spin-orbit coupling of light, which leads to a spin-dependent displacement at the interface. When a linearly polarized light beam is reflected or refracted at a plane interface, it will be laterally divided into left circular polarization (LCP) and right circular polarization (RCP) due to the opposite spin direction. Therefore, photonic SHEs open up a new possibility to control the spin state of photons and have realized potential applications in various fields, such as spin-based spectrometers, photonic sensors, and precision measurements. Due to the weak light-medium interaction, the spin-dependent splitt...

AI Technical Summary

Problems solved by technology

However, considering the higher-order terms, the denominator of the initial displacement formula must be added to the denominator of the partial derivative term and the square of the tangent term. The existence of these two items will reduce the lateral offset

[0005] Although in recent years, researchers have proposed some methods to further enhance the subwavelength scale displacement, such as graphene, hyperbolic metamaterials, surface plasmon resonance, near-zero dielectric constant materials and time-reversal symmetric metamaterials, etc. etc., but in these theoretical or experimental structures, researchers often pay too much attention to changing different materials to achieve a larger reflectance ratio of p-polarization and s-polarization, so that the higher-order terms on the denominator still exist, Its negative effects have not been overcome, which limits the enhancement effect of lateral displacement (in theory, it can reach half of the incident beam waist radius ω 0 / 2)

At the same time, most of these studies are applicable to a single incident linearly polarized beam. Therefore, enhancing photonic SHE and breaking the limitation of polarization conditions is still an urgent topic to be broadened.

Images