Research On Theory And Weak Measurement Model Of Photonic Spin Hall Effect

When a polarized light with confined width is reflected from or transmitted through an interface,its left and right spin components will split in directions perpendicular to the refractive index gradient.This interesting phenomenon called photonic spin Hall effect(PSHE).This spin splitting is typically tens to hundreds of nanometers(on the order of sub-wavelengths).PSHE provides a new way to manipulate photons and has important application prospects in nano-optics,quantum information and semiconductor physics.PSHE is derived from the spin-orbit interaction of light,and the magnitude of the spin splitting displacement is closely related to the optical parameters of the interface medium and the characteristics of the incident light.Therefore,it is also very suitable for characterizing nanoscale material properties and characteristic parameters of incident beams.However,the existing PSHE theoretical model and its weak measurement model have certain shortcomings in terms of integrity and versatility.It is necessary to correct and expand the PHSE theory and weak measurement model.Only in this way can it exert its great potential in various fields.Based on the above background,this paper mainly completed the following research work:1.Based on the classical electrodynamics theory,the modified model of PSHE is established when a linear polarization Gaussian beam is reflected from a non-absorbent interface(its refractive index is real).It solves the problems of the former PSHE model which is not applicable at the Brewster angle,or only applicable to the incident beam being horizontal and vertical polarization,or only describes the spatial spin splitting shift,and does not describe the angular spin splitting shift.The PSHE measurement system is built and the modified model is verified by experiments.2.The model of PSHE is established when a linear polarization Gaussian beam is reflected from an absorptive medium interface(its refractive index is complex).Based on this model,the enhancement of spin splitting in positional space and angular space by surface plasmon resonance and long-range surface plasmon resonance is studied.This model provides a theoretical basis for measuring the properties of the absorptive medium(parameters such as refractive index,thickness and magnetic constant etc.)using PSHE.3.A theoretical model of weak measurement for measuring PSHE is established when the beam is reflected from the interface of the absorptive/non-absorbent medium.The model solves the problem that the former weak measurement model is only applicable when the reflective interface is a non-absorbent medium(its refractive index is real),and it is verified by experiments.4.Based on the established weak measurement model for PSHE,the research on the measurement of the thickness of nano-scale metal film by weak measurement is carried out.It is verified by experiments.The measurement method is reasonable and feasible,and the measurement results are accurate and reliable.