Research On Photon Spin Hall Effect Based On Regression Analysis

Since the discovery of the photonic spin Hall effect,it has attracted widespread attention in the scientific community due to the fact that it has great potential for quantum information,spectroscopic chips,nanophotonic devices,biosensors,precision measurement and other fields.However,the photonic spin Hall effect is very weak,and how to enhance it is very necessary.Topological semimetals are a kind of topological materials discovered in recent years.Their incorporation with the photonic spin Hall effect is still in its infancy,especially the Weyl semimetals known as"three-dimensional graphene"and recently theoretically predicted nodal line semimetalα-Li₃N.They have important applications in optoelectronic devices.In view of these,we adopt Weyl semimetal andα-Li₃N type topological semimetal to study the modulation mechanism of photonic spin Hall effect.Firstly,the main factors affecting the photon spin Hall effect are studied by using statistical methods and machine learning.Then the modulation mechanism of photonic spin Hall effect is analyzed via combing relevant physical theories.Finally,a possible experimental setup for measuring the photonic spin Hall effect is proposed.The corresponding work and research results are as follows:As for the influencing factors of photon spin Hall effect,we utilize multiple linear regression,traditional multiple nonlinear regression and random forest regression to carry out studies.The results show that no matter what kind of topological semimetal,the fitting effect of random forest regression all are optimal,and the goodness of fit is above 0.85.In addition,according to the evaluation results of variable importance,it is found that the physical quantities incident angle,γ/ω_eland dielectric constant are the main factors affecting the photon spin Hall effect in the Weyl semimetal model.In theα-Li₃N type topological semimetal model,the incident angle of incident photons is the main factor affecting the photon spin Hall effect.In the research on the enhancement mechanism of photonic spin Hall effect,the main influencing factors derived from machine learning and related physical theories are analyzed.In the study of Weyl semimetals,it is concluded that epsilon-near-zero substrate material can effectively enhance the photonic spin Hall effect;the photonic spin Hall shift usually occurs when the Fresnel reflection coefficient shows a local minimum.In particular,when the physical quantitiesω/ω_el=0.979 andθ_i=73^o,the maximum displacement of the in-plane（or lateral）photon spin Hall shift is 471（or 55.8）times of the incident wavelength.Forα-Li₃N type topological semimetal,we find that the maximum value of the photon spin Hall shift appears on the high-energy side of the interband absorption,and shows a redshift with increasing the incident angle or dielectric constant of substrate.In contrast,the compressive lattice strain leads the peaks（or valleys）of the photon spin Hall shift to exhibit a blueshift.These results provide insight into the photonic spin Hall effect in topological semimetals,and may also facilitate potential applications of the photonic spin Hall effect in the manipulation and detection of lattice strains or topological phase transitions.