Research On Photonic Spin Hall Effect Based Refractive Index Sensor

In recent years,an interesting phenomenon has attracted widespread attention from researchers,known as the photonic spin Hall effect.The photonic spin Hall effect can be regarded as an analogy to the electron spin Hall effect.Its physical mechanism is the spin-orbit interaction in different physical systems,that is,the mutual coupling between the photonic spin and its spatial degrees of freedom.So far,the photonic spin Hall effect has been widely studied in different physical systems,such as optical physics,semiconductor physics,surface plasmon physics,and so on.However,most studies are based on the theoretical predictions and experimental measurements of the photonic spin Hall effect,and few have studied their practical applications.In fact,the spin shift generated by the photonic spin Hall effect can provide important information of the optical interface and is very sensitive.Therefore,it has hidden application value in precision measurement.Using weak measurement techniques,small offsets can be observed to determine the corresponding physical parameters.At the same time,it can obtain ideal accuracy.For example,the photonic spin Hall effect can be used to measure the thickness of a medium,identify the number of graphene layers,and detect the intensity.This paper proposes to use the photonic spin Hall effect to detect the refractive index change of the sensing medium,and design a refractive index sensor based on photonic spin splitting.The specific research contents are as follows:(1)A refractive index sensor based on the photonic spin Hall effect is proposed in theory.We have established a refractive index sensor model based on the photonic spin Hall effect.By detecting the initial small spindependent displacement in the sensor structure,the change in the refractive index of the sensing medium can be accurately judged,so as to determine the corresponding biomolecular concentration.The study found that the sensor not only has high sensitivity,but also has a good signal-to-noise ratio.(2)A theoretical method of eliminating in-plane wave vector components is proposed to further improve the sensitivity of the refractive index sensor based on the photonic spin Hall effect.In this study,we propose a simple and highly sensitive refractive index sensing model based on the photonic spin Hall effect.It is found that by reducing the in-plane wave vector component,the spin displacement can be greatly amplified.Importantly,while maintaining high sensitivity,the model can be extended to a wide range of refractive index changes in the sensing medium.The above findings further demonstrate the feasibility of precision sensing technology based on the photonic spin Hall effect,and also provide theoretical guidance for the development of spin-based nanophotonic devices,which is of good scientific significance.