ABSTRACT
In this paper, a novel method of film thickness measurement based on weak measurements is proposed by analyzing the quantitative relationship between film thickness and the weak measurement amplified shift of the photonic spin Hall effect, and the corresponding measurement system is established to verify it through experiments. This method can measure the thickness of an arbitrary dielectric film with nanometer resolution. The theoretical analysis and experimental results show that the method is reasonable, feasible, and reliable, and the structure of the measurement system is simple, easy to operate, and easy to assemble into a prototype instrument. The measurement model and method provide not only a new way for the measurement of thin film thickness but also an important reference for the precise measurement of other optical interface parameters.
ABSTRACT
A novel surface plasmon resonance (SPR) biosensor based on Ag-Au bimetallic films with a hybrid structure of blue phosphorene (BlueP)/transition metal dichalcogenides (TMDCs) and graphene is presented. In order to improve the sensitivity, the thickness of silver and gold films is optimized to achieve minimum reflectivity and an adequate level of sensitivity; further, sensitivity for the monolayer BlueP/MoS2 and graphene structure is enhanced by 19.73%, with respect to a traditional sensor. Besides, the effect of layers of different Blue/TMDCs heterostructures to the sensitivity of the SPR biosensor is investigated, and the highest sensitivity with 335.4°/RIU for the bilayer BlueP/WS2 is obtained. Furthermore, distributions of the electric field and the changes of resonance angle to the refractive index of the sensing medium and prism in the visible regime are illustrated at optimal configuration. In virtue of highly sensitive characteristics, the proposed sensor structure will be a much better option to be employed for further biological detection.
