Theoretical investigation of an enhanced Goos-Hänchen shift sensor based on a BlueP/TMDC/graphene hybrid.

The Goos-Hänchen (GH) shift caused by blue phosphorene/transition metal dichalcogenides (BlueP/TMDCs) and graphene surface plasma resonance (SPR) in Kretschmann configuration are studied theoretically. In this structure, graphene and BlueP/TMDCs coated on Cu thin film are optimized to improve the GH shift. The highest GH shift of sensor Cu-BlueP/WS2-graphene is 1004λ with three layers BlueP/WS2 and a graphene monolayer. For the sensing application, the sensitivity corresponding to the optimal GH shift is 3.199×106λ/RIU, which is 210.8 times higher than the traditional Cu film, 181.4 times higher than the Cu-BlueP/WS2 (monolayer) structure, and 56.6 times higher than the Cu-graphene structure. Therefore, the SPR sensor with high GH shift can be extensively used in the fields of chemical, biomedical, and environmental monitoring.

Design of an arbitrary ratio optical power splitter based on a discrete differential multiobjective evolutionary algorithm.

Traditional photonic integrated devices are designed to predict their optical response by transforming the structure and parameters, and it is often difficult to obtain devices with excellent performance in all aspects. The nanophotonic computing design method based on the optimization algorithm has revolutionized the traditional photonic integrated device design technology. Here, we report a discrete differential evolution algorithm that simulates a natural selection process to achieve an ultracompact arbitrary power ratio splitter. The footprint of the designed splitter is only ${2.5}\;\unicode{x00B5} {\rm m} \times {2}.{5}\;\unicode{x00B5} {\rm m}$2.5µm×2.5µm, the simulated total transmission efficiency is above 90%, the power ratio error is less than 3%, and it can work normally over the C-band. Our algorithm can provide new ideas for the application of genetic algorithms to the automatic optimization of photonic integrated devices.

Giant Goos-Hänchen Shifts in Au-ITO-TMDCs-Graphene Heterostructure and Its Potential for High Performance Sensor.

In order to improve the performance of surface plasmon resonance (SPR) biosensor, the structure based on two-dimensional (2D) of graphene and transition metal dichalcogenides (TMDCs) are proposed to greatly enhance the Goos-Hänchen (GH) shift. It is theoretically proved that GH shift can be significantly enhanced in SPR structure coated with gold (Au)-indium tin oxide (ITO)-TMDCs-graphene heterostructure. In order to realize high GH shifts, the number of TMDCs and graphene layer are optimized. The highest GH shift (-801.7 λ) is obtained by Au-ITO-MoSe2-graphene hybrid structure with MoSe2 monolayer and graphene bilayer, respectively. By analyzing the GH variation, the index sensitivity of such configuration can reach as high as 8.02 × 105 λ/RIU, which is 293.24 times of the Au-ITO structure and 177.43 times of the Au-ITO-graphene structure. The proposed SPR biosensor can be widely used in the precision metrology and optical sensing.