# Infrared All-Dielectric Metasurface Beam Splitter Based on Transflective Structures
## 4 Conclusions  
In this paper, we built and simulated an infrared all-dielectric metasurface beam splitter based on the structure of incomplete transmissive unit cells by arranging the metasurface with varied radii of silicon nanocolumns from small to large along the \(y\)-axis. The simulation confirms that the beam-splitting function is realized in the 1.55 \(\upmu\)m infrared communication band with a splitting ratio close to 1:1, a deflection angle of approximately 9\({}^{\circ}\), a theoretical total splitting efficiency of 93.3%, and an angular bandwidth of 32\({}^{\circ}\). The correctness of the results was verified by comparing the simulation results, which were generated by two different numerical simulation methods. This double-ended modulated metasurface also generates a response at the input ends of the metasurface information compared to the existing single-ended phase-modulated metasurface. Therefore, the reflected phase-modulated light after beam-splitting can be used as a feedback signal to make real-time adjustments to the operating parameters of the optical system. Compared to other single-ended metasurface beam splitters, the use of light path conversion devices can be reduced, which can further increase the compactness of the optical system. It is hopeful to provide a new design method for metasurface applications in the fields of machine vision, optical measurement, and so on.  
Conceptualization, Y.R. and Z.L.; methodology, Y.R., Z.L., X.S., F.Y. and S.Z.; validation, Y.R. and F.Y.; formal analysis, Y.R., Z.L., X.S., F.Y. and W.L.; investigation, Y.R., X.S. and X.Z.; resources, Z.L.; data curation, Y.R. and Z.L.; writing--original draft preparation, Y.R.; writing--review and editing, Y.R., Z.L., F.Y., R.D., S.Z. and W.L.; visualization, Y.R. and X.Z.; supervision, Z.L., X.S. and R.D.; project administration, Z.L.; funding acquisition, Z.L. All authors have read and agreed to the published version of the manuscript.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Reference Year** & **Type** & **TES** \\ \hline
2018 [42] & RMBS & 20.3\% \\ \hline
2018 [43] & TMBS & 60–80\% \\ \hline
2021 [36] & TMBS & 93.21\% (theory) \\ \hline
2022 [44] & RMBS & 62–75\% \\ \hline
2023 [37] & TMBS & 93.6\% (theory) \\  & & 78.3 (actuality) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Some data for the total splitting efficiency of previous reports.  
**Funding:** National Natural Science Foundation of China (61735018); The Science Fund for Distinguished Young Scholars of Jilin Province (20230101351 JC); Scientific and Technological Development Project of Jilin Province (20220201080 GX); Excellent Member of the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y201836); Leading Talents and Team Project of Scientific and Technological Innovation for Young and Middle-aged Groups in Jilin Province (20190101012 JH).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data is contained within the article.  
**Acknowledgments:** The authors thank [PERSON], [PERSON], [PERSON], and [PERSON] of the Northeast Normal University for technical assistance in figure drawing and literature investigation.  
**Conflicts of Interest:** The authors declare no conflict of interest.