Jeon Jiyeon, Chun Byong Sun, Seo Youryang, Kim Minkyeong, Kim Hakseong, Kim Yeongho, Kim Jong Su, Lee Sang Jun
Division of Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science Daejeon 34113 Republic of Korea
Department of Physics, Yeungnam University Gyeongsan 38541 Republic of Korea.
Nanoscale Adv. 2022 Dec 14;5(3):633-639. doi: 10.1039/d2na00679k. eCollection 2023 Jan 31.
The optical, plasmonic, and imaging performance of an infra-red polarized system exceeds that of a conventional infra-red detector due to its high resolution and precision. The wire-grid polarizer has large potential for use in an infra-red polarized imaging device owing to its large polarization efficiency. In this study, we theoretically and experimentally investigate a method to improve the polarization efficiency of a wire-grid polarizer. Here, we demonstrated a high-performance wire grid polarizer with a maximum extinction ratio (ER) of 355 using a bilayer structure and dielectric material in the mid-wavelength infra-red (MWIR) region (3000 nm-5000 nm), which is a 4 times higher ER value than that of the monolayer structure. More interestingly, we were able to improve the performance of the bilayer wire-grid polarizer by devising a method to improve the surface roughness using Ar ion milling. The ER for the after-milled sample was 1255, which was markedly larger than that of the before-milled sample. The results of transmittance measurement confirmed that the improvement in the ER was due to the Fabry-Perot (F-P) phenomenon caused by constructive or destructive interference in the bilayer wire-grid structure and the enhancement of the surface smoothness. These results will help design a polarizer structure that will maximize the polarization efficiency and realize a high-performance infrared polarized imaging system.
红外偏振系统的光学、等离子体和成像性能因其高分辨率和精度而超过传统红外探测器。线栅偏振器因其高偏振效率而在红外偏振成像设备中有很大的应用潜力。在本研究中，我们从理论和实验上研究了一种提高线栅偏振器偏振效率的方法。在此，我们展示了一种高性能线栅偏振器，在中波长红外（MWIR）区域（3000 nm - 5000 nm）使用双层结构和介电材料，其最大消光比（ER）为355，这比单层结构的ER值高4倍。更有趣的是，我们通过设计一种使用氩离子铣削来改善表面粗糙度的方法，提高了双层线栅偏振器的性能。铣削后样品的ER为1255，明显大于铣削前样品的ER。透过率测量结果证实，ER的提高是由于双层线栅结构中的相长或相消干涉引起的法布里 - 珀罗（F - P）现象以及表面光滑度的提高。这些结果将有助于设计一种能使偏振效率最大化的偏振器结构，并实现高性能的红外偏振成像系统。
