Subwavelength Gold Grating as Polarizers Integrated with InP-Based InGaAs Sensors
Subwavelength Gold Grating as Polarizers Integrated with InP-Based InGaAs Sensors
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作为偏振器的亚波长金光栅与 InP 基 InGaAs 传感器集成
DOI：
10.1021/acsami.5b03679
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发表时间：
2015-07-08
影响因子：
9.5
通讯作者：
Gong, Haimei
中科院分区：
文献类型：
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作者：
Wang, Rui;Li, Tao;Gong, Haimei
目前在生物科学、通信和农业等领域对红外偏振成像的需求越来越大，亚波长金属光栅能够分离横向磁(TM)模和横向电(TE)模形成偏振光，为偏振检测提供了一种可靠的方法。本工作旨在设计和制作1.0-1.6微米InP基InGaAs传感器的亚波长金光栅作为偏振器，通过理论模拟和光谱测量，系统地研究了间距为200-1200 nm(固定占空比为0.5)的InP衬底上金光栅的偏振性能。用电子束曝光法(EBL)在100 nm厚的金衬底上制作了200 nm线/间距的光栅。研究发现，由于探测波长中存在SPP模，直接集成在InP上的亚波长金光栅不能作为良好的偏振器使用。用200 nm的SiO_2层夹在Au/InP双层膜中是一种有效的解决方案，使得Tm透过率和消光比都有了显著的改善。在1.35亩处，改善因子分别为8和10。因此，Au/SiO_2/InP三层膜有望成为InP基InGaAs传感器用近红外偏振器的候选材料。
There are currently growing needs for polarimetric imaging in infrared wavelengths for broad applications in bioscience, communications and agriculture, etc. Subwavelength metallic gratings are capable of separating transverse magnetic (TM) mode from transvetse electric (TE) mode to form polarized light, offering a reliable approach for the detection in polarization way. This work aims to design and fabricate subwavelength gold gratings as polarizers for InP-based InGaAs sensors in 1.0-1.6 mu m. The polarization capability of gold gratings on InP substrate with pitches in the range of 200-1200 nm (fixed duty cycle of 0.5) has been systematically studied by both theoretical modeling with a finite-difference time-domain (FDTD) simulator and spectral measurements. Gratings with 200 nm lines/space in 100-nm-thick gold have been fabricated by electron beam lithography (EBL). It was found that subwavelength gold gratings directly integrated on InP cannot be applied as good polarizers, because of the existence of SPP modes in the detection wavelengths. An effective solution has been found by sandwiching the Au/InP bilayer using a 200 nm SiO2, layer, leading to significant improvement in both TM transmission and extinction ratio. At 1.35 mu m, the improvement factors are 8 and 10, respectively. Therefore, it is concluded that the Au/SiO2/InP trilayer should be a promising candidate of near-infrared polarizers for the InP-based InGaAs sensors.