150 nm亚波长铝光栅的近红外偏振特性

采用纳米压印、反应离子辅助刻蚀及物理溅射技术制作了周期为150 nm的铝光栅,用分光光度计测量了样品的透过率随入射光偏振方向变化的关系以及在可见、近红外波段TE,TM波的透射光谱。利用严格耦合波理论对光栅的上述性能进行了数值模拟和理论分析。考察了斜入射情况下样品的性能及损耗随入射角的变化关系。理论和实验结果表明,光栅的透过率对入射光的偏振态十分敏感:在近红外范围内(1000~2000 nm)对TE波完全反射,对TM波具有90%的透过率,并且在斜入射时因入射角的增大而轻微加强。此外,还比较了不同金属材料光栅的TM波近红外透射特性,探讨了改善其性能的途径。

Polarization Effect of 150 nm Subwavelength Aluminum Wire Grating in Near Infrared

The 150 nm subwavelength aluminum wire grating was fabricated with nano-imprint technique and reactive ion etching process,and the polarization effect of this grating was also studied both experimentally and theoretically in visible and near infrared.The transmission spectra of transverse electric(TE) and transverse magnetic(TM) wave for this grating sample were measured by spectrophotometer,respectively,which have good agreements with the numerical results of rigorous coupled wave analysis(RCWA).Results show that such grating is sensitive to the polarization of incidence,polarization paralleled to the gratings will be totally reflected while the orthogonal polarization will be transmitted close to 90%.Such performance is uniform with wide variations in wavelength and the angle of incidence.In addition,different metals were simulated to generate a lower reflectivity of TM wave,so as to give further discussion on the improvement and applications of such grating.