基于亚波长金属孔阵列的光控太赫兹强度调制器

太赫兹波强度调制器对太赫兹技术的发展至关重要。亚波长金属孔阵列可以激发表面等离子激元,增加入射电磁波的透射效率,极大地提高调制器的调制深度。提出了一种基于表面等离子激元的光控太赫兹波强度调制器。首先给出了器件所依赖的基本原理;其次利用传统的微纳加工技术在半绝缘砷化镓衬底上制作出二维亚波长金属孔阵列;最后搭建了太赫兹时域光谱系统,测试了器件样品对太赫兹波的透过率。结果表明:亚波长金属孔阵列可以引起透射率的异常增强,且透射率随着泵浦光强的增大而减小,在特定频率点实现了较高的调制深度。此研究为实现高调制深度的太赫兹波强度调制器提供了参考。

Optical-control terahertz modulator based on subwavelength metallic hole arrays

Terahertz modulator plays an important role in the development of terahertz technology. Optical transmission efficiency of subwavelength metallic hole arrays can be much higher because of the excitation of surface plasmon polaritons, and a higher modulation depth could be obtained by using this structure. A terahertz modulator based on subwavelength metallic hole arrays controlled by optical pump was demonstrated. Firstly, the principles of our sample were researched. Secondly, two -dimensional subwavelength metallic hole arrays were fabricated on semi -insulating GaAs substrate. Lastly, utilizing the terahertz time domain spectroscopy system, the transmission of terahertz radiation through subwavelength hole arrays was measured. Experimental results show that extraordinary optical transmission is excited by subwavelength hole arrays, and optically pumping reduces the terahertz transmission. A higher modulation depth is obtained at special frequency. This research can be the reference to the design and fabrication of terahertz modulator with high modulation depth.