太赫兹近场激发型分子传感器

太赫兹（THz）表面等离子体共振型器件在生物大分子识别、微量化学品检测方面呈现巨大的应用前景，成为当今世界各国科学家研究热点。本项目瞄准这一国际前沿，提出了THz近场激发型分子传感器方案：运用半导体微加工技术，在光导材料的一面制备低偏压高THz发射场强的天线，另一面制备亚波长周期结构排列的金属小孔作为表面等离子共振单元。按照近场光学的原理,THz波在表面等离子共振情况下异常透射会显著增强，并且提高THz波的空间分辨率。通过研究THz发射源与亚波长金属小孔之间间距的最佳匹配，以获得高分辨率，高灵敏度的THz分子传感器，从而实现微量化学品的高精度检测，并且简化THz光谱系统的结构布局；同时阐明近场条件下THz波从发射源到金属表面直接耦合的物理机制。本项目的研究结果对THz技术在生物大分子、微量化学品检测领域内提供强有力的技术支持，对探索THz表面等离子的近场行为具有重要的科学意义。

Nowadays, the terahertz (THz) devices based on surface plasmon (SP) present a great prospect in the area of identification of macromolecules and microscale chemicals, so as to give a rise of giant interests all over the world. Here, we propose a near-field excited THz molecular sensor. With the help of micro-processing technology, a photoconductive antenna and a thin-film metal with subwavelength hole array, will be deposited on the two facades of a piece of semi-insulating GaAs wafer. According to the near-field optics, the extraordinary THz transmission will be enhanced by the THz SP, and the spatial resolution of the THz radiation will be improved. The relation of near-field THz SP will be revealed, in order to achieve the optimal THz resolution and sensitivity, as to fulfill the requirement of the accurate detection of macromolecules and microscale chemicals, and to simplify THz spectroscopy layout. Our research will clarify the physical mechanism of the THz waves in the near-field conditions. The outcome of this project is supposed to provide a THz molecular sensor for identification of macromolecules and microscale chemicals.