基于半导体等离子体频率光学调控的太赫兹波调制系统

A terahertz wave modulation system based on optical modulation of the plasma frequency of a semiconductor

介绍了一种太赫兹波光学调制系统,该系统首先通过刀片与半导体之间的狭缝实现太赫兹波和太赫兹表面等离子体波之间的耦合,然后通过改变照射到本征半导体表面的光强用以调控半导体表面的等离子体频率,使得半导体表面的等离子体频率在有光照和无光照条件下分别大于和小于其上传输的太赫兹表面等离子体波的频率,从而实现对在半导体表面传输的太赫兹表面等离子体波以及由其耦合出的太赫兹波的强度调控。该调制方法与传统方法相比具有调控频带宽、速度快、成本低、常温工作等优点,可用于太赫兹波通讯。仿真和实验结果进一步验证了该调制系统应用的可行性。

A terahertz(THz) wave optical modulation system was introduced. The modulation was based on the coupling of THz waves and THz surface plasmon by a simple slit between a razor blade and a semiconductor wafer. The modulation process was realized by changing the illumination intensity on the intrinsic semiconductor surface. With or without the optical illumination, the plasma frequency of the semiconductor was larger or smaller than the frequencies of the surface plasmon. Therefore, the THz surface plasmon propagating on the semiconductor and the THz wave coupled from the surface plasmon can be switched on and off. In comparison with conventional THz modulation approaches, this method has the advantages of wide modulation bandwidth, high speed, low cost and room temperature operation etc., which are favorable to THz wave communication applications. The simulation and experimental results prove the feasibility of the THz wave modulation system.