提出了一种基于掺金硅的全光学宽带太赫兹波幅度调制器,研究了金(Au)点阵掺杂后硅(Si)体内的少数载流子寿命及其太赫兹波调制特性.实验结果表明,掺杂的Au原子为Si中的光生电子-空穴对提供了有效复合中心,使其少数载流子寿命由原来十几微秒降低至110 ns左右.利用波长915 nm 调制激光作为抽运光源,在340 GHz载波的动态调制测试中获得4.3 MHz的调制速率和21%的调制深度,使Si基调制器的调制速率提高了两个数量级.该全光太赫兹调制器可工作在整个太赫兹频段内,具有极化不敏感特性,因而在太赫兹波高速和宽带调控方面具有重要的应用价值,也是构建光控型Si基太赫兹功能器件的重要基础.
In this paper, we present a broadband terahertz wave amplitude modulator based on optically-controlled gold-doped silicon. Gold dots with a diameter of 40 μm are used as a dopant source. Experimental results indicate that interstitial Au atoms provide effective recombination centers for photo-generated electron-hole pairs in Si body, leading to a significant decrease of the minority carrier lifetime from more than 10 μs to about 110 ns. Dynamic modulation measurement at 340 GHz carrier shows a modulation depth of 21% and a maximum modulation speed of 4.3 MHz. This modulator has advantages such as wideband operation, high modulation speed, polarization insensitivity, and easy manufacture by using the large-scale integrated technology, and thus can be widely used in terahertz technology.