Graphene-Integrated Metamaterial Device for All-Electrical Polarization Control of Terahertz Quantum Cascade Lasers
Graphene-Integrated Metamaterial Device for All-Electrical Polarization Control of Terahertz Quantum Cascade Lasers
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DOI：
10.1021/acsphotonics.9b00411
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发表时间：
2019-06-01
期刊：
影响因子：
7
通讯作者：
Degl'Innocenti, Riccardo
中科院分区：
文献类型：
--
作者：
Kindness, Stephen J.;Almond, Nikita W.;Degl'Innocenti, Riccardo
通过等离子体谐振器结构的电调谐操作的光电调制器已经展示了用于通信、成像和光谱应用的太赫兹（THz）辐射的快速（>MHz）操纵。在这类太赫兹器件中，基于手性超材料的偏振调制器由于太赫兹偏振控制对于化学、生物学和光谱学应用以及太赫兹通信协议的重要性而引起了越来越多的关注。本文通过对二维手征超材料阵列的电调谐实现了太赫兹量子级联激光器的主动偏振调制。该设备的工作原理是基于电磁感应透明模拟，由明亮的谐振器和两个黑暗的谐振器之间的耦合产生。这些谐振器的取向使得感应出与入射电场极化正交的辐射电偶极子，从而引起所发射的辐射的极化角的旋转。通过使用石墨烯对暗谐振器进行非线性阻尼，耦合条件被电调制，使得实现对所传输的偏振角的连续调谐。该器件在室温下工作，可以很容易地实现为快速的光电偏振调制器，在1.75 THz下的最大调谐范围为20度，具有>5 MHz的重构速度。
Optoelectronic modulators that operate by the electrical tuning of plasmonic resonator structures have demonstrated fast (>MHz) manipulation of terahertz (THz) radiation for communications, imaging, and spectroscopy applications. Among this class of THz device, chiral metamaterial-based polarization modulators have attracted increasing attention due to the importance of THz polarization control for chemistry, biology, and spectroscopy applications, as well as for THz communication protocols. In this paper, active polarization modulation of a THz quantum cascade laser is demonstrated by the electrical tuning of a 2D chiral metamaterial array. The operating principle of this device is based on an electromagnetically induced transparency analogue, produced by the coupling between a bright resonator and two dark resonators. The orientation of these resonators is such that a radiating electric dipole orthogonal to the incident electric field polarization is induced, causing a rotation of the polarization angle of the transmitted radiation. By variably dampening the dark resonators using graphene, the coupling condition is electrically modulated such that continuous tuning of the transmitted polarization angle is achieved. This device, operating at room temperature, can be readily implemented as a fast, optoelectronic, polarization modulator with a maximum tuning range of 20 degrees at 1.75 THz, with demonstrated reconfiguration speeds of >5 MHz.