Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
Adv Mater. 2017 Aug;29(32). doi: 10.1002/adma.201605881. Epub 2017 Jun 22.
The recent meteoric rise in the field of photovoltaics with the discovery of highly efficient solar-cell devices is inspired by solution-processed organic-inorganic lead halide perovskites that exhibit unprecedented light-to-electricity conversion efficiencies. The stunning performance of perovskites is attributed to their strong photoresponsive properties that are thoroughly utilized in designing excellent perovskite solar cells, light-emitting diodes, infrared lasers, and ultrafast photodetectors. However, optoelectronic application of halide perovskites in realizing highly efficient subwavelength photonic devices has remained a challenge. Here, the remarkable photoconductivity of organic-inorganic lead halide perovskites is exploited to demonstrate a hybrid perovskite-metamaterial device that shows extremely low power photoswitching of the metamaterial resonances in the terahertz part of the electromagnetic spectrum. Furthermore, a signature of a coupled phonon-metamaterial resonance is observed at higher pump powers, where the Fano resonance amplitude is extremely weak. In addition, a low threshold, dynamic control of the highly confined electric field intensity is also observed in the system, which could tremendously benefit the new generation of subwavelength photonic devices as active sensors, low threshold optically controlled lasers, and active nonlinear devices with enhanced functionalities in the infrared, optical, and the terahertz parts of the electromagnetic spectrum.
近年来，随着高效太阳能电池器件的发现，光伏领域取得了飞速发展，这一进展的灵感来自于通过溶液处理的有机-无机卤化铅钙钛矿，这种材料具有前所未有的光电转换效率。钙钛矿的惊人性能归因于其强烈的光响应特性，这些特性被充分利用于设计优秀的钙钛矿太阳能电池、发光二极管、红外激光器和超快速光探测器。然而，卤化物钙钛矿在实现高效亚波长光子器件方面的光电应用仍然是一个挑战。在这里，我们利用有机-无机卤化铅钙钛矿的显著光电导性，展示了一种混合钙钛矿-超材料器件，该器件在太赫兹部分的电磁频谱中表现出极低功率的超材料共振光开关。此外，在更高的泵浦功率下，观察到了耦合声子-超材料共振的特征，其中的 Fano 共振幅度非常微弱。此外，在该系统中还观察到了低阈值、对强受限电场强度的动态控制，这将极大地受益于新一代亚波长光子器件，如作为有源传感器的低阈值光控激光器，以及在红外、光学和太赫兹部分的电磁频谱中具有增强功能的有源非线性器件。
