Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea.
Nanoscale. 2018 May 10;10(18):8496-8502. doi: 10.1039/c8nr01614c.
The electrical control of photonic crystal (PhC) lasers has been an attractive but challenging issue. Laser operation by electrical injection is of key importance for the viability and applicability of the PhC lasers. Another key factor is the electrical modulation of the laser output. The Fermi level of a graphene monolayer can be controlled by electrical gating, which adjusts its optical absorption. In this study, a graphene monolayer sheet is integrated on top of a two-dimensional PhC structure composed of InGaAsP multiple-quantum-wells (MQWs) in order to demonstrate the electrical modulation of a high-power (microwatt-scale) PhC band-edge laser. The introduced dielectric spacer layer presets the delicate balance between the optical gain from the MQWs and optical loss at the graphene monolayer. The proposed device is covered by an ion-gel film, which enables a low-voltage laser modulation at |Vg|≤1 V. The modulation is extensively investigated experimentally, and the obtained results are confirmed by performing numerical simulations.
光子晶体（PhC）激光器的电控制一直是一个吸引人但具有挑战性的问题。通过电注入实现激光操作对于 PhC 激光器的可行性和适用性至关重要。另一个关键因素是激光输出的电调制。通过电门控可以控制单层石墨烯的费米能级，从而调节其光吸收。在这项研究中，在由 InGaAsP 多量子阱（MQW）组成的二维 PhC 结构的顶部集成了一层石墨烯单层片，以演示高功率（微瓦级）PhC 带边激光器的电调制。引入的介电间隔层预设了 MQW 的光增益和石墨烯单层的光损耗之间的微妙平衡。所提出的器件被离子凝胶膜覆盖，这使得在 |Vg|≤1 V 的低电压下实现激光调制成为可能。通过实验广泛研究了调制，并且通过执行数值模拟确认了获得的结果。
