Physics Department, New York City College of Technology, City University of New York , Brooklyn, New York 11201, United States.
ACS Nano. 2014 Oct 28;8(10):10437-47. doi: 10.1021/nn503787q. Epub 2014 Oct 6.
We propose a design of a Y-shaped electrically controlled optical switch based on the studies of propagation of an exciton-polariton condensate in a patterned optical microcavity with an embedded quantum well. The polaritons are driven by a time-independent force due to the microcavity wedge shape and by a time-dependent drag force owing to the interaction of excitons in a quantum well and the electric current running in a neighboring quantum well. It is demonstrated that by applying the drag force one can direct more than 90% of the polariton flow toward the desired branch of the switch with no hysteresis. By considering the transient dynamics of the polariton condensate, we estimate the response speed of the switch as 9.1 GHz. We also propose a design of the polariton switch in a flat microcavity based on the geometrically identical Y-shaped quantum wells where the polariton flow is only induced by the drag force. The latter setup enables one to design a multiway switch that can act as an electrically controlled optical transistor with on and off functions. Finally, we performed the simulations for a microcavity with an embedded gapped graphene layer and demonstrated that in this case the response speed of the switch can be increased up to 14 GHz for the same switch size. The simulations also show that the energy gap in the quasiparticle spectrum in graphene can be utilized as an additional parameter that controls the propagation of the signals in the switch.
我们提出了一种基于在具有嵌入式量子阱的图案化光学微腔中传播激子极化激元凝聚体的研究的 Y 型电控光开关的设计。极化激元由由于微腔楔形形状引起的时不变力和由于量子阱中的激子相互作用以及在相邻量子阱中流动的电流引起的时变拖曳力驱动。结果表明，通过施加拖曳力，可以将超过 90%的极化激元流引导到开关的期望分支，而没有滞后。通过考虑极化激元凝聚体的瞬态动力学，我们估计开关的响应速度为 9.1GHz。我们还提出了基于几何上相同的 Y 型量子阱的平板微腔中的极化激元开关的设计，其中极化激元流仅由拖曳力引起。后者的设置可以设计一种多向开关，它可以用作具有开和关功能的电控光晶体管。最后，我们对具有嵌入式带隙石墨烯层的微腔进行了模拟，并证明在这种情况下，对于相同的开关尺寸，开关的响应速度可以提高到 14GHz。模拟还表明，石墨烯中准粒子能谱中的能隙可被用作控制开关中信号传播的附加参数。
