Guddala Sriram, Kawaguchi Yuma, Komissarenko Filipp, Kiriushechkina Svetlana, Vakulenko Anton, Chen Kai, Alù Andrea, M Menon Vinod, Khanikaev Alexander B
Department of Electrical Engineering, Grove School of Engineering, City College of the City University of New York, New York, NY, USA.
Physics Program, Graduate Center of the City University of New York, New York, NY, USA.
Nat Commun. 2021 Jun 18;12(1):3746. doi: 10.1038/s41467-021-24138-0.
Nonreciprocity and nonreciprocal optical devices play a vital role in modern photonic technologies by enforcing one-way propagation of light. Here, we demonstrate an all-optical approach to nonreciprocity based on valley-selective response in transition metal dichalcogenides (TMDs). This approach overcomes the limitations of magnetic materials and it does not require an external magnetic field. We provide experimental evidence of photoinduced nonreciprocity in a monolayer WS pumped by circularly polarized (CP) light. Nonreciprocity stems from valley-selective exciton population, giving rise to nonlinear circular dichroism controlled by CP pump fields. Our experimental results reveal a significant effect even at room temperature, despite considerable intervalley-scattering, showing promising potential for practical applications in magnetic-free nonreciprocal platforms. As an example, here we propose a device scheme to realize an optical isolator based on a pass-through silicon nitride (SiN) ring resonator integrating the optically biased TMD monolayer.
非互易性和非互易光学器件通过强制光的单向传播在现代光子技术中发挥着至关重要的作用。在此，我们展示了一种基于过渡金属二硫属化物（TMDs）中谷选择性响应的全光非互易性方法。这种方法克服了磁性材料的局限性，并且不需要外部磁场。我们提供了在圆偏振（CP）光泵浦的单层WS₂中光致非互易性的实验证据。非互易性源于谷选择性激子布居，从而产生由CP泵浦场控制的非线性圆二色性。我们的实验结果表明，即使在室温下，尽管存在相当大的谷间散射，仍有显著效应，这表明在无磁非互易平台的实际应用中具有广阔的潜力。例如，在此我们提出一种器件方案，以实现基于集成了光学偏置TMD单层的穿通式氮化硅（SiN）环形谐振器的光隔离器。
