【Link：https://www.nature.com/articles/s41565-022-01217-x】

Integrated circuit (IC) technology is the cornerstone of the development of modern science and technology. Reducing chip size, finding new electronic degrees of freedom and developing new electronic devices have become important research directions in scientific research and industry. Recently, a joint team consisting of researcher Yang Chen, Professor Dong Wu and Professor Jiaru Chu from the University of Science and Technology of China, Professor Kai Wang and Professor Peixiang Lu from Huazhong University of Science and Technology, and Professor Chengwei Qiu from the National University of Singapore has made progress in the interdisciplinary field of valley electronics and micro and nano photonics. Long distance fidelity transmission and directional distribution of WS2 valley photons based on hybrid nanowaveguides are realized for the first time.

In this work, the researchers construct a single in and double out valley photonic router, which realizes the directional and selective distribution of energy valley information.By modulating the circular polarization of the incident pump light, they can selectively excite K or K 'valley excitons at the input. When K 'valley excitons are excited, the generated valley photons will be distributed to the output terminal B; Conversely, when K-valley excitons are excited, the resulting valley photons are distributed to the output. Through calculation, the path selection ratio of energy valley can reach 0.92, and the actual measured value also reaches 0.46.

Although the valleytronic functionalities showcased in this work are still at early stage, our proposed nanocircuit paves a never-explored avenue towards large-scale valleytronic networks. Moreover, it sheds new light on integrating valleytronics, spintronics and photonics on chip, enabling possibilities for hybrid spin-valley-photon systems.

Figure 1.(a, b) device diagram and AFM diagram. (c) Effective wave vector and electric field distribution of two gap waveguide modes. (d, e) Beat field distribution and corresponding energy valley fidelity for right-handed and left-handed dipole excitation at 630 nm and 810 nm.

FIG. 2. (a, d) The electric field distribution of the simulated energy valley distributor under right-handed and left-handed dipole excitation. (b, e) Experimentally measured electric field distribution of an energy valley distributor under right-handed and left-handed dipole excitation. (c, f) Fluorescence spectra of outgoing ports A and B extracted experimentally under right-handed and left-handed dipole excitation.

Figure 3. (a, b) Schematic diagram of nanometer optical path used for unidirectional distribution of energy valley information and fluorescence photos of measurement.