Rong Kexiu, Wang Bo, Reuven Avi, Maguid Elhanan, Cohn Bar, Kleiner Vladimir, Katznelson Shaul, Koren Elad, Hasman Erez
Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel.
Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
Nat Nanotechnol. 2020 Nov;15(11):927-933. doi: 10.1038/s41565-020-0758-6. Epub 2020 Aug 24.
Heterostructures combining a thin layer of quantum emitters and planar nanostructures enable custom-tailored photoluminescence in an integrated fashion. Here, we demonstrate a photonic Rashba effect from valley excitons in a WSe monolayer, which is incorporated into a photonic crystal slab with geometric phase defects, that is, into a Berry-phase defective photonic crystal. This phenomenon of spin-split dispersion in momentum space arises from a coherent geometric phase pickup assisted by the Berry-phase defect mode. The valley excitons effectively interact with the defects for site-controlled excitation, photoluminescence enhancement and spin-dependent manipulation. Specifically, the spin-dependent branches of photoluminescence in momentum space originate from valley excitons with opposite helicities and evidence the valley separation at room temperature. To further demonstrate the versatility of the Berry-phase defective photonic crystals, we use this concept to separate opposite spin states of quantum dot emission. This spin-enabled manipulation of quantum emitters may enable highly efficient metasurfaces for customized planar sources with spin-polarized directional emission.
将薄量子发射体层与平面纳米结构相结合的异质结构能够以集成方式实现定制的光致发光。在此，我们展示了在WSe单分子层中的谷激子产生的光子Rashba效应，该单分子层被整合到具有几何相位缺陷的光子晶体平板中，即整合到贝里相位缺陷光子晶体中。动量空间中这种自旋分裂色散现象源于由贝里相位缺陷模式辅助的相干几何相位拾取。谷激子有效地与缺陷相互作用，以实现位点控制的激发、光致发光增强和自旋相关操纵。具体而言，动量空间中光致发光的自旋相关分支源自具有相反螺旋度的谷激子，并证明了室温下的谷分离。为了进一步证明贝里相位缺陷光子晶体的多功能性，我们使用这一概念来分离量子点发射的相反自旋态。这种对量子发射体的自旋启用操纵可能会实现用于具有自旋极化定向发射的定制平面源的高效超表面。
