Solid-state quantum emitters,such as semiconductor quantum dots(QDs),have numerous significant applications in quantum information science.While there has been some success in controlling structured light from kinds o...Solid-state quantum emitters,such as semiconductor quantum dots(QDs),have numerous significant applications in quantum information science.While there has been some success in controlling structured light from kinds of single-photon sources,the simultaneous on-demand,high-quality,and integrated generation of singlephoton sources with various degrees of freedom remains a challenge.Here,we utilize composite phase-based metasurfaces,comprising transmission phase and geometric phase elements,to modulate the semiconductor QD emission through a simplified fabrication process.This approach enables to decouple the emission into left and right circularly polarized(LCP/RCP)beams in arbitrary directions(e.g.,with zenith angles of 10°and 30°),producing collimated beams with divergence angles less than 6.0°and carrying orbital angular momentum(OAM)modes with different topological charges.Furthermore,we examine the polarization relationship between the output beams and QD emission to validate the performance of our designed devices.Additionally,we achieve eight channels of single-photon emissions,each with well-defined states of spin angular momentum(SAM),OAM,and specific emission directions.Our work not only demonstrates an effective integrated quantum device for the on-demand manipulation of precise direction,collimation,SAM,and various OAM modes,but also significantly advances research efforts in the quantum field related to the generation of multi-OAM single photons.展开更多
Two-dimensional magnets have received increasing attention since Cr_2Ge_2Te_6 and CrI_3 were experimentally exfoliated and measured in 2017. Although layered ferromagnetic metals were demonstrated at room temperature,...Two-dimensional magnets have received increasing attention since Cr_2Ge_2Te_6 and CrI_3 were experimentally exfoliated and measured in 2017. Although layered ferromagnetic metals were demonstrated at room temperature, a layered ferromagnetic semiconductor with high Curie temperature(Tc) is yet to be unveiled. Here, we theoretically predicted a family of high Tcferromagnetic monolayers, namely MnNX and CrCX(X = Cl, Br and I; C = S, Se and Te). Their Tcvalues were predicted from over 100 K to near 500 K with Monte Carlo simulations using an anisotropic Heisenberg model. Eight members among them show semiconducting bandgaps varying from roughly 0.23 to 1.85 eV. These semiconducting monolayers also show extremely large anisotropy, i.e. ～10~1 for effective masses and ～10~2 for carrier mobilities, along the two in-plane lattice directions of these layers. Additional orbital anisotropy leads to a spin-locked linear dichroism, in different from previously known circular and linear dichroisms in layered materials.Together with the mobility anisotropy, it offers a spin-, dichroism-and mobility-anisotropy locking.These results manifest the potential of this 2D family for both fundamental research and high performance spin-dependent electronic and optoelectronic devices.展开更多
基金National Key Research and Development Program of China(2021YFA1400800)National Natural Science Foundation of China(12374363)+1 种基金Guangdong Provincial Quantum Science Strategic Initiative(GDZX2306002,GDZX2206001)Guangdong Provincial Natural Science Fund Projects(2024B1515040013)。
文摘Solid-state quantum emitters,such as semiconductor quantum dots(QDs),have numerous significant applications in quantum information science.While there has been some success in controlling structured light from kinds of single-photon sources,the simultaneous on-demand,high-quality,and integrated generation of singlephoton sources with various degrees of freedom remains a challenge.Here,we utilize composite phase-based metasurfaces,comprising transmission phase and geometric phase elements,to modulate the semiconductor QD emission through a simplified fabrication process.This approach enables to decouple the emission into left and right circularly polarized(LCP/RCP)beams in arbitrary directions(e.g.,with zenith angles of 10°and 30°),producing collimated beams with divergence angles less than 6.0°and carrying orbital angular momentum(OAM)modes with different topological charges.Furthermore,we examine the polarization relationship between the output beams and QD emission to validate the performance of our designed devices.Additionally,we achieve eight channels of single-photon emissions,each with well-defined states of spin angular momentum(SAM),OAM,and specific emission directions.Our work not only demonstrates an effective integrated quantum device for the on-demand manipulation of precise direction,collimation,SAM,and various OAM modes,but also significantly advances research efforts in the quantum field related to the generation of multi-OAM single photons.
基金supported by the National Natural Science Foundation of China(11274380,91433103,11622437 and 61674171)the Fundamental Research Funds for the Central Universities of China+2 种基金the Research Funds of Renmin University of China(16XNLQ01)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)supported by the Outstanding Innovative Talents Cultivation Funded Programs 2017 of Renmin University of China
文摘Two-dimensional magnets have received increasing attention since Cr_2Ge_2Te_6 and CrI_3 were experimentally exfoliated and measured in 2017. Although layered ferromagnetic metals were demonstrated at room temperature, a layered ferromagnetic semiconductor with high Curie temperature(Tc) is yet to be unveiled. Here, we theoretically predicted a family of high Tcferromagnetic monolayers, namely MnNX and CrCX(X = Cl, Br and I; C = S, Se and Te). Their Tcvalues were predicted from over 100 K to near 500 K with Monte Carlo simulations using an anisotropic Heisenberg model. Eight members among them show semiconducting bandgaps varying from roughly 0.23 to 1.85 eV. These semiconducting monolayers also show extremely large anisotropy, i.e. ～10~1 for effective masses and ～10~2 for carrier mobilities, along the two in-plane lattice directions of these layers. Additional orbital anisotropy leads to a spin-locked linear dichroism, in different from previously known circular and linear dichroisms in layered materials.Together with the mobility anisotropy, it offers a spin-, dichroism-and mobility-anisotropy locking.These results manifest the potential of this 2D family for both fundamental research and high performance spin-dependent electronic and optoelectronic devices.
