Multiple frequency conversion via atomic spin coherence of storing a light pulse

We experimentally demonstrate multiple frequency conversion via atomic spin coherence of storing a light pulse in a doped solid. The essence of this multiple frequency conversion is four-wave mixing based on stored atomic spin coherence. Through electromagnetically induced transparency, an input probe pulse is stored into atomic spin coherence by modulating the intensity of the control field. By using two different control fields to interact with the coherently prepared medium, the stored atomic spin coherence can be transformed into three different information channels. Multiple frequency conversion is implemented efficiently by manipulating the spectra of the control fields to scatter atomic spin coherence. This multiple frequency conversion is expected to have potential applications in information processing and communication network.

Atomic Spin Polarization Controllability Analysis:A Novel Controllability Determination Method for Spin-Exchange Relaxation-Free Co-Magnetometers

This paper investigates the atomic spin polarization controllability of spin-exchange relaxation-free co-magnetometers(SERFCMs).This is the first work in the field of controllability analysis for the atomic spin ensembles systems,whose dynamic behaviors of spin polarization are described by the Bloch equations.Based on the Bloch equations,a state-space model of the atomic spin polarization for SERFCM is first established,which belongs to a particular class of nonlinear systems.For this class of nonlinear systems,a novel determination method for the global state controllability is proposed and proved.Then,this method is implemented in the process of controllability analysis on the atomic spin polarization of an actual SERFCM.Moreover,a theoretically feasible and reasonable solution of the control input is proposed under some physical constraints,with whose limitation of realistic conditions,the controller design can be accomplished more practically and more exactly.Finally,the simulation results demonstrate the feasibility and validation of the proposed controllability determination method.

Generation of atomic spin squeezing via quantum coherence:Heisenberg–Langevin approach

Taking into account the dephasing process in the realistic atomic ensemble,we theoretically study the generation of atomic spin squeezing via atomic coherence induced by the coupling and probe fields.Using the Heisenberg–Langevin approach,we find that the perfect spin squeezing in the X component can be obtained while the coupling and probe fields produce the maximum coherence between the ground state sublevels 1 and 2.Moreover,the degree of atomic spin squeezing in the X component can be strengthened with the increasing atomic density and/or Rabi frequency of the mixing field.The theoretical results provide a proof-of-principle demonstration of generating the atomic spin squeezing via quantum coherence in the realistic atomic ensemble which may find potential applications in quantum information processing and quantum networks.

Spin detection and manipulation with scanning tunneling microscopy

Over the past few decades, spin detection and manipulation at the atomic scale using scanning tunneling microcopy has matured, which has opened the possibility of realizing spin-based functional devices with single atoms and molecules.This article reviews the principle of spin polarized scanning tunneling microscopy and inelastic tunneling spectroscopy,which are used to measure the static spin structure and dynamic spin excitation, respectively. Recent progress will be presented, including complex spin structure, magnetization of single atoms and molecules, as well as spin excitation of single atoms, clusters, and molecules. Finally, progress in the use of spin polarized tunneling current to manipulate an atomic magnet is discussed.

Photonic spin Hall effect on the surface of anisotropic two-dimensional atomic crystals

We examine the spin-orbit interaction of light and photonic spin Hall effect on the surface of anisotropic two-dimensional atomic crystals. As an example, the photonic spin Hall effect on the surface of black phosphorus is investigated. The photonic spin Hall effect manifests itself as the spin-dependent beam shifts in both transverse and in-plane directions. We demonstrate that the spin-dependent shifts are sensitive to the orientation of the optical axis, doping concentration, and interband transitions. These results can be extensively extended to other anisotropic two-dimensional atomic crystals. By incorporating the quantum weak measurement techniques, the photonic spin Hall effect holds great promise for detecting the parameters of anisotropic two-dimensional atomic crystals.

Laser-induced topology optimized amorphous nanostructure and corrosion electrochemistry of supersonically deposited Ni_(30)Cr_(25)Al_(15)Co_(15)Mo_(5)Ti_(5)Y_(5) HEA coating based on AIMD

A novel Ni_(30)Cr_(25)Al_(15)Co_(15)Mo_(5)Ti_(5)Y_(5) high-entropy alloy(HEA)coating was irradiated to optimize its internal structure via laser after supersonic particle deposition(SPD).Owing to the high energy density of the laser and large temperature gradient,the crystallization process of the molecules and atoms in the coating was restrained and supercooling occurred.Experimental results showed that a considerable number of nano-crystal grains precipitated and amorphous structures were formed because of the random orientation of the crystals.The baseline of differential scanning calorimetry scans obtained for the coating started to shift at the Tg of 939.37℃ and a step was observed.Multiple dispersion peaks and lattice fringes indicated that the nucleation of the irradiated laser-induced topology optimized(LTO)coating was incomplete.The laser-induced topology optimizing treatment led to quasi-isotropy in the SPD coating.Furthermore,the LTO coating exhibited a residual stress of 18.4 MPa,stress-strain response,and fatigue limit of 265 MPa.Hence,the LTO coating exhibited higher performance than the unirradiated SPD coating.The Nyquist and Bode electrochemical impedance spectra of the LTO coating,including two relaxation processes,indicated that the corrosion process steadily recovered to the equilibrium state.This implies that the uniform oxidation passivation layer on the surface of the LTO coating insulated the material from the corrosive medium,protecting the substrate from further corrosion,thus enhancing the structural security of the material for use in super-intense laser facility applications.