Optical edge-to-screw singularity state conversions

Optical singularity states,which significantly affect propagation properties of light in free space or optical medium,can be geometrically classified into screw and edge types.These different types of singularity states do not exhibit direct connection,being decoupled from each other in the absence of external perturbations.Here we demonstrate a novel optical process in which a higher-order edge singularity state initially nested in the propagating Gaussian light field gradually involves into a screw singularity with a new-born topological charge determined by order of the edge state.The considered edge state comprises an equal superposition of oppositely charged vortex and antivortex modes.We theoretically and experimentally realize this edge-to-screw conversion process by introducing intrinsic vortex–antivortex interaction.We also present a geometrical representation for mapping this dynamical process,based on the higher-order orbital Poincarésphere.Within this framework,the edge-to-screw conversion is explained by a mapping of state evolution from the equator to the north or south pole of the Poincarésphere.Our demonstration provides a novel approach for manipulating singularity state by the intrinsic vortex–antivortex interactions.The presented phenomenon can be also generalized to other wave systems such as matter wave,water wave,and acoustic wave.

Spin-orbit Rabi oscillations in optically synthesized magnetic fields

Rabi oscillation has been proven to be one of the cornerstones of quantum mechanics,triggering substantial investigations in different disciplines and various important applications both in the classical and quantum regimes.So far,two independent classes of wave states in the Rabi oscillations have been revealed as spin waves and orbital waves,while a Rabi wave state simultaneously merging the spin and orbital angular momentum has remained elusive.Here we report on the experimental and theoretical observation and control of spin–orbit-coupled Rabi oscillations in the higher-order regime of light.We constitute a pseudo spin-1/2 formalism and optically synthesize a magnetization vector through light-crystal interaction.We observe simultaneous oscillations of these ingredients in weak and strong coupling regimes,which are effectively controlled by a beam-dependent synthetic magnetic field.We introduce an electrically tunable platform,allowing fine control of transition between different oscillatory modes,resulting in an emission of orbital-angular-momentum beams with tunable topological structures.Our results constitute a general framework to explore spin–orbit couplings in the higher-order regime,offering routes to manipulating the spin and orbital angular momentum in three and four dimensions.The close analogy with the Pauli equation in quantum mechanics,nonlinear optics,etc.,implies that the demonstrated concept can be readily generalized to different disciplines.

Optical superoscillatory waves without side lobes along a symmetric cut

Optical superoscillation refers to an intriguing phenomenon of a wave packet that can oscillate locally faster than its highest Fourier component,which potentially produces an extremely localized wave in the far field.It provides an alternative way to overcome the diffraction limit,hence improving the resolution of an optical microscopy system.However,the optical superoscillatory waves are inevitably accompanied by strong side lobes,which limits their fields of view and,hence,potential applications.Here,we report both experimentally and theoretically a new superoscillatory wave form,which not only produces significant feature size down to deep subwavelength,but also completely eliminates side lobes in a particular dimension.We demonstrate a new mechanism for achieving such a wave form based on a pair of moonlike sharp-edge apertures.The resultant superoscillatory wave exhibits Bessel-like forms,hence allowing long-distance propagation of subwavelength structures.The result facilitates the study of optical superoscillation and on a fundamental level eliminates the compromise between the superoscillatory feature size and the field of view.

In vivo assessment of hepatotoxicity,nephrotoxicity and biodistribution using 3-aminopropyltriethoxysilane-coated magnetic nanoparticles(APTS-MNPs) in ICR mice

The biocompatibility and biodistribution of magnetic nanoparticles(MNPs)in vivo are essential to ensure their safely clinical application.We have studied these aspects with our 3-aminopropyltriethoxysilanecoated magnetic nanoparticles(APTS-MNPs)formulation,which can be used as magnetic induction hyperthermia media.Changes in tissue iron levels were analyzed after intraperitoneal injection of APTS-MNPs to ICR mice.Liver and kidney functions were tested.Heart,liver,spleen,lung,kidney,testis,and brain were sectioned for pathological analysis.Biodistribution of iron in various body tissues changed with time but greater fraction of the injected iron localized in the liver and spleen than in other tissues.Serum showed an increase in AST and LDH following APTS-MNPs injection.Histological analyses of selected tissues showed no obvious abnormal changes.In conclusion,APTS-MNPs did not cause continuing changes in the liver and kidney function and thus can be safely used for in vivo application.