Classification of hyperspectral images for detection of hepatic carcinoma cells based on spectral-spatial features of nucleus

A distinguishing characteristic of normal and cancer cells is the difference in their nuclear chromatin content and distribution.This difference can be revealed by the transmission spectra of nuclei stained with a pH-sensitive stain.Here,we used hematoxylin-eosin(HE)to stain hepatic carcinoma tissues and obtained spectral-spatial data from their nuclei using hyper-spectral microscopy.The transmission spectra of the nuclei were then used to train a support vector machine(SVM)model for cell classification.Especially,we found that the chromatin distribution in cancer cells is more uniform,because of which the correlation coefficients for the spectra at different points in their nuclei are higher.Consequently,we exploited this feature to improve the SVM model.The sensitivity and specificity for the identification of cancer cells could be increased to 99%and 98%,respectively.We also designed an image-processing method for the extraction of information from cell nuclei to automate the identification process.

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.

Higher-order optical rabi oscillations

Rabi oscillations express a phenomenon of periodic conversion between two wave states in a coupled system.The finding of Rabi oscillation has led to important applications in many different disciplines.Despite great progress,it is still unknown whether the Rabi oscillating state can be excited in the framework of the higher-order vector vortex regime.Here,we demonstrate in theory that the higher-order vector vortex light beams can be Rabi oscillating during evolution in an optical coupling system.This new classical oscillating state of light is characterized by a topologically shaped wavefront and coupled with spatially varying polarization.The vector vortex state exhibits a harmonic oscillatory property in the resonant and nonresonant conditions but differs greatly in Rabi oscillating frequencies.During Rabi oscillation,the complex state maintains its topology and intensity profile,while its intrinsic polarization pattern varies adiabatically in a periodic manner.We present an interpretation of the Rabi oscillation of the higher-order wave states in terms of the coupled-mode theory.Furthermore,we reveal a symmetry-protected transition between two Rabi oscillating modes,driven by a slowly varying phase mismatch.This Rabi transition has not been reported in either quantum mechanics or any other physical setting.This work advances the research of Rabi oscillation into the higher-order regime,and it may lead to novel applications in classical and quantum optics.

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.

Optimized weak measurement of orbital angular momentum-induced beam shifts in optical reflection

Tiny but universal beam shifts occur when a polarized light beam is reflected upon a planar interface.Although the beam shifts of Gaussian beams have been measured by the weak measurement technique, the weak measurement for orbital angular momentum(OAM)-induced spatial shifts of vortex beams is still missing.Here, by elaborately choosing the preselection and postselection states, the tiny OAM-induced Goos–H?nchen and Imbert–Fedorov shifts are amplified at an air–prism interface. The maximum shifts along directions both parallel and perpendicular to the incident plane are theoretically predicted and experimentally verified with optimal preselection and postselection states. These maximum shifts can be used to determine the OAM of vortex beams.

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.