ABSTRACT Multichannel vectorial holography has essential applications in the fields of optical information processing and optical communications. With the development of metasurface devices, multiple vortex beams and holographic images with vectorial polarization distributions have been demonstrated in both linear and nonlinear optical regimes. However, most of the metasurface‐based vectorial holography experiences twin‐image problem, affecting the polarization contrast, image quality, and so on. Here, we demonstrate the twin‐image free multichannel vectorial holography with nonlinear chiroptical metasurfaces, which consist of pairs of enantiomeric meta‐atoms. Such meta‐atoms provide two independent channels that rely on the giant circular dichroism effect in second harmonic generation processes for manipulating the amplitude and phase of the nonlinear optical waves. By combining the concept of nonlinear geometric phase and the Gerchberg–Saxton algorithm, the twin‐image free multichannel vectorial vortex beams and holographic images are realized. The proposed nonlinear chiroptical metasurface platform may open new routes to develop ultracompact and multifunctional devices for high‐capacity optical information processing and data storage.

Optical information encoding is promising for many applications in sensing, data storage, and computing. Recently, various strategies have been suggested to encode optical information in planar devices. Among these, optical metasurfaces represent a flexible platform for manipulating multiple degrees of freedom of light with subwavelength scale meta-atoms. However, to realize both amplitude and phase control of light with metasurfaces, usually multiple meta-atoms per unit cell are required, so information density will be greatly reduced. Here, we develop a novel approach of nonlinear optical information encoding with grayscale lithography enabled hybrid metasurfaces composed of gold plasmonic meta-atoms deposited on an epsilon-near-zero material. By controlling the spacer layer thickness with electron beam grayscale lithography and varying orientation angles of the meta-atoms, we can control at the single-pixel level both the amplitude and phase of the generated second-harmonic waves. The proposed method opens new avenues for developing advanced nonlinear nanophotonic sources.

Chiral photonics enables the control of light handedness for many applications in optical communications, biological and chemical sensing, and quantum technologies. While traditional approaches focus on engineering strong linear chiroptical response, nonlinear chiral phenomena remain largely unexplored. Here, we demonstrate experimentally a pronounced nonlinear chiral response of free-standing membrane metasurfaces that are effectively achiral in the linear regime. By employing patterned silicon membranes with both C4 symmetry and intentionally broken in-plane symmetry, we reveal that strong nonlinear circular dichroism can be observed in the third-harmonic generation. An unperturbed metasurface exhibits a strong cross-polarized third-harmonic signal with nonlinear circular dichroism of the value -0.83, whereas in-plane symmetry breaking enables a copolarized channel, and it reverses the sign of the nonlinear circular dichroism, reaching values as large as 0.41. Our findings suggest a novel approach for engineering nonlinear chiral responses in metasurfaces, complementing traditional approaches and paving the way toward advanced chiral metadevices.

Ultrafast modulation of light is of great importance in optical communications, optical spectroscopy, precision measurement and so on. To achieve better modulation performance, various materials platforms including photonic crystals, two-dimensional materials and plasmonic metasurfaces have been extensively explored. In this work, we demonstrate that a thin β-BaB2O4 which has wide band transparence and large nonlinear coefficient can be used to realize ultrafast modulation of second harmonic waves (SHWs). Under the pumping of two femtosecond laser pulses with perpendicular polarizations and variable time delay, the modulation of SHWs exhibits either slow or fast varying characteristics by using the concept of polarization selective interferometric autocorrelation. Interestingly, these two kinds of modulation behaviors depend on the real and imaginary parts of the pulse-width parameter of the chirped laser pulse. The observed physical mechanism is then utilized to generate and modulate the SHWs carrying orbital angular momentum. The proposed strategy in this work may have important applications in parallel ultrafast optical information processing and optical computing.

Metal-free carbon-based materials are one of the most promising electrocatalysts toward 2-electron oxygen reduction reaction (2e-ORR) for on-site production of hydrogen peroxide (H2O2), which however suffer from uncontrollable carbonizations and inferior 2e-ORR selectivity. To this end, a polydopamine (PDA)-modified carbon catalyst with a dipole-dipole enhancement is developed via a calcination-free method. The H2O2 yield rate outstandingly reaches 1.8 mol g(cat)(-1) h(-1) with high faradaic efficiency of above 95% under a wide potential range of 0.4-0.7 V-RHE, overwhelming most of carbon electrocatalysts. Meanwhile, within a lab-made flow cell, the synthesized ORR electrode features an exceptional stability for over 250 h, achieved a pure H2O2 production efficacy of 306 g kWh(-1). By virtue of its industrial-level capabilities, the established flow cell manages to perform a rapid pulp bleaching within 30 min. The superior performance and enhanced selectivity of 2e-ORR is experimentally revealed and attributed to the electronic reconfiguration on defective carbon sites induced by non-covalent dipole-dipole influence between PDA and carbon, thereby prohibiting the cleavage of O-O in OOH intermediates. This proposed strategy of dipole-dipole effects is universally applicable over 1D carbon nanotubes and 2D graphene, providing a practical route to design 2e-ORR catalysts.

Optical switching has important applications in optical information processing, optical computing, and optical communications. The long-term pursuit of optical switch is to achieve short switching time and large modulation depth. Among various mechanisms, all-optical switching based on Kerr effect represents a promising solution. However, it is usually difficult to compromise both switching time and modulation depth of a Kerr-type optical switch. To circumvent this constraint, symmetry selective polarization switching via second-harmonic generation (SHG) in nonlinear crystals has been attracting scientists' attention. Here, we demonstrate SHG-based all-optical ultrafast polarization switching by using geometric phase controlled nonlinear plasmonic metasurfaces. A switching time of hundreds of femtoseconds and a modulation depth of 97% were experimentally demonstrated. The function of dual-channel all-optical switching was also demonstrated on a metasurface, which consists of spatially variant meta-atoms. The nonlinear metasurface proposed here represents an important platform for developing all-optical ultrafast switches and would benefit the area of optical information processing.

Quasicrystal metasurfaces, a kind of two-dimensional artificial optical materials with subwavelength meta-atoms arranged in quasi-periodic tiling schemes, have attracted extensive attentions due to their novel optical properties. In a recent work, a dual-functional quasicrystal metasurface, which can be used to simultaneously generate the diffraction pattern and holographic image, is experimentally demonstrated. The proposed method expands the manipulation dimensions for multi-functional quasicrystal metasurfaces and may have important applications in microscopy, optical information processing, optical encryption, etc.

Pyroptosis is a new type of programmed cell death involved in all stages of tumorigenesis. Herein, a comprehensive study was conducted to evaluate the prognostic significance of pyroptosis-related lncRNAs in bladder cancer. Consensus clustering analysis was performed to identify the subclusters of bladder cancer. The prognostic pyroptosis-related lncRNA signature was constructed using LASSO Cox regression analysis. Consensus clustering identified 2 clusters of bladder cancer. Interestingly, significant differences in the ESTIMAE score, immune cell infiltration and immune checkpoint expression were obtained between the 2 clusters. A signature consisting of 11 pyroptosis-related lncRNAs was established and it had a good performance in predicting the overall survival rate of bladder cancer, with an AUC of 0.713. Moreover, pyroptosis-related lncRNA signature acted as a risk factor in bladder cancer. Bladder cancer patients with high-risk score had a higher tumor grade and higher clinical stage. A significant correlation was obtained between the risk score and immune cell infiltration. The expression of most checkpoints was higher in bladder cancer patients with high-risk score. A novel pyroptosis-related lncRNA signature was identified with prognostic value for bladder cancer patients. Pyroptosis-related lncRNAs have a potential role in cancer immunology and may serve as prognostic or therapeutic targets in bladder cancer.

In order to overcome the selfishness of users and encourage more vehicles to participate in this process, this paper combined the computing and caching capabilities of mobile edge cloud, proposed a new service caching and delivery incentive mechanism, the main research content is as follows: Aiming at the service caching process, this paper designs a reputation incentive mechanism based on SD-VEC framework. Before the user applies for the vehicle service, we need to add the credit evaluation, so as to obtain different quality of service quality. Then, the interaction between the on- board edge cloud server and the vehicle in the process of service caching is modeled as a one-to-many two-stage Stackelberg game. Based on the utility functions of both sides, the existence and uniqueness of Stackelberg equilibrium is proved by backward induction. In addition, a genetic intelligence optimization algorithm is designed to help solve the utility optimization problem.

Renal clear cell carcinoma (KIRC) is a malignancy of the renal epithelial cells with poor prognosis. Notably, the JAK-STAT pathway mediates cell proliferation and immune response. Accumulating evidence suggests that STATs act as immune checkpoint inhibitors in various cancers. Nonetheless, the role of STAT2 in KIRC remains elusive. Herein, analyses were performed using a series of interactive web databases including Oncomine, GEPIA and TIMER. In sub-group analyses, STAT2 was upregulated at both the mRNA and protein levels in KIRC patients. Besides, KIRC patients with high STAT2 expression exhibited a poor overall survival. Moreover, Cox regression analysis revealed that STAT2 expression, nodal metastasis and clinical stage were independent factors affecting the prognosis of KIRC patients. There was a significant positive correlation between STAT2 expression, and the abundance of immune cells as well as the expression of immune biomarker sets. In addition, STAT2 was found to be implicated in immune response, cytokine-cytokine receptor interaction, and Toll-like receptor signaling pathways. Also, several cancer-related kinases, miRNAs, and transcription factors associated with STAT2 were identified. Conclusively, we revealed that STAT2 is a potential prognosis biomarker and associated with immune infiltration in kidney renal clear cell carcinoma. This study offers additional data that will help in further research on the roles of STAT2 protein in carcinogenesis.

The development of Internet and information technology has ushered in a new era of Cloud Computing Technology (CCT). Nowadays CCT has been long developed to make it easy for users to acquire data and software information services as they desire from Data Centers. Currently, data security is all the people focus on. This paper bases on the typical Cloud Computing (CC) security model to modelling the CC multidimensional data and integrates the MIA in biology to propose a MIN-based cloud computing security evaluation approach. Beyond that, DSSim, as a cloud computing data security simulation system, is designed to validate the availability of this approach.

The refractive index of a material determines the fundamental properties of light propagating in it. Developing novel materials with various refractive indices is an important research topic in optics. Among many new optical materials, the zero refractive index materials have attracted much attention due to their unique electromagnetic properties. Zero refractive index requires that both the permittivity and the permeability are zero. The effective zero refractive index is usually achieved based on the metal-dielectric composite structures or photonic crystals. However, the zero refractive index of the artificial materials is a macroscopic effect, and the refractive index is not zero at the microscopic scale. At the same time, researchers are also interested in the near-zero refractive index materials, which have similar electromagnetic properties to that of the zero-index materials. In this kind of material, the real parts of the permittivity of some materials are zero at specific wavelengths and are referred to as Epsilon-near-zero (ENZ) materials. The permeability is usually close to 1. When light propagates in an ENZ material, the phase velocity exceeds the speed of light in a vacuum. Therefore, the propagation phase is small, which can be used for electric field tunneling, electric field shielding, and perfect wave bending in waveguides. ENZ materials can be used to localize the electric field of lincident light, enabling the enhancement of nonlinear optical responses and light-matter interactions. Transparent Conductive Oxides (TCO) , such as the indium tin oxide, aluminum-doped indium oxide, and indium-doped cadmium oxide, have near-zero permittivities in the near-infrared spectral region and have excellent electro-optic tunability, , and have received extensive attentions in recent years. TCO have great application potentials in the fields of electro-optical modulation, nonlinear optical frequency conversion, and all-optical modulation, thus representing an important material platform for developing novel nonlinear optical devices. In this paper, the physical principles and applications of light-matter interactions in the ENZ materials are reviewed from the view points of both linear and nonlinear light-matter interactions. In the part of linear light-matter interaction, this paper discuss the following contents: ENZ materials and their optical properties; optoelectronic properties and dielectric constants of the TCO; preparation methods of the TCO; ENZ mode in ultra-thin film and its optical properties; electro-optic modulation scheme and carrier modulation mechanism of TCO. In the part of nonlinear light-matter interaction, this paper summarize the progress on the following topics: the enhancement mechanism of nonlinear optical response in ENZ materials; the nonlinear refractive index of the ENZ materials and the physical model, and the recent progress on all-optical modulation; the second harmonic generation in ENZ materials, high harmonic generation, generation of supercontinuum and terahertz waves in the ENZ materials; phase conjunction and negative refraction phenomena with the ENZ materials. Finally, the research trends of the ENZ materials are overlooked, and the future research directions and applications in the fileds of ENZ materials are prospected.

Transparent conductive oxides exhibit attractive optical nonlinearity with ultrafast response and giant refractive index change near the epsilon-near-zero (ENZ) wavelength, originating from the intraband dynamics of conduction electrons. The optical nonlinearity of ENZ materials has been explained by using the overall-effective-mass and the overall-scattering-time of electrons in the extended Drude model. However, their response to optical excitation is yet the last building block to complete the theory. In this paper, the concept of thermal energy is theoretically proposed to account for the total energy of conduction electrons exceeding their thermal equilibrium value. The time-varying thermal energy is adopted to describe the transient optical response of indium-tin-oxide (ITO), a typical ENZ material. A spectrally-resolved femtosecond pump-probe experiment was conducted to verify our theory. By correlating the thermal energy with the pumping density, both the giant change and the transient response of the permittivity of ITO can be predicted. The results in this work provide a new methodology to describe the transient permittivities of ENZ materials, which will benefit the design of ENZ-based nonlinear photonic devices.

Optical characteristics of square-latticed metasurfaces are analyzed by equations derived from a dipole-quadrupole system. For the metasurface composed of Si nanospheres, meta-atoms maintain the anapole characteristics of the single scatterer, which are not affected by the lattice period. The far-field response of the metasurface thus can be engineered without significantly disturbing near-fields in meta-atoms. In addition, as exhibited with Ag/Si core-shell nanospheres, the transmittance of metasurface at anapole can also be modulated and even nulled by shifting the lattice magnetic dipole and quadrupole resonances. In a small-period metasurface, the near-field interaction of adjacent meta-atoms manipulates the lattice resonance behavior, leading to significant modulation in transmittance at anapole.

Optical chirality enhancement is highly demanded for enantioselective interaction of circularly polarized light with chiral molecules. The chirality enhancement in the coaxial air hole of a hollow silicon disk depends on three aspects, namely, the enhancements of electric and magnetic fields and a factor determined by the phases of their field components. In the spectral regime of dipole resonances, maximum chirality enhancement with sign consistency and uniform spatial distribution in the air hole can be obtained in association with both magnetic dipole resonance and anapole. Due to dipolar interference, the chirality is nulled at their coincidence, around which the sign of chirality is reversed. Maximum chirality with both positive and negative signs can be found between magnetic dipole resonance and anapole in the vicinity of their coincidence. This situation is maintained under size scaling so that the operation wavelength can be broadly tuned. The optical chirality can be further improved by merely adjusting the hole radius, by which the optimal spatially averaged optical chirality enhancement factor can reach 39 and −23. The simple strategy for optimizing Mie resonators presented in this work may benefit the design of Mie resonator‐based achiral metasurfaces for chirality detection application.

Strong optical nonlinearities of plasmonic thin films exist at their epsilon-near-zero (ENZ) wavelengths, which are essential to be acquired first for the design and fabrication of ENZ photonic devices. However, it has been challenging to obtain the ENZ wavelength precisely when the film thickness is reduced to tens of nanometers or less. By enhancing both electric field intensity and light-matter interaction distance in the film, we propose that the ENZ wavelength and the medium model of ultrathin films can be extracted accurately from the transmittance and reflectance spectra under oblique light excitation. A characteristic valley in the transmittance spectrum, which originates from the increased light absorption caused by the ENZ electric field enhancement, can be used to determine the ENZ wavelength with significantly improved fitting accuracy of the Drude parameters. The work in this paper provides an accurate and effective method for the acquisition of ENZ wavelength and will contribute to the research of nonlinear plasmonic devices.

Sb2S3 has great potential to become a good phase-change material for visible and near-infrared wavebands due to its low loss and high refractive index contrast, so great interest lies in the technology development. This work investigates the intermediate phase-change states and their cycling durabilities by employing a continuous-wave laser for crystallization and a femtosecond laser for amorphization. By considering stratified partial amorphization due to non-uniform intensity distribution along propagation in a film, a double-layer model is proposed to describe intermediate states, which fits experimental data better than the mixture models in effective medium approximation. The phase-change degree is then defined as the ratio of the amorphization depth to the total film thickness, which can be controlled by combination of the pulse energy and the number of pulses in multi-pulse femtosecond laser irradiation for amorphization. The cycling durability is improved by reducing pulse energy and increasing the number of pulses. The experimentally achieved maximum cycling durabilities are 30, 1000, and 7000 cycles for 90%, 60%, and 20% phase-change degrees. The implementation of intermediate states with improved cycling durability may promote the development of Sb2S3-based reconfigurable photonic devices.

Goodness of fit is demonstrated for theoretical calculation of z-scan data based on beams propagating in the nonlinear medium and the Fresnel–Kirchhoff diffraction integral in experiments with high nonlinear refraction and absorption. The constancy of nonlinear optical parameters is achieved regardless of sample thickness and laser intensity, which clarifies the physical significance of optical parameters. We have obtained γ = 2.0 × 10-19 m2/W and β = 5.0 × 10-13 m/W for carbon disulfide excited by a pulsed laser at 800 nm with pulse duration of 35 fs, which are independent of sample thickness and laser intensity. Affirming constancy of the extracted parameters to the incident light intensity may become a practice to verify the goodness of the z-scan experiment.

In this investigation, we report an Au/Si hot electron infrared detector fabricated on an SOI substrate. The simulation and experimental results show that Fabry–Perot cavity resonance on the SOI substrate and the surface plasmons excited by the Au nanostructures enhance the photo absorption in Au. Spectral response peaks of the hot electron photocurrent occur in the infrared band at a photon energy much smaller than the bandgap energy of Si. A maximum photocurrent was obtained at an annealing time of 90 s of the nanostructured Au film, and the SEM image showed the formation of a connected semi-island structure during the annealing. This hot electron device paves the way for extending infrared detection wavelength of SOI based detectors.