Femtosecond laser writing of lithium niobate ferroelectric nanodomains.

Lithium niobate (LiNbO3) is viewed as a promising material for optical communications and quantum photonic chips1,2. Recent breakthroughs in LiNbO3 nanophotonics have considerably boosted the development of high-speed electro-optic modulators3-5, frequency combs6,7 and broadband spectrometers8. However, the traditional method of electrical poling for ferroelectric domain engineering in optic9-13, acoustic14-17 and electronic applications18,19 is limited to two-dimensional space and micrometre-scale resolution. Here we demonstrate a non-reciprocal near-infrared laser-writing technique for reconfigurable three-dimensional ferroelectric domain engineering in LiNbO3 with nanoscale resolution. The proposed method is based on a laser-induced electric field that can either write or erase domain structures in the crystal, depending on the laser-writing direction. This approach offers a pathway for controllable nanoscale domain engineering in LiNbO3 and other transparent ferroelectric crystals, which has potential applications in high-efficiency frequency mixing20,21, high-frequency acoustic resonators14-17 and high-capacity non-volatile ferroelectric memory19,22.

Achromatic CMOS-Integrated Four-Bit Orbital Angular Momentum Mode Detector at Three Wavelengths.

The simultaneous detection of the orbital angular momentum (OAM) and wavelength offers new opportunities for optical multiplexing. However, because of the dispersion of lens functions for Fourier transformation, the mode conversions at distinct wavelengths cannot be achieved in the same plane. Here we propose an ultracompact achromatic complementary metal oxide semiconductor (CMOS)-integrated OAM mode detector. Specifically, a spatial multiplexed scheme, randomly interleaving the phase distributions for distributing the superposed OAM modes into preset positions at distinct wavelengths, is presented. In addition, such a nanoprinted achromatic OAM detector featuring a microscale size and a short focal length can be integrated onto a CMOS chip. Consequently, the four-bit incident light beams at three discrete wavelengths (633, 532, and 488 nm) can be distinguished with a high degree of accuracy evaluated by the average standardized Euclidean distance of ∼0.75 between the analytical and target results. Our results showcase a miniaturized platform for achieving high-capacity information processing.

Hotspots and trends in health-oriented physical literacy research: a visual analysis based on the WOS database.

BACKGROUND: The World Health Organization has proposed that physical activity is a meaningful way to improve the quality of human life and reduce the probability of chronic non-communicable diseases and that humans should change their mindset from the actual effectiveness of physical activity in promoting health to the new view that "physical activity makes life more meaningful." The introduction and development of physical literacy reveal the critical role of physical activity in improving human health and the importance of human initiative in physical activity for healthy development. Therefore, the objectives of this paper are (1) to conduct a bibliometric analysis of the literature on physical literacy, assessing the scope, frequency, and geographical distribution of research publications from various countries and institutions from 2015 to 2023; (2) to visualize keywords in articles on the topic of Physical literacy to analyze whether there is a link between physical literacy and health, and (3) based on the results of the visual analysis, we propose that proper health is built on the sense of physical literacy and further construct the circular path of physical literacy, physical activity, and physical health improvement. METHODS: Using VOSviewer software v.1.6.18, this study searched the core collection of the Web of Science database from 2015 to April 15, 2023, using "physical literacy" as a keyword to explore the current international research on physical literacy. RESULTS: A total of 3,446 articles were included, and a correlation map was derived based on the co-occurrence frequency of keywords, which showed that physical literacy was highly correlated with six concepts: health literacy, physical activity, health, children, adolescents, and prevention. CONCLUSION: Based on the analysis of literature visualization techniques, there is a high correlation between physical literacy and health, and international physical literacy research is in a trend of multi-point amplification, with research hotspots gradually shifting from the field of sports to the field of health and closely related to the field of health, indicating that physical literacy aims to promote the achievement of individual health by driving humans to increase physical activity.

Nanoprinted Diffractive Layer Integrated Vertical-Cavity Surface-Emitting Vortex Lasers with Scalable Topological Charge.

Vertical-cavity surface-emitting lasers (VCSELs) represent an attractive light source to integrate with OAM structures to realize chip-scale vortex lasers. Although pioneering endeavors of VCSEL-based vortex lasers have been reported, they cannot achieve large topological charges (less than l = 5) due to the insufficient space-bandwidth product (SBP) caused by the inherent limited device size. Here, by integrating a nanoprinted OAM phase structure on the VCSELs, we demonstrate a vortex microlaser with a low threshold and simple structure. A monolithic microlaser array with addressable control of vortex beams with different topological charges (l = 1 to l = 5) was achieved. Nanoprinting offers high degrees of freedom for the manipulation of spatial structures. To address the challenge of insufficient SBP, two-layer cascaded spiral phase plates were designed. Thereby, a vortex beam with l = 15 and mode purity of 83.7% was obtained. Our work paves the way for future chip-scale OAM-based information multiplexing with more channels.

Orbital angular momentum holographic multicasting for switchable and secure wireless optical communication links.

The physical dimension of orbital angular momentum (OAM) states of light has been successfully implemented as information carrier in wireless optical communication (WOC) links. However, the current OAM data coding strategies in WOC are mainly limited to the temporal domain, rarely involving the degree of freedom of spatial domain to transmit an image directly. Here, we apply OAM holographic multiplexing technology for spatial information encoding in WOC links. Further, we demonstrate the new concept of OAM holographic multicasting, wherein a beam-steering grating has been utilized for information decoding. To distribute the OAM multiplexing information appropriately in the receiving terminal, the beam-steering grating with controllable topological charges and amplitude weighting coefficients of each diffraction order in the spatial frequency domain has been designed. An iterative algorithm has been introduced to obtain the intensity uniformity >98% at target diffraction orders. As such, this scheme experimentally allows four separate users to receive independent images, which can be switched by modulating the topological charges of the beam-steering gratings at each diffraction order. In addition, this leads to a beam-steering grating-encrypted WOC links, wherein the information can only be decoded by the grating phase with 7 pre-set spatial frequency components. Our results mark a new parallel decoding paradigm of OAM multiplexing holography, which opens up the door for future high-capacity and high-security all-optical holographic communications.

768-ary Laguerre-Gaussian-mode shift keying free-space optical communication based on convolutional neural networks.

Beyond orbital angular momentum of Laguerre-Gaussian (LG) modes, the radial index can also be exploited as information channel in free-space optical (FSO) communication to extend the communication capacity, resulting in the LG- shift keying (LG-SK) FSO communications. However, the recognition of radial index is critical and tough when the superposed high-order LG modes are disturbed by the atmospheric turbulences (ATs). In this paper, the convolutional neural network (CNN) is utilized to recognize both the azimuthal and radial index of superposed LG modes. We experimentally demonstrate the application of CNN model in a 10-meter 768-ary LG-SK FSO communication system at the AT of Cn2 = 1e-14 m-2/3. Based on the high recognition accuracy of the CNN model (>95%) in the scheme, a colorful image can be transmitted and the peak signal-to-noise ratio of the received image can exceed 35 dB. We anticipate that our results can stimulate further researches on the utilization of the potential applications of LG modes with non-zero radial index based on the artificial-intelligence-enhanced optoelectronic systems.

Multiple generations of high-order orbital angular momentum modes through cascaded third-harmonic generation in a 2D nonlinear photonic crystal.

We experimentally demonstrate multiple generations of high-order orbital angular momentum (OAM) modes through third-harmonic generation in a 2D nonlinear photonic crystal. Such third-harmonic generation process is achieved by cascading second-harmonic generation and sum-frequency generation using the non-collinear quasi-phase-matching technique. This technique allows multiple OAM modes with different colors to be simultaneously generated. Moreover, the OAM conservation law guarantees that the topological charge is tripled in the cascaded third-harmonic generation process. Our method is effective for obtaining multiple high-order OAM modes for optical imaging, manipulation, and communications.

Tunable third harmonic generation of vortex beams in an optical superlattice.

We report generation of tunable vortex beams in the blue spectral range, with a 3.3 nm spectral tuning range, by frequency tripling of the near-infrared (IR) wave at around 1.34 um in a LiTaO3 optical superlattice. The nonlinear crystal used in this work has a chirped dual-periodical structure which can provide two expanded reciprocal vectors for tunable performance of the cascaded third harmonic generation (THG). The maximum THG efficiency reaches about 1.4%.

Examining second-harmonic generation of high-order Laguerre-Gaussian modes through a single cylindrical lens.

We experimentally investigate the second-harmonic generation of a high-order Laguerre-Gaussian (LG) mode under the quasi-phase-matching (QPM) configuration. First, we introduce a simple method to observe the azimuthal (l) and radial (p) indices of the high-order LG modes. Based on the astigmatic transformation technique, l and p are revealed in the number of dark stripes of the converted pattern in the focal plane. Then, using this efficient method of measurement, we demonstrate in experiments a second-harmonic LG mode with its radial and azimuthal indices being twice those of the inputted fundamental wave through QPM in a periodically poled KTP crystal. Our results provide a feasible way to obtain simultaneously the LG modes with larger radial and azimuthal indices.

On-chip generation of broadband high-order Laguerre-Gaussian modes in a metasurface.

With experimental results, we demonstrate the generation of high-order Laguerre-Gaussian modes with non-zero radial indices using a metal meta-surface, which is composed of a series of rectangle nanoholes with different orientation angles. The phase shift after transmission through the metasurface is determined by the orientation angle of the nanohole. This device works over a broad wavelength band ranging from 700 to 1000 nm. Moreover, we achieve a LG mode with a radial mode index of 10. Our results provide an integrated method to obtain high-order LG modes, which can be used to enhance the capacity in optical communication and manipulation.

Coupled orbital angular momentum conversions in a quasi-periodically poled LiTaO3 crystal.

We experimentally demonstrate the orbital angular momentum (OAM) conversion by the coupled nonlinear optical processes in a quasi-periodically poled LiTaO3 crystal. In such a crystal, third-harmonic generation (THG) is realized by the coupled second-harmonic generation (SHG) and sum-frequency generation (SFG) processes, i.e., SHG is dependent on SFG and vice versa. The OAMs of the interacting waves are proved to be conserved in such coupled nonlinear optical processes. As we increase the input OAM in the experiment, the conversion efficiency decreases because of the reduced fundamental power density. Our results provide better understanding for the OAM conversions, which can be used to efficiently produce an optical OAM state at a short wavelength.

Orbital angular momentum-mediated machine learning for high-accuracy mode-feature encoding.

Machine learning with optical neural networks has featured unique advantages of the information processing including high speed, ultrawide bandwidths and low energy consumption because the optical dimensions (time, space, wavelength, and polarization) could be utilized to increase the degree of freedom. However, due to the lack of the capability to extract the information features in the orbital angular momentum (OAM) domain, the theoretically unlimited OAM states have never been exploited to represent the signal of the input/output nodes in the neural network model. Here, we demonstrate OAM-mediated machine learning with an all-optical convolutional neural network (CNN) based on Laguerre-Gaussian (LG) beam modes with diverse diffraction losses. The proposed CNN architecture is composed of a trainable OAM mode-dispersion impulse as a convolutional kernel for feature extraction, and deep-learning diffractive layers as a classifier. The resultant OAM mode-dispersion selectivity can be applied in information mode-feature encoding, leading to an accuracy as high as 97.2% for MNIST database through detecting the energy weighting coefficients of the encoded OAM modes, as well as a resistance to eavesdropping in point-to-point free-space transmission. Moreover, through extending the target encoded modes into multiplexed OAM states, we realize all-optical dimension reduction for anomaly detection with an accuracy of 85%. Our work provides a deep insight to the mechanism of machine learning with spatial modes basis, which can be further utilized to improve the performances of various machine-vision tasks by constructing the unsupervised learning-based auto-encoder.

Pathogenicity virulence of Beauveria spp. and biosafety of the BbMQ strain on adult ectoparasitic beetles, Dastarcus helophoroides Fairmaire (Coleoptera: Colydiidae).

Introduction: Beauveria spp. and Dastarcus helophoroides Fairmaire adults were simultaneously released to attack elder larvae or pupae of Monochamus alternatus in pine forests in China. However, little is known about the pathogenicity virulence and biosafety of Beauveria spp. on beneficial adults of D. helophoroides, and specific Beauveria bassiana (Bb) strains should be selected for synthetic release together with D. helophoroides. Methods: A total of 17 strains of Beauveria spp. were collected, isolated, and purified, and then their mortality, cadaver rate, LT50, spore production, spore germination rate, and growth rate of D. helophoroide adults were calculated based on 0-20 days data after spore suspension and powder contact. Results and discussion: The lethality rate of BbMQ, BbFD, and BbMH-03 strains to D. helophoroides exceeded 50%, and the cadaver rate reached 70.6%, among which the mortality rate (82.22%), cadaver rate (47.78%), spore production (1.32 × 109 spores/ml), spore germination rate (94.71%), colony dimension (49.15 mm2), and LT50 (10.62 d) of the BbMQ strain were significantly higher than those of other strains (P < 0.01), and the mortality of D. helophoroides adults increased significantly with increased spore suspension concentration, with the highest mortality reaching 92.22%. This strain was identified as Beauveria bassiana by morphological and molecular methods, while the BbWYS strain had a minimum lethality of only 5.56%, which was safer compared to other strains of adult D. helophoroide. Consequently, the biological characteristics and pathogenicity of different Beauveria bassiana strains varied significantly in their effects on D. helophoroide adults, and the safety of different strains should be assessed when they are released or sprayed to control multiple pests in the forest. The BbMQ strain should not be simultaneously sprayed with releasing D. helophoroide adults in the same forest, while the BbWYS strain can be used in concert with D. helophoroide to synergize their effect.

The complete mitochondrial genome of Choristoneura metasequoiacola Liu,1983 (Lepidoptera: Tortricidae).

Choristoneura metasequoiacola Liu, 1983 is an important caterpillar species that specifically infests the leaves and branches of Metasequoia glyptostroboides Hu & W. C. Cheng 1948 with short larval infestations, long-term dormancy, and has a limited distribution in Lichuan, Hubei, China. The complete mitochondria genome of C. metasequoiacola was determined by using Illumina NovaSeq, and analyzed based on previously annotated sibling species. In total, we obtained mitochondria genome with 15,128 bp in length, circular in shape with a double-stranded closed ring structure, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and an AT-rich region. Of which the nucleotide composition was highly A + T biased, accounting for 81.98% of the whole mitogenome. Thirteen protein-coding genes (PCGs) were 11,142 bp; Twenty-two tRNA genes and AT-rich region were 1,472 and 199 bp, respectively. Phylogenetically, the relationship between Choristoneura spp. (containing C. metasequoiacola) and Adoxophyes spp. was closer than any other two genera from Tortricidae, and the relationship between C. metasequoiacola and C.murinana was the closest among nine sibling species from that genus, which helps to explain species evolution within the family Tortricidae.

Three-dimensional direct lithography of stable perovskite nanocrystals in glass.

Material composition engineering and device fabrication of perovskite nanocrystals (PNCs) in solution can introduce organic contamination and entail several synthetic, processing, and stabilization steps. We report three-dimensional (3D) direct lithography of PNCs with tunable composition and bandgap in glass. The halide ion distribution was controlled at the nanoscale with ultrafast laser-induced liquid nanophase separation. The PNCs exhibit notable stability against ultraviolet irradiation, organic solution, and high temperatures (up to 250°C). Printed 3D structures in glass were used for optical storage, micro-light emitting diodes, and holographic displays. The proposed mechanisms of both PNC formation and composition tunability were verified.

Complex-amplitude metasurface-based orbital angular momentum holography in momentum space.

Digital optical holograms can achieve nanometre-scale resolution as a result of recent advances in metasurface technologies. This has raised hopes for applications in data encryption, data storage, information processing and displays. However, the hologram bandwidth has remained too low for any practical use. To overcome this limitation, information can be stored in the orbital angular momentum of light, as this degree of freedom has an unbounded set of orthogonal helical modes that could function as information channels. Thus far, orbital angular momentum holography has been achieved using phase-only metasurfaces, which, however, are marred by channel crosstalk. As a result, multiplex information from only four channels has been demonstrated. Here, we demonstrate an orbital angular momentum holography technology that is capable of multiplexing up to 200 independent orbital angular momentum channels. This has been achieved by designing a complex-amplitude metasurface in momentum space capable of complete and independent amplitude and phase manipulation. Information was then extracted by Fourier transform using different orbital angular momentum modes of light, allowing lensless reconstruction and holographic videos to be displayed. Our metasurface can be three-dimensionally printed in a polymer matrix on SiO2 for large-area fabrication.

Interpreting the Pharmacological Mechanisms of Huachansu Capsules on Hepatocellular Carcinoma Through Combining Network Pharmacology and Experimental Evaluation.

Hepatocellular carcinoma (HCC) is one of the most fatal cancers across the world. Chinese medicine has been used as adjunctive or complementary therapy for the management of HCC. Huachansu belongs to a class of toxic steroids isolated from toad venom that has important anti-cancer property. This study was aimed to identify the bioactive constituents and molecular targets of Huachansu capsules (HCSCs) for treating HCC using network pharmacology analysis and experimental assays. The major bioactive components of HCSCs were determined using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A series of network pharmacology methods including target prediction, pathway identification, and network establishment were applied to identify the modes of action of HCSCs against HCC. Furthermore, a series of experiments, including MTT, clonogenic assay, 3-D transwell, wound healing assay, as well as flow cytometry, were conducted to verify the inhibitory ability of HCSCs on HCC in vitro. The results showed that 11 chemical components were identified from HCSCs. The network pharmacological analysis showed that there were 82 related anti-HCC targets and 14 potential pathways for these 11 components. Moreover, experimental assays confirmed the inhibitory effects of HCSCs against HCC in vitro. Taken together, our study revealed the synergistic effects of HCSCs on a systematic level, and suggested that HCSCs exhibited anti-HCC effects in a multi-component, multi-target, and multi-pathway manner.

Metasurface orbital angular momentum holography.

Allowing subwavelength-scale-digitization of optical wavefronts to achieve complete control of light at interfaces, metasurfaces are particularly suited for the realization of planar phase-holograms that promise new applications in high-capacity information technologies. Similarly, the use of orbital angular momentum of light as a new degree of freedom for information processing can further improve the bandwidth of optical communications. However, due to the lack of orbital angular momentum selectivity in the design of conventional holograms, their utilization as an information carrier for holography has never been implemented. Here we demonstrate metasurface orbital angular momentum holography by utilizing strong orbital angular momentum selectivity offered by meta-holograms consisting of GaN nanopillars with discrete spatial frequency distributions. The reported orbital angular momentum-multiplexing allows lensless reconstruction of a range of distinctive orbital angular momentum-dependent holographic images. The results pave the way to the realization of ultrahigh-capacity holographic devices harnessing the previously inaccessible orbital angular momentum multiplexing.