Quality Standard of Fuyang Wenshen Granules

[Objectives]To establish the quality standard of Fuyang Wenshen Granules and carry out the routine examination of granule type.[Methods]The particle size,water content,solubility,loading difference and microbial limit of Fuyang Wenshen Granules were examined,and TLC was used for qualitative identification of Astmgali Radix and Notoginseng Radix Et Rhizoma.[Results]The particle size,water content,solubility,loading difference,and microbial limit of Fuyang Wenshen Granules complied with the relevant provisions of the Pharmacopoeia of the People's Republic of China(2020).The TLC spots of Astmgali Radix and Notoginseng Radix Et Rhizoma were clearly colored,and negative had no interference.[Conclusions]The method was simple,accurate,reliable,specific and reproducible,and can effectively control the quality of Fuyang Wenshen Granules.

High-Speed Parallel Plasmonic Direct-Writing Nanolithography Using Metasurface-Based Plasmonic Lens

Simple and efficient nanofabrication technology with low cost and high flexibility is indispensable for fundamental nanoscale research and prototyping.Lithography in the near field using the surface plasmon polariton(i.e.,plasmonic lithography)provides a promising solution.The system with high stiffness passive nanogap control strategy on a high-speed rotating substrate is one of the most attractive highthroughput methods.However,a smaller and steadier plasmonic nanogap,new scheme of plasmonic lens,and parallel processing should be explored to achieve a new generation high resolution and reliable efficient nanofabrication.Herein,a parallel plasmonic direct-writing nanolithography system is established in which a novel plasmonic flying head is systematically designed to achieve around 15 nm minimum flying-height with high parallelism at the rotating speed of 8–18 m·s^(-1).A multi-stage metasurface-based polarization insensitive plasmonic lens is proposed to couple more power and realize a more confined spot compared with conventional plasmonic lenses.Parallel lithography of the nanostructures with the smallest(around 26 nm)linewidth is obtained with the prototyping system.The proposed system holds great potential for high-freedom nanofabrication with low cost,such as planar optical elements and nano-electromechanical systems.

Investigation of electrostatically tunable adhesion and instability of flying head slider

The interfacial adhesion between microstructures is inevitable in a micro-electro-mechanical system(e.g.,hard disk drive(HDD)),which may lead to complicated microtribodynamics problems.This research has investigated the effect of surface potential on the interfacial adhesion and microtribodynamics of the head–disk interface(HDI)in an HDD.A dynamic continuum surface force model,where the electrowetting is considered,is proposed to evaluate the interfacial interaction,and then employed into a two-degree-of-freedom(2DOF)model to theoretically analyze the potential influence mechanism on the microtribodynamics.The results confirm that the elimination of potential can effectively repress the adhesion retention,which is further proved by the measured slider response with a laser Doppler vibrometer(LDV).Moreover,the effect of the potential on the adhesion-induced instability is also analyzed through the phase portrait.It tells that the critical stable flying height can be lowered with the elimination of potential.

Angular momentum holography via a minimalist metasurface for optical nested encryption

Metasurfaces can perform high-performance multi-functional integration by manipulating the abundant physical dimensions of light,demonstrating great potential in high-capacity information technologies.The orbital angular momentum(OAM)and spin angular momentum(SAM)dimensions have been respectively explored as the independent carrier for information multiplexing.However,fully managing these two intrinsic properties in information multiplexing remains elusive.Here,we propose the concept of angular momentum(AM)holography which can fully synergize these two fundamental dimensions to act as the information carrier,via a single-layer,non-interleaved metasurface.The underlying mechanism relies on independently controlling the two spin eigenstates and arbitrary overlaying them in each operation channel,thereby spatially modulating the resulting waveform at will.As a proof of concept,we demonstrate an AM meta-hologram allowing the reconstruction of two sets of holographic images,i.e.,the spin-orbital locked and the spin-superimposed ones.Remarkably,leveraging the designed dual-functional AM meta-hologram,we demonstrate a novel optical nested encryption scheme,which is able to achieve parallel information transmission with ultra-high capacity and security.Our work opens a new avenue for optionally manipulating the AM,holding promising applications in the fields of optical communication,information security and quantum science.

Foveated glasses-free 3D display with ultrawide field of view via a large-scale 2D-metagrating complex

Glasses-free three-dimensional(3D)displays are one of the game-changing technologies that will redefine the display industry in portable electronic devices.However,because of the limited resolution in state-of-the-art display panels,current 3D displays suffer from a critical trade-off among the spatial resolution,angular resolution,and viewing angle.Inspired by the so-called spatially variant resolution imaging found in vertebrate eyes,we propose 3D display with spatially variant information density.Stereoscopic experiences with smooth motion parallax are maintained at the central view,while the viewing angle is enlarged at the periphery view.It is enabled by a large-scale 2D-metagrating complex to manipulate dot/linear/rectangular hybrid shaped views.Furthermore,a video rate full-color 3D display with an unprecedented 160°horizontal viewing angle is demonstrated.With thin and light form factors,the proposed 3D system can be integrated with off-the-shelf purchased flat panels,making it promising for applications in portable electronics.

3D-Integrated metasurfaces for full-colour holography

Metasurfaces enable the design of optical elements by engineering the wavefront of light at the subwavelength scale.Due to their ultrathin and compact characteristics,metasurfaces possess great potential to integrate multiple functions in optoelectronic systems for optical device miniaturisation.However,current research based on multiplexing in the 2D plane has not fully utilised the capabilities of metasurfaces for multi-tasking applications.Here,we demonstrate a 3D-integrated metasurface device by stacking a hologram metasurface on a monolithic Fabry–Pérot cavity-based colour filter microarray to simultaneously achieve low-crosstalk,polarisation-independent,high-efficiency,full-colour holography,and microprint.The dual functions of the device outline a novel scheme for data recording,security encryption,colour displays,and information processing.Our 3D integration concept can be extended to achieve multi-tasking flat optical systems by including a variety of functional metasurface layers,such as polarizers,metalenses,and others.

Metasurface-enabled on-chip multiplexed diffractive neural networks in the visible

Replacing electrons with photons is a compelling route toward high-speed,massively parallel,and low-power artificial intelligence computing.Recently,diffractive networks composed of phase surfaces were trained to perform machine learning tasks through linear optical transformations.However,the existing architectures often comprise bulky components and,most critically,they cannot mimic the human brain for multitasking.Here,we demonstrate a multi-skilled diffractive neural network based on a metasurface device,which can perform on-chip multi-channel sensing and multitasking in the visible.The polarization multiplexing scheme of the subwavelength nanostructures is applied to construct a multi-channel classifier framework for simultaneous recognition of digital and fashionable items.The areal density of the artificial neurons can reach up to 6.25×10^(6)mm^(-2) multiplied by the number of channels.The metasurface is integrated with the mature complementary metal-oxide semiconductor imaging sensor,providing a chip-scale architecture to process information directly at physical layers for energy-efficient and ultra-fast image processing in machine vision,autonomous driving,and precision medicine.

Dielectric metalens for miniaturized imaging systems:progress and challenges

Lightweight, miniaturized optical imaging systems are vastly anticipated in these fields of aerospace exploration, industrial vision, consumer electronics, and medical imaging. However, conventional optical techniques are intricate to downscale as refractive lenses mostly rely on phase accumulation. Metalens, composed of subwavelength nanostructures that locally control light waves, offers a disruptive path for small-scale imaging systems. Recent advances in the design and nanofabrication of dielectric metalenses have led to some high-performance practical optical systems. This review outlines the exciting developments in the aforementioned area whilst highlighting the challenges of using dielectric metalenses to replace conventional optics in miniature optical systems. After a brief introduction to the fundamental physics of dielectric metalenses, the progress and challenges in terms of the typical performances are introduced. The supplementary discussion on the common challenges hindering further development is also presented, including the limitations of the conventional design methods, difficulties in scaling up, and device integration. Furthermore, the potential approaches to address the existing challenges are also deliberated.

Accurate inverse design of Fabry–Perot-cavity-based color filters far beyond sRGB via a bidirectional artificial neural network

Structural color based on Fabry–Perot(F-P) cavity enables a wide color gamut with high resolution at submicroscopic scale by varying its geometrical parameters. The ability to design such parameters that can accurately display the desired color is therefore crucial to the manufacturing of F-P cavities for practical applications.This work reports the first inverse design of F-P cavity structure using deep learning through a bidirectional artificial neural network. It enables the production of a significantly wider coverage of color space that is over 215% of sRGB with extremely high accuracy, represented by an average ΔE_(2000) value below 1.2. The superior performance of this structural color-based neural network is directly ascribed to the definition of loss function in the uniform CIE 1976-Lab color space. Over 100,000 times improvement in the design efficiency has been demonstrated by comparing the neural network to the metaheuristic optimization technique using an evolutionary algorithm when designing the famous painting of "Haystacks, end of Summer" by Claude Monet. Our results demonstrate that, with the correct selection of loss function, deep learning can be very powerful to achieve extremely accurate design of nanostructured color filters with very high efficiency.

Numerical modeling and analysis of plasmonic flying head for rotary near-field lithography technology

Rotary near-field lithography(RNFL) technology provides a route to overcome the diffraction limit with a high throughput and low cost for nanomanufacturing. Utilizing the advantage of the passive flying of a plasmonic head, RNFL can achieve a 10 m/s processing speed with a perfect near-field condition at dozens of nanometers. The flying performance of the plasmonic flying head(PFH) is the pivotal issue in the system. The linewidth has a strong correlation with the near-field gap, and the manufacturing uniformity is directly influenced by the dynamic performance. A more serious issue is that the unexpected contact between the PFH and substrate will result in system failure. Therefore, it is important to model and analyze the flying process of the PFH at the system level. In this study, a novel full-coupled suspension-PFH-air-substrate(SPAS) model that integrates a six-degree of freedom suspension-PFH dynamics, PFH-air-substrate air bearing lubrication, and substrate vibration, is established. The pressure distribution of the air bearing is governed by the molecular gas lubrication equation that is solved by the finite element method(FEM) with a local pressure gradient based adaptive mesh refinement algorithm using the COMSOL Multiphysics software. Based on this model, three designs of the air bearing surface are chosen to study the static, dynamic, and load/unload performance to verify whether it satisfies the design requirements of RNFL. Finally, a PFH analysis solver SKLY.app is developed based on the proposed model.