基于超光栅的3D打印全介质太赫兹超透镜

超透镜是基于超表面和超光栅的器件,可实现对入射光振幅、相位、偏振等的灵活调控,具有轻薄、易集成的特点。但超透镜的制作周期时间长、成本高,寻找一种易加工、低成本、高效的方法制造超透镜是非常有必要的。本文设计了一种高效波前控制电磁波的太赫兹(Terahertz, THz)全介质超光栅,当电磁波垂直入射时,超光栅将电磁波束弯曲至T_-1衍射级。通过仿真模拟可知,当P偏振光入射时,可将83.44%的透射能量集中在T_-1衍射级,S偏振光入射时可达到82.73%。基于设计的超光栅,当0.14 THz电磁波入射时,设计了数值孔径为0.39的超透镜,利用3D打印技术加工工艺制备,并搭建扫描测量系统验证该设计。测量结果表明,超透镜焦距为114.5 mm,与仿真设计相一致,同时测得了光斑的大小,最后搭建的THz透射成像系统表征了超透镜的成像能力。这项工作在光学传感、通信和超分辨率成像中具有潜在的应用价值。     

基于太赫兹技术的熔融沉积3D打印误差分析

熔融沉积(FDM)技术是目前市售3D打印机应用最广泛的材料成型技术,基于这一技术的3D打印机精确度评价与打印试件的误差分析还没有十分完善的标准化方法。FDM 3D打印常用的聚合物材料在太赫兹波段存在明显吸收。基于太赫兹时域光谱(THz-TDS),通过缝隙注水的方式放大试件非实体部分的太赫兹响应,使得太赫兹技术可同时监测3D打印试件实体部分与非实体部分的打印精确度。通过分析试件的太赫兹光谱,能够分辨与原始设计相差0.96%的微米级误差,补充了3D打印误差的分析方法。     

用于太赫兹空间传输的透镜设计及验证

太赫兹激光作为大角度发散的高斯波束不能简化为平面波或球面波.经典电磁理论和ABCD法则传输理论建模显示: 正透镜实现太赫兹激光束的会聚, 会聚后其像距明显小于透镜的焦距;焦距和太赫兹激光光束波前半径相匹配的负透镜可以实现太赫兹激光束的准直.实验证实f′=-188, 的负透镜位于与太赫兹激光光束波前半径相匹配的位置时, 即z=100 mm, 太赫兹激光的发散角从6°提高到0.1°,20 m传输实验中, 负透镜准直探测方案比正透镜准直探测方案更加简单有效.     

基于介质透镜的太赫兹引信天线技术

介绍了太赫兹频段引信天线的优缺点与背景需求。为实现太赫兹频段引信天线工程应用,分析了介质透镜天线在太赫兹频段的工作原理及应用特点,采用H面喇叭嵌装介质透镜天线形成太赫兹频段引信天线,可以有效缩短H面喇叭天线的纵向尺寸。并利用透镜的偏焦技术形成不同波束倾角的引信天线,对不同波束倾角的太赫兹引信天线进行了仿真计算,仿真计算结果验证了该技术方案的可行性。     

3D打印工艺

随着现代科学技术的发展,3D打印技术已经应用到了很多的领域,比在在修复文物,工业制造方面都有着非常出色的表现。本文主要对3D打印工艺进行简单介绍(包括扫描数据,数据处理,3D打印)。     

太赫兹大视场宽带消色差超构透镜北大核心CSCD

基于超构透镜的太赫兹成像系统因紧凑的体积受到广泛关注。现有太赫兹超构透镜仅能实现消色差或大视场成像,需要大视场宽带消色差超构透镜来进一步提升太赫兹系统的成像质量。文中介绍了一种工作在0.3～0.5THz,数值孔径0.707,直径10mm,视场100°的太赫兹大视场消色差硅基超构透镜。该超构透镜采用了二次非球面型相位剖面,减小了轴外像差,实现了大视场;选取了相位和色散满足要求的单元进行布阵,消除了色差。因此,它有望被广泛应用在生物检测、太赫兹成像等领域。     

基于 3D 打印的THz 波导成型技术研究进展

本文首先介绍了太赫兹波导和3D 打印技术的发展现状。3D 打印作为一项新兴的技术,以数字模型文件为基础, 运用粉末状金属或塑料等可粘合材料通过逐层打印的方法构造实体,打破了传统THz 波导技术的局限性。本文介绍的3D 打印THz 波导利用聚合树脂作为打印材料,打印完成的THz 波导在其传输通路上镀500nm 的金,金的厚度足以支持THz 传播。利用这种方法可以打印出直波导、三维弯曲面、三维Y 劈和U 型波导等多种结构。3D 打印THz 波导除传输损耗 略高外,其传输模式及其特性与传统的金属波导基本一致,这种额外的传输损耗归咎于商业3D 打印机的精度。     

太赫兹大孔径折射透镜的焦移特性研究（英文）

研究了利用大孔径折射透镜对太赫兹波进行聚焦时产生的焦移效应。焦移效应所引起的焦点位置偏差会对太赫兹系统的成像或测量质量产生不利影响。通过理论计算和有限元分析仿真,研究并讨论了与透镜孔径、焦距和工作频率有关的焦移参考值。当使用商用透镜时,实际焦点位置需要通过焦移效应来确定,以保证太赫兹系统的工作效率。对于定制透镜的设计,焦移需要根据工作频率,在焦距的设计中进行补偿。这两个途径可以保障太赫兹系统的良好性能。     

太赫兹计量研究进展

太赫兹技术的独特性和优越性吸引着众多科学研究者的关注,在生物医药、信息科学、公共安全、量子研究和太空探测等领域具有巨大应用潜力。这些应用的有效性和可信度都需要以太赫兹相关参数的量值溯源为前提。文章以太赫兹光谱、频率、功率和强度等参数为对象,介绍了太赫兹计量研究的最新进展,分析了各种计量技术的特点,以期促进太赫兹计量技术发展,保障太赫兹研究和应用的量值可靠。     

太赫兹科学与技术

太赫兹电磁波段的开发和利用具有重大的科学意义和潜在的应用价值,太赫兹科学技术已经成为本世纪最为重要的科技问题之一,除了本身具有很多重大的科学问题之外,它还是一种非常有效的研究手段。介绍了太赫兹科学技术的发展历史及国内外相关的发展情况,列举了太赫兹波的独特性质,概述了太赫兹科学技术在基础研究领域和应用研究领域的新进展。     

3D Printed Anatomical Nerve Regeneration Pathways

A 3D printing methodology for the design, optimization, and fabrication of a custom nerve repair technology for the regeneration of complex peripheral nerve injuries containing bifurcating sensory and motor nerve pathways is introduced. The custom scaffolds are deterministically fabricated via a microextrusion printing principle using 3D models, which are reverse engineered from patient anatomies by 3D scanning. The bifurcating pathways are augmented with 3D printed biomimetic physical cues (microgrooves) and path‐specific biochemical cues (spatially controlled multicomponent gradients). In vitro studies reveal that 3D printed physical and biochemical cues provide axonal guidance and chemotractant/chemokinetic functionality. In vivo studies examining the regeneration of bifurcated injuries across a 10 mm complex nerve gap in rats showed that the 3D printed scaffolds achieved successful regeneration of complex nerve injuries, resulting in enhanced functional return of the regenerated nerve. This approach suggests the potential of 3D printing toward advancing tissue regeneration in terms of: (1) the customization of scaffold geometries to match inherent tissue anatomies; (2) the integration of biomanufacturing approaches with computational modeling for design, analysis, and optimization; and (3) the enhancement of device properties with spatially controlled physical and biochemical functionalities, all enabled by the same 3D printing process.     

3D Printed Actuators: Reversibility,Relaxation, and Ratcheting

Additive manufacturing strives to combine any combination of materials into 3D functional structures and devices, ultimately opening up the possibility of 3D printed machines. It remains difficult to actuate such devices, thus limiting the scope of 3D printed machines to passive devices or necessitating the incorporation of external actuators that are manufactured differently. Here, 3D printed hybrid thermoplast/conducter bilayers are explored, which can be actuated by differential heating caused by externally controllable currents flowing through their conducting faces. The functionality of such actuators is uncovered and it is shown that they allow to 3D print, in one pass, simple flexible robotic structures that propel forward under step‐wise applied voltages. Moreover, exploiting the thermoplasticity of the nonconducting plastic parts at elevated temperatures, it is shown that how strong driving leads to irreversible deformations—a form of 4D printing—which also enlarges the range of linear response of the actuators. Finally, it is shown that how to leverage such thermoplastic relaxations to accumulate plastic deformations and obtain very large deformations by alternatively driving both layers of a bilayer; this is called ratcheting. The strategy is scalable and widely applicable, and opens up a new approach to reversible actuation and irreversible 4D printing of arbitrary structures and machines.     

3D Printed Graphene-Based 3000 K Probe

High-temperature heating is ubiquitously utilized in material synthesis and manufacturing, which often features a rapid production rate due to the significantly improved kinetics. However, current technologies generally provide overall and steady-state heating, thereby limiting their applications in micro/nano-manufacturing that require selective patterning and swift heating. Herein, significantly improved control over small-scale heating is reported by utilizing 3D printed reduced-graphene-oxide (RGO) probe triggered by electrical Joule heating, which enables precise heating with high spatial (sub-millimeter scale) and temporal (milliseconds) resolutions. The block copolymer-modified aqueous-based RGO ink enabled 3D printing of high-precision structures, and a bio-inspired cellular microstructure is constructed to achieve control of the electrical conductivity and maximize structure robustness (benefit for efficient heating and operability). In particular, a thermal probe featuring a microscale tip with excellent heating capabilities (up to ≈3000 K, ultra-fast ramping rate of ≈10⁵ K s⁻¹, and durations in milliseconds) is fabricated. This thermal probe is ideal for surface patterning, as it is demonstrated for the selective synthesis of patterned metal (i.e., platinum and silver) nanoparticles on nano-carbon substrates, which is not possible by traditional steady-state heating. The material construction and heating strategy can be readily extended to a range of applications requiring precise control on high-temperature heating.     

裸视3D显示技术概述

裸视三维（3D）显示中,观看者无需配戴眼镜等任何助视设备就能观看到立体效果。随着人们对3D显示的认识不断加深,已提出多种裸视3D显示技术。本文综述了目前主流的裸视3D显示技术,包括光栅3D显示、集成成像3D显示、体3D显示和全息3D显示的基本原理及特性。     

Tailoring 3D Printed Micro-Structured Carbons for Adsorption

The manufacture of tailored carbon-based adsorbent structures with exceptionally low-pressure drops and improved kinetics using stereolithographic 3D printing is presented. Adsorbent structures are printed from commercial resins with square, circular, and hexagonal cross-sectional microchannels. These structures can reduce energy use by 50–95% compared to conventional carbon-packed beds. The activated 3D printed carbon achieves Brunauer–Emmett–Teller surface areas over 1000 m² g⁻¹ and shows outstanding butane adsorption capacities, over twice the capacity of a commercial carbon and a comparable capacity to phenolic-based carbons. The structures also show excellent uptakes of cyclohexane, up to 0.62 g g⁻¹ in a saturated feed. The introduction of complex axial geometries including spirals and chevrons enable superior adsorption kinetics and premature breakthrough of contaminants at high gas flow rates. These results demonstrate the success of intelligent manufacturing of low-pressure drop, high-capacity micro-structured adsorbents, allowing for the development of gas separation technologies for applications such as greenhouse gas removal and respiratory protection.     

3D Printed Enzyme-Functionalized Scaffold Facilitates Diabetic Bone Regeneration

Patients with diabetes mellitus (DM) suffer from a high risk of fractures and poor bone healing ability. Surprisingly, no effective therapy is available to treat diabetic bone defect in clinic. Here, a 3D printed enzyme-functionalized scaffold with multiple bioactivities including osteogenesis, angiogenesis, and anti-inflammation in diabetic conditions is proposed. The as-prepared multifunctional scaffold is constituted with alginate, glucose oxidase (GOx), and catalase-assisted biomineralized calcium phosphate nanosheets (CaP@CAT NSs). The GOx inside scaffolds can alleviate the hyperglycemia environment by catalyzing glucose and oxygen into gluconic acid and hydrogen peroxide (H₂O₂). Both the generated H₂O₂ as well as the overproduced H₂O₂ in DM can be scavenged by CaP@CAT NSs, while the initiated hypoxic microenvironment stimulates neovascularization. Moreover, the incorporation of CaP@CAT NSs not only enhance the mechanical property of the scaffolds, but also facilitate bone regeneration by the degraded Ca²⁺ and PO₄³⁻ ions. The remarkable in vitro and in vivo outcomes demonstrate that enzymes functionalized scaffolds can be an effective strategy for enhancing bone tissue regeneration in diabetic conditions, underpinning the potential of multifunctional scaffolds for diabetic bone regeneration.     

Terahertz Wave Polarization Beam Splitter Using Asymmetrical Coupler

This study has proposed and numerically demonstrated a compact terahertz wave polarization beam splitter. The splitter is built by using a asymmetrical directional coupler consisting of a bend waveguide and a slot bend waveguides and achieves a high extinction ratio of 24.88 dB and 16.55 dB for cross and through ports. The optimal coupling region length is found to be 26 μm. By using such a polarization beam splitter, the size of the terahertz wave system could be reduced significantly. The simulation results show that the designed polarization beam splitter can split TEand TM-polarized terahertz wave into different propagation directions with high efficiency over the terahertz wave frequency range from 9.40 THz to 9.65 THz. The device obtained is readily used for a polarization diversity terahertz wave integrated circuit field, particularly for platforms with slot waveguide.     

基于环形极子的太赫兹超宽带圆极化阵列天线

以方环单极子天线为基础,设计了一种太赫兹频段超宽带圆极化微带阵列天线。提出的新型低剖面环形天线单元由C型结构和改进后的接地结构组成,实现了天线表面电流不对称流动以及电流的最优纵横比,辐射圆极化波;采用2×4天线阵列不仅提高了天线增益,而且增强了其方向特性。仿真结果表明,该阵列天线的阻抗带宽为67.42%(193.86～391.02 GHz),圆极化轴比带宽可完全包含该频段,且在该频段内峰值增益为15 dBi,在太赫兹通信设备中具有广阔的应用前景。