Design and optimization of nano-antenna for thermal ablation of liver cancer cells

One method of cancer therapy is to utilize nano-antenna for thermal ablation.In this method,the electromagnetic waves emitted from the nano-antenna are absorbed by the tissue and lead to heating of cancer cells.If temperature of cancer cells reaches a threshold,they will begin to die.For this purpose,an L-shaped frame nano-antenna(LSFNA) is designed to introduce into the biological tissue.Thus,the radiation characteristics of the LSFNA such as near and far-field intensities,directivity,and sensitivity to its gap width are studied to the optimization of the nano-antenna.The bio-heat and Maxwell equations are solved using the finite element method.To prevent damage to healthy tissues in this method,the antenna radiation must be completely controlled and performed carefully.Thus,penetration depth,special absorption rate,temperature distribution,and the fraction of tissue necrosis are analyzed in the biological tissue.That is why the design and optimization of the nano-antennas as a radiation source is important.Also,a pulsed source is used to excite the LSFNA.Furthermore,focusing and efficiency of the nano-antenna radiation on the cancer cell is tuned using an adjustable liquid crystal lens.The focus of this lens is changing under an electric field applied to its surrounding cathode.

Design and optimization of a nano-antenna hybrid structure for solar energy harvesting application

A novel hybrid structure with high responsivity and efficiency is proposed based on an L-shaped frame nano-antenna(LSFNA)array for solar energy harvesting application.So,two types of LSFNAs are designed and optimized to enhance the harvesting characteristics of traditional simple electric dipole nano-antenna(SEDNA).The LSFNA geometrical dimensions are optimized to have the best values for the required input impedance at three resonance wavelengths ofλ_(res)=10μm,15μm,and 20μm.Then the LSFNAs with three different sizes are modeled like a planar spiral-shaped array(PSSA).Also,a fractal bowtie nano-antenna is connected with the PSSA in the array gap.This proposed hybrid structure consists of two main elements:(I)Three different sizes of the LSFNAs with two different material types are designed based on the thin-film metal-insulator-metal diodes that are a proper method for infrared energy harvesting.(Ⅱ)The PSSA gap is designed based on the electron field emission proposed by the Fowler-Nordheim theory for the array rectification.Finally,the proposed device is analyzed.The results show that the PSSA not only has an averaged 3-time enhancement in the harvesting characteristics(such as return loss,harvesting efficiency,etc.)than the previously proposed structures but also is a multi-resonance wide-band device.Furthermore,the proposed antenna takes up less space in the electronic circuit and has an easy implementation process.

Performance of a superconducting single photon detector with nano-antenna

The performance of single-photon detectors can be enhanced by using nano-antenna. The characteristics of the superconducting nano-wire single-photon detector with cavity plus anti-reflect coating and specially designed nano~ antenna is analysed. The photon collection efficiency of the detector is enhanced without damaging the detector＇s speed, thus getting rid of the dilemma of speed and efficiency. The characteristics of nano-antenna are discussed, such as the position and the effect of the active area, and the best result is given. The photon collection efficiency is increased by 92 times compared with that of existing detectors.

基于纳米金属阵列天线的石墨烯/硅近红外探测器

金属纳米颗粒低聚体不仅具有等离激元共振效应实现光场亚波长范围内的局域化和增强,还可以通过泄漏光场相互干涉实现法诺共振和连续态中的束缚态,从而使得电磁场更强的局域和增强.本文采用金纳米低聚体超构表面作为石墨烯/硅近红外探测器的天线,实现了光响应度2倍的增强;通过调节纳米金属低聚体间夹角,发现当该夹角为40°时,光电流达到最大值,对应法诺共振最大的透射率,此时天线不仅汇聚光场能量还定向发射给探测器;当该夹角为20°时,光电流出现一个低谷,此时能量局域于低聚体内,金属损耗减弱了等离激元增强效果.该工作通过时域有限差分法仿真和实验相结合研究了低聚体超构表面光电耦合效率的动态过程,为提高光电探测效率提供了一种重要的途径.

基于3D打印的柔性三频微带天线的设计与加工

为解决可穿戴设备在复杂应用场景中无线信号响应范围较窄的问题,该文提出了一种柔性三频微带天线,在2.5 GHz、3.5 GHz、5.4 GHz微波频段采用双“T”型+双“L”型表面结构实现天线的谐振,采用聚酰亚胺为基底材料,纳米银为辐射贴片及接地面的导电材料以实现柔性化。使用ANSYS HFSS对天线进行建模并进行仿真分析,使用微滴喷射3D打印工艺对其加工,有效地解决了传统微机电系统(MEMS)加工在柔性电子领域上成本高及步骤复杂等问题。最后使用场发射扫描电镜分析打印面形貌,并使用矢量网络分析仪分别测试天线成品的回波损耗、可弯折性及弯折抗疲劳性,测试结果与仿真结果基本一致,且天线具有较好的弯折性能。

基于3D打印微带贴片天线的近红外烧结研究

本文针对三维打印微带贴片天线中近红外烧结机理不够明确,烧结可控性较差,最终难以保证纳米银层电性能等问题,首先,采用多尺度方法,将近红外烧结温度场传热模型、纳米银层表面形貌和分子动力学模型相结合,系统地揭示了近红外烧结机理。之后,通过参数反馈调控方法实现纳米银墨水的控性烧结。最后,采用参数反馈调控方法实现了微带贴片天线的一体化成形,验证了近红外烧结参数反馈调控方法的有效性。

多谐振U形缝隙纳米天线设计及吸收特性

太阳能收集是解决无线传感器网络能量受限的有效手段。针对传统采用光伏电池收集太阳能的方法易受环境与光照时间限制、吸收波段窄等问题,提出了一种耦合对称U形缝隙的多谐振纳米天线阵列用于太阳能收集。该天线的单元结构是在银介质基板上刻蚀4个对称的U形缝隙,U形缝隙附近产生的表面等离激元相互耦合,使其在宽波段内产生多个谐振点,从而提高宽波段的平均吸收率。利用时域有限差分方法分析了多谐振U形缝隙纳米天线阵列的吸收特性。仿真结果表明,天线阵列在400~870nm,960~1 100nm两个波段内吸收率较高,并出现多个吸收峰,吸收峰值最大可以达到99%。

宽频十字缝隙分形纳米天线及其异常透射特性

针对传统纳米天线结构存在频段窄、透射率低的问题,设计了十字缝隙分形纳米天线结构。采用时域有限差分法计算了十字缝隙分形纳米天线结构的异常透射特性,分析了均匀十字缝隙结构与其之间的透射特性差异,并讨论了物理参数对十字缝隙分形纳米天线异常透射特性的影响及分形尺寸与非分形尺寸下的纳米天线透射谱变化关系。结果表明,较于均匀十字缝隙结构,十字缝隙分形结构实现了光的异常透射及全2π透射光束相位调控,尺寸更小型化,半波宽(FWHM)更宽,透射率更高,最高可达99.51%;通过调整物理参数,透射谱呈现出红移或蓝移的特性,实现了透射谱的可控性;同时,当h=50 nm时,FWHM约为356 nm,透射率仍高达95.66%,普遍高于传统结构;并且在大入射角度(70°)下,峰值透射率仍旧大于74%。总之,较于其他纳米天线结构,十字缝隙分形纳米天线具有宽频、可控可调、结构更微型化等特点,且实现了光的异常透射。

宽谐振区光学纳米天线的谐振

提出了一种有双谐振频率和较宽谐振区域的纳米天线结构。利用有限积分法,计算了由金构成的表面等离子体光学纳米天线的谐振特性,研究了在谐振区域内谐振频率和谐振电场随位置变化的情况。结果表明,在不同谐振频率下存在两个谐振电场,在中间区域,谐振频率为270THz,在侧边间隙区,谐振频率为390THz;激励源为1V/m时,其谐振电场均达700V/m以上,是普通偶极子天线的18倍;第一谐振区域的谐振场集中在10～25nm,在此范围内,谐振电场较大、谐振频率几乎不变;加上折射率为1.5的玻璃衬底后,天线的谐振电场达到800V/m,与没有衬底时相比,谐振频率变化很小。研究的天线结构在高性能的光学纳米天线、太阳能电池和生物传感器方面有潜在的应用价值。

利用纳米技术研制纳米管阵列天线的可能性

在分析传统天线工作机理的基础上,基于纳米物理原理,本文提出了利用纳米管研究纳米管阵列天线的概念.由于纳米管内电子运动固有的弹道输运效应,使得纳米管阵列天线具有辐射效率高的优点.同时,由于纳米管阵列不受趋肤效应影响,在口径面及空间内按一定规律布排纳米管阵列,并形成需要的电流分布,可进一步提高纳米管阵列天线的辐射增益.计算表明,除具有辐射效率高以外,纳米管阵列天线的辐射方向性优于相同表面积上的微带天线.本文同时对纳米管阵列天线可能的馈电方式进行了探讨.

缝隙八木纳米天线设计及宽波段吸收特性

针对传统光伏电池能量收集易受环境与光照时间限制的问题,本文设计了一种用于太阳能收集的缝隙八木纳米天线单元及阵列.采用时域有限差分法分析缝隙间距对纳米天线远场方向性和近场分布的影响,并研究缝隙八木纳米天线阵列的吸收特性及不同缝隙间距对阵列天线吸收率的影响.研究远场方向性发现,当缝隙间距增加到一定距离时,天线方向图出现多个副瓣并产生新的辐射模式;通过对近场分析表明,新辐射模式的产生来源于高阶模式的局域表面等离激元.天线阵列吸收率的仿真结果表明：在400～1 500nm波段,随着缝隙间距的增加,缝隙八木纳米天线阵列吸收率呈上升趋势,当缝隙间距等于80nm时,在400～660nm、760～1 300nm两个波段内吸收率较高,吸收峰值最大可以达到98%;以吸收率大于50%为基准,当缝隙间距等于80nm时,其吸收波段最宽.

射频识别标签天线的按需微喷射制备

基于数字化微喷射技术搭建了射频识别(RFID)标签天线的按需微喷射制备系统。首先,将纳米银导电墨水按需微喷射到镀有疏水化薄膜的聚对苯二甲酸乙二醇脂(PET)基底表面形成天线图形;然后在恒温干燥箱内烧结,形成RFID标签天线。实验研究了微喷射系统参量对液滴产生的影响以及制备参数对纳米银导线成线的影响,制得了最小线宽为100μm、厚度为2.8μm、电阻率为5.2μΩ·cm且阻值具有较好线性度的导线。设计、仿真和制备了弯折偶极子天线,并对其性能参数进行了测试,结果显示其天线谐振频率、带宽和谐振点S11参数等与仿真结果具有较好的一致性。实验结果表明,按需微喷射导电银墨水制备RFID标签天线的方法具有系统结构简单、成本较低、液滴微喷射精确、便于制备任意天线图形等特点;制备的弯折偶极子天线尺寸可控、导电性高、阻值均一性好,并具有较好的天线性能。

准一维量子线阵列天线研究

基于对影响传统天线增益因素以及准一维量子线结构中的电子输运特性的分析,提出了利用准一维量子线阵列构建新型纳米阵列天线的设想,并利用碳纳米管阵列构建了研究纳米阵列天线辐射原理的实验样机.实验结果表明,由准一维量子线构成阵列天线的电磁辐射效率和带宽均优于传统微带天线.

太赫兹光电导天线发射装置的优化设计

为了研究金属纳米狭缝对太赫兹光电导天线辐射功率的影响，基于时域有限差分法对太赫兹波通过金属狭缝时的增强特性进行了分析计算，研究了太赫兹波通过金属纳米狭缝电场的增强幅度与狭缝宽度和太赫兹波频率之间的规律。结果表明，在太赫兹光电导天线发射装置上增加一个纳米狭缝能够增强太赫兹波的发射功率，频率为0．1THz的太赫兹波通过70nm宽度金属狭缝时，辐射功率最大可以增强800倍。该研究结果对太赫兹光电导天线结构的改进有一定的借鉴意义。

一种基于微\纳米加工技术的新型太赫兹片上螺旋天线

给出了一种基于微\纳米加工技术的3D片上天线结构,天线工作频率为1.5 THz。该天线结构包含圆柱形金属螺旋和衬底上的微带馈线2个部分。所提出的天线结构可以在单片晶圆上利用微\纳米加工技术实现,且方便与系统其他部分的电路集成于同一芯片内部。天线在1.4 THz～1.6 THz频段内具有很高的增益(11 dBi)和很宽的工作带宽(200 GHz),非常适合应用于太赫兹通信系统。

Performance of superconducting nanowire single-photon detector with the fan coupling antenna array

The performance of superconducting nanowire single-photon detector （SNSPD） involving niobium nitride with the fan coupling antenna array is analyzed. The SNSPD has a high detection efficiency and counting rate. Hydrogen silsesquioxane and niobium nitride are filled in the gold grating deposited on the substrate in which the fan coupling antenna arrays are embedded. By changing the position of the fan coupling antenna array, the maximum area of optical intensity is obtained and the photon collection efficiency is increased by 26.5 times. The detection efficiency of SNSPD is improved without changing the detection speed. These parameters are important for designing a practical single-photon detector,

Photonic-plasmonic hybrid microcavities: Physics and applications

Photonic-plasmonic hybrid microcavities,which possess a higher figure of merit Q/V(the ratio of quality factor to mode volume)than that of pure photonic microcavities or pure plasmonic nano-antennas,play key roles in enhancing light–matter interaction.In this review,we summarize the typical photonic-plasmonic hybrid microcavities,such as photonic crystal microcavities combined with plasmonic nano-antenna,whispering gallery mode microcavities combined with plasmonic nano-antenna,and Fabry–Perot microcavities with plasmonic nano-antenna.The physics and applications of each hybrid photonic-plasmonic system are illustrated.The recent developments of topological photonic crystal microcavities and topological hybrid nano-cavities are also introduced,which demonstrates that topological microcavities can provide a robust platform for the realization of nanophotonic devices.This review can bring comprehensive physical insights of the hybrid system,and reveal that the hybrid system is a good platform for realizing strong light–matter interaction.

Extraordinary Optical Transmission through Single Sub-Wavelength Slot Nano Antennas

This paper investigates the electromagnetic transmission through the sub-wavelength slot model on a metal film for TM- and TE-polarized light. The influence of several parameters such as the slot width, the metal film thickness and the polarization of the incident field is investigated using FDTD method. The FDTD simulation’s results have shown that the sub-wavelength slot in the metal films has extraordinary optical transmission (EOT) properties for TM-polarized light. The EOT has been observed as being symmetrically punctured and characterized by the appearance of a series of transmission peaks and dips in the transmission field. By varying the slot thickness we have investigated the effect of the Fabry-Pérot like resonance in the sub wavelength slot. This component can be a key element in many applications. High-spatial-resolution imaging and information and communications technologies and sensing with high spectral and spatial precision, enhanced solar cells, efficient optical sources and detectors, disease treatment, are such examples.

基于纳米天线的多通道高强度定向表面等离子体波激发

设计了一种带有纳米天线的金属微腔结构,以实现高强度表面等离子的定向激发.在利用双狭缝结构实现表面等离子体波定向激发的基础上,分别结合共振增强和干涉相长原理,在传统结构的入射端面上添加纳米天线结构,并增加狭缝通道数,实现了定向激发的表面等离子体波的能量增强.基于纳米天线的多通道高强度定向表面等离子体波激发装置结构简单,系统紧凑,并能够有效提高定向传播的表面等离子体波的能量密度和传播距离,其对微纳光学传输和高密度光学集成领域等方面的研究具有重要意义.

面向微集成的金刚石NV色心与微波天线的一体化

针对金刚石氮空位(NV)色心量子传感器中微波天线体积大、无法与金刚石紧密接触造成天线与金刚石位置不固定、引起传感器灵敏度低的问题,设计了一种将微波天线集成到金刚石NV色心的一体化方法。采用导电性更强的金薄膜作为天线材料,通过高频结构模拟器(HFSS)仿真软件确定天线尺寸。利用微纳加工工艺和磁控溅射技术在金刚石NV色心表面制作了微波天线,实现了金刚石一体化微波天线。对金刚石一体化微波天线的仿真与实验数据进行对比分析。与传统微波天线相比,设计的天线体积缩小约50%,激发荧光效率和磁场灵敏度分别提升了约20倍和约10 nT/Hz^(1/2)。该方法结合3D打印技术可有望大幅缩小金刚石NV色心量子传感器的体积,对量子器件的微集成化发展具有重要意义。