THz时域频谱技术中若干效应的研究

在电磁波谱中所处的特殊位置使得THz波在物理、化学、生物医学、电子科学、材料科学、环境监测等领域有着广泛的应用前景。讨论了THz时域频谱技术的若干关键问题：THz发射晶体的双光子吸收、衍射效应和非线性效应（Kerr效应和类Kerr效应）等对THz产生效率的影响,THz辐射脉冲的载波包络相位差,THz小波变换频谱技术,以及利用光子晶体光纤飞秒激光作为激发源对THz时域频谱系统进行小型化和提高能量的方案。     

太赫兹真空电子器件的研究现状及其发展评述

太赫兹真空电子器件具有输出功率高、可在常温下工作等优点,它在军用、民用领域有着广泛的应用前景。本文介绍了国内外各种太赫兹真空电子器件研究的技术水平及应用现状,并对其今后发展趋势作了相应的评述。     

Terahertz Technology Research at NICT

The National Institute of Information and Communications Technology (NICT) has been researching the use of terahertz (THz) band from its source to industrial applications. Major accomplishments to date include the development of THz devices such as a quantum cascade laser source, a portable stand-off imaging system, an establishment of propagation model, and a spectral database. We also encourage applications in a range of research fields, such as art conservation science. Because standardisation will be an important step in making the THz wave a common tool, NICT will be pursuing THz methodological activities.     

太赫兹超常材料及应用

超常材料具有人工设计的结构,并有自然材料所不具备的超常物理性质。超常材料的电磁响应灵活可调,对太赫兹(THz)技术意义非凡。THz超常材料的实现和迅速发展为太赫兹技术的发展和应用带来了新的机遇。总结了THz波段超常材料的研究进展,包括THz波段超常材料的构造及制备、基于超常材料的THz波器件以及超常材料在THz波技术中的其他应用。     

THz波微结构器件特性的研究

在电磁波谱中所处的特殊位置使得THz波在在物理、化学、生物医学、电子科学、材料科学、环境监测等领域有着广泛的应用前景。综述了THz波微结构器件特性方面的研究工作。亚波长金属周期微结构器件的THz波谱选择增强透射现象,亚波长环形槽金属线上的THz等效表面等离子体激元,以及THz光子晶体光纤。     

Tunable THz Sources and Their Applications

In this paper, the technology aspects of the THz laser and spectrometric devices, developed over the last decade are described and their applications in various fields of science and technology are explained. The THz sources of importance are the optically pumped lasers, solid state devices and the backward wave oscillator (BWO) based systems. The BWO system offers the electronic tuning and multiplexing facility like Fourier transform technology. The time resolved and frequency domain aspects with relative merits are discussed. Non-linear optical methods of production of monochromatic radiation using second harmonic generation (SHG) are also considered. The important areas of space applications are described in detail. Present status and future directions are indicated.     

太赫兹真空电子器件用场发射阴极技术分析

本文阐述了太赫兹真空电子器件对阴极电子源的需求条件,分析了在该器件中应用场发射阴极的可能性。介绍 了当前两种主要场发射阴极,即金属薄膜场发射阴极和碳纳米管场发射阴极的国内外发展情况,指出了它们各自的优势 以及实际应用中存在的障碍,并提出了相应的解决途径。试验和分析结果表明,场发射阴极具有很好的太赫兹真空电子 器件应用前景。     

面向生化样品的太赫兹偏振传感研究进展

太赫兹(Terahertz,THz)波具有相干性好、信噪比高、辐射能量低等性质,在传感领域有着广泛应用。此外,THz传感还具有实时、非接触、无标记、非电离等优点,在生化传感特别是生物活性物质的传感中有着重要应用。但THz传感也存在着灵敏度低、水的吸收强、检测信息有限、适用性差等缺陷。介绍在THz时域偏振光谱传感技术方面的系列工作,采用微结构器件作为传感器,使用透射或反射传感方法分别检测了细胞、氨基酸和脱氧核糖核酸(DNA)几种生化样品。实验结果表明：与传统的谐振传感方法相比,偏振传感方法的品质因数和传感灵敏度均有着显著提高;反射式传感有效避免了水对THz的吸收,实现了液体环境下活性生化样品的传感;使用具有手性的微结构器件作为传感器,或利用手性THz波作为激发场,可以增强样品的偏振响应,提高传感灵敏度,实现手性分子的传感。     

Silicon Carbide Terahertz Emitting Devices

In recent years, terahertz (THz) sources between 0.1 THz and 10 THz have attracted much attention for imaging and sensing applications. THz emission from radiative transitions in impurity states has been demonstrated in Si and Ge devices by either electrical or optical pumping. Compared to Si as the material for THz emission, the wide-band-gap material SiC exhibits several advantages such as a higher dopant ionization energy, which allows a higher device operating temperature. Combining with its superior material qualities such as high breakdown field and high thermal conductivity, SiC is a promising material for high-temperature and high-power THz emitting devices. This article describes recent progress in using SiC materials to increase the operating temperature and output power of dopant-based THz sources.     

太赫兹信息超材料与超表面

该文对信息超材料,包括数字超材料、编码超材料、以及可编程超材料的研究进展及其在太赫兹领域的应用进行了综述,从原理分析、数值仿真、样品制备、实际应用等多个角度介绍了信息超材料对电磁波全面而灵活的调控能力,着重探讨了编码超材料在太赫兹领域的发展以及应用,最后阐述了现场可编程超材料的原理及其在构建新型成像系统、新概念雷达中的应用。信息超材料与超表面对太赫兹波束的灵活调控可用于制作波束分离、低雷达散射截面等多种功能器件,为太赫兹频段电磁波的实时调控开辟了新的途径。      

基于高速数字相关器的太赫兹干涉仪系统研究

干涉仪利用通道间的相关运算进行测量,是干涉式成像的基本单元。太赫兹成像在安全检查、军事侦查等方面有着广泛的应用前景。将干涉成像测量引入太赫兹领域后,为解决相关运算中高速信号的相位同步问题,该文提出基于低速FPGA控制的交叉同步方案,用低硬件代价解决高速采样信号的相位同步问题,并完成了一套多通道高速数字相关系统。系统的最高采样速率为5 GHz, ADC有效位数大于等于6位,相关器积分时间可调。最后,利用该数字相关器和相应的太赫兹微波元器件搭建了中心频率为0.44 THz的干涉仪,并得到了清晰的干涉条纹,其线性相位误差小于2 。该研究为今后设计太赫兹干涉成像仪提供了基本单元。     

太赫兹波段电磁超介质的应用及研究进展

太赫兹波和电磁超介质是电磁学领域关注的热点.太赫兹波与电磁超介质相互作用可以实现对太赫兹波的操纵和调控,有望填补"太赫兹空白".介绍了太赫兹波段电磁超介质的研究进展,包括电磁超介质电磁性能可调谐的实施途径,电磁超介质在太赫兹功能器件方面的应用(调制器/开关、传感器/探测器、滤波器、偏振元件和吸波器),太赫兹波段表面等离...     

太赫兹宽带非对称传输器件的研究

提出一款双层双L形太赫兹非对称传输器件,其结构单元由典型的金属-介质-金属结构组成,顶层为轴对称的双L形金属层,底层为中心对称的双L形金属层。在1.174~1.420THz范围内,当x极化波正向垂直入射时,该器件的非对称传输参数大于0.6,其中在1.207~1.377THz范围内非对称传输参数大于0.8,在1.334THz时非对称传输参数达到峰值0.859。最后,讨论了材料的选择和入射角度对器件非对称传输性能的影响。该非对称传输器件具有频带宽、非对称传输明显等特点,可用于太赫兹二极管、太赫兹开关等功能器件。     

微波真空电子器件的发展与应用

根据真空电子器件的工作原理,其百年发展史可分为三个阶段：以静电控制的普通电子管阶段、以动态控制原理工作的微波真空电子器件阶段、基于相对论效应的新型器件阶段,每个阶段的代表管型在各自的应用领域都发挥了重要的作用。随着电磁波谱的开发利用,微波真空电子器件的技术水平向高频率、高功率、高效率方向发展,推动着军用装备和工业应用的不断拓展,特别在航天领域有长足发展。本文综述微波真空电子器件在厘米波段、毫米波段和太赫兹波段技术发展和装备应用概况,探讨未来的发展方向。     

High-Precise Spectrometry of the Terahertz Frequency Range: The Methods, Approaches and Applications

In the paper we present a high precise THz technique (frequency synthesizers and spectrometer) and its applications for noninvasive medical diagnostics and security systems. The cornerstone of the presented devices is multipliers and mixers based on quantum superlattice structures. The multipliers based on superlattice structures are shown to be more effective than Schottky diodes and provide THz radiation up to 8.1 THz.     

太赫兹量子阱探测器研究进展

太赫兹量子阱探测器具有皮秒级的响应时间和1 GHz以上的高速调制性能,是太赫兹快速成像和高速无线通信应用领域非常有前景的探测器.文章综述了太赫兹量子阱探测器的探测原理和设计方法、器件主要性能指标和基于该探测器的应用技术研究进展.研究表明,基于太赫兹量子阱探测器的快速成像系统可以获得物体的细节信息,有望用于安全检查和无损...     

Progress of Terahertz Devices Based on Graphene

Graphene is a one-atom-thick planar sheet of sp2-hybridized orbital bonded honeycomb carbon crystal. Its gapless and linear energy spectra of electrons and holes lead to the unique carrier transport and optical properties, such as giant carrier mobility and broadband flat optical response. As a novel material, graphene has been regarded to be extremely suitable and competent for the development of terahertz （THz） optical devices. In this paper, the fundamental electronic and optic properties of graphene are described. Based on the energy band structure and light transmittance properties of graphene, many novel graphene based THz devices have been proposed, including modulator, generator, detector, and imaging device. This progress has been reviewed. Future research directions of the graphene devices for THz applications are also proposed.     

Compact, High-Power Electron Beam Based Terahertz Sources

Although terahertz (THz) radiation was first observed about 100 years ago, this portion of the electromagnetic spectrum at the boundary between the microwaves and the infrared has been, for a long time, rather poorly explored. This situation changed with the rapid development of coherent THz sources such as solid-state oscillators, quantum cascade lasers, optically pumped solid-state devices, and novel coherent radiator devices. These in turn have stimulated a wide variety of applications from material science to telecommunications, from biology to biomedicine. Recently, there have been two related compact coherent radiation devices invented able to produce up to megawatts of peak THz power by inducing a ballistic bunching effect on the electron beam, forcing the beam to radiate coherently. An introduction to the two systems and the corresponding output photon beam characteristics will be provided.     

基于二氧化钒薄膜的太赫兹开关器件

二氧化钒(VO2)作为一种优质的光电功能材料一直备受人们的关注,在信息存储、光调制器、太阳能电池、光电探测器等方面有着重要应用。采用磁控溅射及原位退火氧化的"两步法"制备了VO2薄膜,并对其进行晶态、形貌表征。设计并搭建VO2薄膜热致相变实验系统,研究了VO2薄膜在变温条件下对2.52 THz辐射的开关特性。结果表明,VO2薄膜样品为多晶态,具有明显的太赫兹调制效果,可以实现对2.52 THz波的调制,并可作为太赫兹开关/调制器件的功能材料。     

Metamaterial Absorbers in Terahertz Band

In recent years, a great deal of effort has been made to a create terahertz （THz） wave absorber based on metamaterials （MM）. Metamaterials absorbers have a variety of potential applications including thermal emitters, detector, stealth technology, phase imaging, etc. In this paper, we firstly introduce the basic structure and work principle of the THz MM absorbers, and a transmission line model is developed for devices analysis. To expand the application of THz absorbers, dual-band and broadband THz MM absorbers are designed, fabricated, and measured. At the end of this article, the future development trends of MM absorbers are discussed.