太赫兹科学与技术进展-张希成

一块火鸡骨头的T-射线 一块火鸡骨头的 射线 CT
Reconstructed Image
火鸡骨头
刊登了我们T-射线 CT 研究的杂志有: 医学设备和诊断工业，高 级专业成像与辐射疗法，工业电视 (旧金山)，每日邮报，光电子 杂志，诊疗世界，医学设备和诊断新闻， RT 成像，商业周刊。
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80 时间延迟 (ps)
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射线成像 飞行时间 T-射线成像 射线
T-ray imaging is fast being recognized as a powerful diagnostic technique.
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Young’s Experiment
a pair of slits T-ray
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X (mm)
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Frequency Dependent T-rayT-Ray Interference Diffraction from Young’s Young’s Interference
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T-Ray Image of A Letter Contains Powders
Image a letter It contains powders
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T-射线用于对抗生物恐怖主义 射线用于对抗生物恐怖主义 射线
微波
MF， HF， VHF， UHF， SHF， EHF
光子 (quantum transition)
x-射线 γ –射线
可见光
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1024 Hz
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kilo
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tera
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yotta
频率 (Hz) 1 THz ~ 1 ps ~ 300 m ~ 33 cm-1 ~ 4.1 meV ~ 47.6 K
1 1 1 + = z z′ f v
0.75THz 1.24THz 1.57THz Fresnel lens sensor
z
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Laser Focus World August issue
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Future Work for T-Ray Imaging
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International Symposium of Ultrafast Phenomena and Terahertz Radiation /~zhangxc
NRC Report: Harnessing Light
“A particularly novel and unexpected application of femtosecond light pulses is the generation of terahertz radiation, or T-rays. T-rays in the wavelength range of 0.05 to 1 mm provide a new technology for imaging hidden items and some invisible materials properties.” --- 1998 电子 THz 间隙 (classical transport)
Tomographic imaging system offers cross-sectional information within a target, provides functional imaging. Problems need to be solved: [1] Imaging Time should be from hours to less than one minute, with a target time of a few seconds. [2] Imaging Area should be from 2 cm to 20 cm, with a target area of 40 cm. [3] Imaging Resolution should be from 3 mm to sub-mm, with a target resolution of 0.1 mm. [4] Imaging Distance should be from 20 cm to 2 meter, with a target distance of a few hundred meters.
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Wave’s Nature: Diffraction
single hole T-ray
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Diffraction from a Hole (φ=1.8 mm) φ
2 0.5 THz 2 1 THz
一个球状物体(φ 一个球状物体 φ=36 mm)的T-射线 CT成像 的 射线 成像
Photo Reconstructed Image
在 Laser Focus World上发表的一篇图文, 5 月, 2002
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2-, 4-, and 8-Level T-Ray Fresnel Lenses
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T-Ray Imaging and Tomography
Why T-ray imaging modality? Functional imaging! T-ray imaging with standard x-y scan Transmission and reflection mode Tomography T-ray computed tomography (CT) T-ray diffractive tomography (DT) Tomography with a binary lens and a broadband pulse
2 0.5 THz 2 1 THz
cm
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01Biblioteka 0 0112
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T-射线 的一些重要特性 射线
T-射线 具有较低光子能量 (4 meV @ 1 THz) ，不会在 生物组织中产生有害的光致电离。 很多有机分子由于偶极子的旋转和震动跃迁, 在 GHz 到 THz 频段，都具有很强的吸收和色散；分子的这些 光谱特征使得T-射线 鉴别成为可能。 T相干T-射线 信号瞬时电场的强度和相位可以同时被测 量; 这样我们就可以通过对T-射线 进行时域探测，获得 THz 吸收光谱和色散光谱。 THz 时域光谱提供了非常高的信噪比，而且对黑体辐 射 (热背景)不敏感。
Recent Progress for THz Science & Technology
X.-C. Zhang (张希成 张希成) 张希成
Center for THz Research Rensselaer Polytechnic Institute, USA
THz Group at Rensselaer
2-Level
4-Level
8-Level
S. Wang, et al, OL, 27, 1183 (2002).
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Tomography with a T-Ray Binary Lens
simultaneously image 3 targets at different frequencies
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Prof. Ci-Ling Pan’s THz Lab (Clean-Room)
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THz Lab at Capital Normal University of Beijing
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22% gas sensing 5%
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Research Highlights in Year 2002
Solid state THz laser (Italy and UK) High power THz source from Jefferson Lab (US) T-ray tomographic imaging (US) THz resonant structure for label-free DNA detection (Germany) T-ray for biological and chemical agents sensing and imaging (US) THz radiation from semiconductor under strong B field (Japan) Nonlinear THz wave spectroscopy (US) THz wave quantum optics and quantum computing (US) THz wave for medical application (Europe and US)
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THz Lab at National Normal University of Taipei
A fiber laser as a source
信封中。 THz像中其吸收/ 散射清晰可见， 但是为了准确地辨别，需要对样品 的THz 响应进行全面的分析。
Thurengiensis 杆状菌 孢子被放入
信封中的“炭疽热”病菌粉末成像
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T-射线 透视衣物？ 射线 透视衣物？