Terahertz vibrational absorption spectroscopy using microstrip-line waveguides
Terahertz vibrational absorption spectroscopy using microstrip-line waveguides
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DOI：
10.1063/1.3013349
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发表时间：
2008-11-03
影响因子：
4
通讯作者：
Davies, A. G.
中科院分区：
文献类型：
--
作者：
Byrne, M. B.;Cunningham, J.;Davies, A. G.
我们表明，太赫兹微带线波导可用于测量吸收光谱的多晶材料具有高频率分辨率（类似于2 GHz）和空间分辨率，这是由微带线的尺寸，而不是自由空间波长确定。在微带线上方延伸的倏逝太赫兹带宽电场与覆盖的电介质样品相互作用，并被覆盖的电介质样品修改，从而使得能够探测样品中的特征振动吸收共振。作为一个例子，太赫兹吸收光谱的多晶乳糖一水合物进行了研究;最低的躺模式观察到在534（+/- 2）GHz，在良好的协议与自由空间测量。这种微带技术提供了比自由空间太赫兹时域光谱更高的空间和频率分辨率，并且不需要波导和样品之间的接触。
We demonstrate that terahertz microstrip-line waveguides can be used to measure absorption spectra of polycrystalline materials with a high frequency resolution (similar to 2 GHz) and with a spatial resolution that is determined by the microstrip-line dimensions, rather than the free-space wavelength. The evanescent terahertz-bandwidth electric field extending above the microstrip line interacts with, and is modified by, overlaid dielectric samples, thus enabling the characteristic vibrational absorption resonances in the sample to be probed. As an example, the terahertz absorption spectrum of polycrystalline lactose monohydrate was investigated; the lowest lying mode was observed at 534(+/- 2) GHz, in excellent agreement with free-space measurements. This microstrip technique offers both a higher spatial and frequency resolution than free-space terahertz time-domain spectroscopy and requires no contact between the waveguide and sample.