Nanostructured gold films as broadband terahertz antireflection coatings
被引:150
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作者:
Thoman, Andreas
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h-index: 0
机构:
Univ Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, GermanyUniv Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, Germany
Thoman, Andreas
[1
]
Kern, Andreas
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h-index: 0
机构:
Univ Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, GermanyUniv Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, Germany
Kern, Andreas
[1
]
论文数: 引用数:
h-index:
机构:
Helm, Hanspeter
[1
]
Walther, Markus
论文数: 0引用数: 0
h-index: 0
机构:
Univ Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, GermanyUniv Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, Germany
Walther, Markus
[1
]
机构:
[1] Univ Freiburg, Freiburg Mat Res Ctr, D-79104 Freiburg, Germany
来源:
PHYSICAL REVIEW B
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2008年
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77卷
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19期
关键词:
D O I:
10.1103/PhysRevB.77.195405
中图分类号:
T [工业技术];
学科分类号:
08 ;
摘要:
The potential of nanometer-thick, randomly nanostructured gold films as broadband wave impedance-matching coatings for nondispersive substrates in the terahertz frequency range is demonstrated. Based on a wave impedance approach and the specific non-Drude conductivity of our films, we model the reflectivity at the coated inter-face between silicon and air and show that nanostructured films offer a considerably better broadband performance than conventional bulk metallic layers. The predictions from the theoretical model are verified in experimental studies of different gold nanostructures investigated by terahertz time-domain spectroscopy in the frequency range of 0.2-2.2 THz. An extension of a previously developed subgridding scheme for the finite-difference time-domain method allows us to simulate terahertz-pulse propagation through uncoated and coated samples and to follow attenuation and reshaping of the internally reflected pulse when the film thickness is varied with subnanometer precision.