1. Diffraction of terahertz waves after passing through a Fresnel lens.
- Author
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Yu, Shi, Qing, Zhou, and, Li, and Cun, Zhang
- Subjects
WAVE diffraction ,FRESNEL lenses ,TERAHERTZ technology ,SPECTRUM analysis ,SIMULATION methods & models ,GAUSSIAN beams - Abstract
The spatiotemporal and spectral characteristics of ultrawide-band terahertz pulses after passing through a Fresnel lens are studied by using the scalar diffraction theory. The simulation shows that the transmitted terahertz waveforms compress with increasing propagation distance, and the multi-frequency focusing phenomenon at different focal points is observed. Additionally, the distribution of terahertz fields in a plane perpendicular to the axis is also discussed, and it is found that the diffraction not only induces focusing on-axis but also inhibits focusing at off-axis positions. Therefore, the Fresnel lens may be a useful alternative approach to being a terahertz filter. Moreover, the terahertz pulses travelling as a basic mode of a Gaussian beam are discussed in detail. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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