Three-dimensional direct observation of Gouy phase shift in a terajet produced by a dielectric cuboid
Three-dimensional direct observation of Gouy phase shift in a terajet produced by a dielectric cuboid
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DOI：
10.1063/1.4949014
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发表时间：
2016-05-09
影响因子：
4
通讯作者：
Nagatsuma, Tadao
中科院分区：
文献类型：
--
作者：
Hai Huy Nguyen Pham;Hisatake, Shintaro;Nagatsuma, Tadao
在太赫兹（THz）频率下产生具有亚波长光束压缩能力的太赫兹（THz）射流吸引了越来越多的研究兴趣，在光学频率下产生纳米射流也是如此。特别是，从介电长方体产生的terajet以前没有在太赫兹区域实验研究。在这里，我们实验演示了三维可视化和表征的terajet产生的介电长方体的折射率为n = 1.46，在125 GHz。直接观察到了亚波长压缩光束和太赫兹射流的Gouy相移现象。同时还发现，基于高斯光束经透镜聚焦的Gouy相移计算模型不能很好地解释太赫兹射流压缩光束的Gouy相移。在距离长方体0.5 λ处获得约7.4 dB的强度增强和0.6 λ的半高全宽。出版社：AIP Publishing
The generation of the terajet at the terahertz (THz) frequency with the capability of subwavelength beam-compression has been attracting increasing research interest, as did the generation of the nanojet at the optical frequency. In particular, a terajet generated from a dielectric cuboid was not previously studied experimentally in the THz region. We here experimentally demonstrate three-dimensional visualizations and characterization of a terajet generated from a dielectric cuboid with a refractive index of n = 1.46 at 125GHz. The subwavelength compressed beam and the Gouy phase shift phenomena of the terajet are directly observed. It is also found out that a calculation model of Gouy phase shift based on focused Gaussian beam by a lens cannot explain the Gouy phase shift of compressed beam by the terajet. The intensity enhancement of about 7.4 dB and full width at half maximum of 0.6 lambda are obtained at the distance 0.5 lambda from the cuboid. Published by AIP Publishing.