Abstract
Terahertz time-domain spectroscopy probes anomalous phase-shift caused by wave diffraction from a subwavelength-scale metal slit or aperture. Carrier frequency phase measurements in the far-field region reveals that nearly 30° phase advance is induced from a subwavelength slit diffraction and that 180° phase-advance from a subwavelength aperture. These results indicate that the conventional 90° phase advance of diffracted waves in the far-field region, known as the Gouy phase shift, is not valid for subwavelength diffraction phenomena. The physical origin of these phase-shift anomalies is attributed to induced electric currents or magnetic dipole radiation, and theoretical analyses based on these factors are in good agreement with the experimental results.
© 2013 Optical Society of America
Full Article | PDF ArticleMore Like This
Kanghee Lee, Jongseok Lim, and Jaewook Ahn
Opt. Express 21(16) 18805-18811 (2013)
Daehoon Han, Kanghee Lee, Hanlae Jo, Yunheung Song, Minhyuk Kim, and Jaewook Ahn
Opt. Express 24(19) 21276-21285 (2016)
Myun-Sik Kim, Toralf Scharf, Christoph Menzel, Carsten Rockstuhl, and Hans Peter Herzig
Opt. Express 21(1) 1287-1300 (2013)