Phase-shift anomaly caused by subwavelength-scale metal slit or aperture diffraction

作者：Lee Kanghee; Yi Minwoo; Park Sang Eon; Ahn Jaewook^*

来源：Optics Letters, 2013, 38(2): 166-168.

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 degrees phase advance is induced from a subwavelength slit diffraction and that 180 degrees phase-advance from a subwavelength aperture. These results indicate that the conventional 90 degrees 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.

• 出版日期2013-1-15