Young’s experiment with a double slit of sub-wavelength dimensions

Kanghee Lee,Jaewook Ahn,Jongseok Lim

doi:10.1364/oe.21.018805

Kanghee Lee, Jaewook Ahn + Show 1 more

Open Access

https://doi.org/10.1364/oe.21.018805

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Abstract

We report that the interference pattern of Young's double-slit experiment changes as a function of polarization in the sub-wavelength diffraction regime. Experiments carried out with terahertz time-domain spectroscopy reveal that diffracted waves from sub-wavelength-scale slits exhibit either positive or negative phase shift with respect to Gouy phase depending on the polarization. Theoretical explanation based on the induction of electric current and magnetic dipole in the vicinity of the slits shows an excellent agreement with the experimental results.

Highlights

Wave diffraction from an aperture is considered well understood in the context of Kirchhoff’s scalar diffraction theory [1, 2]
Our previous study considered the diffraction phase of sub-wavelength-scale apertures and slits, in which the size-dependent phase shifts were caused by induced electric currents and effective magnetic dipoles in the sub-wavelength regime [12, 13]
We study the polarization dependence of the sub-wavelength diffraction phase and its consequence on Young’s double-slit interference patterns

Summary

Introduction

Wave diffraction from an aperture is considered well understood in the context of Kirchhoff’s scalar diffraction theory [1, 2]. When aperture size becomes equivalent to or smaller than the wavelength, vectorial nature of electromagnetic waves results in novel sub-wavelength optical phenomena [3,4,5,6,7,8,9,10,11]. Our previous study considered the diffraction phase of sub-wavelength-scale apertures and slits, in which the size-dependent phase shifts were caused by induced electric currents and effective magnetic dipoles in the sub-wavelength regime [12, 13]. We study the polarization dependence of the sub-wavelength diffraction phase and its consequence on Young’s double-slit interference patterns. As the diffraction phase is strongly coupled with the polarization state of the incident wave, the diffraction pattern shows polarization-dependent behavior

Young’s double-slit interference pattern in the sub-wavelength regime

Experimental description

Polarization dependence of sub-wavelength-scale single-slit diffraction

Results of double-slit interference pattern in the sub-wavelength regime

Conclusion