Open AccessOptical field enhancement of nanometer-sized gaps at near-infrared frequencies
Author(s) -
J. S. Ahn,
Tae Sun Kang,
Dilip K. Singh,
YoungMi Bahk,
Hyunhwa Lee,
Soo Bong Choi,
DaiSik Kim
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.004897
Subject(s) - optics , materials science , electric field , terahertz radiation , near and far field , field (mathematics) , near field scanning optical microscope , interferometry , infrared , optoelectronics , physics , optical microscope , scanning electron microscope , mathematics , quantum mechanics , pure mathematics
We report near-field and far-field measurements of transmission through nanometer-sized gaps at near-infrared frequencies with varying the gap size from 1 nm to 10 nm. In the far-field measurements, we excluded direct transmission on the metal film surface via interferometric method. Kirchhoff integral formalism was used to relate the far-field intensity to the electric field at the nanogaps. In near-field measurements, field enhancement factors of the nanogaps were quantified by measuring transmission of the nanogaps using near-field scanning optical microscopy. All the measurements produce similar field enhancements of about ten, which we put in the context of comparing with the giant field enhancements in the terahertz regime.