Effect of Nanohole Spacing on the Self-Imaging Phenomenon Created by the Three-Dimensional Propagation of Light through Periodic Nanohole Arrays

• Published in: Journal of physical chemistry. C Vol. 116; no. 37; pp. 19958 - 19967
• Main Authors: Chowdhury, Mustafa H, Lindquist, Nathan C, Lesuffleur, Antoine, Oh, Sang-Hyun, Lakowicz, Joseph R, Ray, Krishanu
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 20.09.2012
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanoscale pattern formation; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Silver; Optical microscopy; Nanopatterning; Light propagation; Illumination; Near-field scanning optical microscopy; Nanostructures; Plasmonics; Arrays; Focused ion beam technology; Finite difference method; Near-field microscopy; Subwavelength structures; Surface plasmons; Talbot and self-imaging effects
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp306179d

We present a detailed study of the inter-nanohole distance that governs the self-imaging phenomenon created by the three-dimensional propagation of light through periodic nanohole arrays on plasmonic substrates. We used scanning near-field optical microscopy (SNOM) to map the light intensity distributions at various heights above 10 × 10 nanohole arrays of varying pitch sizes on silver films. Our results suggest the interhole spacing has to be greater than the wavelength of the incident light to create the self-imaging phenomenon. We also present finite-difference time-domain (FDTD) calculations which show qualitative corroboration of our experimental results. Both our experimental and FDTD results show that the self-imaging phenomenon is more pronounced for structures with larger pitch sizes. We believe this self-imaging phenomenon is related to the Talbot imaging effect that has also been modified by a plasmonic component and can potentially be used to provide the basis for a new class of optical microscopes.