Controlling the phase delay of light transmitted through double-layer metallic subwavelength slit arrays

• Published in: Optics letters 2008-07, Vol.33 (13), p.1410-1412
• Main Authors: MARCET, Z, PASTER, J. W, CARR, D. W, BOWER, J. E, CIRELLI, R. A, KLEMENS, F, MANSFIELD, W. M, MINER, J. F, PAI, C. S, CHAN, H. B
• Format: Article
• Language: English
• Subjects: Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Micro- and nanooptical devices; Optics; Physics; Surface and interface electron states
• ISSN: 0146-9592; 1539-4794
• DOI: 10.1364/OL.33.001410

We demonstrate that the phase of light transmitted through double-layer subwavelength metallic slit arrays can be controlled through lateral shift of the two layers. Our samples consist of two aluminum layers, each of which contains an array of subwavelength slits. The two layers are placed in sufficient proximity to allow coupling of the evanescent fields at resonance. By changing the lateral shift between the layers from zero to half the period, the phase of the transmitted electromagnetic field is increased by pi, while the transmitted intensity remains high. Such a controllable phase delay could open new capabilities for nanophotonic devices that cannot be achieved with single-layer structures.