In-Plane Plasmonic Antenna Arrays with Surface Nanogaps for Giant Fluorescence Enhancement.
Optical nanoantennas have a great potential for enhancing light-matter interactions at the nanometer scale, yet fabrication accuracy and lack of scalability currently limit ultimate antenna performance and applications. In most designs, the region of maximum field localization and enhancement (i.e., hotspot) is not readily accessible to the sample because it is buried into the nanostructure. Moreover, current large-scale fabrication techniques lack reproducible geometrical control below 20 nm. Here, we describe a new nanofabrication technique that applies planarization, etch back, and template stripping to expose the excitation hotspot at the surface, providing a major improvement over conventional electron beam lithography methods. We present large flat surface arrays of in-plane nanoantennas, featuring gaps as small as 10 nm with sharp edges, excellent reproducibility and full surface accessibility of the hotspot confined region. The novel fabrication approach drastically improves the optical performance of plasmonic nanoantennas to yield giant fluorescence enhancement factors up to 104-105times, together with nanoscale detection volumes in the 20 zL range. The method is fully scalable and adaptable to a wide range of antenna designs. We foresee broad applications by the use of these in-plane antenna geometries ranging from large-scale ultrasensitive sensor chips to microfluidics and live cell membrane investigations.
Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland.
Valentin
0000-0002-1393-3198
V
Flauraud
Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France.|ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
Raju
R
Regmi
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
Pamina M
PM
Winkler
Interdisciplinary Center for Electron Microscopy (CIME) Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland.
Duncan T L
DT
Alexander
Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France.
Hervé
H
Rigneault
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.|ICREA , Pg. Lluís Companys 23, 08010 Barcelona, Spain.
Niek F
0000-0003-4630-1776
NF
van Hulst
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.|ICREA , Pg. Lluís Companys 23, 08010 Barcelona, Spain.
María F
MF
García-Parajo
Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France.
Jérôme
0000-0002-2145-5341
J
Wenger
Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland.
Jürgen
0000-0002-7710-5930
J
Brugger
Optical nanoantennas; electron beam lithography; fluorescence enhancement; plasmonics; template stripping