Sub-10-nm three-dimensional plasmonic probes and sensors

Plasmonic antennas have been investigated as potential sensing element since long, but great part of the efforts on the nanofabrication have been devoted to the 2 dimensional patterning. Many times the the “sensing or probing” processes require geometries of the probe that are more complicated than the simple flat surface. In this paper we are going to show some example of three dimensional structures and their plasmonic properties as well as their application as sensors for IR spectroscopy and probes for Near-field scanning optical microscopy. We will present a series of structures and their characterization in IR as well as visible light. Particularly we will focus on the NSOM application. It is a powerful and unique approach to characterize the chemical, physical and biochemical properties of materials with the nanometer scale resolution in real-time [1]. One of the main challenges in using NSOM for a broad range of applications is the development of reproducible and efficient near-field probes. A novel class of nano-optical probes has been recently proposed, namely “campanile”. Campanile tips consist of a 3-Dimensional (3D) tapered structure terminated by a plasmonic nano-antenna, which provides superior NSOM performance and decisive advantages [2]. We will present a novel approach to drastically simplify the fabrication of Campanile probes by ultraviolet nanoimprint lithography (UV-NIL) directly on the facet of commercial optical fibers, without the need to use FIB (Fig. 1). The 3D mold is fabricated by a combination of polymer embossing and FIB lithography in a Helium Ion Beam. We will show some characterization [3] measurement as well as some NSOM hyperspectral images.