Aperture Probes Conditioning for Scanning Near-Field Optical Microscopy

This application note is part of the Top Nano 21 Project #5101.1 conducted by Julien Toquant, Alexandre Bouhelier*, D.W. Pohl, and H.-J. Guenterhodt. Institute for Physics, University of Basel - Switzerland. (*) present address: Institute of Optics, Rochester, USA

Introduction

Since the middle of the eighties, SNOM promised the chemical specificity not provided by any other scanning probe microscopy. Up to now the application of SNOM was limited by the lack of precision, stability and reproducibility to a large extend. Indeed probes were manufactured at low production cost. CASSE (Controlled All Solid State Electrolysis), the technique we developed here, overcomes these drawbacks, allowing SNOM to be a promising tool for future science.

See also the precise scans made with demetallized tips and the BioLyser SNOM

Principal
Legend: L: laser source, CE: control electronics, S: voltage source, I/V: current/tension converter

For more information about the process contact Julien Toquant at Univeristy of Basel
Demetallization & Remetallization

In situ conditioning of the tip:

-demetallization (opening)
-remetallization (closing)

Patent application # 0810319.4-2217.
Side view Top view After closing of the aperture (SEM image)
Gallery of tips end faces with aperture between 25 and 60 nm (electron microscope images)