A new detection system for extremely small vertically mounted cantilevers

M Antognozzi, A Ulcinas, L Picco, S.H Simpson, P.J Heard, M.D Szczelkun, B Brenner, M.J Miles

Research output: Contribution to journalArticle (Academic Journal)

33 Citations (Scopus)

Abstract

Detection techniques currently used in scanning force microscopy impose limitations on the geometrical dimensions of the probes and, as a consequence, on their force sensitivity and temporal response. A new technique, based on scattered evanescent electromagnetic waves ( SEW), is presented here that can detect the displacement of the extreme end of a vertically mounted cantilever. The resolution of this method is tested using different cantilever sizes and a theoretical model is developed to maximize the detection sensitivity. The applications presented here clearly show that the SEW detection system enables the use of force sensors with sub-micron size, opening new possibilities in the investigation of biomolecular systems and high speed imaging. Two types of cantilevers were successfully tested: a high force sensitivity lever with a spring constant of 0.17 pN nm(-1) and a resonant frequency of 32 kHz; and a high speed lever with a spring constant of 50 pN nm(-1) and a resonant frequency of 1.8 MHz. Both these force sensors were fabricated by modifying commercial microcantilevers in a focused ion beam system. It is important to emphasize that these modified cantilevers could not be detected by the conventional optical detection system used in commercial atomic force microscopes.
Translated title of the contributionA new detection system for extremely small vertically mounted cantilevers
Original languageEnglish
Article number384002
Pages (from-to)1 - 10
Number of pages10
JournalNanotechnology
Volume19
Issue number38
DOIs
Publication statusPublished - Aug 2008

Bibliographical note

Publisher: IOP Publishing

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