A SHEAR FORCE FEEDBACK-CONTROL SYSTEM FOR NEAR-FIELD SCANNING OPTICALMICROSCOPES WITHOUT LOCK-IN DETECTION

Authors
HSU JWP MCDANIEL AA HALLEN HD
Citation
Jwp. Hsu et al., A SHEAR FORCE FEEDBACK-CONTROL SYSTEM FOR NEAR-FIELD SCANNING OPTICALMICROSCOPES WITHOUT LOCK-IN DETECTION, Review of scientific instruments, 68(8), 1997, pp. 3093-3095
Citations number
7
Categorie Soggetti
Physics, Applied","Instument & Instrumentation
Journal title
Review of scientific instruments → ACNP
ISSN journal
00346748
Volume
68
Issue
8
Year of publication
1997
Pages
3093 - 3095
Database
ISI
SICI code
0034-6748(1997)68:8<3093:ASFFSF>2.0.ZU;2-#
Abstract
An improvement to the currently used ac impedance detection method for tip-sample distance control in near-field scanning optical microscope s is described and demonstrated. The output signal of the electronic b ridge is increased by a factor of 5000 so that a root-mean-square chip can be used in place of sensitive lock-in detection. It is shown that the signal-to-noise ratio of this new method is high enough to detect 0.07 nm changes in topography. In addition, this modification makes t he electronics for the shear force feedback compact and inexpensive. ( C) 1997 American Institute of Physics.