Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.


Microcantilever based distance control between a probe and a surface

(full pdf)

R. Molenaar, J. C. Prangsma, K. O. van der Werf, M. L. Bennink, C. Blum and V. Subramaniam
Review of Scientific Instruments
vol. 86, p. 063706 june 2015

We demonstrate a method to control the distance between a custom probe and a sample on a ┬Ám to
nm scale. The method relies on the closed-loop feedback on the angular deflection of an in-contact AFM microcantilever. High performance in stability and accuracy is achieved in this method by taking advantage of the small mechanical feedback path between surface and probe. We describe how internal error sources that find their origin in the microcantilever and feedback can be minimized to achieve an accurate and precise control up to 3 nm. In particular, we investigated how hysteresis effects in the feedback caused by friction forces between tip and substrate can be minimized.
By applying a short calibration procedure, distance control from contact to several micrometers
probe-sample distance can be obtained with an absolute nanometer-scale accuracy. The method
presented is compatible with any probe that can be fixed on a microcantilever chip and can be easily built into existing AFM systems.
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