Vision-based position control applied to probe positioning for Tip Enhanced Raman Spectroscopy

This paper describes equipment and method for an automatic three-dimensional object positioning system using two-dimensional visual feedback provided by a single camera. This is one variation of the vision-based position control technique, which is widely used in many robotics applications for object manipulation. The instrumentation here presented handles the automatic positioning of a nanometric scanning probe over a laser spot, using visual information to provide feedback for a control logic. This procedure is one of the necessary setup steps to perform Tip Enhanced Raman Spectroscopy (TERS), which requires a nanoantenna to be positioned at a distance of only a few nanometers away from the sample, and located at the center of a laser spot. The proposed methodology is then tested on an experimental TERS setup, illustrating the method's performance.