Ultra-Fast Dual-Stage Vertical Positioning for High Performance SPMs

A major speed limitation of Scanning Probe Microscopes (SPMs) is the low vertical feedback bandwidth imposed by the mechanical scanner resonances. The vertical feedback controller regulates the tip-sample interaction in application modes such as constant-current scanning tunneling microscopy and constant-force atomic force microscopy. To increase the vertical feedback bandwidth, dual-stage actuators have been proposed to increase the first resonance frequency. In this work, an ultra-fast dual-stage vertical positioner and control system are described. The first resonance frequency of the dual-stage positioner is 88 kHz which permits a one-hundred fold speed increase of a commercial AFM. The dual-stage system is simple, low-cost and can be retrofitted to almost any commercial SPM.