Lateral deflection-based optimization achieves sub-picometer detection limit

Sub-picometer precision displacement measurement at the tip position is a key goal in high-precision characterization techniques such as piezoresponse force microscopy, photo-induced force microscopy, and scanning Joule expansion microscopy (SJEM). However, these methods require specialized atomic force microscopy (AFM) probes, which increase cost and complexity. This work proposes a generalized strategy and demonstrates its implementation in SJEM. By exploiting the torsional response of a tilted AFM probe to amplify the deformation signal, we enhanced the sensitivity by nearly an order of magnitude, achieving a record-breaking displacement resolution of 0.37 pm. This method allows flexible adjustment of sensitivity and decouples in-plane and out-of-plane displacements. This work establishes a transferable, AFM-based strategy for high-sensitivity displacement detection, providing valuable guidance for high-precision characterization and analysis of materials and devices at the nanoscale.