Scanning probe microscopy upgrade for double-modulation imaging capability

扫描探针显微镜（SPM）是纳米技术研究中常用的一种系统，用于在原子和分子尺度上研究表面和界面的性质。自发明以来，SPM经历了一系列的变革，不断提高其可靠性和适用性。特别地，增加调制能力允许在待探测的系统的多样性中的相当大的增加。一个典型的SPM系统由一个“显微镜”和一个“控制器”组成。显微镜包含一个用于探测样品的“工具”（通常是尖锐的尖端），一个能够控制尖端相对于样品的位置的电气/机械设备（通常是压电扫描仪）和一个控制尖端和样品之间相互作用的系统。控制器是一组产生显微镜操作所需信号的电子模块，可以被视为用户和实验之间的接口。因此，SPM系统的整个多功能性取决于控制器提供的能力。

A scanning probe microscope (SPM) is a system commonly used in Nanotechnology research to study the properties of surfaces and interfaces at the atomic and molecular scale. Since its invention, the SPM has undergone a series of transformations that continuously improved its reliability and applicability. In particular, adding modulation capability allows for a considerable increase in the diversity of systems to be probed. A typical SPM system is composed of a "microscope" and a "controller". The microscope contains a "tool" used to probe the sample (typically a sharp tip), an electric/mechanical device able to control both the position of the tip with respect to the sample (usually a piezoelectric scanner) and a system that controls the interaction between tip and sample. The controller is a set of electronic modules that generate the signals necessary for the operation of the microscope, and can be regarded as an interface between the user and the experiment. Thus the whole versatility of the SPM system depends on the capabilities offered by the controller.