Nanoscale optical imaging with photoinduced force microscopy in heterodyne amplitude modulation and heterodyne frequency modulation modes

In this review, we introduce the operating principle of photoinduced force microscopy (PiFM) and its applications. First, we introduce that the photoinduced force includes the gradient force and the scattering force. Next, we explain how to eliminate the effects of photothermal effects on the metal tip and sample surface caused by light irradiation. Then, we introduce a PiFM operating in air based on the tapping mode and present images of SiNc clusters. Furthermore, we introduce a PiFM operating in vacuum based on the frequency modulation (FM) mode, and present the results of three-dimensional photo-induced force vector measurements of semiconductor quantum dots.