scattering-type Scanning Near-field Optical Microscope based on pseudoheterodyne detection method to map near-field phase and intensity  Available scanning probe methods include Atomic Force Microscopy (AFM), Conductive AFM, Kelvin Force Probe Microscopy, Piezo-Scanning Microscope, and Apertureless-Tip scattering-SNOM etc.  AFM scanning modes include tapping mode and contact mode. s-SNOM can be with or without pseudoheterodyne mode (Ps-Het) where the Ps-Het mode not only enables the phase and intensity near-field measurements but also suppresses the background and enhances the near-field optical resolution.  Spatial and optical resolutions depend on the tip apex size which is about 20 nm.  The sample illumination can be either from above in reflection mode (incoming and detection beam paths coincide) or from bottom in transmission mode (incoming and detection beam paths do not coincide). The samples are observed from above and can be opaque or transparent.  Thanks to the mirror optics used in the system, the system can work with lasers from VIS to IR (400-10000 nm). Currently, the system integrated with excitation lasers at 640 nm (CW) and 530 nm (CW) and a tunable laser 1260-1630 nm.