Near-field microscopy system and construction method thereof

The invention provides a near-field microscopy system and a construction method thereof. The near-field microscopy system comprises an infrared/terahertz laser, a light path coupling module and an atomic force microscope. Accurate imaging and spectrum formation can carried out on morphology, physicochemical and molecular characteristics of a sample under a sub-wavelength scale. According to the photo-induced thermal expansion effect of infrared/terahertz dual-band adjustable radiation, thermal expansion deformation of the material is associated with infrared/terahertz characteristic absorption, and structural property information of the material is directly extracted through an atomic force probe. According to the invention, an infrared/terahertz optical detector does not need to be arranged at the far end, thereby avoiding violent signal attenuation caused by long-distance transmission; a reference light path does not need to be arranged, and the repeatability and reliability of material sub-wavelength struc