Near Axis Theory in Optics——A Discussion of Optical Path Calculation in Geometrical Optics

The physical optics shows that light has both wave and particle characteristic. The quality of an image in a real optical system will be limited by diffraction. In the geometrical optics, the research of light propagation is only approximate. In the light of the near axis theory in geometrical optics,this paper discusses the imagery experiment and theory calculation when light goes through an optical system. It gets a feasible conclusion of optical path calculation in geometrical optics.