摘要
The atom force microscope (AFM)can be used to investigate surface structures of different kinds of materials including organic molecules, and without any requirement for material conduction. N-(4-nitmphenyl)-(L)-prolinol (NPP), as one organic second-order nonlinear optical crystal, has very large nonlinear efficiency. This is attributed to the employment of the chirality and hydrogen-bonding in the molecule, so that the angle between the molecular charge transfer axis and the binary axis (58.6°) is close to the optimal angle (54.74°). Since its fast publication in 1984, there have been many studies about
