[The interior relation between FDP and SHG]

Abstract

The fluorescence-disappearing phenomenon (FDP) was used due to the nonlinear interaction between the laser and the matter, a universal phenomenon. It was often neglected during the research of surface-harmonic generation (SHG). Many experiments showed that there was a interior relation between FDP and SHG. In this paper, the mechanism of surface-harmonic generation has been discussed in detail, according to the fluorescence-disappear viewpoint and the fluorescence-disappear model (FDM) proposed also. The new mechanism was summarized by following three points: (a) The multiphoton absorption generated visible fluorescence spot, (b) Laser-heating effect and other effects promoted the conversion from spontaneous emission into quasi-stimulated emission, (c) Being accompanied by the fluorescence disappear, the part of laser energy which was initially used to cause fluorescence was now converted into developing the harmonic signal.