A Simple Model to Describe the Requirement of Realizing All-Optical Poling

All-optical poling (AOP) of a crosslinkable polymer based on hexamethoxymethyl melamine (HMMM) and Disperse red 1 (DR-1) is investigated. It is found that the saturation second harmonic generation (SHG) intensity decreases significantly with the increase of the sample temperature from 33°C to 63°C. From the perspective of energy equilibrium, the main factors of AOP are analysed, and by introducing the classical ideal gas model, a simple inequation is first deduced to describe the requirement of realizing AOP.