Abstract
Generation fields in a laser ablation system for synthesizing ultra-fine particles in He gas were dynamically visualized by using a scatterplate interferometer, which was designed for in-situ and real-time observation of gas density and furthermore temperature distribution. The observed time-variation of the generation field's gas density distribution, which relates to the gas temperature distribution, shows that the Hegas temperature does not exactly correspond to the ablation laser shots, there exists a time constant which leads to the He gas slowly being heated up and cooling off between laser shots. Since the diameter distribution ofthe synthesized nano particles is sensitive to the ambient gas temperature, real-time observation of the gas temperature variation will be useful for controlling the particle properties.
