Evolution of Laser-Induced Incandescence of Porous Carbon Materials under Irradiation by a Sequence of Laser Pulses

For porous carbon samples made of bio-materials (nutshells) by pyrolysis, laser-induced incandescence is investigated under irradiation by a sequence of pulses of a Q-switched YAG:Nd laser. For the intensity of LII as a function of the laser irradiation dose, two- or threestage kinetics is observed depending on the incident laser intensity. Physical mechanisms of the observed increase and decrease of LII with the irradiation dose are discussed. The mechanisms include transformations of structure of the irradiated surface layer due to the vaporization of carbon. Besides, the effect of heating of the whole sample on the intensity of LII is also considered.