Pulsed laser heating of soot: morphological changes Original Research Article

Pulsed laser heating of carbon soot is used here to achieve heating in excess of 1011 K s−1, cooling rates on the order of 109 s−1 and total integrated times at elevated temperature of ca 1 milliseconds. To resolve detailed morphological changes induced in the soot by pulsed high intensity laser light, high resolution transmission electron microscopy and selected area electron diffraction are used to examine the laser-heated soot. Partial graphitization, formation of hollow particles and the average number of graphitic planes formed within soot primary particles upon high intensity pulsed laser heating are explained via a thermal annealing mechanism. This mechanism is discussed in the context of the initial physical structure of the soot.