Laser-induced thermal emission of boron carbide

Properties of laser-induced thermal emission of surface layers of boron carbide under irradiation with Q-switched laser pulses were experimentally investigated. A significant dependence of the amplitude and duration of thermal radiation pulses on the intensity and dose of laser irradiation was revealed. Irradiation with a sequence of laser pulses reduced the amplitude and duration of thermal emission pulses by several times. Anisotropy of the laser-induced thermal emission, manifested as dependence of the emission pulse duration on the observation direction, was observed. In particular, when the emission was detected along the sample surface, the pulse duration was several times longer than when observing perpendicular to the sample surface. These features were explained by melting and solidification processes of boron carbide under laser irradiation and by inhomogeneity of laser heating of rough surfaces.