Interactions of microwaves with alumina surface in microwave-enhanced laser-induced breakdown spectroscopy

•The microwave and the laser-induced plasma interaction were analyzed using an alumina target.•Delayed microwave-plasma interaction slowed down the plasma expansion.•At maximum absorbed power, the microwave enlarged the plasma.•The microwave also enhanced the emission of the laser-induced plasma.•The microwave did not influence the ablation crater generated by laser ablation.