Research on acoustical properties of the femtosecond laser ablation targets using fiber optic sensing probe

The acoustic signals of the laser micro plasma expansion for the femtosecond laser ablating pure Al, Cu and Fe target materials have been detected by the fiber Fabry–Perot (F–P) acoustic emission sensing probe. The frequency and amplitude of the acoustic emission spectrum have been analyzed. The results show that the detected acoustic emission frequency spectrum pattern is fixed and different for the three kinds of target materials. The amplitude of the acoustic emission spectrum grows up along with the enhancement of laser ablation energy. The amplitude of the acoustic emission spectrum decreases when the detection distance is enlarged. The developed measuring system provides a potential method aiming at the detection of solid materials based on the acoustic signals excided by femtosecond laser ablating target materials using the fiber F–P acoustic emission sensing probe.