Femtosecond laser filament ablated grooves of SiC ceramic matrix composite and its grooving monitoring by plasma fluorescence

Silicon carbide ceramic matrix composites (SiC CMC) have excellent properties for applications but is challenging to precisely process, in particular for curved surfaces and deep through-holes. A long interaction range of femtosecond laser filament with sufficiently high intensity may open the opportunity. In this work, femtosecond laser filament was used to ablate grooves on the surface of SiC CMC. The effects of different filament positions, pulse energies, scanning speeds and scanning times on filament ablated grooves were investigated. The plasma fluorescence from filament ablated SiC CMC was collected to monitor filament micro-grooving processes. The variation of fluorescence spectral lines of SiⅠ390.55 nm reflects the removal rate of material surface with different processing parameters, which helps understand the filament ablated grooves processes. Although using plasma fluorescence to monitor filament ablated SiC CMC was demonstrated by the intensity measurement, the method can be in principle extended for online imaging the laser ablation process.