Morphological and spectroscopic characterization of laser-ablated tungsten at various laser irradiances

摘要: The variation in surface morphology and plasma parameters of laser irradiated tungsten has been investigated as a function irradiance. For this purpose, Nd:YAG (1064 nm, 10 ns, 10 Hz) is employed. Tungsten targets were exposed to various irradiances ranging from 6 50 GW/cm2 under ambient environment argon at pressure 20 Torr. Scanning electron microscope analysis performed analyze the modification tungsten. It revealed formation micro- nanoscale structures. In central ablated area, distinct grains crack are observed, whereas peripheral areas dominated by cones pinhole formation. was observed that exceeding value 13 GW/cm2, morphological trend structures changed erosion melting re-deposition dominant phase. Ablation efficiency irradiance also measuring crater depth using profilometry analysis. found be maximum an decreases high irradiances. order correlate accumulated effects with modification, laser-induced breakdown spectroscopy performed. temperature number density have evaluated Initially increase up increasing for both due enhanced energy deposition. Afterward, decreasing achieved which attributed shielding effect. With further irradiance, saturation stage comes insignificant changes parameters. This explainable on basis self-regulating regime near target surface. Surface modifications correlated