Resonance-enhanced Third Harmonic Generation in Mn⁺-dominated Laser-induced Plasmas

Even though laser-produced plasmas (LPPs) have been known and employed for a long time, a complete understanding of certain aspects of their generation and dynamics remains elusive, owing to the strong interactions among the contributing processes, especially in the nanosecond-pulse irradiation regime. A profound understanding of LPPs is important for their applications in fields like laser-induced breakdown spectroscopy, pulsed laser deposition (PLD), laser processing of materials, nanofabrication and nano-structuring, material analysis and monitoring in medicine, harmonic generation or extreme-ultraviolet lithography, among others. Given the complex processes involved, its transient nature, and the significant variations in plasma properties with space and time, analyzing LPPs can be a truly challenging task. Optical emission spectroscopy (OES) with time and space resolution is a powerful method that can help better understand the laser-plasma interaction [1], [2].