Laser-sustained plasmas (LSPs), as broadband high-intensity light sources for wafer inspection, are currently limited by brightness instability from buoyancy-induced convective oscillations. In this work, we derive a vorticity-resolved scaling law for LSP oscillation frequencies $f_{\mathrm{os}}$, fully incorporating heat capacity $C_{\mathrm{p}}$, thermal conductivity $k_{\mathrm{T}}$, gravitational acceleration $g$, mass density $\rho$, and density ratio ${\sigma }_{\mathrm{den}}$, i.e., $f_{\mathrm{os}}=\mathcal{F}({\sigma }_{\mathrm{den}},g,C_{\mathrm{p}},k_{\mathrm{T}},\rho )$, providing a generalized scaling relation for LSP oscillations. The established hydro-thermal-laser-coupled simulations reveal that higher $(C_{\mathrm{p}},\rho )$ or lower $k_{\mathrm{T}}$ reduces vortex detachment height through thermal diffusivity modulation, while a larger $g$ theoretically amplifies the vortex transport, both increasing the LSP oscillation frequency. The generalized scaling law enables predictive control of LSP stability, enhancing the precision of high-resolution wafer optical inspection.

Close

PrevNext

View figure in article

• Laser-plasma interactions
• Plasma instabilities
• Plasma oscillations
• Vortex dynamics
• Arc discharge
• Imaging & optical processing
• Navier-Stokes equation
• Scaling methods