FDTD method for laser absorption in metals for large scale problems.

Area of Science:

• Computational Electromagnetics
• Laser-Material Interactions
• Computational Physics

Background:

• The Finite-Difference Time-Domain (FDTD) method is a powerful tool for electromagnetic simulations.
• Traditional FDTD applications in laser material processing are constrained by the computational cost of large grid sizes.
• Simulating millimeter-scale domains for laser absorption in metals requires significant computational resources.

Purpose of the Study:

• To develop a novel FDTD method for simulating large-scale laser beam absorption problems, particularly in metals.
• To overcome the limitations of conventional FDTD methods in handling extensive simulation domains for laser processing.
• To enable more efficient and accurate simulations of laser-metal interactions.

Main Methods:

• Proposed a modified FDTD approach by enlarging the laser wavelength while preserving material reflection properties.
• Validated the novel FDTD method using in-house FDTD codes.
• Simulated irradiation of Fe and Sn targets with p-, s-, and circularly polarized 1.06 μm laser light.

Main Results:

• The developed FDTD method successfully simulated large-scale laser beam absorption problems.
• Simulation outcomes for iron (Fe) and tin (Sn) targets showed excellent agreement with theoretical predictions.
• The method demonstrated effectiveness for various polarization states of laser irradiation.

Conclusions:

• The novel FDTD method provides an efficient solution for simulating large-scale laser absorption in metals.
• This approach significantly reduces the computational burden associated with traditional FDTD simulations in laser material processing.
• The validated method offers a promising tool for advancing research and applications in laser-based material treatments.