Modified driving force profile in the coupled oscillator model of femtosecond pulsed laser ablation

Abstract

We explore the response of an oscillator system subjected to various driving force profiles specifically, Lorentzian, hyperbolic secant (sech), and linear exponential (LE) functions to better understand the energy deposition described by the TTM. By incorporating the thermophysical properties of copper into the model, we assess how each driving force profile influences the motion of the oscillator. Among the driving force profile, Lorentzian and sech profiles exhibit high sideband forces with reduced magnitude of force, resulting in earlier but lower displacement for m₁. The velocity of m₁ decelerates after the driving force, while m₂ shows a gradual increase in velocity. The LE profile delivers force rapidly due to its inherent skewness but eventually mimics the response of a Gaussian pulse. Our analysis highlights that although sideband forces contribute to early motion, the magnitude of force ultimately dominates the system’s response.