The results from our recent molecular dynamics and electronic calculations studies of the interaction of ultraviolet light with poly(methyl methacrylate) are discussed. Molecular dynamics simulations in the photochemical and photothermal regimes demonstrate the delayed onset of ablation due to the slow pressure relaxation in the polymeric material. Electronic structure calculations show the pos...

In this work, large-scale hybrid atomistic-macroscale simulation is performed to study the long-time material behavior in nanosecond laser–material interaction. Different phase change phenomena are studied, including solid–liquid interface speed, temperature, maximummelting depth, and ablation rate. Full solidification/epitaxial re-growth is observed within 60 ns for the laser fluence of 5 J/m....

A laser ablation-inductively coupled plasma-mass spectrometric (LA-ICPMS) technique utilizing a titanium-sapphire (TiS) femtosecond laser (fs-laser) has been developed for elemental and isotopic analysis. The signal intensity profile, depth of the ablation pit and level of elemental fractionation were investigated in order to evaluate the analytical capability of the present fs-laser ablation-I...

Nanoporous carbon films were deposited by 248 nm pulsed laser ablation of a graphite target in different background pressures of argon (PAr). The morphology changed from smooth, high-density amorphous carbon films at PAr = 20 mTorr to ultra-low density nanoporous material at PAr = 380 mTorr. Subsequently, the nanostructural, chemical and electrical properties of metal containing nanoporous carb...

The drilling of copper using a dual-pulse femtosecond laser with wavelength of 800 nm, pulse duration of 120 fs and a variable pulse separation time (0.1–150 ps) is investigated theoretically. A one-dimensional two-temperature model with temperature-dependent material properties is considered, including dynamic optical properties and the thermal-physical properties. Rapid phase change and phase...

In 1982, the first reports of laser ablation of polymers were issued almost simultaneously by Y. Kawamura et al.1 and R. Srinivasan et al.2 Srinivasan went on to become a leader in the field of polymer ablation. Srinivasan probably also coined the terms laser ablation and ablative photodecomposition, now in common use. The onset of material removal by laser ablation characteristically occurs at...

Thermal-optical evolved gas analysis (TOEGA) is a conventional method for classifying carbonaceous aerosols as organic carbon (OC) and elemental carbon (EC). Its main source of uncertainty arises from accounting for pyrolized OC (char), which has similar behavior to the EC originally present on the filter. Sample composition can also cause error, at least partly by complicating the charred carb...