Modeling the effects of high laser intensity on liquid crystals using real-time, time-dependent density functional theory (RT-TDDFT)

Liquid crystals (LC’s) are remarkably resistant to damage from high-energy single-or multi-pulse laser beams. Their laser-induced damage threshold (LIDT) depends on both the incident laser properties and pi-electron delocalization in the LC molecular structure. Real-time, time-dependent density functional theory (RT-TDDFT) was employed to model changes in pi-electron density distribution in LC’s as a function of time and laser fluence as 1053 nm, 22 fs laser pulses propagated though the material. Electron density maps reveal that changes in-pielectron density distribution become irreversible above a certain threshold fluence, which may signal the onset of chemical changes leading to laser damage.