Modeling nonlinear photonics of nonlinear fiber core for optical limiting application

A quantitative model for nonlinear photonic absorption processes in a liquid and their effects in the nonlinear transmission and limiting of a laser pulse are studied. The theoretical simulation results accounting for two-photon- and excited-state absorption processes, and the dynamic evolution of the molecular level populations and propagation of picosecond and nanosecond laser pulses through a fiber core formed by such liquid are in good agreement with experimental observations. In pump-probe studies using picosecond and nanosecond laser pump pulses and cw probe, we have also observed oscillatory transmission associated with laser induced thermal/density effects. We also discuss applications of the supra optical nonlinearity of nematic liquid crystal film for anti-laser jamming and optical limiting operation against long-pulse or cw lasers.