Propagation dynamics of hollow Gaussian pulse in photonic crystal fiber

This paper explores the behavior of a hollow Gaussian pulse (HGP) as it evolves in a nonlinear photonic crystal fiber (PCF). A particular emphasis is given to studying the impact of infiltration of nonlinear liquids and suspension of the fiber core on the evolution of HGPs. We found that the critical power of self-trapping and self-trapping period are higher in conventional silica-core PCF than that of liquid-core PCF. The suspension factor enhances the critical power of self-trapping and self-trapping periods in conventional and liquid core PCFs. When the HGP propagates half of the self-trapping period, it may transform into a focused intensity distribution with a central bright spot. The infiltration of nonlinear liquids and suspension of the fiber core significantly influence this focussed intensity distribution. Compared to the conventional silica PCF in liquid core PCF the pulse compression is high due to enhancement in the nonlinearity, as a result, the HGP evolves to a tightly focussed structure with comparatively high intensity at the center of the pulse. The tight-focussed pulse can be used to trap nanosized particles.