Flattened and broadband mid-infrared supercontinuum generation in As₂S₃ photonic crystal fibers with a square air-hole lattice

This paper analyzes smooth and broadband supercontinuum (SC) generation in the mid-infrared range using square-lattice As₂S₃-based photonic crystal fiber (PCF). Simulation of short pulse transmission in optimal PCFs is performed by solving the generalized nonlinear Schrödinger equation with different parameters of pump sources. The first fiber has an anomalous dispersion curve that is flattest and closest to the zero dispersion of all reported fibers. It can generate a broad SC bandwidth covering a 2–11.5 μm range after injecting a pump pulse of 700 pJ energy of (5.83 kW peak power), 120 fs of duration, and 6.5 µm wavelength into 10 cm of fiber length. For the input energy of 810 pJ (9 kW peak power) and pump wavelength of 5 μm, SC spanning 1.9–8.6 μm wavelength region is observed in the second PCF with all-normal dispersion. The achieved SC could find many potential applications in material structure detection, biomedicine, environment monitoring, and food quality control.