Size-Dependent Nonlinear Optical Response of Black Phosphorus Liquid Phase Exfoliated Nanosheets in Nanosecond Regime

Atomically thin materials are exhibiting unique physical properties. This work investigates the size dependent nonlinear optical response of black phosphorus nanosheets for nanosecond laser pulses. Material is prepared with the use of Liquid Phase Exfoliation. Experiments are performed using open aperture Z-scan technique at 532 nm wavelength with ND:Yag, 10 Hz ns as laser source. We report that the nonlinear absorption coefficient of black phosphorus is strongly dependent on flake lateral dimension as well as laser intensity.