We report the decrease in absorption caused by a near-infrared laser pulse in the visible region in monolayer graphene. This absorption decrease shows the existence of a two-step excitation process of carriers, in which one-photon absorption and Auger recombination sequentially occur. This process results from the linear dispersion nature of monolayer graphene. In addition, the monolayer graphene shows the ultrafast decay of carrier population. The observed properties are of importance for ultrafast optical switching utilizing the optical nonlinearity induced by carrier excitation.
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