Giant Three-Photon Absorption in Monolayer MoS2 and Its Application in Near-Infrared Photodetection

Feng Zhou, Wei Ji

Index: 10.1002/lpor.201700021

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Abstract

For decades, there has been extensive research on exploring fundamental physical mechanisms for strong and fast optical nonlinearities. One of the important nonlinear-optical mechanisms is multiphoton absorption which has a wide range of photonic applications. Herein, a theoretical model is proposed for three-photon absorption (3PA) in monolayer MoS2. The model shows that the 3PA coefficients are on the order of 0.1 cm3/GW2. As compared to bulk semiconductors, these coefficients are enhanced by several orders of magnitude due to excitonic effects. Such exciton-enhanced 3PA is validated by light-intensity-dependent photocurrent measurements on a monolayer MoS2 photodetector with femtosecond laser pulses. These results lay both theoretical and experimental foundation for developing sensitive near-infrared MoS2-based three-photon detectors.