Third order nonlinear optical response exhibited by mono- and fewlayers of WS₂

In this work, strong third order nonlinear optical properties exhibited by WS₂layers are presented. Optical Kerr effect was identifiedasthe dominant physical mechanism responsible for these third order optical nonlinearities. An extraordinary nonlinear refractive index together with an important contributionofasaturated absorptive response was observedto dependon the atomic layer stacking. Comparative experiments performedinmono- and few-layer samples of WS₂ revealed that this material is potentially capable of modulating nonlinear optical processes by selective near resonant induced birefringence. We envision applications for developing all-optical bidimensional nonlinear optical devices.