Transition-metal dichalcogenides [1] (TMDs) are particularly appealing for photonics due to their rich photophysical effects and strong light-matter-interaction per unit length [1] . Two-dimensional (2D) TMDs also exhibit strong optical nonlinearity [2] which opens up novel potential applications in nonlinear optics. However, the total optical response of TMDs is limited by the sub-nanometer interaction length, imposed by their atomic thickness. Hence, the enhancement of the interaction length is essential for any future application.