Characterization of the second-and third-order nonlinear optical susceptibilities of monolayer MoS 2 ... Supplementary Information forCharacterization of the second-and third-order nonlinear optical susceptibilities of monolayer MoS 2 using multiphoton microscopy

We demonstrated a method to construct high efficiency saturable absorbers based on the evanescent light field interaction of CVD monolayer graphene deposited on side-polished D-shaped optical fiber. A set of samples was fabricated with two different core-graphene distances (0 and 1 μm), covered with graphene ranging between 10 and 25 mm length. The mode-locking was achieved and the best pulse duration was 256 fs, the shortest pulse reported in the literature with CVD monolayer graphene in EDFL. As result, we find a criterion between the polarization relative extinction ratio in the samples and the pulse duration, which relates the better mode-locking performance with the higher polarization extinction ratio of the samples. This criterion also provides a better understanding of the graphene distributed saturable absorbers and their reproducible performance as optoelectronic devices for optical applications.

Optical frequency conversion via the nonlinear effect of third harmonic generation is shown to be resonantly enhanced in few-layer black phosphorus. This feature is believed to be a consequence of exciton-related resonance, as the enhancement is strongly correlated with the observation of exciton-recombination photoluminescence. Few-layer thicknesses are obtained both via mechanical exfoliation and laser thinning.