TMDC Resonators for Second Harmonic Signal Enhancement

Abstract: In addition to their strong nonlinear optical response, transition metal dichalcogenides (TMDCs) possess a high refractive index in the visible and infrared regime. Therefore, by patterning those TMDCs into dielectric nanoresonators, one can generate highly confined electromagnetic modes. Controlled fabrication of TMDC nanoresonators does not only enhance the material's intrinsic nonlinear response, but also allows for spatially shaping the emission via nanoresonator arrays. Here we fabricate patterned WS2 disks that support a high internal resonant electric field and show strong enhancement of second harmonic (SH) generation in the visible regime. In addition, we assemble the WS2 disks in arrays to spatially direct the coherent SH emission, in analogy to phased array antennas. Finally, we investigate and discuss drastic differences in the areal emission origin and intensity of the measured SH signals, which we find to depend on material variations of the used bulk WS2.