Broadband negative group velocity dispersion in all-dielectric metamaterial and its role in supercontinuum generation.

All-dielectric metamaterials conforming to an optical reflectionless potential (ORP) offer broadband, omni-directional suppression of reflection. Though they are predicted to possess broadband negative group velocity dispersion (GVD), ultrashort pulse propagation through such materials has not been studied so far, to the best of our knowledge. In this work, we demonstrate negative GVD and group delay dispersion over broadband covering visible to near-infrared wavelengths. We investigate the role of ORP in supercontinuum generation (SC), which is observed to be polarization independent. The negative GVD in ORPs is interesting for pulse compression, phase compensation, dispersion engineering, and controlled SC generation.