Realizing plasmonic nanogaps with a refractive index ( = 1) environment in metallic nanoparticle (NP) structures is highly attractive for a wide range of applications. So far in self-assembly-based approaches, without surface functionalization of metallic NPs, achieving such extremely small nanogaps is challenging. Surface functionalization introduces changes in the refractive index at nanogaps, which in turn deteriorates the desired plasmonic properties.
View Article and Find Full Text PDFPerfect vector vortex beams (PVVBs) have attracted considerable interest due to their peculiar optical features. PVVBs are typically generated through the superposition of perfect vortex beams, which suffer from the limited number of topological charges (TCs). Furthermore, dynamic control of PVVBs is desirable and has not been reported.
View Article and Find Full Text PDFWe present strong enhancement of third harmonic generation in an amorphous silicon metasurface consisting of elliptical nano resonators. We show that this enhancement originates from a new type of multi-mode Fano mechanism. These 'Super-Fano' resonances are investigated numerically in great detail using full-wave simulations.
View Article and Find Full Text PDFDispersion is present in every optical setup and is often an undesired effect, especially in nonlinear-optical experiments where ultrashort laser pulses are needed. Typically, bulky pulse compressors consisting of gratings or prisms are used to address this issue by precompensating the dispersion of the optical components. However, these devices are only able to compensate for a part of the dispersion (second-order dispersion).
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