Optical polarization based logic functions (XOR or XNOR) with nonlinear Gallium nitride nanoslab

Abstract

We present a scheme of XOR/XNOR logic gate, based on non phase-matched noncollinear second harmonic generation from a medium of suitable crystalline symmetry, Gallium nitride. The polarization of the noncollinear generated beam is a function of the polarization of both pump beams, thus we experimentally investigated all possible polarization combinations, evidencing that only some of them are allowed and that the nonlinear interaction of optical signals behaves as a polarization based XOR. The experimental results show the peculiarity of the nonlinear optical response associated with noncollinear excitation, and are explained using the expression for the effective second order optical nonlinearity in noncollinear scheme.

Transition Metal Dichalcogenide Dimer Nanoantennas for Tailored Light–Matter Interactions

“…For the first time, we couple monolayer WSe 2 emission to dimer resonances in the same, TMD, material system and achieve PL enhancement factors of more than 240 and a Purcell enhancement factor lower bound of nearly 2 for a large dimer gap of 150 nm. Through the use of a dimer anapole mode we show polarization-dependent SHG enhancement, not present in bulk TMD flakes or monomer nanoantennas, that can be rotated by a change in excitation polarization which may prove advantageous for the realization of optical logic gates . Post-fabrication repositioning of dimer nanoantennas utilizing AFM led us to attain ultrasmall gaps of 10 ± 5 nm, on the order of the feature resolution limit set by FIB milling, which we achieve through a more precise, less damaging technique.…”

“…Through the use of a dimer anapole mode we show polarization-dependent SHG enhancement, not present in bulk TMD flakes or monomer nanoantennas, that can be rotated by a change in excitation polarization which may prove advantageous for the realization of optical logic gates. 55 Post-fabrication repositioning of dimer nanoantennas utilizing AFM led us to attain ultrasmall gaps of 10 ± 5 nm, on the order of the feature resolution limit set by FIB milling, 56 which we achieve through a more precise, less damaging technique. Although a previous report has demonstrated AFM positioning of plasmonic bowtie nanoantennas, 57 this technique has only become possible for dielectric nanoantennas made from layered materials because of their intrinsic van der Waals attractive forces.…”

Van der Waals Materials for Applications in Nanophotonics

“…We also characterize the nonlinear optical properties of some of the most widely studied vdW crystals by extracting the THG susceptibility of various thin-film TMDs near the telecom C band, advantageous for quantum applications, [76] yielding values up to an order of magnitude higher than in monolayers [64][65][66] and up to four orders of magnitude larger than in BBO crystals regularly used for laser frequency tripling applications. [67] We also explore a method of enhancing such nonlinear signals via coupling to resonances in monomer nanoantennas of WSe 2 .…”