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

TL;DR

This paper demonstrates a polarization-based optical XOR/XNOR logic gate using noncollinear second harmonic generation in Gallium Nitride, highlighting the nonlinear optical response's potential for optical computing applications.

Contribution

It introduces a novel scheme for optical logic gates based on polarization control in nonlinear Gallium Nitride nanoslabs, with experimental validation.

Findings

Only specific polarization combinations are allowed for the nonlinear interaction.

The nonlinear response behaves as a polarization-based XOR gate.

Experimental results align with theoretical models of second order nonlinearity.

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.