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

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.