  We apply inverse design methods to produce two-dimensional plasma
metamaterial (PMM) devices. Backpropagated finite difference frequency domain
(FDFD) simulations are used to design waveguides and demultiplexers operating
under both transverse electric (TE) and transverse magnetic (TM) modes.
Demultiplexing and waveguiding are demonstrated for devices composed of plasma
elements with reasonable plasma densities ~7 GHz, allowing for future in-situ
training and experimental realization of these designs. We also explore the
possible applicability of PMMs to nonlinear boolean operations for use in
optical computing. Functionally complete logical connectives (OR and AND) are
achieved in the TM mode.
