Modulational instability in a non-Kerr photonic Lieb lattice with metamaterials

We present an analysis of modulational instability diffractionless waves in a face-centered-square lattice waveguides featuring non-Kerr nonlinearity, which are composed combination positive and negative refractive indices. The unit cell the consists three different with optical properties. dispersion curve supports flatbands thereby base equations describing model have particular solutions that correspond to propagating along waveguides. also observe unique ramification nonlinearities controlling optically. wave derived stability these distributions is investigated concisely by adopting standard linear approach.