Metamaterial structures of variable and gradient basis orientations embedded with periodic linear defects: phase engineered design, single step optical realization, and applications

Metamaterial structures of different basis shapes and orientations and with gradient refractive index variations are applicable in integrated photonics, miniaturized optoelectronics, diffraction limited focusing, and super-resolution imaging. We present design and experimental realizations of gradient metamaterial structures embedded with linear periodic defects and propose its applications in on-substrate color filtering through a simulation-based study. A combination of phase engineered plane beams in double cone geometry and an axial plane beam are interfered to obtain different gradient basis metamaterial structures with linear defects in two dimensions and three dimensions, respectively. The defect size and spatial gradient amplitude modulations can be controlled computationally through shifts in the interference angle for some of the plane beams in double cone geometry without changing any optical components in the experiment. The designed and realized metamaterial structures upon transferring to certain materials will find application in optical circuits and metalenses for enhanced light matter interactions.