12. Perspective and Future Trends

Leveraging structured materials systems to generate tailored response to a stimulus, metamaterials have grown to encompass research in optics, electromagnetics, acoustics, mechanics, and, increasingly, novel hybrid material responses. The field is shifting towards tunable, switchable, nonlinear and sensing functionalities of metamaterials and their applications, involving metasurfaces, metadevices and metasystems. For instance, optical metamaterials have redefined light behaviors from strong response to optical magnetic fields, negative refraction, fast and slow light propagation in zero index and trapping structures, to flat, thin and perfect lenses. This chapter will present emerging fronts and future trends of metamaterials and metadevices, focusing on emerging metamaterials capabilities and new concepts; manipulation of metasurface properties; research trends of nonlinear, active and tunable properties; future metadevices and applications; and prospective manufacturing and assembly technologies.