In these two tutorial-style talks, I will introduce the field of metamaterials, and its subsequent developments towards “metaphotonics”. The word “metamaterials” was coined about 25 years ago, with “meta” taken from the Greek word μετά meta meaning "beyond", and it was used to describe artificial, man-made materials engineered to have unusual properties typically rarely or never observed in Nature.

Metamaterials are usually composed from subwavelength elements (often called “meta-atoms”) made of conventional materials such as metals and dielectrics, and they are arranged in simple or complex lattices. The meta-atoms can be engineered at will by varying their material, shape, size, and lattice arrangement, engineering their collective "smart" properties for manipulating electromagnetic, acoustic, or even seismic waves. Metamaterials were first demonstrated to control electromagnetic radiation in a manner not observed in bulk materials, in particular, they allow realizing the so-called negative index of refraction for particular wavelengths and were known as negative-index metamaterials.

Recent progress in the field of metamaterials is driven by the physics of optical resonances. Resonances in nanoantennas and metasurfaces provide a novel platform for subwavelength localization of light, and they open new horizons for metamaterial-enabled photonics, or metaphotonics. Recently emerged field of Mie-resonant metaphotonics (also called "Mie-tronics") employs resonances in high-index dielectric nanoparticles and dielectric metasurfaces aiming for novel applications of subwavelength optics and photonics.