The article reviews general properties of time-varying dispersive materials. We first briefly
discuss different dispersion models that have been proposed in the literature, the role of the …

The engineering of the spatial and temporal properties of both the electric permittivity and
the refractive index of materials is at the core of photonics. When vanishing to zero, those …

Meta-lenses composed of artificial meta-atoms have stimulated substantial interest due to
their compact and flexible wavefront sha** capabilities, outperforming bulk optical …

We present an experimental study of optical time-refraction caused by time-interfaces as
short as a single optical cycle. Specifically, we study the propagation of a probe pulse …

Active metasurfaces enable dynamic manipulation of the scattered electromagnetic
wavefront by spatially varying the phase and amplitude across arrays of subwavelength …

Control over the intensity, shape, direction and phase of coherent light is essential in
numerous fields, from gravitational wave astronomy, quantum metrology and ultrafast …

We study the time reflection and time refraction of waves caused by a spatial interface with a
medium undergoing a sudden temporal change in permittivity. We show that monochromatic …

Regarded as a promising alternative to spatially sha** matter, time-varying media can be
seized to control and manipulate wave phenomena, including thermal radiation. Here …

This tutorial offers a comprehensive overview of photonic time crystals: artificial materials
whose electromagnetic properties are periodically modulated in time at scales comparable …

Time-varying metamaterials rely on large and fast changes of the linear permittivity. Beyond
the linear terms, however, the effect of a non-perturbative modulation of the medium on …