Time-varying media have recently emerged as a new paradigm for wave manipulation, due
to the synergy between the discovery of highly nonlinear materials, such as epsilon-near …

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 …

The rapid development of space-time-coding metasurfaces (STCMs) offers a new avenue to
manipulate spatial electromagnetic beams, waveforms, and frequency spectra …

Manipulations of multiple carrier frequencies are especially important in a variety of fields
like radar detection and wireless communications. In conventional radio-frequency …

Gratings which are in apparent motion reveal some startling properties for classical
radiation, especially for luminal gratings traveling at or around the speed of light. We show …

We present a general framework for the homogenization theory of space-time
metamaterials. By map** to a frame comoving with the space-time modulation, we derive …

We study light propagation in spatiotemporal photonic crystals: dielectric media that vary
periodically in both space and time. While photonic crystals (spatially periodic media) are …

Time-dependent systems do not in general conserve energy, invalidating much of the theory
developed for static systems and turning our intuition on its head. This is particularly acute in …

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

In this opinion article, we briefly summarize some of the background materials and recent
developments in the field of temporal and spatiotemporal media and provide our opinion on …