In this thought-provoking episode, we are joined by Dr. Alù, a trailblazer in the realm of photonic manipulation, to discuss the fascinating concept of time reflection. Traditionally seen as the uniform inversion of a signal's temporal evolution following an abrupt change in material properties, time reflection has recently become the object of groundbreaking research, propelling us closer to the realization of time metamaterials and Floquet matter.

Dr. Alù guides us through the sophisticated processes underlying time reflection, shedding light on how time can serve as an additional degree of freedom in wave manipulation. We delve into the dynamics of a switched transmission-line metamaterial whose effective capacitance is homogeneously and abruptly changed via a synchronized array of switches, leading to photonic time reflection and associated broadband frequency translation.

Highlighting a new frontier in physics, we also explore the concept of time-reflection-induced wave interference, drawing parallels between temporal interfaces and the spatial counterparts found in a Fabry–Pérot cavity. With these groundbreaking insights, Dr. Alù offers a glimpse into a future where time metamaterials and Floquet photonic crystals can provide unprecedented opportunities for extreme photon manipulation in both space and time.

Join us on this fascinating journey that merges physics, time, and light, creating an intricate tapestry of scientific exploration.

Dr. Alù, Time Reflection, Metamaterials, Floquet Matter, Photonic Manipulation, Spatial Interface, Temporal Interface, Frequency Translation, Wave Interference, Fabry–Pérot Cavity, Time Metamaterials, Floquet Photonic Crystals.

Moussa, H., Xu, G., Yin, S. et al. Observation of temporal reflection and broadband frequency translation at photonic time interfaces. Nat. Phys. (2023). https://doi.org/10.1038/s41567-023-01975-y