Metamaterials at Crossroads: from Quantum to Space-Time Photonics

In this talk we first discuss quantum photonic integrated circuitry (qPIC) based on the recently discovered single-photon emitters in silicon nitride and the avalanche-enhanced optical modulation in silicon at singlephoton intensities. Then, we show that transparent conducting oxides (TCOs) operating in the near-zero index (NZI) regime can provide strong ultrafast modulation, enabling novel optical phenomena in such extreme time-varying media, including photonic time crystals and 4D space-time metamaterials.