Ultraslow Waves and Photonic Quantum Dynamics on the Nanoscale

Recent broad interest in the physics and applications of ultraslow waves in nanoscale structures range from lightwaves or surface plasmons in nanoplasmonic devices to sound waves in acoustic-metamaterial waveguides, as well as plasmons and phonon polaritons in graphene and van der Waals crystals. Here we highlight that combining ultraslow waves with active photonic quantum materials opens up new domains for science, materials physics and engineering, providing the foundation for novel photonic quantum and communication technologies and nanolasing. We will outline the underlying physics of ultraslow waves on the nanoscale and discuss far-reaching opportunities resulting from a combination of ultraslow waves and active photonic quantum materials enabling single quantum emitter strong coupling. The ultrafast spatio-temporal dynamics of cavity-free stopped-light nanolasing and surface plasmon polariton condensation in nanoplasmonic hetero structures are yet further reflections of the special properties of light in the vicinity of stopped-light singularities, while a combination of stopped-light modes with epsilon-near-zero and topological materials with vanishing refractive index offer further exciting possibilities for nanophotonics.