Nonlinear polaritons in metamaterials with plasmon-induced transparency [Invited]

Electromagnetically induced transparency(EIT), a typical quantum interference effect, has been extensively investigated in coherent atomic gases. In recent years, it has been recognized that the plasmonic analog of atomic EIT, called plasmon-induced transparency(PIT), is a fruitful platform for the study of EIT-like propagation and interaction of plasmonic polaritons. Many proposals have been presented for realizing PIT in various metamaterials, which possess many unique characters, including the suppression of absorption of electromagnetic radiation, the reduction of propagation velocity, etc. Especially, nonlinear PIT metamaterials, obtained usually by embedding nonlinear elements into meta-atoms, can be used to acquire an enhanced Kerr effect resulted from the resonant coupling between radiation and the meta-atoms and to actively manipulate structural and dynamical properties of plasmonic metamaterials. In this article, we review recent research progress in nonlinear PIT metamaterials, and elucidate their interesting properties and promising applications. In particular, we give a detailed description on the propagation and interaction of nonlinear plasmonic polaritons in metamaterials via PIT,which are promising for chip-scale applications in information processing and transmission.

Magnetic-field-induced deflection of nonlocal light bullets in a Rydberg atomic gas

Light bullets(LBs)are localized nonlinear waves propagating in high spatial dimensions.Finding stable LBs and realizing their control are desirable due to the interesting physics and potential applications.Here,we show that nonlocal LBs generated in a cold Rydberg atomic gas via the balance among the dispersion,diffraction,and giant nonlocal Kerr nonlinearity contributed by long-range Rydberg-Rydberg interaction can be actively manipulated by using a weak gradient magnetic field.Nonlocal LBs are generated by a balance among dispersion,diffraction,and large nonlocal Kerr nonlinearities contributed by long-range Rydberg-Rydberg interactions.Here,we find that active manipulation can be achieved by weak gradient magnetic fields in cold Rydberg atomic gases.Especially,the LBs may undergo significant Stern-Gerlach deflections,and their motion trajectories can be controlled by adjusting the magnetic-field gradient.The results reported here are helpful not only for understanding unique properties of LBs in nonlocal optical media but also for finding ways for precision measurements of magnetic fields.