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.
We propose a scheme to exhibit Stern-Gerlach deflection of high-dimensional vector optical solitons at a weak-light level in a cold atomic gas via electromagnetically induced transparency. We show that the propagating velocity and generation power of such solitons can be reduced to ${10}^{\ensuremath{-}6}\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}c$ (
c is light speed in vacuum) and lowered to magnitude of nanowatt, respectively. The stabilization of the solitons is realized by using an optical lattice potential formed by a far-detuned laser field, and trajectories of them are deflected significantly by using a transversal Stern-Gerlach gradient magnetic field. Deflection angles of the solitons can be of magnitude of ${10}^{\ensuremath{-}3}$ rad when propagating several millimeters. Different from atomic Stern-Gerlach deflection, deflection angles of the solitons can be distinct for different polarization components and can be manipulated in a controllable way. The result obtained can be described in terms of the Stern-Gerlach effect for vector optical solitons with quasispin and effective magnetic moment.
Realizing single light bullets and vortices that are stable in high dimensions is a long-standing goal in the study of nonlinear optical physics. On the other hand, the storage and retrieval of such stable high dimensional optical pulses may offer a variety of applications. Here we present a scheme to generate such optical pulses in a cold Rydberg atomic gas. By virtue of electromagnetically induced transparency, strong, long-range atom-atom interaction in Rydberg states is mapped to light fields, resulting in a giant, fast-responding nonlocal Kerr nonlinearity and the formation of light bullets and vortices carrying orbital angular momenta, which have extremely low generation power, very slow propagation velocity, and can stably propagate, with the stability provided by the combination of local and the nonlocal Kerr nonlinearities. We demonstrate that the light bullets and vortices obtained can be stored and retrieved in the system with high efficiency and fidelity. Our study provides a new route for manipulating high-dimensional nonlinear optical processes via the controlled optical nonlinearities in cold Rydberg gases.
We propose a scheme to realize an optical Thirring model and create temporal optical Thirring solitons in a tripod-type atomic gas via double electromagnetically induced transparency (EIT). We show that giant enhancement of the cross-phase modulation for the two polarization components of the probe pulse can be obtained under the condition of the double EIT, and hence the optical Thirring model can be realized. We also show that the system supports stable temporal optical Thirring solitons, which have ultralow generation power and ultraslow propagation velocity. In particular, these temporal optical Thirring solitons may experience a significant Stern-Gerlach deflection when a gradient magnetic field is applied to the system. The results reported here are useful not only for extending the research realm of nonlinear magneto-optics but also for the application in precision measurements, such as the detection of microgradient magnetic fields.
X waves are a special type of wave packet that can maintain their transverse profile of
X shape during propagation, and they are of much interest for the study of fundamental physics and practical applications. Here we present a scheme to generate nonlinear
X waves and realize their active control by using a cold gas of Rydberg atoms via electromagnetically induced transparency (EIT). We show that, due to the EIT effect contributed by a control laser field and the strong, nonlocal Kerr nonlinearity contributed by Rydberg-Rydberg interaction between atoms, the system supports high-dimensional, nonlocal, and nonlinear optical
X waves, which have low propagation loss, ultraslow propagation velocity, and ultralow generation power. We also show that the stability domain of such
X waves can be greatly enlarged by increasing the nonlocality degree of the Kerr nonlinearity, and their motion trajectory can be manipulated by using an external magnetic field. Our study opens a route for generating and controlling nonlocal ultraslow nonlinear optical
X waves, which may have promising applications in optical information processing and transmission.