Nonlocal Nonlinear Optical X Waves And Their Active Controls In A Rydberg Atomic Gas

X waves,a special type of wave packets that can maintain their transverse profile of X shape during propagation.It will evolve into a more localized nonlinear X wave when the X wave propagates in a nonlinear medium.Researching on the generation,propagation,and manipulation of nonlinear X waves has gradually become a hot spot in recent years.However,these studies are mainly concentrated in traditional optical materials in the field of optics.Due to the strong binding effect of the medium on the electrons,a very strong laser is required to effectively produce the nonlinear response.On the other hand,people have successfully made the Kerr nonlinear effect of super-cooled Rydberg atomic gas greatly enhanced without obvious absorption through the use of electromagnetically induced transparency technology.Therefore,studying nonlinear X-waves in super-cooled Rydberg atomic gas based on electromagnetically induced transparency can not only realize nonlinear X-waves under weak light conditions,deepen the understanding of its various physical properties,but also explore its potential application value in information processing and transmission.The results obtained in this paper include the following aspects: the formation mechanism of nonlinear X-waves is studied,and found that the nonlinear X-waves can be formed by themselves when the dispersion and diffraction signs of the medium are opposite;the propagation characteristics of nonlinear X-waves are studied,and found that it has ultra-slow propagation speed and ultra-low input power;the stability interval of nonlinear X-waves is discussed,and found that increasing the non-locality of Kerr nonlinearity can make the nonlinear X-waves more stable;we also studied active control,and found that active control of the nonlinear X-wave propagation orbit can be achieved by applying a gradient magnetic field.