Optical bistability in Rydberg linear and nonlinear processes

Optical bistability has high potential for application in the fields of all-optical communication and optical bistability devices. In this paper, we experimentally present the nonreciprocity "co"-shaped optical bistability in linear and nonlinear processes involving Rydberg atoms in a thermal vapour gas under cavityless conditions. The "co"-shaped optical bistability is shown through a nonoverlapping region by scanning the optical field frequency. The nonoverlapping region generated by frequency differences can be modulated by different Rydberg densities and polarizations of the probe field. In addition, optical bistability of the non-Rydberg state can be induced by the Rydberg state, and the results are presented.