Novel Rydberg eight-wave mixing process controlled in the nonlinear phase of a circularly polarized field

Eight-wave mixing (EWM) is a seven-order nonlinear process that can reflect nonclassical features within multiple optical fields, thus imparting certain advantages. In this study, we directly observed the EWM spectrum and spatial images that show Rydberg atoms under a circularly polarized probe field in a five-level coherently prepared atomic system. Such circular polarization dressing fields can obtain high-contrast Rydberg EWM overcome the difficulties of several multi-wave mixing (MWM) signals always coexist, and the multi-parameter controlling Rydberg EWM mechanism is established by changing the power and detuning and polarization of the dressing fields. These controllable high-order MWM processes present a contrast ratio of 96% and a narrow linewidth of <30 MHz compared with low-order mixing processes under identical conditions (e.g., six-wave mixing). The corresponding MWM spatial images are presented, and they can partly reflect the underlying nonlinear phase variation, whereas the given theory can predict the experimental results.