LAUSR

This work presents a theoretical analysis of the helical phase steering via a four-wave mixing (FWM) process in a closely cycled double-ladder atomic system. Our focus is to understand the contribution of the two-photon resonant process governed by a probe field and a driving laser in the control of the helical phase. The theoretical analysis allows us to understand the helical phase can be effectively steered when the two-photon resonant condition Δ=−δ is satisfied. Moreover, we investigate the superposition modes of the FWM field and a same-frequency Gaussian beam, which testify the two-photon resonant condition Δ=−δ plays an important role in the steering of the helical phase.