Nonreciprocal transmission of an optical vortex based on Raman transition in a three-level atomic system

Abstract Vortex beams have important applications in a number of physical fields such as optical information processing, optical imaging, etc. Nonreciprocal propagation of light often plays a key role in some occasions in these applications. In this work, we investigate the nonreciprocal propagation of a vortex beam using a far-off resonant Raman process in a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Λ</mml:mi> </mml:mrow> </mml:math> -type three-level thermal atomic system. The probe vortex can propagate with high transmission in the backward direction and be well isolated in the forward direction. Via adjusting the strong control field and the atom temperature, the forward transmission of the probe vortex can be further suppressed, and higher isolation can be achieved under the use of a controlled vortex with the same orbital angular momentum. This work may provide reference for experimental studies on the nonreciprocal transmission of vortex beams and find applications in vortex isolators and circulators.