Abstract

We study an optical torque emerging through the interaction of orbital angular momentum with atoms/molecules in quantum systems with closed-loop interactions. First, we show how atoms with a closed-loop scheme experience a well-controlled torque whose features depend on the relative phase of applied fields. Such a controllable torque, along with simplicity of tuning the relative phase, can simplify the implementation of current flows in atomic Bose–Einstein condensates. Moreover, we calculate the optical torque exerted on chiral molecules with cyclic-transition structures and find that the enantiomers can experience different torques for proper choice of the parameters. Such features may find applications in sorting and separation of enantiomers.

© 2019 Optical Society of America