Terahertz Folded Transmitarray With Co-Modulated Spin and Orbital Angular Momentum

The simultaneous control of the spin and orbital angular momentum of light beams has attracted considerable interest from researchers. While some reports have explored this topic in the microwave band, studies focusing on the optical terahertz band remain scarce. Furthermore, most devices operating in the terahertz band tend to have larger profiles and narrower bandwidths. This research presents a terahertz folded transmitarray that enables the simultaneous manipulation of the spin angular momentum, orbital angular momentum, and beam deflection direction of terahertz light waves. The device has an overall profile of approximately one-third of the focal length and operates within a relative bandwidth of 18.2%. The proposed device has promising potential in the field of high-performance information technology.