Modified optical vortices for encoding topological charges with principal-sidelobe ring relationships

Chiral optical field generated by an annular subzone vortex phase plate

We proposed and experimentally demonstrated a novel method for generating a chiral beam with controllable intensity twist lobes and direction by using annular subzone (AS) vortex phase plates, which is composed of different ASs and different vortex phases. The phase distribution continuity between two adjacent ASs determines the intensity distribution of the light field. The rotated direction of the optical filed is determined by the topological charge sign. The number of intensity twist lobes is determined by the topological charge gradient between adjacent subzones. The experimental results show that this method is effective and practical, which offers broad potential applications in particle manipulation, chiral microstructure fabrication, and optical tweezers.

Sidelobe-modulated optical vortices for free-space communication

We propose and experimentally demonstrate a new method for free-space optical (FSO) communication, where the transmitter encodes data into a composite computer-generated hologram and the receiver decodes through a retrieved array of sidelobe-modulated optical vortices (SMOVs). By employing the SMOV generation and detection technique, the usual stringent alignment and phase-matching requirement of the detection of optical vortices is released. In transmitting a gray-scale picture with 180×180 pixels, a bit error rate as low as 3.01×10(-3) has been achieved. Due to the orbital angular momentum multiplexing and spatial paralleling, this FSO communication method possesses the ability to greatly increase the capacity of data transmission.