Cover Story：Wang HT, Hao CL, Lin H, Wang YT, Lan T et al. Generation of super-resolved optical needle and multifocal array using graphene oxide metalenses. Opto-Electron Adv 4, 200031 (2021).

Metalenses have numerous advantages, including lightweight, ultrathin, integratable, and controllable polarization states compared to conventional bulky lenses. As atomically thin materials, graphene enables unique light-matter interaction and provides more accurate control over phase and amplitude modulations simultaneously at a single position due to changes in refractive index, thickness, and absorption induced by laser photo reduction of graphene oxide (GO). Sophisticated wavefront modulations can be achieved via the simple patterns within a single GO film, making focus shaping more approachable than ever. A team of researchers led by Prof. Baohua Jia at Swinburne University of Technology, Australia, Prof. Cheng-Wei Qiu at National University of Singapore, and Prof. Tian Lan at Beijing Institute of Technology, China, reported a 200 nm thick GO metalenses, which is able to tightly focus light waves into a super-resolved ultralong optical needle or an axial multifocal array. The holistic design of the metalenses allows the exploit of the unique properties of graphene-based materials to simultaneously provide accurate phase and amplitude modulations. The metalens is fabricated with a single step 3D laser printing technology and can be integrated with photonic devices. Thus, this research opens up new possibility in designing ultrathin metalenses for broad applications, especially those ones requiring structured focal intensity distributions, such as microscopy imaging, optical particle manipulation, and parallel optical data storage.