Abstract:

The angular momentum, both spin and orbital (OAM), carried by vortex light beams holds great promise for forefront development of high-capacity multi-dimensional spin-OAM optical communication and quantum information technologies. While the newly developed integrated meta-surfaces could flexibly generate vortex beams in a compact fashion, active generation and dynamic control of spin-OAM laser emissions from compact microlasers, suitable for high-speed, high-density and low-energy optical communication and computing, remains challenging. In this talk, I will present our recent works on developing various spin-OAM microlasers through non-Hermitian symmetry engineering. We demonstrated the first OAM microlaser by engineering the complex index modulation at an exceptional point. Furthermore, by harnessing optically controlled non-Hermitian symmetry breaking, we demonstrated an on-chip integrated spin-OAM tunable vortex microlaser. Recently, we scaled up the design and achieved a hyper-dimensional spin-OAM microlaser emitting in a 4-dimensional Hilbert space. Beyond, based on super-symmetry theory, we realized a 2-dimensional microlaser array with enhanced laser emission in radiance and divergence. Our work provides a route for the development of the next generation of multi-dimensional high-capacity information system in both classical and quantum regimes.  

Bio:

Zhifeng Zhang has been a tenure-tracked Associate Professor in the College of Engineering and Applied Science at Nanjing University since September 2022. He received his Ph.D. in Electrical and Systems Engineering from University of Pennsylvania in 2020 and was subsequently a postdoc researcher in the Department of Materials Science and Engineering at Penn. Currently his research interests include integrated photonics, metamaterials and microlasers. He has authored and coauthored more than 10 peer-reviewed papers in journals including Science, Nature, Light: Science & Applications, Laser & Photonics Reviews and PRL. He received NSFC Excellent Young Scientist Fund (Overseas) in 2021.