Author Affiliations

Yijie Shen,¹ Zhaoyang Wang,^2,3 Xilin Yang,⁴ Isaac Nape,⁵ Darryl Naidoo,^5,6 Xing Fu,^2,3 and Andrew Forbes⁵

¹Optoelectronics Research Centre & Centre for Photonic Metamaterials, University of Southampton, Southampton SO17 1BJ, UK

²Key Laboratory of Photonic Control Technology (Tsinghua University), Ministry of Education, Beijing 100084, China

³State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China

⁴Electrical and Computer Engineering Department, University of California, Los Angeles, CA 90095, USA

⁵School of Physics, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa

⁶CSIR National Laser Centre, PO Box 395, Pretoria 0001, South Africa