1. Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
2. Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong SAR, China
3. The State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong, Kowloon, Hong Kong SAR, China