Yongquan Zeng | Topological Laser- A Practical Application of Photonic Topological Insulators

►【International Young Scholar Forum】

Title：Topological Laser- A Practical Application of Photonic Topological Insulators

Time: 10:00 am, October 20th, 2020

Speaker: Dr. Yongquan Zeng, School of Electrical and Electronic Engineering, Nanyang

Abstract:

Topological protected states arise at the interface between the spatial domains that have distinct topology phases. There have been substantial efforts to implement such states in photonics, motivated by potential applications in robust optical delay lines, amplifiers, and other devices. Recently, the photonic topological insulators have been incorporated with gain materials, giving rise to a practical application as robust coherent light sources. In this seminar, I will firstly review this new type of lasers based on topologically protected photonic modes with different operating mechanisms. Then, I will present our recent results of magnetic-free electrically-pumped topological laser based on a compact valley photonic crystal design. Different cavities designs were prepared to provide a chain of evidence for the existence of topologically protected valley edge lasing states. Besides, the laser works in the scientifically important terahertz band, paving the way for the exploration and application of 6G topological photonic physics and devices. Finally, I will discuss the future perspectives of the topological laser at the aspects of physics and its applications.

Reference

[1] F. Yang et al., "dc electric invisibility cloak," Phys. Rev. Lett., 109, 053902 (2012).

[2] F. Yang et al., "Design and experiment of perfect relay lens based on the Schwarz-Christoffel mapping," Appl. Phys. Lett., 104, 073510 (2014)

[3] F. Yang et al., "Transformation optics approach to singular metasurfaces," Phys. Rev. B, 98, 125409 (2018).

[4] F. Yang et al., "Nonlocal effects in singular plasmonic metasurfaces," Phys. Rev. B, 99, 165423 (2019).

[5] F. Yang et al., “Nonlocal effects in plasmonic metasurfaces with almost touching surfaces,Phys. Rev. B, 101, 075434 (2020).

[6] F. Yang et al., “Electron Energy Loss Spectroscopy of singular metasurfaces”, Laser Photonics Rev., 14, 2000055 (2020).

[7] F. Yang et al., “Continuous topological transition from metal to dielectric”, Proc. Natl. Acad. Sci., 117, 16739 (2020).

[8] F. Yang et al., “Hidden topological effect in plasmonic system”, manuscript in preparation.

Brief CV of Dr. Yongquan Zeng :

Dr. Yongquan Zeng is currently a research fellow in the School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore. He received his B.S. degree in material physics from the University of Science and Technology of China, Heifei, China, in 2013 and obtained his Ph.D. degree in electrical and electronic engineering from NTU in 2018. Since 2013, Yongquan has been working with Prof. Qijie Wang on the photonic engineering, device fabrication and characterization of the III-V infrared semiconductor lasers with new functionalities. His research interests include novel semiconductor lasers, topological photonics, integrated photonic devices and the application of mid-infrared and terahertz quantum cascade lasers. He has innovatively developed the first electrically-pumped topological insulator laser in 2020.