The Office of Research and Innovation congratulates Prof. Dr. Ong Chong Kim and Assistant Professor Dr. Kelvin Ooi Jian Aun of Electrical and Electronics Engineering (EEE) programme for their success in mentoring second year XMUM undergraduate student, Zhai Qingwei, to contribute positively to their invited research paper entitled “Nonlinear Plasmonics of Three-Dimensional Dirac Semimetals” which was published in  journal APL Photonics on 11 December 2018. This paper was co-authored by 5 scientists and one XMUM undergraduate student. The participating scientists came from XMUM, Singapore University of Technology and Design, and National University of Singapore.

Schematic drawing of the Dirac energy dispersion and the intraband optical processes. The three-dimensional Dirac semimetal hosts gapless Dirac nodal points in the bulk.

The research team targets a new class of material to overcome speed limits of computers. In their research, the team explores the possibility of using three-dimensional Dirac semimetal (3D DSM) that has very high optical nonlinearities. Their research finding concludes that 3D DSM has respectable nonlinear plasmonic performance in comparison with 2D graphene, while retaining the structural benefits of bulk metals, having reduced passive plasmonic losses, and is much easier to handle in fabrication facilities.

The authors stated the significance of their study:

“This is the first investigation into the nonlinear optics of 3D Dirac Semimetals (DSM), and also a preliminary study on the technical possibilities of making all-optical plasmonic devices on this platform. Our results show that 3D DSM is a strong contender and a viable alternative to graphene, as it bears a competitively high nonlinearity as graphene and its bulk form offers more versatility in optical platform integration and also fabrication feasibility in existing semiconductor foundries.”

Prof. Ong (sitting in the middle) led the project; Dr. Kelvin Ooi (right) contributed to the theoretical derivations and formulation of nonlinear optics; and Zhai Qingwei did calculations and simulation for the project.

Dr. Kelvin Ooi Jian Aun, one of the corresponding authors, commented on the mentorship:

“The mentorship exemplifies real teaching and student-centred learning that goes beyond the classroom. It was a very rewarding experience. I get to nurture talent and at the same time gain ideas and insights from the student.”

Zhai Qingwei reflected on his experience:

“When I learnt about this research program, I knew this was a perfect opportunity. As I intend to go for graduate studies, I am very grateful to Dr. Kelvin and Prof. Ong for giving me the guidance and encouragement. Through exposure to new knowledge and new technique during this project, I not only gained confidence, but also broadened my horizon.”

Prof. Ong Chong Kim led the project; Dr. Kelvin Ooi contributed to the theoretical derivations and formulation of nonlinear optics; Zhai Qingwei did calculations and electromagnetic simulation using MATLAB and COMSOL. 

This paper is available online: https://aip.scitation.org/doi/10.1063/1.5042450