On June 11, 2018, Prof. Qiwen Zhan from University of Shanghai for Science and Technology/University of Dayton was invited by Prof. Yiping Cui to visit Advanced Photonics Center (APC) and conduct academic exchanges. Some teachers and graduate students from APC attended the meeting.
In this academic event, Prof. Qiwen Zhan made a wonderful academic report entitled Enabling Nanophotonic Functionalities with Tailored Photonic Spin Density Distribution.
Prof. Qiwen Zhan introduced the spin angular momentum density distribution in the focused light field in detail. By using electric dipole radiation theory, the required pupil field for the generation of arbitrary spin orientation at the optical focus can be found analytically. Moreover, the focal field has a volume size beyond the classical diffraction limit, and the spin orientation within the focal spot can be arbitrarily tuned. A very special situation arises when the spin orientation becomes orthogonal to the optical axis direction. Such an optical field with purely transverse spin density is called “photonic wheel”. Experimental realization of the calculated pupil field illumination, and research optical fields with tailored spin density distribution exhibit unique interaction phenomena with nanophotonic structures and enable novel functionalities. Specifically, Prof. Qiwen Zhan reported an augmented photonic spin-Hall effect using hyperbolic metamaterials with curved surfaces. Extremely large angular separation of emission under different spin excitation is obtained. The finding leads to an ultra-compact polarimeter on an integrated photonic chip.
After the reports, we had a discussion and exchange in view of the development trend and problems in the field of light manipulation. This forum strengthened academic exchanges between teachers and students, deepen our understanding in nanophotonic, and provided a good opportunity to boost the scientific research level and expanded the research area in APC. In particular, the application of light field manipulation technique in the field of controlling the spin of light provides a good opportunity for the scientific research of APC to be cross integration of scientific research, improving the level of scientific research, and development of the research content.
A brief introduction to the expert:
Dr. Qiwen Zhan, received a Bachelor of physics from University of Science & Technology of China in 1996 and a Ph. D. in electronic engineering from University of Minnesota in 2002. He was appointed assistant professor (2002), associate professor of life tenure (2008), full professor of life tenure (2012), founded Nano Electro-Optics Laboratories of Dayton University, and also was the director of the Fraunhofer Center at Dayton University and currently an outstanding professor of nano-photonics at University of Shanghai for Science and Technology. The main fields of research include field of light manipulation and its interaction with micro/nanostructures, nanophotonic, biophotonic, super-resolution imaging and nanostructure characterization. He has taken vice editor of Optica of the Optical Society of American (OSA), the editorial board of Scientific Reports of Natural publishing group, and the editorial board of Journal of Nondestructive Evaluation, Nature - Springer. Presiding or participating in the research funds over 11 million dollars; published more than 120 SCI papers, more than 6000 times; 1 publications and 9 chapters of monograph; 6 items of authorization in the United States and international patents; the outstanding contributions to the polarization optics and nanoscale are elected to OSA Fellow and SPIE Fellow.
(Contribution by Bing Gu and Guanghao Rui)