To reduce the plasmonic line width of the metallic nano-structures and improve its performance when used in sensing, a hybrid structure consisting of a graphene stripe and a gold gap-ring is proposed and studied numerically. The structure works at Middle-IR band(3-6μm). Through strong coupling, some narrow dips caused by absorption of graphene appear on the wide background scattering spectrum of the metallic structure. Due to the high plasmonic confinement of graphene, the line width of these dips is around several tens nano-meters. In addition, the resonance intensity of graphene is enhanced significantly. By index changing, the sensing property of this composite structure is also studied. Simulation results show that its sensitivity exceeds 3000 nm/RIU (refractive index unit) and the figure of merit can reach up to 109 which prove our structure a good sensor.
'Micro- and nano-photonics' is a course for PhD candidates in School of Optoelectronics, Beijing Institute of Technology. The aim of the course is to introduce the recent development of micro- and nano-photonics to PhD students of optical engineering. The teaching content includes new branches of photonics, including basic theories and developments of plasmonics, matamaterials, photonics crystals and fibers. Then theoretical analysis of nanophotonics, as well as the simulation methods and software are introduced. The fabrication methods of nanophotonic devices are also introduced. More than 30 PhD students have been taught by this course since 2012. In this paper, we give an introduction about our course and its effects on the students' research. We also give a discussion about how to give class to PhD students with backgrounds of optics and photonics.
The real-time holographic display encounters heavy computational load of computer-generated holograms and precisely intensity modulation of 3D images reconstructed by phase-only holograms. In this study, we demonstrate a method for reducing memory usage and modulating the intensity in 3D holographic display. The proposed method can eliminate the redundant information of holograms by employing the non-uniform sampling technique. By combining with the novel look-up table method, 70% reduction in the storage amount can be reached. The gray-scale modulation of 3D images reconstructed by phase-only holograms can be extended either. We perform both numerical simulations and optical experiments to verify the practicability of this method, and the results match well with each other. It is believed that the proposed method can be used in 3D dynamic holographic display and design of the diffractive phase elements.