电子科学与技术学院2018年学术报告会之二十八-Photonic and Plasmonic Designs for the Enhanced Raman and Brillouin Scatterings
来源：电子科学与技术学院 浏览：226 时间：2018-06-20
题目：Photonic and Plasmonic Designs for the Enhanced Raman and Brillouin Scatterings
Raman and Brillouin scatterings are inelastic scattering processes in which the frequency of the scattered photon is shifted from that of the pump photon by the interacting medium. Thus the Raman shift and Brillouin shift have wide applications in telecommunication, fiber-optic-sensing and quantum-mechanical information processing, etc. To distinguish between the two scattering processes, the internal mode in the medium should be considered. In Raman scattering (RS), the pump photons interact with collective modes that do not propagate; lattice vibrations and optical phonons in solids which have high energy are good examples. In Brillouin scattering (BS), on the other hand, the interaction process involves propagating modes such as ion-acoustic phonons in plasmas and acoustic phonons in solids, which have low energy.
A lot of similarities and differences can be found in both scattering processes. In this talk, we will review the enhanced stimulated RS in micro-cavity designs based on silicon and diamond photonic crystals (PCs). The Raman shifts, selection rules in respective PCs-lattice-type designs, and cavity enhancement in terms of Quality factor versus modal volume will be compared. Further, a brief introduction on the mechanism that governs the stimulated BS will be presented. Here photonic and mechanical modes are strongly coupled because of radiation pressure (RP) and electrostrictive (ES) forces. We provide an example of a conceptual design that is based on a plasmonic waveguide in diamond. The RP forces are compared by using scaling law and Maxwell stress tensor method. Simulation results show that the Brillouin gain and optomechanical coupling rate can be boosted in plasmonic waveguide, as compared to conventional designs using dielectric materials.
Qiang Liu received his Ph.D. in Materials Science & Engineering from Norfolk State University, USA in 2014. In March 2016, He joined the College of Electronic Science & Technology of Shenzhen University (China) as assistant professor. He has published more than 10 papers in reputed journals, including Optics Expressand Scientific Reports. His research interests include optomechanics, low-threshold Raman laser, and photonic crystals.