题目：Optical measurements of graphene- from strain induced pseudo fields to oilwell pressure sensors 

报告人：Prof. Anna K. Swan （ECE Department，Boston University，USA）

 The last 30 years, three novel forms of carbon has been found; Bucky balls (~1985), carbon nanotubes (~1991) and isolated graphene (~2004). The youngest member in the sp2 carbon family has taken the world by storm since the seminal work by Geim and Novoselov in 2004. It is just one atom layer thick, but is impermeable to gases and very chemically stable. It is the strongest material and is yet supple and flexible. It has enormous intrinsic carrier mobility and can sustain current densities many order of magnitude higher than metals. The electron transport is described by a Dirac-like equation. In my talk I will focus on optics of strained graphene, both the physics and applications. Since graphene is impermeable to gases and also very elastic, one can use graphene devices as pressure sensors in harsh environments. I will also discuss how strain-induced vector potential and a pseudo-magnetic field that can fool the carriers to behave like they move in a magnetic field. When graphene is strained, the lattice responds by deformation, which affects electronics levels, the phonons and the Raman response, the shape and size of the Brillouin zone, and the position of the Dirac points. Strain engineering of graphene’s electronics structure has been suggested as a way of generating electron collimation, “surface states” and confinement.  Here I will discuss how varying non-uniforms strain can be used to get energy quantization via Pseudo Landau levels, and the effect of including the hitherto ignored effect of lattice angle deformation. In an effort to develop specific structures with tunable strain, we report on experiments on pressurized graphene sealed microchambers, representing a first step toward engineered graphene strain devices. We compare continuum predictions to the measured strain inferred from spatially resolved Raman G band measurements. If time permits I will also discuss my work on the now less fashionable topic carbon nanotubes, in particular exciton dynamics or “Why are nanotubes not brighter?”

 

Anna K. Swan is an Associate Professor of Electrical and Computer Engineering at Boston University with joint appointments in the Physics Department. She is a faculty member of the Photonics Center and the Center for Nano-science and Nano-biotechnology. Prof. Swan received a B.Sc. degree in Physics Engineering from Chalmers University in Gothenburg Sweden, and a Ph.D. in Physics at Boston University.  She joined the Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN, as a Wigner Fellow where she studied the initial stages of thin film growth kinetics and structural and morphological effects on thin film magnetism before joining the ECE department at BU. Her current research is clustered around optical spectroscopy of nanoscale systems, in particular single carbon nanotubes and graphene. She is currently on a sabbatical stay at University of Queensland, Brisbane Australia.

 

 

 

 

联系人：尹 彦 副研究员（Tel：82648061）

                金奎娟 研究员 （Tel：82648099）

 

主办单位：中国科学院光物理重点实验室，中国科学院物理研究所-美国光学学会学生俱乐部