Nanosystems in Ultrafast and Superstrong Fields: Attosecond Phenomena

06.12.2016, 13:30

Prof Mark I. Stockman, Center for Nano-Optics (CeNO) and Department of Physics and Astronomy, Georgia State University, Atlanta, USA

We present our latest results for a new class of phenomena in condensed matter nanooptics when a strong optical field ˜1 - 3 V/Å changes a solid within optical cycle. Such a pulse drives ampere-scale currents in dielectrics and adiabatically controls their properties, including optical absorption and reflection, extreme UV absorption, and generation of high harmonics in a non-perturbative manner on a 100-as temporal scale. Applied to a metal, such a pulse causes an instantaneous and, potentially, reversible change from the metallic to semimetallic properties. We will also discuss our latest theoretical results on graphene (semimetal) and other two-dimensional solids such as transitional metal dichalcogenides (semiconductors), black phosphorus, and boron nitride (dielectric). Such materials in the reciprocal space are characterized by such nontrivial topological properties as Berry curvature and Berry flux. In particular, graphene in a strong ultrashort pulse field exhibits unique behavior related to its topological properties. The corresponding phenomena are among the fastest processes in optics unfolding within a half period of light. They offer potential for petahertz-bandwidth signal processing, generation of high harmonics on a nanometer spatial scale, valleytronics, etc.