Condensed Matter in Ultrafast and Superstrong Fields: Attosecond Phenomena

We present our latest results for a new class of phenomena in condensed matter optics when a strong optical field ~1-3 V/Å changes a solid within optical cycle [1-7]. 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 [8] 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 that in a strong ultrashort pulse field exhibits unique behavior [9, 10]. New phenomena are predicted for buckled two-dimensional solids, silicene and germanine [11]. These are fastest phenomena in optics unfolding within half period of light. They offer potential for petahertz-bandwidth signal processing, generation of high harmonics on a nanometer spatial scale, etc.\\ References\\ [1] M. Durach et al., Phys. Rev. Lett. 105, 086803 (2010). [2] M. Durach et al., Phys. Rev. Lett. 107, 086602 (2011). [3] A. Schiffrin et al., Nature 493, 70 (2013). [4] M. Schultze et al., Nature 493, 75 (2013). [5] V. Apalkov, and M. I. Stockman, Phys. Rev. B 88, 245438 (2013). [6] V. Apalkov, and M. I. Stockman, Phys. Rev. B 86, 165118 (2012). [7] F. Krausz, and M. I. Stockman, Nat. Phot. 8, 205 (2014). [8] T. Higuchi, M. I. Stockman, and P. Hommelhoff, Phys. Rev. Lett. 113, 213901 (2014). [9] H. K. Kelardeh, V. Apalkov, and M. I. Stockman, Phys. Rev. B 90, 085313 (2014). [10] H. K. Kelardeh, V. Apalkov, and M. I. Stockman, Phys. Rev. B 91, 045439 (2015). [11] H. K. Kelardeh, V. Apalkov, and M. I. Stockman, Phys. Rev. B 92, 045413 (2015).