Plasmonics is commonly explored and interpreted within the framework of classical electrodynamics. On the other hand, with the increasing ability to explore plasmons in nanostructures with yet smaller characteristic dimensions, intrinsic length scales of the electron gas are anticipated to manifest in a nonlocal plasmonic response and other quantum corrections to the light-matter interactions. Efforts to make semi-classical hydrodynamic extensions of the Drude model [1,2] will be addressed, as well as developments beyond these simplified models [3,4,5]. In nanoparticles, nonlocal response promotes frequency blueshifts and nonlocal damping of high-order modes, as has been observed in single-particle EELS [6]. As to the quantum mechanical origin of these effects, one can quantify the degree of nonclassical effects from an energy perspective [7]. This provides a direct link between the experimentally observed resonance blueshift and the fraction of electromagnetic energy attributed to quantum degrees of freedom. Finally, implications of nonlocal dynamics for both classical and quantum optical problems in nanoplasmonics will be discussed [8].
[1] N.A. Mortensen, S. Raza, M. Wubs, T. Søndergaard, and S.I. Bozhevolnyi, "A generalized non-local optical response theory for plasmonic nanostructures", Nature Communications 5, 3809 (2014)
[2] S. Raza, S.I. Bozhevolnyi, M. Wubs, and N.A. Mortensen, "Nonlocal optical response in metallic nanostructures", J. Phys. Cond. Matter. 27, 183204 (2015)
[3] G. Toscano, J. Straubel, A. Kwiatkowski, C. Rockstuhl, F. Evers, H. Xu, N.A. Mortensen, and M. Wubs, "Resonance shifts and spill-out effects in self-consistent hydrodynamic nanoplasmonics," Nature Communications 6, 7132, (2015)
[4] W. Yan, M. Wubs, and N. A. Mortensen, "Projected Dipole Model for Quantum Plasmonics", Phys. Rev. Lett. 115, 137403 (2015)
[5] T. Christensen, W. Yan, A.-P. Jauho, M. Soljacic, and N.A. Mortensen, "Quantum corrections in nanoplasmonics: shape, scale, and material", Phys. Rev. Lett. 118, 157402 (2017)
[6] S. Raza, S. Kadkhodazadeh, T. Christensen, M. Di Vece, M. Wubs, N.A. Mortensen, and N. Stenger, "Multipole plasmons and their disappearance in few-nanometer silver nanoparticles", Nature Communications 6, 8788 (2015)
[7] W. Yan and N.A. Mortensen, "Nonclassical effects in plasmonics: An energy perspective to quantify nonclassical effects", Phys. Rev. B 93, 115439 (2006)
[8] A.I. Fernández-Domínguez, S.I. Bozhevolnyi, and N.A. Mortensen, "Plasmon-enhanced generation of non-classical light", ACS Photonics 5, 3447 (2018)
Biography: Mortensen is a full professor & VILLUM Investigator in the Center for Nano Optics and a Chair of Technical Science in the Danish Institute for Advanced Study, both at the University of Southern Denmark. Previously, he held a full professorship (faculty since 2004) at the Technical University of Denmark, from where he was also awarded his academic degrees [Dr. Techn. (2006), PhD (2001), MSc (1998)]. He is a fellow of APS, OSA, SPIE, and IOP. His current work on quantum plasmonics is supported through a personal grant (5+ MEUR) from VILLUM FONDEN.