Mark I. Stockman
Center for Nano-Optics (CeNO) and
Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302, USA
E-mail: mstockman@gsu.edu, web: http://www.phy-astr.gsu.edu/stockman/
Nanoplasmonics deals with collective electron excitations at the surfaces of metal nanostructures, called surface plasmons. The surface plasmons localize and nano-concentrate optical energy creating highly enhanced local fields. Nanoplasmonics has numerous applications in science, technology, biomedicine, environmental monitoring, and defense, which will be briefly reviewed.
There is an all-important need in active devices capable of generating and amplifying coherent optical fields on the nanoscale analogous to lasers and amplifiers of the conventional optics or transistors of microelectronics. Such an active device is the spaser (surface plasmon amplification by stimulated emission of radiation). We will review theory extensive experiments on spasers. We will focus on two new theoretical ideas in the field of spasers: spaser with electric pumping via quantum wire [D. Li and M. I. Stockman, Electric Spaser in the Extreme Quantum Limit, Phys. Rev. Lett. 110, 106803-1-5 (2013)] and quantum-cascade graphene spaser [V. Apalkov, M. I. Stockman, Proposed graphene nanospaser. Light Sci. Appl. 3, e191-191-196 (2014)]. A recent breakthrough in ultrasensitive detection of explosives using the spaser [R.-M. Ma, S. Ota, Y. Li, S. Yang, X. Zhang, Explosives Detection in a Lasing Plasmon Nanocavity, Nat. Nano 9, 600-604 (2014)] will be reviewed.
In perspective, the spasers will have applications as ultrafast nanoamplifiers for petahertz processors, nanoscale sources of coherent and intense optical fields, ultrabright nano-labels, and others.