The main objective of this research is to develop a theoretical framework capable of making practical recommendations for the design of new spaser (surface plasmon amplification by stimulated emission of radiation) based metamaterials with strong nonlinear response to low intensity optical fields. Since spasers were discovered only recently, their description has relied on simplistic models. With support from the Division of Materials Research, this Materials World Network project will carry out analytical and numerical calculations using a realistic model that takes into account the anisotropy of interactions of the spaser's component parts, which allow for excitation of magnetic modes that are essential for metamaterials. Metamaterials suffer from an unacceptable level of Joule losses. Moreover, for metamaterial based devices it is necessary not only to overcome these losses but to achieve exact compensation. The purpose of this research project is to demonstrate that spasers, as active inclusions in metamaterials and magnetooptical materials, are ideal candidates for achieving this goal. For metaplasmonics, it is important to consider not a single spaser but a system of spasers, such as ordered chains and lattices. The collective interaction of spasers in such a system may substantially change generation conditions, properties of auto-oscillations, and may engender new phenomena and instabilities. With Russian and US teams working in collaboration, the project will study the collective behavior of a system of spasers in an external electromagnetic field including spaser synchronization by the external field as well as their mutual synchronization.
NON-TECHNICAL SUMMARY: In the last decade, the field of quantum nanoplasmonics has experienced explosive growth due to numerous anticipated revolutionary applications in optics, which are expected to lead to the future development of ultrafast and supersmall optoelectronic devices. Nanoplasmonics utilizes outstanding optical properties of metal nanoparticles, which when combined with a nanoscale active medium, results in the emergence of a "spaser" (surface plasmon amplification by stimulated emission of radiation), which is a nanoplasmonic counterpart of the laser. Since spasers were discovered only recently, their description is based on simplistic models. In this Materials World Network project, a novel realistic model of spasers will be developed. This model will reveal new properties of spasers, such as magnetic modes, which are crucial for applications of artificial materials having unusual properties "metamaterials." Applications of metamaterials have been inhibited by high levels of energy loss. The proposed project will demonstrate that this drawback can be overcome with the help of spasers. Metamaterials with spaser inclusions provide an ideal low-cost platform for future optical devices. This study will extend the fundamental understanding of the light-matter interaction at the nanoscale. This proposal will facilitate international contacts between US and Russian research institutions. Graduate and undergraduate students from diverse social, ethnic and national backgrounds will be involved in the research. They will be exposed to the research at the collaborating institutions in an effort to acquaint them with complementary methods, approaches, and techniques that will broaden their scientific horizons.
