Jul 29, '20In the last decade, the field of quantum nanoplasmonics has experienced explosive growth due to numerous revolutionary applications in optics, which are expected to lead to the future development of ultrafast and super small optoelectronic devices. Nano-size light sources are integral parts of many of these applications. They are used in optoelectronics, quantum-information transmission lines, the spectroscopy of single-photon sources, long-distance signal transmission through the atmosphere, and sensor applications. All these areas are important for the Department of Navy mission. One of the most important characteristics of a light source is its coherent properties. Some applications even require light sources with predetermined or tunable photon statistics. However, for many plasmonic nano-size light sources, coherent properties are not well studied. For them, reliable theoretical estimates or unambiguous experimental data do not exist. Another vital characteristic of a light source is its linewidth. In this project, we will investigate analytically and numerically the photon statistics and linewidths of some of the most promising nano-size light sources that are based on amplified spontaneous emission (ASE), distributed feedback (DFB) plasmonic lasers, superradiant lasers, and nitrogen-vacancy (NV) centers interacting with nanoplasmonic structures. For these systems, we plan to calculate theoretically the second-order coherence function, which determines the coherence properties. We will study how this function and the linewidth depend on the level of loss, the pump rate, and the geometry of the system. Our studies will be based on using a master equation for the density matrix in the Lindblad form. Using this equation after eliminating the reservoir variables, we will obtain the Heisenberg equations of motion for the operators of the system that take into account fluctuations and dissipation. From these equations after using proper approximations, we will obtain the system of differential equations for expectation values. The latter system will be solved numerically by using off-the-shell mathematical packages and new algorithms that we will develop. As a result, we expect to find the most efficient regimes and the optimal parameters of light sources and possibilities for their tunability. We also plan to study the change in the light coherency during the transition from spontaneous radiation to ASE. In this transitional regime, the system is the most sensitive for absorbing molecules and can be used, therefore, for creating supersensitive nano-size sensors.