Stimulated Raman Adiabatic Passage in a Quantum Emitter Near to a Gold Nanoparticle

In the last three decades, stimulated Raman adiabatic passage (STIRAP) has been proven a robust and high-efficient technique for population transfer in a three-level quantum system and beyond that. As coupled quantum-plasmonic nanostructures are widely used in recent nanophotonics for the superior properties that the coupled structures have over their constituents, a series of studies have analyzed the influence of a spherical metallic nanoparticle, which is a basic plasmonic nanosystem, on coherent population transfer methods in nearby quantum systems. For several recent proposals, it is important to understand the behavior of STIRAP near metallic nanoparticles. Therefore, in this work we present numerical results on the influence of a spherical metallic nanoparticle to the population transfer in a Λ-type quantum system under conditions of STIRAP. For the study of the system’s dynamics, we use the density matrix approach for the quantum system, where the parameters for the electric field amplitudes and the spontaneous decay rates have been calculated using ab initio electromagnetic calculations for the plasmonic nanoparticle. We then present results for the evolution of the populations of the different levels of the quantum system as a function of different parameters, in the presence and the absence of the plasmonic nanoparticle. We find that the presence of the plasmonic nanoparticle and the polarization of the pump and Stokes fields with respect to the surface of the nanoparticle, affect the efficiency of the population transfer inside the three-level quantum system. For the right combination of the values of the free space spontaneous decay rates and the fields intensities, high efficiency population transfer is obtained in the quantum system near a plasmonic nanoparticle using the STIRAP process.