Influence of Different Gain Models on the Performance of Active Nano Particles

Coated nanoparticles (CNPs) have over the past two decades attracted notable attention due to their promising potential in a wide range of applications, e.g., antennas and sensors at the nanoscale, lasers, energy harvesting, biomedicine, and optical communication, to mention a few.As a material choice, efforts have typically emphasized plasmonic materials, e.g., gold and silver, in passive as well as active CNP designs of primarily spherical and cylindrical shapes.While the performance of passive solutions is hindered by the large plasmonic losses at optical frequencies, it was demonstrated that the use of gain media inside of the CNPs, thus making them active, can fully overcome the large losses leading to strongly resonant particles.Consequently, active CNPs can significantly enhance radiation and scattering phenomena, respectively, of nearby localized sources and exciting plane waves; a feature which emphasizes their potential in the said applications.