Plasmonics is a field of research dedicated to the study and application of plasmons, which are collective oscillations of free electrons in a material. This discipline investigates the unique optical phenomena arising from the interaction of electromagnetic radiation with these charge oscillations, particularly focusing on surface plasmon polaritons propagating along metal-dielectric interfaces and localized surface plasmon resonances in metallic nanostructures. Key characteristics include the ability to confine light to nanoscale volumes and achieve strong light-matter coupling, enabling applications in areas such as enhanced spectroscopy, biosensing, nanoscale imaging, and optical circuitry.