Gian electric and magnetic Purcell factor in dielectric oligomers

We study the near-field enhancement of oligomers composed of high-refractive-index spherical particles. The huge enhancement of the electromagnetic field in the gap between the particles is observed. We reveal that this phenomenon is associated with the Fano-like resonances of both electric and magnetic multipole contributions inside each particle. We also predict that electric and magnetic Purcell factors can be strongly enhanced, being larger than 10(3). The obtained results represent an important guideline for the realization of dielectric structures to enhance the spontaneous emission rate of quantum sources and various two-level systems. (C) 2020 Optical Society of America