Optical Magnetism and Fundamental Modes of Nanodiamonds

The optical properties of color centers in nanodiamonds are widely used in various branches of photonics and interdisciplinary studies. Here, we report on an experimental study of the fundamental eigenmodes of subwavelength diamond nanoparticles. The eigenmodes reveal themselves as scattering resonances, which were measured by single-particle dark-field spectroscopy and calculated both numerically and analytically. The resonances experience a red-shift with increasing particle size, and in the case of an anisotropic particle, they change depending on the polarization of the input light. As an example of an application, the Purcell enhancement of the dipole emission from such nanodiamonds is numerically demonstrated. This study demonstrates a simple way to improve the efficiency of diamond-based sensors and single-photon sources by choosing nanoparticles of optimal size and shape