Enhanced spontaneous emission from nanodiamond colour centres on opal photonic crystal

TL;DR

This study demonstrates a 1.5-fold enhancement in spontaneous emission rates of nitrogen-vacancy centres in nanodiamonds placed on opal photonic crystals, advancing quantum and biomedical imaging applications.

Contribution

It provides detailed characterization and modeling of emission rate enhancements of colour centres on structured photonic substrates, highlighting the effects of dipole orientation and polarization.

Findings

Average 1.5x increase in emission rate on opal photonic crystal surface

Observed changes in lifetime distribution of emitters

Model links lifetime variations to dipole orientation and polarization

Abstract

Colour centres in diamond are promising candidates as a platform for quantum technologies and biomedical imaging based on spins and/or photons. Controlling the emission properties of colour centres in diamond is a key requirement for developing efficient single photon sources with high collection efficiency. A number of groups have produced enhancement in the emission rate over narrow wavelength ranges by coupling single emitters in nanodiamond crystals to resonant electromagnetic structures. Here we characterise in detail the spontaneous emission rates of nitrogen-vacancy centres positioned in various locations on a structured substrate. We show an average factor of 1.5 enhancement of the total emission rate when nanodiamonds are on an opal photonic crystal surface, and observe changes in the lifetime distribution. We present a model to explain these observations and associate the lifetime properties with dipole orientation and polarization effects.