Polarization Modulation Spectroscopy of Single Fluorescent Nanodiamonds with Multiple Nitrogen Vacancy Centers

Abstract

A technique based on polarization modulation spectroscopy (PMS) has been developed to determine quantitatively the number of fluorophores in nanoparticles at the single-molecule level. The technique involves rotation of the polarization of the excitation laser on a millisecond time scale, leading to fluorescence intensity modulation. By taking account of the heterogeneous orientation among the dipoles of the fluorophores and simulating the modulation depth distribution with Monte Carlo calculations, we show that it is possible to deduce the ensemble average and number distribution of the fluorophores. We apply the technique to fluorescent nanodiamonds (FNDs) containing multiple nitrogen vacancy (NV) centers. Comparing the experimental and simulated modulation depth distributions of 11 nm FNDs, we deduce an average number of <N> = 3, which is in good agreement with independent photon correlation measurements. The method is general, rapid, and applicable to other nanoparticles, polymers, and molecular complexes containing multiple and randomly orientated fluorophores as well.

Directional fluorescence emission from a compact plasmonic‐diamond hybrid nanostructure

“…The results indicate that the angular distribution of a single FND is also quite similar to that of a dipole emitter. The experimental and simulation results confirmed that for a specific configuration, single FNDs can be modeled as a “point dipole emitter” , which is necessary to observe directional emission from the FND and GNR coupled system.…”

Metallofullerol Nanoparticles with Low Toxicity Inhibit Tumor Growth by Induction of G0/G1 Arrest

“…23,117 This defect center absorbs light photons at ∼560 nm and fluoresces brightly at ∼700 nm with a quantum efficiency close to 1. 25,69,120 As such, these centers offer characteristically bright red fluorescence to diamond particles upon excitation with green-yellow light, 22 hence have found applications for high-pressure high-temperature NDs in imaging studies. 19,25 The extreme photostability of (N-V)defect centers 121,122 provides a greater advantage to NDs to emerge as an excellent candidate for long-term cellular imaging over commonly used fluorophores.…”

Nanodiamonds as novel nanomaterials for biomedical applications: drug delivery and imaging systems

“…23,117 This defect center absorbs light photons at ∼560 nm and fluoresces brightly at ∼700 nm with a quantum efficiency close to 1. 25,69,120 As such, these centers offer characteristically bright red fluorescence to diamond particles upon excitation with green-yellow light, 22 hence have found applications for high-pressure high-temperature NDs in imaging studies. 19,25 The extreme photostability of (N-V)…”