Nitrogen-Vacancy Centers in Diamond for High-Performance Detection of Vacuum Ultraviolet, Extreme Ultraviolet, and X-rays

Fluorescent nanodiamonds (FNDs) containing nitrogen-vacancy (NV) centers as built-in fluorophores exhibit a nearly constant emission profile over 550–750 nm upon excitation by vacuum-ultraviolet (VUV), extreme ultraviolet (EUV), and X-radiations from a synchrotron source over the energy (wavelength) range of 6.2–1450 eV (0.86–200 nm). The photoluminescence (PL) quantum yield of FNDs increases steadily with the increasing excitation energy, attaining a value as great as 1700% at 700 eV (1.77 nm). Notably, the yield curve is continuous, having no gap in the VUV to X-ray region. In addition, no significant PL intensity decreases were observed for hours. Applying the FND sensor to measure the absorption cross-sections of gaseous O2 over 110–200 nm and comparing the measurements with the sodium-salicylate scintillator, we obtained results in agreement with each other within 5%. The superb photostability and broad applicability of FNDs offer a promising solution for the long-standing problem of lacking a robust and reliable detector for VUV, EUV, and X-radiations.