Homogeneity of the negatively charged assembly of nitrogen vacancy centres in diamonds using the Quasi-finite-element optical scanning position method

Abstract

We developed a versatile Quasi-finite-element scanning method to analyse the concentration and homogeneity of the ensembles of nitrogen-vacancy (NV−) centres in block diamonds. In this method, area of the bulk diamond with high-density NV− centres was divided into small pieces at the nanoscale by using a focused light beam. The concentration of NV− centres was obtained and imaged through the fluorescence intensity of each pixel by employing a home-built spectrometer. In addition, global and local homogeneities were introduced to evaluate the NV− centre distribution. NV− centres in a specific pixel exhibited preferred direction growth peaks attributed to the diamond crystal orientation. Moreover, the uniformity of NV− centres was not proportional to the electron irradiation duration, but an optimal time was observed. This study can be beneficial for enhancing the sensitivities of bulk magnetometry based on confocal systems.