• Schirhagl, Romana
• Chipaux, Mayeul
• Martinez, Felipe Perona
• Hamoh, Thamir H.
• Vedelaar, Thea A.

Abstract

The negatively charged nitrogen-vacancy (NV) center in diamond has emerged as a powerful and versatile quantum sensor for diverse quantities. In particular, all-optical diamond based relaxometry or T1, which consists of monitoring the NV centers' photoluminescence submitted to a train of green laser pulses, allows to detect magnetic noise and its origin. When applied on diamond nanoparticles, it allows nanoscale resolution and has many applications in biology, for monitoring chemical reactions metabolic activity or diagnostic markers. While increasing the number of NV centers in a nanodiamond allows to collect more signal, a standardized method to extract information from relaxometry experiments of such NV ensembles is still missing. In this article, we use a set of T1 relaxation curves acquired at different concentrations of gadolinium ions to calibrate and optimize the entire data processing flow, from the acquired raw data to the extracted T1. In particular, we use a bootstrap to derive a signal to noise ratio that can be quantitatively compared from one method to another. At first, T1 curves are extracted from photoluminescence pulses. We compare integrating their signal through an optimized window as performed conventionally, to fitting a known function on it. Fitting the decaying T1 curves allows to obtain the relevant T1 value. We compared here the three most commonly used fit models that are, single, bi, and stretched exponential. We finally investigated the effect of the bootstrap itself on the precision of the result as well as the use of a rolling window to allows time-resolution.

Topics

• nanoparticle
• impedance spectroscopy
• photoluminescence
• experiment
• Nitrogen
• Gadolinium
• vacancy