Efficient signal processing for time-resolved fluorescence detection of nitrogen-vacancy spins in diamond

Room-temperature fluorescence detection of the nitrogen-vacancy center electronic spin typically has low signal to noise, requiring long experiments to reveal an averaged signal. Here, we present a simple approach to analysis of time-resolved fluorescence data that permits an improvement in measurement precision through signal processing alone. Applying our technique to experimental data reveals an improvement in signal to noise, which is equivalent to a 14% increase in photon collection efficiency. We further explore the dependence of the signal-to-noise ratio on excitation power and analyze our results using a rate equation model. Our results provide a rubric for optimizing fluorescence spin detection, which has direct implications for improving precision of nitrogen-vacancy-based sensors. (C) 2016 Optical Society of America