In situ electron paramagnetic resonance spectroscopy using single nanodiamond sensors

Abstract

An ultimate goal of electron paramagnetic resonance (EPR) spectroscopy is to analyze molecular dynamics in place where it occurs, such as in a living cell. The nanodiamond (ND) hosting nitrogen-vacancy (NV) centers will be a promising EPR sensor to achieve this goal. However, ND-based EPR spectroscopy remains elusive, due to the challenge of controlling NV centers without well-defined orientations inside a flexible ND. Here, we show a generalized zero-field EPR technique with spectra robust to the sensor's orientation. The key is applying an amplitude modulation on the control field, which generates a series of equidistant Floquet states with energy splitting being the orientation-independent modulation frequency. We acquire the zero-field EPR spectrum of vanadyl ions in aqueous glycerol solution with embedded single NDs, paving the way towards \emph{in vivo} EPR.

References in corpus (5)

• Nanoscale magnetic imaging of a single electron spin under ambient conditions
• Efficient readout of a single spin state in diamond via spin-to-charge conversion
• Single DNA Electron Spin Resonance Spectroscopy in Aqueous Solutions
• Nanoscale zero-field electron spin resonance spectroscopy
• Kilohertz electron paramagnetic resonance spectroscopy of single nitrogen centers at zero magnetic field