1108.0178 (A. Dréau et al.)

Avoiding power broadening in optically detected magnetic resonance of
single NV defects for enhanced DC-magnetic field sensitivity    [PDF]

A. Dréau, M. Lesik, L. Rondin, P. Spinicelli, O. Arcizet, J. -F. Roch, V. Jacques

We report a systematic study of the magnetic field sensitivity of a magnetic
sensor based on a single Nitrogen-Vacancy (NV) defect in diamond, by using
continuous optically detected electron spin resonance (ESR) spectroscopy. We
first investigate the behavior of the ESR contrast and linewidth as a function
of the microwave and optical pumping power. The experimental results are in
good agreement with a simplified model of the NV defect spin dynamics, yielding
to an optimized sensitivity around 2 \mu T/\sqrt{\rm Hz}. We then demonstrate
an enhancement of the magnetic sensitivity by one order of magnitude by using a
simple pulsed-ESR scheme. This technique is based on repetitive excitation of
the NV defect with a resonant microwave \pi-pulse followed by an optimized
read-out laser pulse, allowing to fully eliminate power broadening of the ESR
linewidth. The achieved sensitivity is similar to the one obtained by using
Ramsey-type sequences, which is the optimal magnetic field sensitivity for the
detection of DC magnetic fields.

View original: http://arxiv.org/abs/1108.0178