  Integrated and fiber-packaged magnetic field sensors with a sensitivity
sufficient to sense electric pulses propagating along nerves in life science
applications and with a spatial resolution fine enough to resolve their
propagation directions will trigger a tremendous step ahead not only in medical
diagnostics, but in understanding neural processes. Nitrogen-vacancy centers in
diamond represent the leading platform for such sensing tasks under ambient
conditions. Current research on uniting a good sensitivity and a high spatial
resolution is facilitated by scanning or imaging techniques. However, these
techniques employ moving parts or bulky microscope setups. Despite being far
developed, both approaches cannot be integrated and fiber-packaged to build a
robust, adjustment-free hand-held device. In this work, we introduce novel
concepts for spatially resolved magnetic field sensing and 2-D gradiometry with
an integrated magnetic field camera. The camera is based on infrared absorption
optically detected magnetic resonance (IRA-ODMR) mediated by perpendicularly
intersecting infrared and pump laser beams forming a pixel matrix. We
demonstrate our 3-by-3 pixel sensor's capability to reconstruct the position of
an electromagnet in space. Furthermore, we identify routes to enhance the
magnetic field camera's sensitivity and spatial resolution as required for
complex sensing applications.
