  The electronic spins of the nitrogen-vacancy centers (NV centers) in
Chemical-Vapor-Deposition (CVD) grown diamonds form ideal probes of magnetic
fields and temperature, as well as promising qu-bits for quantum information
processing. Studying and controlling the magnetic environment of NV centers in
such high purity crystals is thus essential for these applications. We
demonstrate optical detection of paramagnetic species, such as hydrogen-related
complexes, in a CVD-grown diamond. The resonant transfer of the NV centers'
polarized electronic spins to the electronic spins of these species generates
conspicuous features in the NV photoluminescence by employing magnetic field
scans along the [100] crystal direction. Our results offer prospects for more
detailed studies of CVD-grown processes as well as for coherent control of the
spin of novel classes of hyper-polarized paramagnetic species.
