  The nitrogen-vacancy (NV) center in diamond is a heavily studied defect due
to its potential applications to quantum metrology and computation,
particularly in ambient conditions. The key mechanism to using the NV in any
application lies in the ability to read out the spin state of the defect which
is typically done optically. The optical contrast is then the key metric for
electron spin readout fidelity and one of the key limiting factors in the NV's
overall performance. We present a new mechanism for high contrast readout using
the spin-to-charge conversion (SCC) mechanism in conjunction with an electrode
to improve the spin contrast by altering the NV energy levels relative to the
diamond conduction band. Theoretical modelling predicts an optical spin
contrast at 42% which would be the highest optical contrast for the NV at room
temperature and the technique opens up a range of alternative research pathways
for the NV which are discussed.
