  We have developed an inelastic wave scattering based colliding-probe
bi-atomic magnetometer theory. We show a propagation growth blockade in single
probe based magnetic field sensing schemes, revealing the root cause of strong
suppression of nonlinear magneto-optical rotation effect (NMORE) in single
probe based atomic magnetometers. We further show, both experimentally and
theoretically, a colliding probe bi-atomic magnetometer that lifts this NMORE
blockade. The directional energy circulation in this new atomic magnetometry
technique results in more than two orders of magnitude increase in NMORE signal
as well as greater than 6dB increase of magnetic field detection sensitivity.
The new technique may have broad applications in photon gates and switching
operations.
