  We propose a novel experimental approach to explore exotic spin-dependent
interactions using a spin-exchange relaxation-free (SERF) magnetometer, the
most sensitive non-cryogenic magnetic-field sensor. This approach studies the
interactions between optically polarized electron spins located inside a vapor
cell of the SERF magnetometer and unpolarized or polarized particles of
external solid-state objects. The coupling of spin-dependent interactions to
the polarized electron spins of the magnetometer induces the tilt of the
electron spins, which can be detected with high sensitivity by a probe laser
beam similarly as an external magnetic field. We estimate that by moving
unpolarized or polarized objects next to the SERF Rb vapor cell, the
experimental limit to the spin-dependent interactions can be significantly
improved over existing experiments, and new limits on the coupling strengths
can be set in the interaction range below 0.01 m.
