  We propose a magnetomechanical device that exhibits many properties of a
laser. The device is formed by a nanocantilever and dynamically polarized
paramagnetic nuclei of a solid sample in a strong external magnetic field. The
corresponding quantum oscillator and effective two-level systems are coupled by
the magnetostatic dipole-dipole interaction between a permanent magnet on the
cantilever tip and the magnetic moments of the spins, so that the entire system
is effectively described by the Jaynes-Cummings model. We consider the
possibility of observing transient and cw lasing in this system, and show how
these processes can be used to improve the sensitivity of magnetic resonance
force microscopy.
