Nuclear spin gyroscope based on an atomic co-magnetometer
  We describe a nuclear spin gyroscope based on an alkali-metal-noble-gas co-magnetometer. An optically pumped alkali-metal vapor is used to polarize the noble gas atoms and detect their gyroscopic precession. Spin precession due to magnetic fields as well as their gradients and transients can be cancelled in this arrangement. The sensitivity is enhanced by using a high-density alkali-metal vapor in a spin-exchange relaxation free (SERF) regime. With a K-3He co-magnetometer we demonstrate rotation sensitivity of 5 10^(-7) rad/sec/Hz^(1/2). The rotation signal can be increased by a factor of 10 using 21Ne due to its smaller magnetic moment and the fundamental rotation sensitivity limit for a 21Ne gyroscope with a 10 cm^3 measurement volume is about 2 10^(-10) rad/sec/Hz^(1/2). 
T. W. Kornack, R. K. Ghosh and M. V. Romalis