  The quantum correlation of light and atomic collective excitation can be used
to compose an SU(1,1)-type hybrid light-atom interferometer, where one arm in
optical SU(1,1) interferometer is replaced by the atomic collective excitation.
The phase-sensing probes include not only the photon field but also the atomic
collective excitation inside the interferometer. For a coherent squeezed state
as the phase-sensing field, the phase sensitivity can approach the Heisenberg
limit under the optimal conditions. We also study the effects of the loss of
light field and the dephasing of atomic excitation on the phase sensitivity.
Since nonlinear processes are involved in this interferometer, they can couple
a variety of different waves and form new types of hybrid interferometers,
which provides a new method for basic measurement using the hybrid
interferometers.
