Nondestructive imaging of cold atoms relies on the phase shift of probe light while passing theatomic sample.The working condition is fulfilled as the probe is far off the atomic resonaneeswhere the refractive process dominates.Hence, the near-resonance photon absorption,often causing atom heating and state flipping, is strongly suppressed and much longer probingtime is permitted.Nondestructive imaging thus provides tremendous advantages over theabsorption method, especially when atoms are extremely cold [1].