text: where Ω*R*
  resonance, 
  the Rabi 
  *DS T*=*g*2 ˜*Nass*/*I*0γ*ab*
  ,*DRam*
  and 
  *ab*, 
  ∆2 = ω 
  ω*b*2) presents the detuning in the free 
  (ω*a*2 − 
  drift region.*p*is a parameter, which characterizes the pump- 
  ing statistics: a Poissonian excitation statistics corresponds to 
  *p*= 0 , and for a regular statistics we have*p*= 1. 
  
  is 
  
  − 
  
  *Laser linwidth:*Suppose the quantum ﬂuctuation is small, 
  the evolution of the ﬂuctuations can be obtained by making a 
  linearization of the c-number Langevin equations around the 
  steady-state solution. Then the measured spectra of ﬁeld ﬂuc- 
  tuations will be directly related to these quantities. By Fourier 
  transformations of the linearized equation, we get the ampli- 
  tude and phase quadrature components δ*X*(ω) and δ*Y*(ω) [26]. 
  Well above threshold, one can neglect the amplitude ﬂuctu- 
  ations, and the linewidth inside the cavity is related to the 
  phase-diﬀusion coeﬃcient [25]. For small ﬂuctuation of laser 
  phase, the spectrum of phase ﬂuctuations is simply related to 
  the spectrum of the phase quadrature component of the ﬁeld 
  ﬂuctuations, namely, 
  
  Then the linewidth of Ramsey laser with bad cavity is given 
  by 
  
  γ2 
  *ab*
  (κ/2 + γ*ab*)2 { 
  
  . 
  } 
  (11) 
  Since*DS T*/*DRam*≪ 
  1 in our situation, and in the case of max- 
  imal photon number, the steady state value of ˜*Nass*is about 
  *R*τ/2. Then we get the 
  
  2*g*2 
  κ  ≈  − 