A cavity-modified master equation is derived for a coherently driven V-type three-level atom coupled to a singlemode cavity in the bad cavity limit.The influences of the cavity-induced quantum interference on the stea...A cavity-modified master equation is derived for a coherently driven V-type three-level atom coupled to a singlemode cavity in the bad cavity limit.The influences of the cavity-induced quantum interference on the steady-state populations are analysed.We show that the population inversion can occur due to the effect of cavity-induced quantum interference.展开更多
The analysis of the RCS from the rough sea and ground surface is made. The two dimensionally band limited fractal function is used to model the sea and ground surface, the scattered electromagnetic field is calculat...The analysis of the RCS from the rough sea and ground surface is made. The two dimensionally band limited fractal function is used to model the sea and ground surface, the scattered electromagnetic field is calculated by using Kirchhoff approximation. The validity of this result is assured by some references, which indicates that the methods are reliable.展开更多
Effects of detunings on dynamically induced irreversibility is studied for coherently driven V systems in which there is no conventional source of irreversible population pumping.For atomic barium(γ1/γ2=400>>1...Effects of detunings on dynamically induced irreversibility is studied for coherently driven V systems in which there is no conventional source of irreversible population pumping.For atomic barium(γ1/γ2=400>>1,whereγ1 andγ2 are the rates of the spontaneous decay from the excited states 6s6p^(1)P_(1)and 6s6p^(3)P_(1)to the ground state 6s^(2)^(1)S_(0),respectively),the strong irreversibility is found to lead to a maximum inversion of 0.77[only 0.1 in Phys.Rev.Lett.71(1993)4311].The maximum population inversion requires relatively strong Gelds coupled respectively to two transitions,a disparity in two atomic decay rates,and the atom-field detunings of opposite signs.However,it is also shown that even in the cases where two detunings have the same sign,or where two decay rates are equal,population inversion takes place.展开更多
The absorption spectrum of a driven two-level atom in a frequency tunable cavity with injected squeezed vacuum is investigated. The line shape of the spectra depends on the relative phase between the driving field and...The absorption spectrum of a driven two-level atom in a frequency tunable cavity with injected squeezed vacuum is investigated. The line shape of the spectra depends on the relative phase between the driving field and the squeezed vacuum, and the frequency detuning between the driving field and the cavity mode. Line narrowing and probe gain can occur and be enhanced by adjusting the phase and detuning.展开更多
A quantum-beat laser without inversion is proposed for producing two-mode suqeezing.Using the dressed-atom-dressed-mode approach,the master equation is derived and the variances in the sum mode intensity and in the re...A quantum-beat laser without inversion is proposed for producing two-mode suqeezing.Using the dressed-atom-dressed-mode approach,the master equation is derived and the variances in the sum mode intensity and in the relative amplitude and phase are calculated.When the laser is operated well above threshold,the intensity fluctuations in the sum mode are reduced below the shot noise limit with an optimum Mandel parameter of-0.5.At the same time,the fluctuations in the relative amplitude and phase are retained at their vaccum noise levels.展开更多
The effects of the pump phase fluctuation on aΛ-laser with and without inversion are investigated.It is shown that the pump phase fluctuation can reduce the linewidth of the laser without inversion.It is also shown t...The effects of the pump phase fluctuation on aΛ-laser with and without inversion are investigated.It is shown that the pump phase fluctuation can reduce the linewidth of the laser without inversion.It is also shown that,when the system exhibits a transition from lasing without inversion to lasing with inversion,the laser linewidth can still be reduced.展开更多
Noise squeezing of intensity difference between the pair of sum modes may be generated in a cascade laser of A and U quantum-beats.The best achievable squeezing is up to 50%below the shot noise limit.This new kind of ...Noise squeezing of intensity difference between the pair of sum modes may be generated in a cascade laser of A and U quantum-beats.The best achievable squeezing is up to 50%below the shot noise limit.This new kind of squeezed lasers has potential for quantum communications and precision measurements.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.17774024the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘A cavity-modified master equation is derived for a coherently driven V-type three-level atom coupled to a singlemode cavity in the bad cavity limit.The influences of the cavity-induced quantum interference on the steady-state populations are analysed.We show that the population inversion can occur due to the effect of cavity-induced quantum interference.
文摘The analysis of the RCS from the rough sea and ground surface is made. The two dimensionally band limited fractal function is used to model the sea and ground surface, the scattered electromagnetic field is calculated by using Kirchhoff approximation. The validity of this result is assured by some references, which indicates that the methods are reliable.
基金Supported by the National Natural Science Foundation of China under Grant No.69708001the Natural Science Foundation of Hubei Province under Grant No.97J013.
文摘Effects of detunings on dynamically induced irreversibility is studied for coherently driven V systems in which there is no conventional source of irreversible population pumping.For atomic barium(γ1/γ2=400>>1,whereγ1 andγ2 are the rates of the spontaneous decay from the excited states 6s6p^(1)P_(1)and 6s6p^(3)P_(1)to the ground state 6s^(2)^(1)S_(0),respectively),the strong irreversibility is found to lead to a maximum inversion of 0.77[only 0.1 in Phys.Rev.Lett.71(1993)4311].The maximum population inversion requires relatively strong Gelds coupled respectively to two transitions,a disparity in two atomic decay rates,and the atom-field detunings of opposite signs.However,it is also shown that even in the cases where two detunings have the same sign,or where two decay rates are equal,population inversion takes place.
基金Supported by the National Natural Science Foundation of China under Grant No.17774024and the Scientific Research Foundation for Returned Overseas Chinese Scholars,State Education Ministry.
文摘The absorption spectrum of a driven two-level atom in a frequency tunable cavity with injected squeezed vacuum is investigated. The line shape of the spectra depends on the relative phase between the driving field and the squeezed vacuum, and the frequency detuning between the driving field and the cavity mode. Line narrowing and probe gain can occur and be enhanced by adjusting the phase and detuning.
基金Supported by the National Natural Science Foundation of China under Grant No.69708001the Natural Science Foundation of Hubei Province under Grant No.97J013.
文摘A quantum-beat laser without inversion is proposed for producing two-mode suqeezing.Using the dressed-atom-dressed-mode approach,the master equation is derived and the variances in the sum mode intensity and in the relative amplitude and phase are calculated.When the laser is operated well above threshold,the intensity fluctuations in the sum mode are reduced below the shot noise limit with an optimum Mandel parameter of-0.5.At the same time,the fluctuations in the relative amplitude and phase are retained at their vaccum noise levels.
基金Supported by the National Natural Science Foundation of China under Grant No.69708001the National Natural Science Foundation of Hubei Province under Grant No.97J013。
文摘The effects of the pump phase fluctuation on aΛ-laser with and without inversion are investigated.It is shown that the pump phase fluctuation can reduce the linewidth of the laser without inversion.It is also shown that,when the system exhibits a transition from lasing without inversion to lasing with inversion,the laser linewidth can still be reduced.
基金the National Natural Science Foundation of China under Grant No.69708001the Natural Science Foundation of Hubei Province under Grant No.97J013.
文摘Noise squeezing of intensity difference between the pair of sum modes may be generated in a cascade laser of A and U quantum-beats.The best achievable squeezing is up to 50%below the shot noise limit.This new kind of squeezed lasers has potential for quantum communications and precision measurements.