【摘要】 研究了具有真空诱导相干的准∧型四能级原子系统中Doppler展宽以及探测场和驱动场之间的相对相位对瞬态演化的影响。研究结果表明:相对相位对无反转增益(GWI)的瞬态演化规律有明显的影响,对泵浦场和驱动场增益(吸收)的瞬态演化规律只有很小的影响;Doppler展宽宽度D值的改变也对相位相关的GWI的瞬态演化有显著的调制作用;在取固定值的情况下,D值越大,增益达到稳定值所需的演化时间越长;D值不同时,达到增益极大值的演化时间也不同;最大瞬态增益和最大稳定增益并不对应相同的D值;选取适当的和D值,存在Doppler展宽时可以得到比无Doppler展宽时更大的增益;当存在Doppler展宽时,光场的传播方向对相位相关的GWI瞬态演化也有显著的影响,探测场与驱动场传播方向相同时比传播方向相反时可以获得更大的GWI。更多还原

【Abstract】 The influence of Doppler broadening and relative phase between probe and driving fields on transient evolution in a quasi ∧-type four-level atomic system with spontaneously generated coherence is studied.It is shown that the relative phase(φ) has an obvious effect on transient evolution rule of gain without inversion(GWI) but just a small effect on transient evolution rule of gains(absorptions) of the pumping and driving fields;the variation of the Doppler broadening width(D) also has a considerable modulation role on phase-dependent transient evolution of GWI;for a fixed value of φ,with D increasing,the time needed to obtain steady GWI becomes longer;for different values of D,the time needed to obtain maximum GWI is also different;the value of D corresponding to the largest transient GWI is different from that corresponding to the largest steady GWI;when Doppler broadening appears,larger GWI can be obtained by choosing suitable values of φ and D,and propagation directions of the probe and driving fields also have a remarkable effect on phase-dependent transient evolution of GWI;when the propagation directions of the probe and driving fields are the same,a larger GWI can be obtained.更多还原