修饰态布居的选择性激发对无反转激光的作用

以三能级V型系统为例研究修饰态布居的选择性激发对无反转激光增益的作用. 当非 相干驱动场的频谱宽度远小于驱动场产生的修饰态能级的间距时，非相干驱动场只将一个修 饰态的布居抽运至激发态. 借助原子的衰减通道，系统中形成单向布居转移通道，从而建立 修饰态布居的选择性激发. 利用修饰态布居的选择性激发，可以摆脱裸态共振无反转激光的 三个限制: (1) 不再要求辅助的低频驱动跃迁比高频激光跃迁具有更高的衰减速率；(2) 显 著降低非相干激发速率的阈值；(3) 无反转激光的线性增益不再反比于相干驱动场的强 关键词： 修饰态布居的选择性激发 无反转激光增益 原子衰减速率 非相干激发阈值速率

Role of selective excitation of dressed populations in lasing without inversion

Exemplifying the three_level systems in the V configuration, we investigate the role of selective excitation of dressed populations in lasing without inversion. Incoherent driving field transfers population from either of the dressed states to excited state when the level spacing between dressed states produced by the coherent field is much larger than the spectral width of the incoherent driving field. With atomic decay pathways,unidirectional channel of population transfer is formed and selective excitation of dressed populations is established. Employing selective excitation of dressed populations,three severe limits are relaxed. First,it is no longer required that the decay rate of the low_frequency driving transition is larger than that of high_frequency laser transition. Second,the threshold for incoherent driving rate is remarkably lowered. Third,linear gain of the laser without inversion is no longer inversely proportional to the coherent driving field intensity, and the gain is significantly enhanced.