论文标题
旋转量子击败激光无反转
Rotational Quantum Beat Lasing Without Inversion
论文作者
论文摘要
在标准激光器中，光放大需要上层和下部状态之间的种群倒置，以破坏吸收和刺激发射之间的互惠。但是，在以特定叠加态制备的培养基中，量子干扰可能会完全抑制吸收，同时保持刺激的发射完整，从而打开无反转的激光的可能性。在这里，我们表明，在空气中强烈飞秒激光脉冲传播时，没有反转的激光自然出现。它是由分子电离和分子比对的组合触发的，这两者在强烈的光场中都不可避免。这种效果可以使许多分子气体中宽带辐射的不可倒数放大，从而为遥感打开了异常的机会。
In standard lasers, light amplification requires population inversion between an upper and a lower state to break the reciprocity between absorption and stimulated emission. However, in a medium prepared in a specific superposition state, quantum interference may fully suppress absorption while leaving stimulated emission intact, opening the possibility of lasing without inversion. Here we show that lasing without inversion arises naturally during propagation of intense femtosecond laser pulses in air. It is triggered by the combination of molecular ionization and molecular alignment, both unavoidable in intense light fields. The effect could enable inversionless amplification of broadband radiation in many molecular gases, opening unusual opportunities for remote sensing.
