We propose a novel nonequilibrium phenomenon, through which a prompt quench from a metal to a transient superconducting state can induce large oscillations of the order parameter amplitude. We argue that this oscillating mode acts as a source of parametric amplification of the incident radiation. We report experimental results on optically driven ${\mathrm{K}}_3{\mathrm{C}}_{60}$ that are consistent with these predictions. The effect is found to disappear when the onset of the excitation becomes slower than the Higgs-mode period, consistent with the theory proposed here. These results open new possibilities for the use of collective modes in many-body systems to induce nonlinear optical effects.

中文翻译：

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非平衡超导体中的希格斯介导的光放大

我们提出了一种新的非平衡现象，通过这种现象，从金属迅速淬灭到瞬态超导状态会引起阶次参数振幅的大振荡。我们认为这种振荡模式是入射辐射的参数放大源。我们报告光驱的实验结果${\mathrm{ķ}}_3{\mathrm{C}}_{60}$与这些预测一致的。当激发的开始变得比希格斯模式周期慢时，发现这种作用消失了，这与这里提出的理论是一致的。这些结果为在多体系统中使用集合模来诱导非线性光学效应开辟了新的可能性。