Phonon lasers, the mechanical analogs of optical lasers, have long been a subject of interest as they provide coherent sound waves. We numerically study a magnomechanical phonon laser that operates under a general continuous-wave pump. This system consists of a microwave cavity, a sphere of magnetic material (yttrium iron garnet), a microwave drive pump, and a uniform external bias magnetic field. A population inversion between the supermodes of the system leads to phonon laser action. We study the population inversion and the stimulated emission of phonons under various conditions, such as different drive pump powers and detunings. Unlike previous studies, our results show that the population inversion between the supermodes oscillates with time. Despite the oscillations of the population inversion, one can achieve relatively large stimulated phonon emission if the power of the drive pump is beyond a threshold. Moreover, the optimum operation occurs if the frequency of the drive field matches the frequencies of the cavity photons and magnons. Since it is highly tunable with low loss and has an extra degree of freedom provided by the constant magnetic field, it is possible to develop the system into an alternative to the optomechanical phonon lasers.

中文翻译：

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超越稳态的磁力学声子激光

声子激光器是光学激光器的机械类似物，长期以来一直是人们感兴趣的主题，因为它们提供相干的声波。我们数值研究了在一般连续波泵浦下运行的磁力学声子激光器。该系统由微波腔、磁性材料球体（钇铁石榴石）、微波驱动泵和均匀的外部偏置磁场组成。系统超模之间的粒子数反转导致声子激光作用。我们研究了不同条件下声子的粒子数反转和受激发射，例如不同的驱动泵功率和失谐。与之前的研究不同，我们的结果表明，超模式之间的粒子数反转会随着时间而振荡。尽管人口反转的振荡，如果驱动泵的功率超过阈值，则可以实现相对较大的受激声子发射。此外，如果驱动场的频率与腔光子和磁振子的频率相匹配，则会出现最佳操作。由于它具有高可调谐性和低损耗，并具有由恒定磁场提供的额外自由度，因此可以将该系统发展为光机械声子激光器的替代品。