The bifurcations or transitions of the classical nonlinear systems with finite degrees of freedom exhibit some dynamical behaviors that are similar to those in the phase transitions of many-body systems. A dynamical type of them in the form of a sudden transition of the amplitudes between two harmonic oscillations, which are stable under periodically driving force, is not so common to see. We show that a sudden transition of this type can be realized in a system of coupling a microresonator that supports a mechanical vibration to another microresonator, and the system was experimentally demonstrated as a phonon laser. If the pump laser power or the intercavity coupling strength is adjusted to a critical value, the cavity field patterns will suddenly change, together with a jump of the stabilized mechanical amplitude. Such transition can be applied to a precise measurement of the optomechanical coupling constant, which is hard to measure due to its proportion to a tiny zero-point mechanical fluctuation amplitude.

中文翻译：

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声子激光器中动态模式之间的灾难性转变

具有有限自由度的经典非线性系统的分岔或转变表现出一些类似于多体系统相变中的动力学行为。在周期性驱动力下稳定的两个谐波振荡之间的振幅突然转变形式的动态类型并不常见。我们表明，这种类型的突然转变可以在将支持机械振动的微谐振器耦合到另一个微谐振器的系统中实现，并且该系统被实验证明为声子激光器。如果将泵浦激光功率或腔间耦合强度调整到临界值，腔场模式将突然发生变化，同时稳定的机械振幅会发生跳跃。