Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, 6020 Innsbruck, Austria.
Institute for Experimental Physics, University of Innsbruck, 6020 Innsbruck, Austria.
Phys Rev Lett. 2023 Jan 20;130(3):033601. doi: 10.1103/PhysRevLett.130.033601.
Optomechanics is a prime example of light matter interaction, where photons directly couple to phonons, allowing the precise control and measurement of the state of a mechanical object. This makes it a very appealing platform for testing fundamental physics or for sensing applications. Usually, such mechanical oscillators are in highly excited thermal states and require cooling to the mechanical ground state for quantum applications, which is often accomplished by using optomechanical backaction. However, while massive mechanical oscillators are desirable for many tasks, their frequency usually decreases below the cavity linewidth, significantly limiting the methods that can be used to efficiently cool. Here, we demonstrate a novel approach relying on an intrinsically nonlinear cavity to backaction-cool a low frequency mechanical oscillator. We experimentally demonstrate outperforming an identical, but linear, system by more than 1 order of magnitude. Furthermore, our theory predicts that with this approach we can also surpass the standard cooling limit of a linear system. By exploiting a nonlinear cavity, our approach enables efficient cooling of a wider range of optomechanical systems, opening new opportunities for fundamental tests and sensing.
光机械学是光物质相互作用的一个主要例子，其中光子直接与声子耦合，允许对机械物体的状态进行精确控制和测量。这使其成为测试基础物理或传感应用的极具吸引力的平台。通常，这种机械振荡器处于高度激发的热状态，需要冷却到机械基态才能用于量子应用，这通常通过光机械反作用来实现。然而，虽然大量的机械振荡器在许多任务中是可取的，但它们的频率通常会低于腔线宽，这极大地限制了可以用来有效冷却的方法。在这里，我们展示了一种新颖的方法，该方法依赖于内在非线性腔来反作用冷却低频机械振荡器。我们通过实验证明，与相同的，但线性的系统相比，我们的方法提高了超过 1 个数量级。此外，我们的理论预测，通过这种方法，我们还可以超过线性系统的标准冷却极限。通过利用非线性腔，我们的方法可以实现更广泛的光机械系统的高效冷却，为基础测试和传感开辟新的机会。
