Micromechanical and nanomechanical systems with exceptionally low dissipation rates are enabling the next-generation technologies of ultrasensitive detectors and quantum information systems. New techniques and methods for lowering the dissipation rate have in recent years been discovered and allowed for the engineering of mechanical oscillators with phononic modes that are extremely well isolated from the environment and thus possess quality factors close to and beyond $1\times {10}^9$. A powerful strategy for isolating and controlling a single phononic mode is based on phononic crystal engineering. Here we propose a new method for phononic crystal engineering of nanomechanical oscillators that is based on a periodic variation of the material density. To circumvent the introduction of additional bending losses resulting from the variation of material density, the added mass constitutes an array of nanopillars in which the losses will be diluted. Using this novel technique for phononic crystal engineering, we design and fabricate corrugated mechanical oscillators with quality factors approaching $1\times {10}^9$ in a room temperature environment. The flexibility space of these new phononic crystals is large and further advancement can be attained through optimized phononic crystal patterning and strain engineering via topology optimization. This will allow for the engineering of mechanical membranes with quality factors beyond $1\times {10}^9$ at room temperature. Such extremely low mechanical dissipation rates will enable the development of radically new technologies such as quantum-limited atomic force microscopy at room temperature, ultrasensitive detectors of dark matter, spontaneous waveform collapses, gravity, and high-efficiency quantum information transducers.

中文翻译：

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基于密度声子晶体工程的超相干纳米机械谐振器

具有极低耗散率的微机械和纳米机械系统正在使超灵敏探测器和量子信息系统的下一代技术成为可能。近年来，人们发现了降低耗散率的新技术和方法，并允许对具有声子模式的机械振荡器进行工程设计，这些声子模式与环境隔离得非常好，因此具有接近或超越的品质因数。$1\times {10}^9$。隔离和控制单声子模式的强大策略基于声子晶体工程。在这里，我们提出了一种基于材料密度周期性变化的纳米机械振荡器声子晶体工程的新方法。为了避免由于材料密度的变化而引入额外的弯曲损耗，增加的质量构成了纳米柱阵列，其中的损耗将被稀释。利用这种声子晶体工程新技术，我们设计和制造了品质因数接近的波纹机械振荡器$1\times {10}^9$在室温环境下。这些新型声子晶体的灵活性空间很大，可以通过拓扑优化优化声子晶体图案和应变工程来实现进一步的进步。这将使机械膜的工程质量因素超出$1\times {10}^9$在室温下。如此极低的机械耗散率将有助于开发全新技术，例如室温下的量子限制原子力显微镜、暗物质超灵敏探测器、自发波形塌缩、重力和高效量子信息传感器。