The small mass and high coherence of nanomechanical resonators render them the ultimate mechanical probe, with applications that range from protein mass spectrometry and magnetic resonance force microscopy to quantum optomechanics. A notorious challenge in these experiments is the thermomechanical noise related to the dissipation through internal or external loss channels. Here we introduce a novel approach to define the nanomechanical modes, which simultaneously provides a strong spatial confinement, full isolation from the substrate and dilution of the resonator material's intrinsic dissipation by five orders of magnitude. It is based on a phononic bandgap structure that localizes the mode but does not impose the boundary conditions of a rigid clamp. The reduced curvature in the highly tensioned silicon nitride resonator enables a mechanical Q > 10⁸ at 1 MHz to yield the highest mechanical Qf products (>10¹⁴ Hz) yet reported at room temperature.

中文翻译：

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通过软钳位和耗散稀释的超相干纳米机械谐振器

纳米机械谐振器的小质量和高相干性使其成为终极机械探针，其应用范围从蛋白质质谱、磁共振力显微镜到量子光力学。这些实验中的一个臭名昭著的挑战是与通过内部或外部损耗通道耗散相关的热机械噪声。在这里，我们介绍了一种定义纳米力学模式的新颖方法，该方法同时提供强大的空间限制、与基板的完全隔离以及将谐振器材料的固有耗散稀释五个数量级。它基于声子带隙结构，该结构可对模式进行局域化，但不会施加刚性钳位的边界条件。高张力氮化硅谐振器的曲率减小，使得 1 MHz 下的机械Q 值 > 10 ⁸ ，从而产生 迄今为止在室温下报道的最高机械Qf产品（> 10 ^{14 Hz）。}