ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain.
Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
Nat Nanotechnol. 2014 Dec;9(12):1007-11. doi: 10.1038/nnano.2014.234. Epub 2014 Oct 26.
Carbon nanotube mechanical resonators have attracted considerable interest because of their small mass, the high quality of their surfaces, and the pristine electronic states they host. However, their small dimensions result in fragile vibrational states that are difficult to measure. Here, we observe quality factors Q as high as 5 × 10(6) in ultra-clean nanotube resonators at a cryostat temperature of 30 mK, where we define Q as the ratio of the resonant frequency over the linewidth. Measuring such high quality factors requires the use of an ultra-low-noise method to rapidly detect minuscule vibrations, as well as careful reduction of the noise of the electrostatic environment. We observe that the measured quality factors fluctuate because of fluctuations of the resonant frequency. We measure record-high quality factors, which are comparable to the highest Q values reported in mechanical resonators of much larger size, a remarkable result considering that reducing the size of resonators is usually concomitant with decreasing quality factors. The combination of ultra-low mass and very large Q offers new opportunities for ultra-sensitive detection schemes and quantum optomechanical experiments.
碳纳米管力学谐振器因其质量小、表面质量高以及具有原始电子态而受到广泛关注。然而，它们的小尺寸导致了脆弱的振动状态，难以测量。在这里，我们在 30 mK 的低温恒温器温度下观察到超高清洁度纳米管谐振器的品质因数 Q 高达 5×10(6)，其中 Q 定义为谐振频率与线宽之比。要测量如此高的品质因数，需要使用超低声学方法来快速检测微小的振动，同时还需要仔细减少静电环境的噪声。我们观察到测量到的品质因数会因谐振频率的波动而波动。我们测量到了创纪录的高品质因数，与尺寸大得多的机械谐振器中报告的最高 Q 值相当，考虑到减小谐振器的尺寸通常伴随着品质因数的降低，这是一个显著的结果。超低质量和非常大的 Q 的结合为超灵敏检测方案和量子光机械实验提供了新的机会。
