Evidence of universality in the dynamical response of micromechanical diamond resonators at millikelvin temperatures

Scaling of dissipation in megahertz-range micromechanical diamond oscillators

We report frequency and dissipation scaling laws for doubly-clamped diamond resonators. The device lengths range from 10 microns to 19 microns corresponding to frequency and quality-factor ranges of 17 MHz to 66 MHz and 600 to 2400 respectively. We find that the resonance frequency scales as 1/L^2 confirming the validity of the thin-beam approximation. The dominant dissipation comes from two sources; for the shorter beams, clamping loss is the dominant dissipation mechanism; while for the longer beams, surface losses provide a significant source of dissipation. We compare and contrast these me…

Quantum Friction in Nanomechanical Oscillators at Millikelvin Temperatures

We report low-temperature measurements of dissipation in megahertz-range, suspended, single-crystal nanomechanical oscillators. At millikelvin temperatures, both dissipation (inverse quality factor) and shift in the resonance frequency display reproducible features, similar to those observed in sound attenuation experiments in disordered glasses and consistent with measurements in larger micromechanical oscillators fabricated from single-crystal silicon. Dissipation in our single-crystal nanomechanical structures is dominated by internal quantum friction due to an estimated number of roughly 5…

High quality factor single-crystal diamond mechanical resonators

Single-crystal diamond is a promising material for MEMs devices because of its low mechanical loss, compatibility with extreme environments, and built-in interface to high-quality spin centers. But its use has largely been limited by challenges in processing and growth. We demonstrate a wafer bonding-based technique to form diamond on insulator, from which we make single-crystal diamond micromechanical resonators with mechanical quality factors as high as 338,000 at room temperature. Variable temperature measurements down to 10 K reveal a nonmonotonic dependence of quality factor on temperatur…

Single-Crystal Diamond Nanomechanical Resonators with Quality Factors exceeding one Million

We present nanofabrication and mechanical measurements of single-crystal diamond cantilevers with thickness down to 85 nm, thickness uniformity better than 20 nm, and lateral dimensions up to 240 um. Quality factors exceeding one million are found at room temperature, surpassing those of state-of-the-art single-crystal silicon cantilevers of similar dimensions by roughly an order of magnitude. Force sensitivities of a few hundred zeptonewtons result for the best cantilevers at millikelvin temperatures. Single-crystal diamond could thus directly improve existing force and mass sensors by a simp…

毫开尔文温度下中性氮空位中心的轨道态控制

Quantum Orbital-State Control of a Neutral Nitrogen-Vacancy Center at Millikelvin Temperatures

毫开尔文温度下通过动态去耦脉冲显著提升中性氮空位中心轨道相干时间，使其能与高阻抗微波谐振腔实现强耦合，为微波量子电动力学提供新可能。

Ultra-sensitive hybrid diamond nanothermometer

Nitrogen-vacancy (NV) centers in diamond are promising quantum sensors for their long spin coherence time under ambient conditions. However, their spin resonances are relatively insensitive to non-magnetic parameters such as temperature. A magnetic-nanoparticle-nanodiamond hybrid thermometer, where the temperature change is converted to the magnetic field variation near the Curie temperature, was demonstrated to have enhanced temperature sensitivity (11 mK Hz^{-1/2}) [Phys. Rev. X 8, 011042 (2018)], but the sensitivity was limited by the large spectral broadening of ensemble spins in nanodiamo…