We report observations of the electron spin resonance (ESR) of nitrogen vacancy centers in diamonds that are levitating in an ion trap. Using a needle Paul trap operating under ambient conditions, we demonstrate efficient microwave driving of the electronic spin and show that the spin properties of deposited diamond particles measured by the ESR are retained in the Paul trap. We also exploit the ESR signal to show angle stability of single trapped mono-crystals, a necessary step towards spincontrolled levitating macroscopic objects.The negatively charged nitrogen vacancy (NV − ) center in diamond has emerged as a very efficient source of single photons and a promising candidate for quantum control and sensing via its electron spin. Recently, there has been much interest in the electronic spin of the NV − center in levitating diamonds [1,2]. This interest is partly motivated by proposals for hybrid optomechanics [3], and implications in ultrahigh force sensitivity [4] where the NV center's spin response to magnetic fields is exploited to read-out the motion of the diamond with high spatial resolution under ambient conditions [5]. Amongst the many levitation schemes, optical traps are the most widely used [1,[6][7][8]. They provide efficient localization for neutral and charged particles and can work under liquid or atmospheric environnements. However the trap light that is scattered from the object means that excessive heating can be at work [6,7,9,10]. Furthermore, optical traps may quench the fluorescence of NV centers [7] and affect the electronic spin resonance contrast.Being able to trap diamonds hosting NV centers without light scattering could thus offer a better control of the spin-mechanical coupling and enlarge the range of applications of levitating diamonds. Levitation techniques such as ion traps [11] or magneto-gravitational traps [12] are tantalizing approaches for reaching this goal. Ion traps could not only provide an escape route for scattering free trapping, but also enable a high localization of the particles together with large trap depths as demonstrated by the impressive control over the motion that have been developped with single ions in the past [13]. Various nano-objects have been confined in ion traps already, from coloidal nanocrystals [14], silica nanospheres [15,16], graphene flakes [17], micron size diamond clusters containing NV centers [18], showing their potential for the motional control of macroscopic objects.In this work, we report measurements of the electronic spin resonance of NV centers embedded in diamonds that are levitating in an ion trap. Further, we observe high contrast Zeeman-splitted levels, demonstrating angular stability over single levitating monocrystals on time scales of minutes, paving the way towards single spin opto-mechanical schemes in scattering-free traps. The Paul trapAn ion trap typically consists of electrodes that are placed at an oscillating potential generating a time-varying quadrupolar electric field. In the adiabatic regime, this provides a pon...

We report on observations of Ramsey interferences and spin echoes from electron spins inside a levitating macroscopic particle. The experiment is realized using nitrogen-vacancy (NV) centers hosted in a micron-sized diamond stored in a Paul trap both under atmospheric conditions and under vacuum. Spin echoes are used to show that the Paul trap preserves the coherence time of the embedded electron spins for more than microseconds. Conversely, the NV spin is employed to demonstrate high angular stability of the diamond even under vacuum. These results are significant steps towards strong coupling of NV spins to the rotational mode of levitating diamonds.

Atomic force spectroscopy and microscopy (AFM) are invaluable tools to characterize nanostructures and biological systems. Most experiments, including state--of--the--art images of molecular bonds, are achieved by driving probes at their mechanical resonance. This resonance reaches the MHz for the fastest AFM micro--cantilevers, with typical motion amplitude of a few nanometres. Next--generation investigations of molecular scale dynamics, including faster force imaging and higher--resolution spectroscopy of dissipative interactions, require more bandwidth and vibration amplitudes below interatomic distance, for non--perturbative short--range tip--matter interactions. Probe frequency is a key parameter to improve bandwidth while reducing Brownian motion, allowing large signal-to--noise for exquisite resolution. Optomechanical resonators reach motion detection at 10 --18 m.Hz --1/2 , while coupling light to bulk vibration modes whose frequencies largely surpass those of cantilevers. Here we introduce an optically operated resonating optomechanical atomic force probe of frequency 2 decades above the fastest functional AFM cantilevers while Brownian motion is 4 orders below. Based on a Silicon--On--Insulator technology, the probe demonstrates high--speed sensing of contact and non--contact interactions with sub-picometre driven motion, breaking open current locks for faster and finer atomic force spectroscopy.

Atomic force microscopy (AFM) has been consistently supporting nanosciences and nanotechnologies for over 30 years and is used in many fields from condensed matter physics to biology. It enables the measurement of very weak forces at the nanoscale, thus elucidating the interactions at play in fundamental processes. Here, we leverage the combined benefits of micro/nanoelectromechanical systems and cavity optomechanics to fabricate a sensor for dynamic mode AFM at a frequency above 100 MHz. This frequency is two decades above the fastest commercial AFM probes, suggesting an opportunity for measuring forces at timescales unexplored thus far. The fabrication is achieved using very-large-scale integration technologies derived from photonic silicon circuits. The probe’s optomechanical ring cavity is coupled to a 1.55 μm laser light and features a 130 MHz mechanical resonance mode with a quality factor of 900 in air. A limit of detection in the displacement of 3 × 10−16 m/√Hz is obtained, enabling the detection of the Brownian motion of the probe and paving the way for force sensing experiments in the dynamic mode with a working vibration amplitude in the picometer range. When inserted in a custom AFM instrument embodiment, this optomechanical sensor demonstrates the capacity to perform force-distance measurements and to maintain a constant interaction strength between the tip and sample, an essential requirement for AFM applications. Experiments indeed show a stable closed-loop operation with a setpoint of 4 nN/nm for an unprecedented subpicometer vibration amplitude, where the tip–sample interaction is mediated by a stretched water meniscus.

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We show all-optical operation of a VLSI optomechanical micro-resonator designed for high resolution sensing applications. Mechanical resonance frequency is above 100 MHz with Q-factor of 1 000 in air, yielding measurement bandwidth above 100 kHz. We demonstrate low thermomechanical noise floor resolved with exquisite motion detection limit down to 4.10 -16 m.Hz -0.5 . This performance, enabled by optomechanical transduction, paves the way for very high-speed and ultra-sensitive sensing applications.