Synchronization of Micromechanical Oscillators Using Light

Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through optical radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path towards reconfigurable massive synchronized oscillator networks

Classical and fluctuation-induced electromagnetic interactions in micronscale systems: designer bonding, antibonding, and Casimir forces

Whether intentionally introduced to exert control over particles and macroscopic objects, such as for trapping or cooling, or whether arising from the quantum and thermal fluctuations of charges in otherwise neutral bodies, leading to unwanted stiction between nearby mechanical parts, electromagnetic interactions play a fundamental role in many naturally occurring processes and technologies. In this review, we survey recent progress in the understanding and experimental observation of optomechanical and quantum-fluctuation forces. Although both of these effects arise from exchange of electromagnetic momentum, their dramatically different origins, involving either real or virtual photons, lead to different physical manifestations and design principles. Specifically, we describe recent predictions and measurements of attractive and repulsive optomechanical forces, based on the bonding and antibonding interactions of evanescent waves, as well as predictions of modified and even repulsive Casimir forces between nanostructured bodies. Finally, we discuss the potential impact and interplay of these forces in emerging experimental regimes of micromechanical devices.Comment: Review to appear on the topical issue "Quantum and Hybrid Mechanical Systems" in Annalen der Physi

Opto-electronic feedback for stabilizing oscillators

This application describes use of an opto-electronic feedback in oscillators to suppress phase noise based on the high Q factor of the opto-electronic feedback

Measurement and control of a mechanical oscillator at its thermal decoherence rate

In real-time quantum feedback protocols, the record of a continuous measurement is used to stabilize a desired quantum state. Recent years have seen highly successful applications in a variety of well-isolated micro-systems, including microwave photons and superconducting qubits. By contrast, the ability to stabilize the quantum state of a tangibly massive object, such as a nanomechanical oscillator, remains a difficult challenge: The main obstacle is environmental decoherence, which places stringent requirements on the timescale in which the state must be measured. Here we describe a position sensor that is capable of resolving the zero-point motion of a solid-state, nanomechanical oscillator in the timescale of its thermal decoherence, a critical requirement for preparing its ground state using feedback. The sensor is based on cavity optomechanical coupling, and realizes a measurement of the oscillator's displacement with an imprecision 40 dB below that at the standard quantum limit, while maintaining an imprecision-back-action product within a factor of 5 of the Heisenberg uncertainty limit. Using the measurement as an error signal and radiation pressure as an actuator, we demonstrate active feedback cooling (cold-damping) of the 4.3 MHz oscillator from a cryogenic bath temperature of 4.4 K to an effective value of 1.1$\pm$0.1 mK, corresponding to a mean phonon number of 5.3$\pm$0.6 (i.e., a ground state probability of 16%). Our results set a new benchmark for the performance of a linear position sensor, and signal the emergence of engineered mechanical oscillators as practical subjects for measurement-based quantum control.Comment: 24 pages, 10 figures; typos corrected in main text and figure

Frequency tuning of a triply-resonant whispering-gallery mode resonator to MHz wide transitions for proposed quantum repeater schemes

Quantum repeaters rely on an interfacing of flying qubits with quantum memories. The most common implementations include a narrowband single photon matched in bandwidth and central frequency to an atomic system. Previously, we demonstrated the compatibility of our versatile source of heralded single photons, which is based on parametric down-conversion in a triply-resonant whispering-gallery mode resonator, with alkaline transitions [Schunk et al., Optica 2, 773 (2015)]. In this paper, we analyze our source in terms of phase matching, available wavelength-tuning mechanisms, and applications to narrow-band atomic systems. We resonantly address the D1 transitions of cesium and rubidium with this optical parametric oscillator pumped above its oscillation threshold. Below threshold, the efficient coupling of single photons to atomic transitions heralded by single telecom-band photons is demonstrated. Finally, we present an accurate analytical description of our observations. Providing the demonstrated flexibility in connecting various atomic transitions with telecom wavelengths, we show a promising approach to realize an essential building block for quantum repeaters.Comment: 18 pages, 14 figure

Levitodynamics on-a-chip: from planar Paul traps to near-field optical nanocavities

The field of levitation optomechanics---or levitodynamics---studies the manipulation and control of small trapped objects in an isolated environment, providing a gateway to answer fundamental questions in physics and expanding the range of applications at the nanoscale. Levitation of particles can be achieved through different tools and techniques such as Paul traps and optical tweezers. Paul traps are created by alternating electric fields to levitate charged particles, while optical traps are based on optical forces that confine and manipulate nano-objects with high polarizability and low absorption. Both have the potential to be reduced to on-a-chip systems, enabling the miniaturization of the experiment, its interface with other photonic devices, and the expansion of trapping tools to on-a-chip technologies. In particular, a nanocavity coupled with a levitated particle is a promising platform to attain higher per-photon sensitivities than far-field detection schemes. The further study of on-a-chip levitated optomechanics systems will allow for new applications that enable sub-wavelength control and near-field detection in vacuum conditions. In this thesis, we describe our work with two on-a-chip levitodynamics experiments. Firstly, we have designed and built a planar Paul trap to levitate nanoparticles. This integrated device allows to manipulate and interrogate the trapped specimen, even over long periods of time. We optimized the geometry of the trap to a confinement of 4 microns in each direction. This on-a-chip levitation tool has potential to become a clean loading mechanism to trap particles in vacuum, avoiding current techniques that are unsuitable for contamination-sensitive experiments. Secondly, we have also designed, fabricated and tested a 1D photonic crystal nanocavity suspended on a silicon nitride membrane to study near-field levitodynamics. We have approached a levitated nanoparticle by an optical tweezer to the near-field of the nanocavity and measured the dynamics of the nanoparticle through the nanocavity. From the output signal of the nanocavity, we have estimated the single-photon optomechanical strength g0 along each axis. We have also characterized the thermal dynamics of the nanocavity. The power circulating inside the cavity increases the temperature of the device, inducing rich and tunable behavior in the transmission, such as bistability and self-induced oscillations. Control over these thermal effects is fundamental to create all-optical integrated circuits. This technology, exploited alongside the miniaturization of Paul traps and near-field schemes, could enable on-a-chip levitodynamical devices that are able to trap, manipulate, and detect nano-objects with unprecedented precision.El campo de la optomecánica de levitación---o levitodinámica---estudia la manipulación y el control de objetos pequeños atrapados, proporcionando un entorno aislado, para dar respuesta a preguntas fundamentales en física y para expandir las aplicaciones nanotecnológicas. Se puede levitar partículas mediante diferentes técnicas, como por ejemplo, las trampas de Paul y las pinzas ópticas. Las trampas de Paul se generan mediante campos eléctricos variables en el tiempo y permiten levitar partículas cargadas. Por otro lado, las trampas ópticas se basan en fuerzas ópticas, que confinan nano-objetos con alta polarizabilidad y baja absorción. Ambas opciones ofrecen la posibilidad de convertirse en un sistema integrado: minituarizando el experimento, facilitando su interacción con otros sistemas fotónicos y expandiendo así las herramientas de levitación hacia una tecnología "on-a-chip''. En particular, una nanocavidad acoplada a una nanopartícula levitada es una plataforma prometedora para alcanzar una alta sensitividad por fotón en comparación con técnicas de detección de campo lejano. El estudio de sistemas optomecánicos levitados permitirá el desarrollo de nuevas aplicaciones, control inferior a la longitud de onda y detección de campo cercano. En esta tesis, describimos dos sistemas levitodinámicos ``on-a-chip''. Primero, hemos diseñado y construido una trampa de Paul plana para hacer levitar nanopartículas. Este sistema integrado permite manipular el espécimen atrapado durante largos periodos de tiempo. Hemos optimizado la geometría de la trampa hasta un confinamiento de 4 micras en cada dirección. Esta herramienta de levitación `"on-a-chip'' permitirá un procedimiento limpio para cargar partículas a una trampa óptica directamente en vacío, evitando técnicas inapropiadas para experimentos sensibles a contaminación. Segundo, hemos diseñado, fabricado y caracterizado una nanocavidad de cristal fotónico 1D en una membrana suspendida de nitruro de silicio para estudiar la levitodinámica de campo cercano. Hemos acercado una partícula levitada ópticamente al campo cercano de la nanocavidad y, a través de ella, hemos medido la dinámica de la nanopartícula. Mediante la señal de transmisión de la nanocavidad, hemos estimado la fuerza optomecánica por fotón g0 para cada eje de movimiento. También hemos caracterizado el comportamiento térmico de la nanocavidad. La potencia que circula por ella aumenta su temperatura, dando lugar a biestabilidad y oscilaciones auto-inducidas en su transmisión, elementos claves para crear circuitos de óptica integrada. Esta tecnología, junto a la minituarización de las trampas de Paul y sistemas de campo cercano darán lugar a sistemas levitodinámicos "on-a-chip'' capaces de atrapar, manipular y detectar nano-objetos con una precisión sin precedentes

Levitodynamics on-a-chip: from planar Paul traps to near-field optical nanocavities

The field of levitation optomechanics---or levitodynamics---studies the manipulation and control of small trapped objects in an isolated environment, providing a gateway to answer fundamental questions in physics and expanding the range of applications at the nanoscale. Levitation of particles can be achieved through different tools and techniques such as Paul traps and optical tweezers. Paul traps are created by alternating electric fields to levitate charged particles, while optical traps are based on optical forces that confine and manipulate nano-objects with high polarizability and low absorption. Both have the potential to be reduced to on-a-chip systems, enabling the miniaturization of the experiment, its interface with other photonic devices, and the expansion of trapping tools to on-a-chip technologies. In particular, a nanocavity coupled with a levitated particle is a promising platform to attain higher per-photon sensitivities than far-field detection schemes. The further study of on-a-chip levitated optomechanics systems will allow for new applications that enable sub-wavelength control and near-field detection in vacuum conditions. In this thesis, we describe our work with two on-a-chip levitodynamics experiments. Firstly, we have designed and built a planar Paul trap to levitate nanoparticles. This integrated device allows to manipulate and interrogate the trapped specimen, even over long periods of time. We optimized the geometry of the trap to a confinement of 4 microns in each direction. This on-a-chip levitation tool has potential to become a clean loading mechanism to trap particles in vacuum, avoiding current techniques that are unsuitable for contamination-sensitive experiments. Secondly, we have also designed, fabricated and tested a 1D photonic crystal nanocavity suspended on a silicon nitride membrane to study near-field levitodynamics. We have approached a levitated nanoparticle by an optical tweezer to the near-field of the nanocavity and measured the dynamics of the nanoparticle through the nanocavity. From the output signal of the nanocavity, we have estimated the single-photon optomechanical strength g0 along each axis. We have also characterized the thermal dynamics of the nanocavity. The power circulating inside the cavity increases the temperature of the device, inducing rich and tunable behavior in the transmission, such as bistability and self-induced oscillations. Control over these thermal effects is fundamental to create all-optical integrated circuits. This technology, exploited alongside the miniaturization of Paul traps and near-field schemes, could enable on-a-chip levitodynamical devices that are able to trap, manipulate, and detect nano-objects with unprecedented precision.El campo de la optomecánica de levitación---o levitodinámica---estudia la manipulación y el control de objetos pequeños atrapados, proporcionando un entorno aislado, para dar respuesta a preguntas fundamentales en física y para expandir las aplicaciones nanotecnológicas. Se puede levitar partículas mediante diferentes técnicas, como por ejemplo, las trampas de Paul y las pinzas ópticas. Las trampas de Paul se generan mediante campos eléctricos variables en el tiempo y permiten levitar partículas cargadas. Por otro lado, las trampas ópticas se basan en fuerzas ópticas, que confinan nano-objetos con alta polarizabilidad y baja absorción. Ambas opciones ofrecen la posibilidad de convertirse en un sistema integrado: minituarizando el experimento, facilitando su interacción con otros sistemas fotónicos y expandiendo así las herramientas de levitación hacia una tecnología "on-a-chip''. En particular, una nanocavidad acoplada a una nanopartícula levitada es una plataforma prometedora para alcanzar una alta sensitividad por fotón en comparación con técnicas de detección de campo lejano. El estudio de sistemas optomecánicos levitados permitirá el desarrollo de nuevas aplicaciones, control inferior a la longitud de onda y detección de campo cercano. En esta tesis, describimos dos sistemas levitodinámicos ``on-a-chip''. Primero, hemos diseñado y construido una trampa de Paul plana para hacer levitar nanopartículas. Este sistema integrado permite manipular el espécimen atrapado durante largos periodos de tiempo. Hemos optimizado la geometría de la trampa hasta un confinamiento de 4 micras en cada dirección. Esta herramienta de levitación `"on-a-chip'' permitirá un procedimiento limpio para cargar partículas a una trampa óptica directamente en vacío, evitando técnicas inapropiadas para experimentos sensibles a contaminación. Segundo, hemos diseñado, fabricado y caracterizado una nanocavidad de cristal fotónico 1D en una membrana suspendida de nitruro de silicio para estudiar la levitodinámica de campo cercano. Hemos acercado una partícula levitada ópticamente al campo cercano de la nanocavidad y, a través de ella, hemos medido la dinámica de la nanopartícula. Mediante la señal de transmisión de la nanocavidad, hemos estimado la fuerza optomecánica por fotón g0 para cada eje de movimiento. También hemos caracterizado el comportamiento térmico de la nanocavidad. La potencia que circula por ella aumenta su temperatura, dando lugar a biestabilidad y oscilaciones auto-inducidas en su transmisión, elementos claves para crear circuitos de óptica integrada. Esta tecnología, junto a la minituarización de las trampas de Paul y sistemas de campo cercano darán lugar a sistemas levitodinámicos "on-a-chip'' capaces de atrapar, manipular y detectar nano-objetos con una precisión sin precedentes.Postprint (published version

Evanescent straight tapered-fiber coupling of ultra-high Q optomechanical micro-resonators in a low-vibration helium-4 exchange-gas cryostat

We developed an apparatus to couple a 50-micrometer diameter whispering-gallery silica microtoroidal resonator in a helium-4 cryostat using a straight optical tapered-fiber at 1550nm wavelength. On a top-loading probe specifically adapted for increased mechanical stability, we use a specifically-developed "cryotaper" to optically probe the cavity, allowing thus to record the calibrated mechanical spectrum of the optomechanical system at low temperatures. We then demonstrate excellent thermalization of a 63-MHz mechanical mode of a toroidal resonator down to the cryostat's base temperature of 1.65K, thereby proving the viability of the cryogenic refrigeration via heat conduction through static low-pressure exchange gas. In the context of optomechanics, we therefore provide a versatile and powerful tool with state-of-the-art performances in optical coupling efficiency, mechanical stability and cryogenic cooling.Comment: 8 pages, 6 figure