Matthew H. Matheny

Bio: Matthew H. Matheny is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Resonator & Nanoelectromechanical systems. The author has an hindex of 19, co-authored 38 publications receiving 2177 citations.

Generalized non-reciprocity in an optomechanical circuit via synthetic magnetism and reservoir engineering

Abstract: Synthetic magnetism has been used to control charge neutral excitations for applications ranging from classical beam steering to quantum simulation. In optomechanics, radiation-pressure-induced parametric coupling between optical (photon) and mechanical (phonon) excitations may be used to break time-reversal symmetry, providing the prerequisite for synthetic magnetism. Here we design and fabricate a silicon optomechanical circuit with both optical and mechanical connectivity between two optomechanical cavities. Driving the two cavities with phase-correlated laser light results in a synthetic magnetic flux, which, in combination with dissipative coupling to the mechanical bath, leads to non-reciprocal transport of photons with 35 dB of isolation. Additionally, optical pumping with blue-detuned light manifests as a particle non-conserving interaction between photons and phonons, resulting in directional optical amplification of 12 dB in the isolator through-direction. These results suggest the possibility of using optomechanical circuits to create a more general class of non-reciprocal optical devices, and further, to enable new topological phases for both light and sound on a microchip.

Phase Synchronization of Two Anharmonic Nanomechanical Oscillators

Abstract: We investigate the synchronization of oscillators based on anharmonic nanoelectromechanical resonators. Our experimental implementation allows unprecedented observation and control of parameters governing the dynamics of synchronization. We find close quantitative agreement between experimental data and theory describing reactively coupled Duffing resonators with fully saturated feedback gain. In the synchronized state we demonstrate a significant reduction in the phase noise of the oscillators, which is key for sensor and clock applications. Our work establishes that oscillator networks constructed from nanomechanical resonators form an ideal laboratory to study synchronization— given their high-quality factors, small footprint, and ease of cointegration with modern electronic signal processing technologies.

Optical transduction and routing of microwave phonons in cavity-optomechanical circuits

Abstract: Going beyond the canonical cavity-optomechanical system consisting of a Fabry–Perot cavity with a movable end mirror, here we explore a new paradigm in which phononic crystal waveguides are used to wire together local cavity elements to form interacting microcircuits of photons and phonons. Single cavity-waveguide elements, fabricated in the device layer of a silicon-on-insulator microchip, are used to optically excite and detect C-band (∼6 GHz) microwave phonons propagating in phononic-bandgap-guided acoustic waveguides. Interconnecting a pair of optomechanical cavities via a phonon waveguide is then used to demonstrate a tunable delay and filter for microwave-over-optical signals in the 1,500 nm wavelength band. Finally, we realize a tight-binding form of mechanical coupling between distant optomechanical cavities, leading to direct phonon exchange without dissipation in the waveguide. These initial demonstrations indicate the potential of cavity-optomechanical circuits for performing coherent signal processing as well as for realizing new modalities of optical readout in distributed micromechanical sensors.

Low Voltage Nanoelectromechanical Switches Based on Silicon Carbide Nanowires

Abstract: We report experimental demonstrations of electrostatically actuated, contact-mode nanoelectromechanical switches based on very thin silicon carbide (SiC) nanowires (NWs). These NWs are lithographically patterned from a 50 nm thick SiC layer heteroepitaxially grown on single-crystal silicon (Si). Several generic designs of in-plane electrostatic SiC NW switches have been realized, with NW widths as small as ∼20 nm and lateral switching gaps as narrow as ∼10 nm. Very low switch-on voltages are obtained, from a few volts down to ∼1 V level. Two-terminal, contact-mode "hot" switching with high on/off ratios (>10 2 or 10 3 ) has been demonstrated repeatedly for many devices. We find enhanced switching performance in bare SiC NWs, with lifetimes exceeding those based on metallized SiC NWs.

Piezoelectric nanoelectromechanical resonators based on aluminum nitride thin films

Abstract: We demonstrate piezoelectrically actuated, electrically tunable nanomechanical resonators based on multilayers containing a 100-nm-thin aluminum nitride (AlN) layer Efficient piezoelectric actuation of very high frequency fundamental flexural modes up to ~80 MHz is demonstrated at room temperature Thermomechanical fluctuations of AlN cantilevers measured by optical interferometry enable calibration of the transduction responsivity and displacement sensitivities of the resonators Measurements and analyses show that the 100 nm AlN layer employed has an excellent piezoelectric coefficient, d_(31)=24 pm/V Doubly clamped AlN beams exhibit significant frequency tuning behavior with applied dc voltage

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The geometry of biological time , by A. T. Winfree. Pp 544. DM68. Corrected Second Printing 1990. ISBN 3-540-52528-9 (Springer)

Abstract: 1980 Preface * 1999 Preface * 1999 Acknowledgements * Introduction * 1 Circular Logic * 2 Phase Singularities (Screwy Results of Circular Logic) * 3 The Rules of the Ring * 4 Ring Populations * 5 Getting Off the Ring * 6 Attracting Cycles and Isochrons * 7 Measuring the Trajectories of a Circadian Clock * 8 Populations of Attractor Cycle Oscillators * 9 Excitable Kinetics and Excitable Media * 10 The Varieties of Phaseless Experience: In Which the Geometrical Orderliness of Rhythmic Organization Breaks Down in Diverse Ways * 11 The Firefly Machine 12 Energy Metabolism in Cells * 13 The Malonic Acid Reagent ('Sodium Geometrate') * 14 Electrical Rhythmicity and Excitability in Cell Membranes * 15 The Aggregation of Slime Mold Amoebae * 16 Numerical Organizing Centers * 17 Electrical Singular Filaments in the Heart Wall * 18 Pattern Formation in the Fungi * 19 Circadian Rhythms in General * 20 The Circadian Clocks of Insect Eclosion * 21 The Flower of Kalanchoe * 22 The Cell Mitotic Cycle * 23 The Female Cycle * References * Index of Names * Index of Subjects

Topological Photonics

Abstract: Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators in condensed matter, recent advances have shown how to engineer analogous effects also for photons, leading to remarkable phenomena such as the robust unidirectional propagation of light, which hold great promise for applications. Thanks to the flexibility and diversity of photonics systems, this field is also opening up new opportunities to realize exotic topological models and to probe and exploit topological effects in new ways. This article reviews experimental and theoretical developments in topological photonics across a wide range of experimental platforms, including photonic crystals, waveguides, metamaterials, cavities, optomechanics, silicon photonics, and circuit QED. A discussion of how changing the dimensionality and symmetries of photonics systems has allowed for the realization of different topological phases is offered, and progress in understanding the interplay of topology with non-Hermitian effects, such as dissipation, is reviewed. As an exciting perspective, topological photonics can be combined with optical nonlinearities, leading toward new collective phenomena and novel strongly correlated states of light, such as an analog of the fractional quantum Hall effect.