Optical and mechanical mode tuning in an optomechanical crystal with light-induced thermal effects

Under the terms of the Creative Commons Attribution (CC BY) license to their work.We report on the modification of the optical and mechanical properties of a silicon 1D optomechanical crystal cavity due to thermo-optic effects in a high phonon/photon population regime. The cavity heats up due to light absorption in a way that shifts the optical modes towards longer wavelengths and the mechanical modes to lower frequencies. By combining the experimental optical results with finite-difference time-domain simulations, we establish a direct relation between the observed wavelength drift and the actual effective temperature increase of the cavity. By assuming that the Young's modulus decreases accordingly to the temperature increase, we find a good agreement between the mechanical mode drift predicted using a finite element method and the experimental one.This work was supported by the EU through the project TAILPHOX (ICT-FP7-233883) and the ERC Advanced Grant SOULMAN (ERC-FP7-321122) and the Spanish projects TAPHOR (MAT2012-31392).Peer Reviewe

Localized thinning for strain concentration in suspended germanium membranes and optical method for precise thickness measurement

We deposited Ge layers on (001) Si substrates by molecular beam epitaxy and used them to fabricate suspended membranes with high uniaxial tensile strain. We demonstrate a CMOS-compatible fabrication strategy to increase strain concentration and to eliminate the Ge buffer layer near the Ge/Si hetero-interface deposited at low temperature. This is achieved by a two-steps patterning and selective etching process. First, a bridge and neck shape is patterned in the Ge membrane, then the neck is thinned from both top and bottom sides. Uniaxial tensile strain values higher than 3% were measured by Raman scattering in a Ge membrane of 76 nm thickness. For the challenging thickness measurement on micrometer-size membranes suspended far away from the substrate a characterization method based on pump-and-probe reflectivity measurements was applied, using an asynchronous optical sampling technique.EC/FP7/628197/EU/Heat Propagation and Thermal Conductivity in Nanomaterials for Nanoscale Energy Management/HEATPRONAN

Propuesta de sistema de cobertura universal de salud en el Per?, y evaluaci?n de los costos y beneficios asociados

Implementaci?n del Sistema de Cobertura Universal de Salud en el Per?, basada en la experiencia del modelo colombiano, proponiendo la implementaci?n de un marco de gesti?n basado en el an?lisis de los costos de implementaci?n, la estructura org?nica, el financiamiento, la demanda objetivo, la oferta disponible y el servicio a brindar que en esta investigaci?n abarcan las tres enfermedades no transmisibles con mayor mortalidad en el Per? aplicando la metodolog?a AVISA

Nanocrystalline silicon optomechanical cavities

"© 2018 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited"[EN] Silicon on insulator photonics has offered a versatile platform for the recent development of integrated optomechanical circuits. However, there are some constraints such as the high cost of the wafers and limitation to a single physical device level. In the present work we investigate nanocrystalline silicon as an alternative material for optomechanical devices. In particular we demonstrate that optomechanical crystal cavities fabricated of nanocrystalline silicon have optical and mechanical properties enabling non-linear dynamical behaviour and effects such as thermo-optic/free-carrier-dispersion self-pulsing, phonon lasing and chaos, all at low input laser power and with typical frequencies as high as 0.3 GHz. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing AgreementEuropean Commission project PHENOMEN (H2020-EU-713450), MINECO Severo Ochoa Excellence program (SEV-2013-0295), MINECO (FIS2015-70862-P, RYC-2014-15392) and CERCA Programme/Generalitat de Catalunya.Navarro-Urrios, D.; Capuj, N.; Maire, J.; Colombano, M.; Jaramillo-Fernandez, J.; Chavez-Angel, E.; Martín-Rodríguez, LL.... (2018). Nanocrystalline silicon optomechanical cavities. Optics Express. 26(8):9829-9839. https://doi.org/10.1364/OE.26.009829S98299839268Kippenberg, T. J., & Vahala, K. J. (2008). Cavity Optomechanics: Back-Action at the Mesoscale. Science, 321(5893), 1172-1176. doi:10.1126/science.1156032Aspelmeyer, M., Kippenberg, T. J., & Marquardt, F. (2014). Cavity optomechanics. Reviews of Modern Physics, 86(4), 1391-1452. doi:10.1103/revmodphys.86.1391Navarro-Urrios, D., Capuj, N. E., Gomis-Bresco, J., Alzina, F., Pitanti, A., Griol, A., … Sotomayor Torres, C. M. (2015). A self-stabilized coherent phonon source driven by optical forces. Scientific Reports, 5(1). doi:10.1038/srep15733Navarro-Urrios, D., Capuj, N. E., Colombano, M. F., García, P. D., Sledzinska, M., Alzina, F., … Sotomayor-Torres, C. M. (2017). Nonlinear dynamics and chaos in an optomechanical beam. Nature Communications, 8(1). doi:10.1038/ncomms14965Leijssen, R., La Gala, G. R., Freisem, L., Muhonen, J. T., & Verhagen, E. (2017). Nonlinear cavity optomechanics with nanomechanical thermal fluctuations. Nature Communications, 8(1). doi:10.1038/ncomms16024Gil-Santos, E., Labousse, M., Baker, C., Goetschy, A., Hease, W., Gomez, C., … Favero, I. (2017). Light-Mediated Cascaded Locking of Multiple Nano-Optomechanical Oscillators. Physical Review Letters, 118(6). doi:10.1103/physrevlett.118.063605Shah, S. Y., Zhang, M., Rand, R., & Lipson, M. (2015). Master-Slave Locking of Optomechanical Oscillators over a Long Distance. Physical Review Letters, 114(11). doi:10.1103/physrevlett.114.113602Weis, S., Rivière, R., Deléglise, S., Gavartin, E., Arcizet, O., Schliesser, A., & Kippenberg, T. J. (2010). Optomechanically Induced Transparency. Science, 330(6010), 1520-1523. doi:10.1126/science.1195596Verhagen, E., Deléglise, S., Weis, S., Schliesser, A., & Kippenberg, T. J. (2012). Quantum-coherent coupling of a mechanical oscillator to an optical cavity mode. Nature, 482(7383), 63-67. doi:10.1038/nature10787Tomes, M., & Carmon, T. (2009). Photonic Micro-Electromechanical Systems Vibrating atX-band (11-GHz) Rates. Physical Review Letters, 102(11). doi:10.1103/physrevlett.102.113601Thompson, J. D., Zwickl, B. M., Jayich, A. M., Marquardt, F., Girvin, S. M., & Harris, J. G. E. (2008). Strong dispersive coupling of a high-finesse cavity to a micromechanical membrane. Nature, 452(7183), 72-75. doi:10.1038/nature06715Eichenfield, M., Chan, J., Camacho, R. M., Vahala, K. J., & Painter, O. (2009). Optomechanical crystals. Nature, 462(7269), 78-82. doi:10.1038/nature08524Chan, J., Alegre, T. P. M., Safavi-Naeini, A. H., Hill, J. T., Krause, A., Gröblacher, S., … Painter, O. (2011). Laser cooling of a nanomechanical oscillator into its quantum ground state. Nature, 478(7367), 89-92. doi:10.1038/nature10461Safavi-Naeini, A. H., Alegre, T. P. M., Chan, J., Eichenfield, M., Winger, M., Lin, Q., … Painter, O. (2011). Electromagnetically induced transparency and slow light with optomechanics. Nature, 472(7341), 69-73. doi:10.1038/nature09933Pennec, Y., Laude, V., Papanikolaou, N., Djafari-Rouhani, B., Oudich, M., El Jallal, S., … Martínez, A. (2014). Modeling light-sound interaction in nanoscale cavities and waveguides. Nanophotonics, 3(6), 413-440. doi:10.1515/nanoph-2014-0004Davanço, M., Ates, S., Liu, Y., & Srinivasan, K. (2014). Si3N4 optomechanical crystals in the resolved-sideband regime. Applied Physics Letters, 104(4), 041101. doi:10.1063/1.4858975Balram, K. C., Davanço, M. I., Song, J. D., & Srinivasan, K. (2016). Coherent coupling between radiofrequency, optical and acoustic waves in piezo-optomechanical circuits. Nature Photonics, 10(5), 346-352. doi:10.1038/nphoton.2016.46Bochmann, J., Vainsencher, A., Awschalom, D. D., & Cleland, A. N. (2013). Nanomechanical coupling between microwave and optical photons. Nature Physics, 9(11), 712-716. doi:10.1038/nphys2748Xiong, C., Pernice, W. H. P., Sun, X., Schuck, C., Fong, K. Y., & Tang, H. X. (2012). 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Photonic crystal nanocavity with a Q-factor of ~9 million. Optics Express, 22(1), 916. doi:10.1364/oe.22.000916Almeida, V. R., Barrios, C. A., Panepucci, R. R., & Lipson, M. (2004). All-optical control of light on a silicon chip. Nature, 431(7012), 1081-1084. doi:10.1038/nature02921Narayanan, K., & Preble, S. F. (2010). Optical nonlinearities in hydrogenated-amorphous silicon waveguides. Optics Express, 18(9), 8998. doi:10.1364/oe.18.008998Preston, K., Dong, P., Schmidt, B., & Lipson, M. (2008). High-speed all-optical modulation using polycrystalline silicon microring resonators. Applied Physics Letters, 92(15), 151104. doi:10.1063/1.2908869Wang, K.-Y., & Foster, A. C. (2012). Ultralow power continuous-wave frequency conversion in hydrogenated amorphous silicon waveguides. Optics Letters, 37(8), 1331. doi:10.1364/ol.37.001331Matres, J., Ballesteros, G. C., Gautier, P., Fédéli, J.-M., Martí, J., & Oton, C. J. (2013). High nonlinear figure-of-merit amorphous silicon waveguides. Optics Express, 21(4), 3932. doi:10.1364/oe.21.003932Waldow, M., Plötzing, T., Gottheil, M., Först, M., Bolten, J., Wahlbrink, T., & Kurz, H. (2008). 25ps all-optical switching in oxygen implanted silicon-on-insulator microring resonator. Optics Express, 16(11), 7693. doi:10.1364/oe.16.007693Wang, K.-Y., Petrillo, K. G., Foster, M. A., & Foster, A. C. (2012). Ultralow-power all-optical processing of high-speed data signals in deposited silicon waveguides. Optics Express, 20(22), 24600. doi:10.1364/oe.20.024600Ylönen, M., Torkkeli, A., & Kattelus, H. (2003). In situ boron-doped LPCVD polysilicon with low tensile stress for MEMS applications. Sensors and Actuators A: Physical, 109(1-2), 79-87. doi:10.1016/j.sna.2003.09.017Theodorakos, I., Zergioti, I., Vamvakas, V., Tsoukalas, D., & Raptis, Y. S. (2014). Picosecond and nanosecond laser annealing and simulation of amorphous silicon thin films for solar cell applications. Journal of Applied Physics, 115(4), 043108. doi:10.1063/1.4863402Navarro-Urrios, D., Gomis-Bresco, J., El-Jallal, S., Oudich, M., Pitanti, A., Capuj, N., … Sotomayor Torres, C. M. (2014). Dynamical back-action at 5.5 GHz in a corrugated optomechanical beam. AIP Advances, 4(12), 124601. doi:10.1063/1.4902171Barclay, P. E., Srinivasan, K., & Painter, O. (2005). Nonlinear response of silicon photonic crystal micresonators excited via an integrated waveguide and fiber taper. Optics Express, 13(3), 801. doi:10.1364/opex.13.000801Cuffe, J., Ristow, O., Chávez, E., Shchepetov, A., Chapuis, P.-O., Alzina, F., … Sotomayor Torres, C. M. (2013). Lifetimes of Confined Acoustic Phonons in Ultrathin Silicon Membranes. Physical Review Letters, 110(9). doi:10.1103/physrevlett.110.095503Volklein, F., & Balles, H. (1992). A Microstructure For Measurement Of Thermal Conductivity Of Polysilicon Thin Films. Journal of Microelectromechanical Systems, 1(4), 193-196. doi:10.1109/jmems.1992.752511Pennec, Y., Rouhani, B. D., El Boudouti, E. H., Li, C., El Hassouani, Y., Vasseur, J. O., … Martinez, A. (2010). Simultaneous existence of phononic and photonic band gaps in periodic crystal slabs. Optics Express, 18(13), 14301. doi:10.1364/oe.18.014301Escalante, J. M., Martínez, A., & Laude, V. (2014). Design of single-mode waveguides for enhanced light-sound interaction in honeycomb-lattice silicon slabs. Journal of Applied Physics, 115(6), 064302. doi:10.1063/1.486466

Optical and mechanical mode tuning in an optomechanical crystal with light-induced thermal effects

[EN] We report on the modification of the optical and mechanical properties of a silicon 1D optomechanical crystal cavity due to thermo-optic effects in a high phonon/photon population regime. The cavity heats up due to light absorption in a way that shifts the optical modes towards longer wavelengths and the mechanical modes to lower frequencies. By combining the experimental optical results with finite-difference time-domain simulations, we establish a direct relation between the observed wavelength drift and the actual effective temperature increase of the cavity. By assuming that the Young's modulus decreases accordingly to the temperature increase, we find a good agreement between the mechanical mode drift predicted using a finite element method and the experimental one.This work was supported by the EU through the project TAILPHOX (ICT-FP7-233883) and the ERC Advanced Grant SOULMAN (ERC-FP7-321122) and the Spanish projects TAPHOR (MAT2012-31392). The authors thank A. Tredicucci for a critical reading of the manuscript and A. Pitanti for fruitful discussions.Navarro-Urrios, D.; Gomis-Bresco, J.; Capuj, NE.; Alzina, F.; Griol Barres, A.; Puerto Garcia, D.; Martínez Abietar, AJ.... (2014). Optical and mechanical mode tuning in an optomechanical crystal with light-induced thermal effects. Journal of Applied Physics. 116(9):93506-93510. https://doi.org/10.1063/1.4894623S93506935101169Kippenberg, T. J., & Vahala, K. J. (2008). Cavity Optomechanics: Back-Action at the Mesoscale. Science, 321(5893), 1172-1176. doi:10.1126/science.1156032Chan, J., Alegre, T. P. M., Safavi-Naeini, A. H., Hill, J. T., Krause, A., Gröblacher, S., … Painter, O. (2011). Laser cooling of a nanomechanical oscillator into its quantum ground state. Nature, 478(7367), 89-92. doi:10.1038/nature10461Teufel, J. D., Donner, T., Li, D., Harlow, J. W., Allman, M. S., Cicak, K., … Simmonds, R. W. (2011). Sideband cooling of micromechanical motion to the quantum ground state. Nature, 475(7356), 359-363. doi:10.1038/nature10261Barclay, P. E., Srinivasan, K., & Painter, O. (2005). Nonlinear response of silicon photonic crystal micresonators excited via an integrated waveguide and fiber taper. Optics Express, 13(3), 801. doi:10.1364/opex.13.000801Ding, L., Senellart, P., Lemaitre, A., Ducci, S., Leo, G., & Favero, I. (2010). GaAs micro-nanodisks probed by a looped fiber taper for optomechanics applications. Nanophotonics III. doi:10.1117/12.853985Eichenfield, M., Michael, C. P., Perahia, R., & Painter, O. (2007). Actuation of micro-optomechanical systems via cavity-enhanced optical dipole forces. Nature Photonics, 1(7), 416-422. doi:10.1038/nphoton.2007.96Carmon, T., Yang, L., & Vahala, K. J. (2004). Dynamical thermal behavior and thermal self-stability of microcavities. Optics Express, 12(20), 4742. doi:10.1364/opex.12.004742Camacho, R. M., Chan, J., Eichenfield, M., & Painter, O. (2009). Characterization of radiation pressure and thermal effects in a nanoscale optomechanical cavity. Optics Express, 17(18), 15726. doi:10.1364/oe.17.015726Eichenfield, M., Chan, J., Camacho, R. M., Vahala, K. J., & Painter, O. (2009). Optomechanical crystals. Nature, 462(7269), 78-82. doi:10.1038/nature08524Oskooi, A. F., Roundy, D., Ibanescu, M., Bermel, P., Joannopoulos, J. D., & Johnson, S. G. (2010). Meep: A flexible free-software package for electromagnetic simulations by the FDTD method. Computer Physics Communications, 181(3), 687-702. doi:10.1016/j.cpc.2009.11.008Ding, L., Belacel, C., Ducci, S., Leo, G., & Favero, I. (2010). Ultralow loss single-mode silica tapers manufactured by a microheater. Applied Optics, 49(13), 2441. doi:10.1364/ao.49.002441J. Chan , Ph.D. dissertation, California Institute of Technology, Los Angeles, 2014.Priem, G., Dumon, P., Bogaerts, W., Van Thourhout, D., Morthier, G., & Baets, R. (2005). Optical bistability and pulsating behaviour in Silicon-On-Insulator ring resonator structures. Optics Express, 13(23), 9623. doi:10.1364/opex.13.009623Liu, Y., & Tsang, H. K. (2007). Time dependent density of free carriers generated by two photon absorption in silicon waveguides. Applied Physics Letters, 90(21), 211105. doi:10.1063/1.2741611Johnson, J. A., Maznev, A. A., Cuffe, J., Eliason, J. K., Minnich, A. J., Kehoe, T., … Nelson, K. A. (2013). Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane. Physical Review Letters, 110(2). doi:10.1103/physrevlett.110.025901Hopkins, P. E., Reinke, C. M., Su, M. F., Olsson, R. H., Shaner, E. A., Leseman, Z. C., … El-Kady, I. (2011). Reduction in the Thermal Conductivity of Single Crystalline Silicon by Phononic Crystal Patterning. Nano Letters, 11(1), 107-112. doi:10.1021/nl102918qMarconnet, A. M., Asheghi, M., & Goodson, K. E. (2013). From the Casimir Limit to Phononic Crystals: 20 Years of Phonon Transport Studies Using Silicon-on-Insulator Technology. Journal of Heat Transfer, 135(6). doi:10.1115/1.4023577Jellison, G. E., & Burke, H. H. (1986). The temperature dependence of the refractive index of silicon at elevated temperatures at several laser wavelengths. Journal of Applied Physics, 60(2), 841-843. doi:10.1063/1.337386Xu, Q., & Lipson, M. (2006). Carrier-induced optical bistability in silicon ring resonators. Optics Letters, 31(3), 341. doi:10.1364/ol.31.000341Vanhellemont, J., & Simoen, E. (2007). Brother Silicon, Sister Germanium. Journal of The Electrochemical Society, 154(7), H572. doi:10.1149/1.2732221C. Bourgeois , E. Steinsland , N. Blanc , and N. F. de Rooij , in Proceedings of the 1997 IEEE International Frequency Control Symposium (1997), pp. 791–799

Dynamical back-action at 5.5 GHz in a corrugated optomechanical beam

[EN] We report on the optomechanical properties of a breathing mechanical mode oscillating at 5.5 GHz in a 1D corrugated Si nanobeam. This mode has an experimental single-particle optomechanical coupling rate of vertical bar g(o, OM)vertical bar= 1.8 MHz (vertical bar g(o, OM)vertical bar/2 pi=0.3 MHz) and shows strong dynamical back-action effects at room temperature. The geometrical flexibility of the unit-cell would lend itself to further engineering of the cavity region to localize the mode within the full phononic band-gap present at 4 GHz while keeping high go, OM values. This would lead to longer lifetimes at cryogenic temperatures, due to the suppression of acoustic leakage.This work was supported by the EU through the FP7 project TAILPHOX (ICT-FP7-233883) and the ERC Advanced Grant SOULMAN (ERC-FP7-321122) and the Spanish projects TAPHOR (MAT2012-31392). D.N-U and J.G-B acknowledge support in the form of postdoctoral fellowships from the Catalan (Beatriu de Pinos) and the Spanish (Juan de la Cierva) governments, respectively.Navarro-Urrios, D.; Gomis-Bresco, J.; El-Jallal, S.; Oudich, M.; Pitanti, A.; Capuj, N.; Tredicucci, A.... (2014). Dynamical back-action at 5.5 GHz in a corrugated optomechanical beam. AIP Advances. 4(12). https://doi.org/10.1063/1.4902171S412Aspelmeyer, M., Kippenberg, T. J., & Marquardt, F. (Eds.). (2014). Cavity Optomechanics. doi:10.1007/978-3-642-55312-7Kippenberg, T. J., Rokhsari, H., Carmon, T., Scherer, A., & Vahala, K. J. (2005). Analysis of Radiation-Pressure Induced Mechanical Oscillation of an Optical Microcavity. Physical Review Letters, 95(3). doi:10.1103/physrevlett.95.033901Hossein-Zadeh, M., Rokhsari, H., Hajimiri, A., & Vahala, K. J. (2006). Characterization of a radiation-pressure-driven micromechanical oscillator. Physical Review A, 74(2). doi:10.1103/physreva.74.023813Eichenfield, M., Chan, J., Camacho, R. M., Vahala, K. J., & Painter, O. (2009). Optomechanical crystals. Nature, 462(7269), 78-82. doi:10.1038/nature08524Pennec, Y., Laude, V., Papanikolaou, N., Djafari-Rouhani, B., Oudich, M., El Jallal, S., … Martínez, A. (2014). Modeling light-sound interaction in nanoscale cavities and waveguides. Nanophotonics, 3(6). doi:10.1515/nanoph-2014-0004Chan, J., Alegre, T. P. M., Safavi-Naeini, A. H., Hill, J. T., Krause, A., Gröblacher, S., … Painter, O. (2011). Laser cooling of a nanomechanical oscillator into its quantum ground state. Nature, 478(7367), 89-92. doi:10.1038/nature10461Safavi-Naeini, A. H., Alegre, T. P. M., Chan, J., Eichenfield, M., Winger, M., Lin, Q., … Painter, O. (2011). Electromagnetically induced transparency and slow light with optomechanics. Nature, 472(7341), 69-73. doi:10.1038/nature09933Pennec, Y., Rouhani, B. D., Li, C., Escalante, J. M., Martinez, A., Benchabane, S., … Papanikolaou, N. (2011). Band gaps and cavity modes in dual phononic and photonic strip waveguides. AIP Advances, 1(4), 041901. doi:10.1063/1.3675799Gomis-Bresco, J., Navarro-Urrios, D., Oudich, M., El-Jallal, S., Griol, A., Puerto, D., … Torres, C. M. S. (2014). A one-dimensional optomechanical crystal with a complete phononic band gap. Nature Communications, 5(1). doi:10.1038/ncomms5452Oudich, M., El-Jallal, S., Pennec, Y., Djafari-Rouhani, B., Gomis-Bresco, J., Navarro-Urrios, D., … Makhoute, A. (2014). Optomechanic interaction in a corrugated phoxonic nanobeam cavity. Physical Review B, 89(24). doi:10.1103/physrevb.89.245122Chan, J., Safavi-Naeini, A. H., Hill, J. T., Meenehan, S., & Painter, O. (2012). Optimized optomechanical crystal cavity with acoustic radiation shield. Applied Physics Letters, 101(8), 081115. doi:10.1063/1.4747726Safavi-Naeini, A. H., Hill, J. T., Meenehan, S., Chan, J., Gröblacher, S., & Painter, O. (2014). Two-Dimensional Phononic-Photonic Band Gap Optomechanical Crystal Cavity. Physical Review Letters, 112(15). doi:10.1103/physrevlett.112.153603Johnson, S. G., Ibanescu, M., Skorobogatiy, M. A., Weisberg, O., Joannopoulos, J. D., & Fink, Y. (2002). Perturbation theory for Maxwell’s equations with shifting material boundaries. Physical Review E, 65(6). doi:10.1103/physreve.65.066611Navarro-Urrios, D., Gomis-Bresco, J., Capuj, N. E., Alzina, F., Griol, A., Puerto, D., … Sotomayor-Torres, C. M. (2014). Optical and mechanical mode tuning in an optomechanical crystal with light-induced thermal effects. Journal of Applied Physics, 116(9), 093506. doi:10.1063/1.4894623Barclay, P. E., Srinivasan, K., & Painter, O. (2005). Nonlinear response of silicon photonic crystal micresonators excited via an integrated waveguide and fiber taper. Optics Express, 13(3), 801. doi:10.1364/opex.13.000801J. Chan, Ph.D. thesis, California Institute of Technology, Los Angeles, 2014.Gorodetsky, M. L., Schliesser, A., Anetsberger, G., Deleglise, S., & Kippenberg, T. J. (2010). Determination of the vacuum optomechanical coupling rate using frequency noise calibration. Optics Express, 18(22), 23236. doi:10.1364/oe.18.02323

Accuracy of unenhanced magnetic resonance angiography for the assessment of renal artery stenosis

Purpose: To evaluate the accuracy of unenhanced magnetic resonance angiography (U-MRA) using balanced steady-state free precession (SSFP) sequences with inversion recovery (IR) pulses for the evaluation of renal artery stenosis. Materials and methods: U-MRA was performed in 24 patients with suspected main renal artery stenosis. Two radiologists evaluated the quality of the imaging studies and the ability of U-MRA to identify hemodynamically significant main renal artery stenosis (RAS) defined as a stenosis ≥50% when compared to gold standard tests: contrast-enhanced magnetic resonance angiography (CE-MRA) (18 patients) or digital subtraction arteriography (DSA) (6 patients). Results: A total of 44 main renal arteries were evaluated. Of them, 32 renal arteries could be assessed with U-MRA. When CE-MRA or DSA was used as the reference standard, nine renal arteries had hemodynamically significant RAS. U-MRA correctly identified eight out of nine arteries as having ≥50% RAS, and correctly identified 22 out of 23 arteries as not having significant RAS, with a sensitivity of 88.8%, a specificity of 95.65%, positive and negative predictive value of 88.8% and 95.65%, respectively, and an accuracy of 93.75%. Renal artery fibromuscular dysplasia (FMD) was observed in the two misclassified arteries. Conclusion: U-MRA is a reliable diagnostic method to depict normal and stenotic main renal arteries. U-MRA can be used as an alternative to contrast-enhanced magnetic resonance angiography or computer tomography angiography in patients with renal insufficiency unless FMD is suspected. Keywords: Unenhanced magnetic resonance angiography (U-MRA), Renal artery stenosis (RAS), Contrast-enhanced magnetic resonance angiography (CE-MRA), Fibromuscular dysplasia (FMD), Hypertension (HTA

Dataset related to the publication "Optical modulation of coherent phonon emission in optomechanical cavities", DOI: 10.1063/1.5040061

This folder contains the raw data from which the graphs in paper "Optical modulation of coherent phonon emission in optomechanical cavities", DOI: 10.1063/1.5040061, have been obtained.European Commission: PHENOMEN - All-Phononic circuits Enabled by Opto-mechanics (713450)Peer reviewe

Room-Temperature Silicon Platform for GHz-Frequency Nanoelectro-Opto-Mechanical Systems

Nanoelectro-opto-mechanical systems enable the synergistic coexistence of electrical, mechanical, and optical signals on a chip to realize new functions. Most of the technology platforms proposed for the fabrication of these systems so far are not fully compatible with the mainstream CMOS technology, thus, hindering the mass-scale utilization. We have developed a CMOS technology platform for nanoelectro-opto-mechanical systems that includes piezoelectric interdigitated transducers for electronic driving of mechanical signals and nanocrystalline silicon nanobeams for an enhanced optomechanical interaction. Room-Temperature operation of devices at 2 GHz and with peak sensitivity down to 2.6 cavity phonons is demonstrated. Our proof-of-principle technology platform can be integrated and interfaced with silicon photonics, electronics, and MEMS devices and may enable multiple functions for coherent signal processing in the classical and quantum domains.This research has received funding from the European Union H2020 FET Open Project PHENOMEN (No. 713450). The ICN2 authors acknowledge support by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2019-0706), the MCIN project SIP (PGC2018-101743-B-100), and by the CERCA Programme Generalitat de Catalunya. G.A. was supported by a BIST and MFC by a S. Ochoa Project Ph.D. studentships. G. M. acknowledges support from the EU ERC project LEIT (GA Nr. 885689). A.M. acknowledges support from MCIN/AEI/10.13039/501100011033/ (Projects PGC2018-094490-BC21 and ICTS-2017-28-UPV-9), from Generalitat Valenciana (BEST/2020/178, PROMETEO/2019/123, and IDIFEDER/2021/061) and from “Unión Europea NextGenerationEU/PRTR”

Dataset related to the publication "Nonlinear dynamics and chaos in an optomechanical beam", DOI: 10.1038/ncomms14965

This folder contains the raw data from which the graphs in paper "Nonlinear dynamics and chaos in an optomechanical beam", DOI: 10.1038/ncomms14965, have been obtainedPHENOMEN - H2020 Fet Open projectPeer reviewe