Real-Time and Low-Cost Sensing Technique Based on Photonic Bandgap Structures

This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.36.002707. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] A technique for the development of low-cost and high-sensitivity photonic biosensing devices is proposed and experimentally demonstrated. In this technique, a photonic bandgap structure is used as transducer, but its readout is performed by simply using a broadband source, an optical filter, and a power meter, without the need of obtaining the transmission spectrum of the structure; thus, a really low-cost system and real-time results are achieved. Experimental results show that it is possible to detect very low refractive index variations, achieving a detection limit below 2 x 10(-6) refractive index units using this low-cost measuring technique. (C) 2011 Optical Society of America[This work was funded by the Spanish Ministerio de Ciencia e Innovacion (MICINN) under contracts TEC2008-06333, JCI-009-5805, and TEC2008-05490. Support by the Universidad Politecnica de Valencia through program PAID-06-09 and the Conselleria d'Educacio through program GV-2010-031 is acknowledged.García Castelló, J.; Toccafondo, V.; Pérez Millán, P.; Sánchez Losilla, N.; Cruz, JL.; Andres, MV.; García-Rupérez, J. (2011). Real-Time and Low-Cost Sensing Technique Based on Photonic Bandgap Structures. Optics Letters. 36(14):2707-2709. https://doi.org/10.1364/OL.36.002707S270727093614Fan, X., White, I. M., Shopova, S. I., Zhu, H., Suter, J. D., & Sun, Y. (2008). Sensitive optical biosensors for unlabeled targets: A review. 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IEEE Journal of Selected Topics in Quantum Electronics, 16(3), 654-661. doi:10.1109/jstqe.2009.2032510Xu, D.-X., Vachon, M., Densmore, A., Ma, R., Delâge, A., Janz, S., … Schmid, J. H. (2010). Label-free biosensor array based on silicon-on-insulator ring resonators addressed using a WDM approach. Optics Letters, 35(16), 2771. doi:10.1364/ol.35.002771Skivesen, N., Têtu, A., Kristensen, M., Kjems, J., Frandsen, L. H., & Borel, P. I. (2007). Photonic-crystal waveguide biosensor. Optics Express, 15(6), 3169. doi:10.1364/oe.15.003169Lee, M. R., & Fauchet, P. M. (2007). Nanoscale microcavity sensor for single particle detection. Optics Letters, 32(22), 3284. doi:10.1364/ol.32.003284García-Rupérez, J., Toccafondo, V., Bañuls, M. J., Castelló, J. G., Griol, A., Peransi-Llopis, S., & Maquieira, Á. (2010). Label-free antibody detection using band edge fringes in SOI planar photonic crystal waveguides in the slow-light regime. 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Rietveld refinement of langbeinite-type K2YHf(PO4)3

Potassium yttrium hafnium tris­(orthophosphate) belongs to the langbeinite-family and is built up from [MO6] octa­hedra [in which the positions of the two independent M sites are mutually occupied by Y and Hf in a 0.605 (10):0.395 (10) ratio] and [PO4] tetra­hedra connected via vertices into a three-dimensional framework. This framework is penetrated by large closed cavities in which the two independent K atoms are located; one of the K atoms is nine-coordinated and the other is 12-coordinated by surrounding O atoms. The K, Y and Hf atoms lie on threefold rotation axes, whereas the P and O atoms are located in general positions

Identification of plastic constitutive parameters at large deformations from three dimensional displacement fields

The aim of this paper is to provide a general procedure to extract the constitutive parameters of a plasticity model starting from displacement measurements and using the Virtual Fields Method. This is a classical inverse problem which has been already investigated in the literature, however several new features are developed here. First of all the procedure applies to a general three-dimensional displacement field which leads to large plastic deformations, no assumptions are made such as plane stress or plane strain although only pressure-independent plasticity is considered. Moreover the equilibrium equation is written in terms of the deviatoric stress tensor that can be directly computed from the strain field without iterations. Thanks to this, the identification routine is much faster compared to other inverse methods such as finite element updating. The proposed method can be a valid tool to study complex phenomena which involve severe plastic deformation and where the state of stress is completely triaxial, e.g. strain localization or necking occurrence. The procedure has been validated using a three dimensional displacement field obtained from a simulated experiment. The main potentialities as well as a first sensitivity study on the influence of measurement errors are illustrated

Sub-50 nm positioning of organic compounds onto silicon oxide patterns fabricated by local oxidation nanolithography

We present a process to fabricate molecule-based nanostructures by merging a bottom-up interaction and a top-down nanolithography. Direct nanoscale positioning arises from the attractive electrostatic interactions between the molecules and silicon dioxide nanopatterns. Local oxidation nanolithography is used to fabricate silicon oxide domains with variable gap separations ranging from 40 nm to several microns in length. We demonstrate that an ionic tetrathiafulvalene (TTF) semiconductor can be directed from a macroscopic liquid solution (1 μM) and selectively deposited onto predefined nanoscale regions of a 1 cm2 silicon chip with an accuracy of 40 nm.This work was supported by the European Commission under contract numbers G5RD-CT-2000-00349 and NAIMO integrated project no. NMP4-CT-2004-500355. Financial support from the DGI, MEC (Spain) (contract nos. MAT2006- 03849 and CTQ2006-06333/BQU) and DGR, Catalonia (contract no. 2005SGR00591) is also acknowledged.Peer reviewe

Exploring working conditions as determinants of job satisfaction: an empirical test among Catalonia service workers

Job satisfaction is particularly important in the service industry since it involves direct contact with customers and thus has a direct influence on company performance. We analyzed the impact of ten working conditions on job satisfaction by means of structural equation modelling in a representative stratified random sample of 1553 service sector employees in Catalonia (Spain). We found significant effects in social aspects (recognition of a job well done and social support), followed by psychological loads (emotional demands and job insecurity) and by task contents (development & meaning and predictability). These variables explained 50% of the variance in job satisfaction

Placement and orientation of individual DNA shapes on lithographically patterned surfaces

Artificial DNA nanostructures show promise for the organization of functional materials to create nanoelectronic or nano-optical devices. DNA origami, in which a long single strand of DNA is folded into a shape using shorter 'staple strands', can display 6-nm-resolution patterns of binding sites, in principle allowing complex arrangements of carbon nanotubes, silicon nanowires, or quantum dots. However, DNA origami are synthesized in solution and uncontrolled deposition results in random arrangements; this makes it difficult to measure the properties of attached nanodevices or to integrate them with conventionally fabricated microcircuitry. Here we describe the use of electron-beam lithography and dry oxidative etching to create DNA origami-shaped binding sites on technologically useful materials, such as SiO_2 and diamond-like carbon. In buffer with ~ 100 mM MgCl_2, DNA origami bind with high selectivity and good orientation: 70–95% of sites have individual origami aligned with an angular dispersion (±1 s.d.) as low as ±10° (on diamond-like carbon) or ±20° (on SiO_2)

Guest Molecule-Responsive Functional Calcium Phosphonate Frameworks for Tuned Proton Conductivity

We report the synthesis, structural characterization, and functionality of an open-framework hybrid that combines Ca2+ ions and the rigid polyfunctional ligand 5-(dihydroxyphosphoryl) isophthalic acid (PiPhtA). Ca-PiPhtA-I is obtained by slow crystallization at ambient conditions from acidic (pH≈3) aqueous solutions. It possesses a high water content (both Ca coordinated and in the lattice), and importantly, it exhibits water-filled 1D channels. At 75 °C, Ca-PiPhtA-I is partially dehydrated and exhibits a crystalline diffraction pattern that can be indexed in a monoclinic cell with parameters close to the pristine phase. Rietveld refinement was carried out for the sample heated at 75 °C, Ca-PiPhtA-II, using synchrotron powder X-ray diffraction data.All connectivity modes of the “parent” Ca-PiPhtA-I framework are retained in Ca-PiPhtA-II. Upon Ca-PiPhtA-I exposure to ammonia vapors (28% aqueous NH3) a new derivative is obtained (Ca-PiPhtA-NH3) containing 7 NH3 and 16 H2O molecules according to elemental and thermal analyses. Ca-PiPhtA-NH3 exhibits a complex X-ray diffraction pattern with peaks at 15.3 and 13.0 Å that suggest partial breaking and transformation of the parent pillared structure. Although detailed structural identification of Ca-PiPhtA-NH3 was not possible, due in part to nonequilibrium adsorption conditions and the lack of crystallinity, FT-IR spectra and DTA-TG analysis indicate profound structural changes compared to the pristine Ca-PiPhtA-I. At 98% RH and T = 24 °C, proton conductivity, σ, for Ca PiPhtA-I is 5.7 ×10−4 S·cm−1. It increases to 1.3 × 10−3 S·cm−1 upon activation by preheating the sample at 40 °C for 2 h followed by water equilibration at room temperature under controlled conditions. Ca-PiPhtA-NH3 exhibits the highest proton conductivity, 6.6 × 10−3 S·cm−1, measured at 98% RH and T = 24 °C. Ea for proton transfer in the above-mentioned frameworks range between 0.23 and 0.4 eV, typical of a Grothuss mechanism of proton conduction.Proyecto nacional MAT2010-1517

Variable carrier reduction in radio-over-fiber systems for increased modulation efficiencyusing a Si3N4 tunable extinction ratio ring resonator

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.025478 e. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] Variable optical carrier reduction via the use of a Si3N4 ring resonator notch filter with tunable extinction ratio is demonstrated in a 10 GHz radio-over-fiber system for improving the modulation efficiency. The extinction of the filter notch is tuned with micro-heaters, by setting the Mach-Zehnder coupler of the ring. Experimental results showing a modulation depth improvement of up to 20 dB are providedThis work was supported by the NANOCAP project A-1084-RT-GC that is coordinated by the European Defence Agency (EDA) and funded by 11 contributing Members (Cyprus, France, Germany, Greece, Hungary, Italy, Norway, Poland, Slovakia, Slovenia and Spain) in the framework of the Joint Investment Programme on Innovative Concepts and Emerging Technologies (JIP-ICET).Perentos, A.; Cuesta, F.; Rodrigo, M.; Canciamilla, A.; Vidal Rodriguez, B.; Pierno, L.; Griol Barres, A.... (2012). Variable carrier reduction in radio-over-fiber systems for increased modulation efficiencyusing a Si3N4 tunable extinction ratio ring resonator. Optics Express. 20(23):25478-25488. doi:10.1364/OE.20.025478S25478254882023Lim, C., Nirmalathas, A., Bakaul, M., Gamage, P., Ka-Lun Lee, Yizhuo Yang, … Waterhouse, R. (2010). Fiber-Wireless Networks and Subsystem Technologies. 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Analysis of optical carrier-to-sideband ratio for improving transmission performance in fiber-radio links. IEEE Transactions on Microwave Theory and Techniques, 54(5), 2181-2187. doi:10.1109/tmtt.2006.872809Barwicz, T., Popovic, M. A., Watts, M. R., Rakich, P. T., Ippen, E. P., & Smith, H. I. (2006). Fabrication of add-drop filters based on frequency-matched microring resonators. Journal of Lightwave Technology, 24(5), 2207-2218. doi:10.1109/jlt.2006.872298Ferrari, C., Canciamilla, A., Morichetti, F., Sorel, M., & Melloni, A. (2011). Penalty-free transmission in a silicon coupled resonator optical waveguide over the full C-band. Optics Letters, 36(19), 3948. doi:10.1364/ol.36.003948Gasulla, I., Lloret, J., Sancho, J., Sales, S., & Capmany, J. (2011). Recent Breakthroughs in Microwave Photonics. IEEE Photonics Journal, 3(2), 311-315. doi:10.1109/jphot.2011.2130517Capmany, J., Gasulla, I., & Sales, S. (2011). Harnessing slow light. Nature Photonics, 5(12), 731-733. doi:10.1038/nphoton.2011.290Kopp, C., Bernabé, S., Bakir, B. B., Fedeli, J., Orobtchouk, R., Schrank, F., … Tekin, T. (2011). Silicon Photonic Circuits: On-CMOS Integration, Fiber Optical Coupling, and Packaging. IEEE Journal of Selected Topics in Quantum Electronics, 17(3), 498-509. doi:10.1109/jstqe.2010.2071855Xu, D. W., Yoon, S. F., Tong, C. Z., Zhao, L. J., Ding, Y., & Fan, W. J. (2009). High-Temperature Continuous-Wave Single-Mode Operation of 1.3-$\mu$m p-Doped InAs–GaAs Quantum-Dot VCSELs. IEEE Photonics Technology Letters, 21(17), 1211-1213. doi:10.1109/lpt.2009.2024220Green, W. M. J., Lee, R. K., DeRose, G. A., Scherer, A., & Yariv, A. (2005). Hybrid InGaAsP-InP Mach-Zehnder Racetrack Resonator for Thermooptic Switching and Coupling Control. Optics Express, 13(5), 1651. doi:10.1364/opex.13.001651Li, C., Zhou, L., & Poon, A. W. (2007). Silicon microring carrier-injection-based modulators/switches with tunable extinction ratios and OR-logic switching by using waveguide cross-coupling. Optics Express, 15(8), 5069. doi:10.1364/oe.15.005069Espinola, R. L., Tsai, M. C., Yardley, J. T., & Osgood, R. M. (2003). Fast and low-power thermooptic switch on thin silicon-on-insulator. IEEE Photonics Technology Letters, 15(10), 1366-1368. doi:10.1109/lpt.2003.818246Barwicz, T., Popovic, M. A., Rakich, P. T., Watts, M. R., Haus, H. A., Ippen, E. P., & Smith, H. I. (2004). Microring-resonator-based add-drop filters in SiN: fabrication and analysis. Optics Express, 12(7), 1437. doi:10.1364/opex.12.00143