| 1. |
- Adrian-Martinez, S., et al.
(författare)
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The First Combined Search For Neutrino Point-Sources In The Southern Hemisphere With The Antares And Icecube Neutrino Telescopes
- 2016
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 823:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of searches for point-like sources of neutrinos based on the first combined analysis of data from both the ANTARES and IceCube neutrino telescopes. The combination of both detectors, which differ in size and location, forms a window in the southern sky where the sensitivity to point sources improves by up to a factor of 2 compared with individual analyses. Using data recorded by ANTARES from 2007 to 2012, and by IceCube from 2008 to 2011, we search for sources of neutrino emission both across the southern sky and from a preselected list of candidate objects. No significant excess over background has been found in these searches, and flux upper limits for the candidate sources are presented for E-2.5 and E-2 power-law spectra with different energy cut-offs.
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| 2. |
- Ainsbury, Elizabeth, et al.
(författare)
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Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans - joint RENEB and EURADOS inter-laboratory comparisons
- 2017
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 93:1, s. 99-109
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: RENEB, 'Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,' is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation. Materials and methods: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation induced thermoluminescent signals in glass screens taken from mobile phones. Results: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques. Conclusions: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios.
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| 3. |
- Angulo Barrios, Carlos, 1974-
(författare)
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Gallium arsenide based buried heterostructure laser diodes with aluminium-free semi-insulating materials regrowth
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Semiconductor lasers based on gallium arsenide and relatedmaterials are widely used in applications such as opticalcommunication systems, sensing, compact disc players, distancemeasurement, etc. The performance of these lasers can beimproved using a buried heterostructure offering lateralcarrier and optical confinement. In particular, if theconfinement (burying) layer is implemented by epitaxialregrowth of an appropriate aluminium-free semi-insulating (SI)material, passivation of etched surfaces, reduced tendency tooxidation, low capacitance and integration feasibility areadditional advantages.The major impediment in the fabrication of GaAs/AlGaAsburied-heterostructure lasers is the spontaneous oxidation ofaluminium on the etched walls of the structure. Al-oxide actsas a mask and makes the regrowth process extremely challenging.In this work, a HCl gas-basedin-situcleaning technique is employed successfully toremove Al-oxide prior to regrowth of SI-GaInP:Fe and SI-GaAs:Fearound Al-containing laser mesas by Hydride Vapour PhaseEpitaxy. Excellent regrowth interfaces, without voids, areobtained, even around AlAs layers. Consequences of usinginadequate cleaning treatments are also presented. Regrowthmorphology aspects are discussed in terms of different growthmechanisms.Time-resolved photoluminescence characterisation indicates auniform Fe trap distribution throughout the regrown GaInP:Fe.Scanning capacitance microscopy measurements demonstrate thesemi-insulating nature of the regrown GaInP:Fe layer. Thepresence of EL2 defects in regrown GaAs:Fe makes more difficultthe interpretation of the characterisation results in the nearvicinity of the laser mesa.GaAs/AlGaAs buried-heterostructure lasers, both in-planelasers and vertical-cavity surface-emitting lasers, withGaInP:Fe as burying layer are demonstrated for the first time.The lasers exhibit good performance demonstrating thatSI-GaInP:Fe is an appropriate material to be used for thispurpose and the suitability of our cleaning and regrowth methodfor the fabrication of this type of semiconductor lasers.Device characterisation indicates negligible leakage currentalong the etched mesa sidewalls confirming a smooth regrowthinterface. Nevertheless, experimental and simulation resultsreveal that a significant part of the injected current is lostas leakage through the burying material. This is attributed todouble carrier injection into the SI-GaInP:Fe layer.Simulations also predict that the function of GaInP:Fe ascurrent blocking layer should be markedly improved in the caseof GaAs-based longer wavelength lasers.Keywords:semiconductor lasers, in-plane lasers, VCSELs,GaAs, GaInP, semi-insulating materials, hydride vapour phaseepitaxy, regrowth, buried heterostructure, leakage current,simulation.
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| 4. |
- Aparicio, Francisco, et al.
(författare)
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Incorporation of luminescent nanometric films in photonic crystals and devices for the development of photonic sensors
- 2010
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Konferensbidrag (refereegranskat)abstract
- Dye molecules embedded in different matrices in the form of thin films are the basis of specific materials used for laser cavities, optical filters, optical gas sensors, etc. In the present communication we discuss a new methodology based on the remote microwave plasma assisted deposition of dye containing thin films that circumvent the above mentioned problems. It permits a tailored synthesis of optically active nanometric thin films containing dye molecules which are active as fluorescence emitters (i.e., coloured and fluorescent films). The principle of this new procedure is the partial polymerization of dye molecules that are evaporated over a substrate while exposed to a remote microwave Ar plasma. As a result of this process a polymeric thin film is produced in one step where some dye molecules keep intact their optical activity (although eventually, their optical response can be slightly modified by matrix effects). This methodology has been recently used for the deposition of novel plasma nanocomposites containing non-aggregated laser dyes to maximize the fluorescent emission of the materials and for the fabrication of optical NO2 sensing nanocomposites. To illustrate the possibilities of the technique we present here results for different fluorescent dye molecules, as perylene dyes, and several xanthene and oxazine derivative cationic dyes which are typically used as gain media in tuneable laser dyes. The luminescent, optical and sensing properties of these dye containing nanocomposites will be presented. These active optical layers are being developed for the fabrication of photonic sensor devices, optical filters and photonic chips (PHODYE EU Project). This is due to the full compatibility of the synthetic methodology with the present integrated microelectronic and optoelectronic technology. The possibilities for the fabrication of photonic devices integrating these active optical layers will be demonstrated. Especial attention will be paid to recent results about the incorporation of the luminescent films in photonic crystals and about the conformal growth of luminescent planar defects within artificial opals.
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| 5. |
- Aparicio, Francisco J., et al.
(författare)
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Transparent Nanometric Organic Luminescent Films as UV-Active Components in Photonic Structures
- 2011
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 23:6, s. 761-765
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Tidskriftsartikel (refereegranskat)abstract
- A new kind of visible-blind organic thin-film material, consisting of a polymeric matrix with a high concentration of embedded 3-hydroxyflavone (3HF) dye molecules, that absorbs UV light and emits green light is presented. The thin films can be grown on sensitive substrates, including flexible polymers and paper. Their suitability as photonic active components in photonic devices is demonstrated.
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| 6. |
- Barrios, Carlos Angulo, et al.
(författare)
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Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform
- 2007
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Ingår i: Optics Express. - 1094-4087. ; 15:11, s. 6846-6856
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Tidskriftsartikel (refereegranskat)abstract
- We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of < 20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.
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| 7. |
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| 8. |
- Barrios, Carlos Angulo, et al.
(författare)
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Label-free optical biosensing with slot-waveguides
- 2008
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 33:7, s. 708-710
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate label-free molecule detection by using an integrated biosensor based on a Si3N4/SiO2 Slot-waveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/(ng/mm(2)) for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm(2) for anti-BSA and BSA, respectively, limited by wavelength resolution.
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| 9. |
- Barrios, Carlos Angulo, et al.
(författare)
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Slot-waveguide biochemical sensor
- 2007
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 32:21, s. 3080-3082
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Tidskriftsartikel (refereegranskat)abstract
- We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguidemicroring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 mu m. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n = 1. 33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2 X 10(-4) RIU.
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| 10. |
- Barrios, Carlos A., et al.
(författare)
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Slot-waveguide biochemical sensor (vol 32, pg 2080, 2007)
- 2008
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Ingår i: Optics Letters. - : OPTICAL SOC AMER. - 0146-9592 .- 1539-4794. ; 33:21, s. 2554-2555
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Tidskriftsartikel (refereegranskat)abstract
- The group index, instead of the effective index, is used to analyze the performance of a Si(3)N(4)-SiO(2) slot-waveguide microring refractive index sensor [Opt. Lett. 32, 3080 (2007)]. Assuming that the slot is fully filled with liquid, excellent agreement is found between experimental results and calculations.
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| 11. |
- Barrios, Carlos, et al.
(författare)
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Integrated Si3N4/SiO2 Slot-Waveguide Microresonators
- 2007
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Konferensbidrag (refereegranskat)abstract
- We demonstrate slot-waveguide microring resonators and Fabry-Perot microcavities on Si3N4/SiO2. Characterization indicates guiding and confinement in the waveguide nanometric-size low-index slot region at O-band (1260-1370nm) wavelengths. We measured propagation losses <20 dB/cm.
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| 12. |
- Barrios, David, et al.
(författare)
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Determination of the optical constants of the active layer of a suspended particle device smart window with multilayer structure at the clear and dark states, with and without applied voltage.
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Smart windows based on suspended particle devices (SPDs) are able to switch optically from dark to clear visual appearance when applying an AC electrical signal. This effect is due to light absorbing nanoparticles that get aligned by the applied voltage. The sandwich structure of a SPD consist of several layers and includes two outer glass substrates, each one covered on its inwards-facing side with a transparent conducting thin layer surrounding the centrally positioned SPD active layer. A knowledge of the optical constants of each layer—i.e., the complex refractive index, including its real and imaginary (absorption and scattering) parts—is a key in the design of the visual appearance of the SPD window and is a useful tool to determine the optimum thickness of the active layer.
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| 13. |
- Barrios, David, et al.
(författare)
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Inversion of two-flux and four-flux radiative transfer models for determining scattering and absorption coefficients for a suspended particle device
- 2019
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Ingår i: Applied Optics. - : OPTICAL SOC AMER. - 1559-128X .- 2155-3165. ; 58:32, s. 8871-8881
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Tidskriftsartikel (refereegranskat)abstract
- Intrinsic and extrinsic scattering and absorption coefficients of a suspended particle device (SPD) smart window sample at dark and dear appearance states-without and with applied electrical voltage, respectively-were determined by means of the Maheu, Letoulouzan, and Gouesbet four-flux (intrinsic) and Kubelka-Munk two-flux ( extrinsic) radiative transfer models, respectively. Extrinsic values were obtained from fitting to the two-flux model taking into account the predominantly forward scattering of the SPD. As an approximation, the Fresnel reflection coefficients were integrated out to the critical angle of total internal reflection in order to compute diffuse interface reflectances. Intrinsic coefficients were retrieved by adding a new proposed approximation for the average crossing parameter based on the collimated and diffuse light intensities at each interface. This approximation, although an improvement of previous approaches, is not entirely consistent with the two-flux model results. However, it paves the way for further development of methods to solve the inverse problem of the four-flux model.
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| 14. |
- Barrios, David, et al.
(författare)
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Light Scattering Parameters of Polymer Dispersed Liquid Crystals Obtained by Inversion of Experimental Data
- 2022
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2022. - : Leibniz Institute for Materials Engineering IWT. ; , s. 8-11
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Polymer Dispersed Liquid Crystal (PDLC) devices are electrically controlled smart windows, that switch from a translucent milky appearance (off state) to a transparent clear appearance (on state). We have studied the intrinsic and extrinsic scattering and absorption coefficients obtained by inversion of spectrophotometric transmittance and reflectance data. The inversion procedure uses two flux and four flux models and similar approximations for the average crossing parameter (ACP) as in our previous workon suspended particle devices [1]. Good fits are obtained, but the ACP approximation was found to be inconsistent with fitted parameters.
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| 15. |
- Carlborg, Carl Fredrik, et al.
(författare)
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A packaged optical slot-waveguide ring resonator sensor array for multiplex label-free assays in labs-on-chips
- 2010
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 10:3, s. 281-290
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Tidskriftsartikel (refereegranskat)abstract
- We present the design, fabrication, and characterisation of an array of optical slot-waveguide ring resonator sensors, integrated with microfluidic sample handling in a compact cartridge, for multiplexed real-time label-free biosensing. Multiplexing not only enables high throughput, but also provides reference channels for drift compensation and control experiments. Our use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, our novel use of a dual surface-energy adhesive film to bond a hard plastic shell directly to the PDMS microfluidic network allows for fast and leak-tight assembly of compact cartridges with tightly spaced fluidic interconnects. The high sensitivity of the slot-waveguide resonators, combined with on-chip referencing and physical modelling, yields a volume refractive index detection limit of 5 x 10(-6) refractive index units (RIUs) and a surface mass density detection limit of 0.9 pg mm(-2), to our knowledge the best reported values for integrated planar ring resonators.
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| 16. |
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| 17. |
- Ferrando, Carlos, et al.
(författare)
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Individualised perioperative open-lung approach versus standard protective ventilation in abdominal surgery (iPROVE) : a randomised controlled trial
- 2018
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Ingår i: The Lancet Respiratory Medicine. - : ELSEVIER SCI LTD. - 2213-2600 .- 2213-2619. ; 6:3, s. 193-203
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Tidskriftsartikel (refereegranskat)abstract
- Background The effects of individualised perioperative lung-protective ventilation (based on the open-lung approach [OLA]) on postoperative complications is unknown. We aimed to investigate the effects of intraoperative and postoperative ventilatory management in patients scheduled for abdominal surgery, compared with standard protective ventilation. Methods We did this prospective, multicentre, randomised controlled trial in 21 teaching hospitals in Spain. We enrolled patients who were aged 18 years or older, were scheduled to have abdominal surgery with an expected time of longer than 2 h, had intermediate-to-high-risk of developing postoperative pulmonary complications, and who had a body-mass index less than 35 kg/m(2). Patients were randomly assigned (1: 1: 1: 1) online to receive one of four lung-protective ventilation strategies using low tidal volume plus positive end-expiratory pressure (PEEP): open-lung approach (OLA)-iCPAP (individualised intraoperative ventilation [individualised PEEP after a lung recruitment manoeuvre] plus individualised postoperative continuous positive airway pressure [CPAP]), OLA-CPAP (intraoperative individualised ventilation plus postoperative CPAP), STD-CPAP (standard intraoperative ventilation plus postoperative CPAP), or STD-O-2 (standard intraoperative ventilation plus standard postoperative oxygen therapy). Patients were masked to treatment allocation. Investigators were not masked in the operating and postoperative rooms; after 24 h, data were given to a second investigator who was masked to allocations. The primary outcome was a composite of pulmonary and systemic complications during the first 7 postoperative days. We did the primary analysis using the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02158923. Findings Between Jan 2, 2015, and May 18, 2016, we enrolled 1012 eligible patients. Data were available for 967 patients, whom we included in the final analysis. Risk of pulmonary and systemic complications did not differ for patients in OLA-iCPAP (110 [46%] of 241, relative risk 0.89 [95% CI 0.74-1.07; p=0.25]), OLA-CPAP (111 [47%] of 238, 0.91 [0.76-1.09; p=0.35]), or STD-CPAP groups (118 [48%] of 244, 0.95 [0.80-1.14; p=0.65]) when compared with patients in the STD-O-2 group (125 [51%] of 244). Intraoperatively, PEEP was increased in 69 (14%) of patients in the standard perioperative ventilation groups because of hypoxaemia, and no patients from either of the OLA groups required rescue manoeuvres. Interpretation In patients who have major abdominal surgery, the different perioperative open lung approaches tested in this study did not reduce the risk of postoperative complications when compared with standard lung-protective mechanical ventilation.
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| 18. |
- Gylfason, Kristinn B., 1978-, et al.
(författare)
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A packaged optical slot-waveguide ring resonator sensor array for multiplex assays in labs-on-chip
- 2009
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Ingår i: Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. - 9780979806421 ; , s. 2004-2006
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Konferensbidrag (refereegranskat)abstract
- We present the design, fabrication, and characterization of a packaged array of individually addressable slot-waveguide ring resonator sensors in a compact cartridge for sensitive, label-free, multiplex assays. The novel use of a dual surfaceenergy adhesive film enables simple generic packaging method for multiple sensors in a single cartridge. The use of optical slot-waveguides, and drift compensation by on-chip light splitting to reference sensors, gives the best refractive-index limit of detection reported for planar ring resonator sensors.
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| 19. |
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Gylfason, Kristinn, 1978-, et al.
(författare)
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On-chip temperature compensation in an integrated slot-waveguide ring resonator refractive index sensor array
- 2010
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Ingår i: Optics Express. - 1094-4087. ; 18:4, s. 3226-3237
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental study of an integrated slot-waveguide refractive index sensor array fabricated in silicon nitride on silica. We study the temperature dependence of the slot-waveguide ring resonator sensors and find that they show a low temperature dependence of -16.6 pm/K, while at the same time a large refractive index sensitivity of 240 nm per refractive index unit. Furthermore, by using on-chip temperature referencing, a differential temperature sensitivity of only 0.3 pm/K is obtained, without individual sensor calibration. This low value indicates good sensor-to-sensor repeatability, thus enabling use in highly parallel chemical assays. We demonstrate refractive index measurements during temperature drift and show a detection limit of 8.8 x 10(-6) refractive index units in a 7 K temperature operating window, without external temperature control. Finally, we suggest the possibility of athermal slot-waveguide sensor design.
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| 24. |
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| 25. |
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