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Detection of molecules is a key issue for many applications. Surface enhanced infrared absorption (SEIRA) uses arrays of resonant nanoantennas with good quality factors which can be used to locally enhance the illumination of molecules. The technique has proved to be an effective tool to detect small amount of material. However the use of nanoresonators only enables the detection of a few absorption lines, hampering the identification of the spectral fingerprint of a molecule. Here, we introduce a new paradigm and use low quality factor resonators with large radiative losses (over-coupled resonators). The bandwidth enables to detect all absorption lines between 5 and 10 μm. Counterintuitively, despite a lower quality factor, the system sensitivity is improved and we report a reflectivity variation as large as one percent per nanometer of molecular layer of PMMA. This paves the way to specific identification of molecules. We illustrate the potential of the technique with the detection of the explosive precursor dinitrotoluene (DNT). We compare the data with numerical simulations and introduce an analytic model of the results.

International audience; While the integration of nanocrystals as an active medium for optoelectronic devices progresses, light management strategies become required. Over recent years, several photonic structures (plasmons, cavities, mirrors, etc.) have been coupled to nanocrystal films to shape the absorption spectrum, tune the directionality, and so on. Here, we explore a photonic equivalent of the acoustic Helmholtz resonator and propose a design that can easily be fabricated. This geometry combines a strong electromagnetic field magnification and a narrow channel width compatible with efficient charge conduction in spite of hopping conduction. At 80 K, the device reaches a responsivity above 1 A•W-1 and detectivity above 10 11 Jones (3 µm cutoff) while offering a significantly faster time-response than vertical geometry diodes.

In this paper we experimentally demonstrate second-harmonic generation (SHG) enhancement in thin 1D periodic plasmonic nanostructures on GaAs in the infrared spectral range. Due to the properly designed coupling of horizontal Fabry–Perot nanoresonators that occurs inside these structures, the obtained conversion efficiencies go up to the 10−7 W−1 range. Moreover, we demonstrate that the engineering of the plasmonic nanoantenna dimensions on the same GaAs layer can lead to SHG enhancement for pump wavelengths ranging from 2.8 µm to 3.3 µm.

Metasurfaces able to concentrate light at various wavelengths are promising for enhancing nonlinear interactions. In this Letter, we experimentally demonstrate infrared second-harmonic generation (SHG) by a multi-resonant nanostructure. A 100 GaAs layer embedded in a metal-insulator-metal waveguide is shown to support various localized resonances. One resonance enhances the nonlinear polarization due to the transverse magnetic (TM)-polarized pump wavelength near 3.2 µ m , while another is set near the TE-polarized generated wavelength ( 1.6 µ m ). The measured SHG efficiency is higher than 10 − 9 W − 1 for pump wavelengths ranging from 2.9 to 3.3 µ m , which agrees with theoretical computations. This is typically 4 orders of magnitude higher than the equivalent GaAs membrane.

Metasurfaces able to concentrate light at various wavelengths are promising for enhancing nonlinear interactions. In this Letter, we experimentally demonstrate infrared second-harmonic generation (SHG) by a multi-resonant nanostructure. A 100 GaAs layer embedded in a metal-insulator-metal waveguide is shown to support various localized resonances. One resonance enhances the nonlinear polarization due to the transverse magnetic (TM)-polarized pump wavelength near 3.2µ

International audience; A specific organization of optically active nanoscale objects can greatly affect the optical response of a system. Here, we report the controlled modification of the fluorescent emission by the assembly of water-soluble quantum rods (QRs). Our study combines optical, electron microcopy, and X-ray scattering characterizations to reveal a correlation between the self-assembly behavior of QRs into ordered 3D-arrays and the optical properties (luminescence) of formed assemblies, where the observed optical response is highly dependent on the QR aspect ratio. Specifically, shorter, 18 nm long QRs (QR18), exhibiting a well-defined smectic packing, demonstrate an enhancement of the emission intensity accompanied by a red shift and a lifetime reduction. In contrast, 40 nm long QRs (QR40), forming a columnar phase, does not show these optical properties.

Surface enhanced infrared absorption (SEIRA) spectroscopy and surface plasmon resonance (SPR) make possible, thanks to plasmonics nanoantennas, the detection of low quantities of biological and chemical materials. Here, we investigate the infrared response of 2,4-dinitrotoluene deposited on various arrays of closely arranged metal-insulator-metal (MIM) resonators and experimentally show how the natural dispersion of the complex refractive index leads to an intertwined combination of SEIRA and SPR effect that can be leveraged to identify molecules. They are shown to be efficient for SEIRA spectroscopy and allows detecting of the dispersive explosive material, 2,4-dinitrotoluene. By changing the in-plane parameters, a whole spectral range of absorptions of 2,4-DNT is scanned. These results open the way to the design of sensors based on SEIRA and SPR combined effects, without including a spectrometer.

One of the small wireless embedded systems issues is to gather low energy, small power consumption, small mechanical dimensions (related to frequency) and communication efficiency. In this paper we describe a way to improve the properties of a watch based GPS antenna for outdoor sports. If the key would be the study of microwave and mechanical watch properties? We try to answer with a 3D small LDS (Laser Direct Structuring) [1] antenna.

Conventional photovoltaic devices are currently made from relatively thick semiconductor layers, ~150 µm for silicon and 2–4 µm for Cu(In,Ga)(S,Se)2, CdTe or III–V direct bandgap semiconductors. Ultrathin solar cells using 10 times thinner absorbers could lead to considerable savings in material and processing time. Theoretical models suggest that light trapping can compensate for the reduced single-pass absorption, but optical and electrical losses have greatly limited the performances of previous attempts. Here, we propose a strategy based on multi-resonant absorption in planar active layers, and we report a 205-nm-thick GaAs solar cell with a certified efficiency of 19.9%. It uses a nanostructured silver back mirror fabricated by soft nanoimprint lithography. Broadband light trapping is achieved with multiple overlapping resonances induced by the grating and identified as Fabry–Perot and guided-mode resonances. A comprehensive optical and electrical analysis of the complete solar cell architecture provides a pathway for further improvements and shows that 25% efficiency is a realistic short-term target. Ultrathin solar cells having thicknesses below 1 µm can still reach efficiencies comparable to their thicker counterparts, but require less material to manufacture. By exploiting light-trapping nanostructures, Chen and colleagues achieve GaAs solar cells with 20% efficiency at just 205 nm thicknesses.

The development of sensors working in a large range of temperature is of crucial importance in areas such as monitoring of industrial processes or personal tracking using smart objects. Devices integrating GaN/Ga2O3 core/shell nanowires (NWs) are a promising solution for monitoring carbon monoxide (CO). Because the performances of sensors primarily depend on the material properties composing the active layer of the device, it is essential to control them and achieve material synthesis in the first time. In this work, we investigate the synthesis of GaN/Ga2O3 core-shell NWs with a special focus on the formation of the shell. The GaN NWs grown by plasma-assisted molecular beam epitaxy, are post-treated following thermal oxidation to form a Ga2O3-shell surrounding the GaN-core. We establish that the shell thickness can be modulated from 1 to 14 nm by changing the oxidation conditions and follows classical oxidation process: A first rapid oxide-shell growth, followed by a reduced but continuous oxide growth. We also discuss the impact of the atmosphere on the oxidation growth rate. By combining XRD-STEM and EDX analyses, we demonstrate that the oxide-shell is crystalline, presents the &beta, Ga2O3 phase, and is synthesized in an epitaxial relationship with the GaN-core.

The development of sensors for monitoring Carbon Monoxide (CO) in a large range of temperature is of crucial importance in areas as monitoring of industrial processes or personal tracking using smart objects. Devices integrating GaN/Ga2O3 core/shell nanowires (NWs) is a promising solution allowing combining the high sensitivity of the electronic properties to the states of GaN-core surface; and the high sensitivity to CO of Ga2O3-shell. Because the performances of sensors primarily depend on the material properties composing the active layer of the device, it is essential to control these properties and in first time its synthesis. In this work, we investigate the synthesis of GaN/Ga2O3 core-shell NWs with a special focus on the formation of the shell. The GaN NWs grown by Plasma-assisted molecular beam epitaxy, are post-treated following thermal oxidation to form Ga2O3-shell surrounding the GaN-core. We establish that the Ga2O3-shell thickness can be modulated from 1 up to 14 nm by changing the oxidation conditions, and follows the diffuse-controlled reaction. By combining XRD-STEM and EDX analysis, we also demonstrate that the oxide shell formed by thermal oxidation is crystalline and presents the β-Ga2O3 crystalline phase, and is synthesized in epitaxial relationship with the GaN-core.

A modal method is developed analytically to investigate the THz optical transmission and reflection of a metallic thin film perforated by a 2D array of rectangular apertures. For subwavelength apertures, this optical model is interpreted in terms of passive electrical circuits, with interface admittances accounting for the THz surface conduction properties of the metallic film. The reactive component of the admittance of the evanescent diffraction cloud is shown to exhibit resonant behavior governed by the shape factors of the array. Interaction of such an electrodynamic resonance with the Rayleigh diffraction orders may alter their standard Fano profiles. Experimental evidence of the resonance is obtained owing to lineshape analysis of transmittance measurements in the THz range on metallic thin films deposited on a dielectric substrate, both above and below the first Wood-Rayleigh anomaly.

International audience; Optical nanoantennas are studied to manipulate light and enhance light matter interactions. Here, we experimentally demonstrate the optical Helmholtz resonance in a metallic slit-box structure, which is predicted to be harmonic and to enhance the electric field intensity by several orders of magnitude. It is fabricated thanks to a two step electron beam lithography process, between which the box was filled with benzocyclobutene (BCB). Up to 80% of the light is absorbed at a λ = 2.84 μm wavelength under a beam focused by a Cassegrain objective (NA = 0.4), even if the dimensions of this resonator are deeply subwavelength for both the slit (width λ/55 and height λ/77) and the box (width λ/7 and height λ/37). As expected from the inductance nature of the box, the optical properties of the BCB filling the box have no influence on the resonance behavior.

Coupled waveguide arrays lend themselves very well to photonic engineering through tailoring of the propagation and coupling constants [1]. Especially interesting is the manipulation of collective Floquet Bloch waves (extended beams see Figure 1 top, a and d) that propagate over several waveguides through evanescent coupling and their manipulation for classical and quantum data processing. Phase-front shaping of these waves is crucial for compact imaging and photonic circuitry in the classical and quantum regime up to multiqbit architectures where phase-shifters are instrumental [2]. Segmentation of a waveguide enables a change of its propagation constant [3] and thus segmentation patterns can shape the phase front of a beam. Image reconstruction has indeed been demonstrated using π shifts [4]. We demonstrate here complete phase-front shaping in waveguide arrays by means of more general segmented patterns for a novel imaging approach. We implement three emblematic functions related to three phase profiles in III-V waveguide arrays: beam steering (linear wedge-profile), focusing and defocusing (quadratic lens-like profile) and diffraction (cosine profile). We evaluate the operation of those patterns by measuring maps of the output intensity profile as a function of the position of injection (x injection =0 corresponds to the center of the patterns). The experimental maps clearly exhibit the desired effects (see Figure 1 for steering and focusing). The excellent agreement between the simulation and the experiment validates the concept of extensive phase front shaping via segmentation patterns, the fabrication and our capacity to design and fabricate more complex functions.

Through a tightly integrated collaboration between an operator and a service company, the world's northernmost horizontal well was successfully drilled and tested. Set in the Barents Sea at 73° latitude 350km from Hammerfest, this project de-risked a future commercial field development plan for the Wisting field, which holds some of the largest known oil reserves in the Barents Hoop Area. All three major well objectives were achieved: (1) proving drillability by landing the horizontal well approximately 250m from the seabed (a record for subsea wells) and geosteering for 1400m across several fault blocks, (2) performing a well test within a long interval of reservoir exposure (over 460m) to prove the added productivity of horizontals, (3) acquiring appraisal information: reservoir data in new blocks, estimated oil / water contact (OWC), geomechanical properties, etc. This well was outside the envelope achieved before, and such an extended reach drilling (ERD) operation required a customized well engineering approach at every step. In addition, the hole design was adopted to cater for the drillstem test (DST) string. Different casing designs, string designs and operating parameters were screened in dedicated studies, looking at equivalent circulating density (ECD), torque and drag, hole cleaning, prior experience and contingencies. A combined 3D subsurface, pressure and stress model was built, calibrated to drilling observations, core data and leak off tests and then used as input for subsequent studies (mud window, rock strength for drill ability). The geometry required a constant 9°/30m dogleg from kickoff (no tangent section) to land at reservoir depth. Any interval where that performance was not achieved would have resulted in overshooting the reservoir (too deep). An oil-based mud design was adopted for several reasons, and a dedicated lost circulation material (LCM) strategy established to manage potential losses in the reservoir matrix, in fractures or faults. Important planning and operational considerations were given to safety and logistics, and no issues resulted in this remote and environmentally sensitive area. The mud motor strategy selected after careful engineering simulations landed the well at the reservoir depth, before geosteering near-horizontally for the required 1400m. The partnership has gained invaluable information about the drill ability of such wells in Wisting. Several fault blocks could be accessed with a long horizontal, giving a positive impact on the field economics.

Summary Landing horizontal wells in a reservoir is a critical task, and the accuracy of the result drives the economics of a well. Except when the geological environment is largely predictable, relying on well-to-well correlation techniques or on pilot holes fails to mitigate important risks in landing most wells. This paper details how a different solution more effectively manages the risks of a landing operation. The deep directional resistivity (DDR) logging-while-drilling (LWD) tool has been in use in dozens of fields around the world. The key features of the technology that play a role in derisking the landing of wells range from the tool hardware (which enables a deep depth of investigation, sensitivity to direction, and a wide frequency range) to the surface interpretation software, which provides real-time automatic multilayer inversion. Applied to a landing in a North Sea field, the DDR LWD service was part of the solution for meeting ambitious field-development targets.

Most plasmonic super absorbers use the excitation of surface plasmons to achieve perfect absorption in metal nanostructures. We present a design for an ultrathin metal–semiconductor–metal super absorber where light is mainly absorbed within a flat 25 nm thick GaAs semiconductor layer. The top metal layer is patterned as a two-dimensional grid with a subwavelength period and is covered with a thin embedding dielectric layer. We show numerically multiresonant absorption with low polarization and angular dependence. We experimentally demonstrate optical absorption above 80% over the 450–830 nm spectral range using a gold nanogrid. This work opens perspectives toward ultrathin active plasmonic optoelectronic devices and, in particular, highly efficient ultrathin solar cells.

We review and propose light trapping strategies in ultra-thin solar cell. We demonstrate JSC=24.8 mA/cm2 in 205 nm-thick GaAs solar cell using a nanostructured TiO2/Ag back mirror fabricated by Nanoimprint lithography.

Goliat was the first oil discovery in the Barents Sea and holds 174 million barrels of recoverable oil. It is operated by Eni Norge (65% share, with Statoil holding the rest of the equity). Finding oil is important, but safely and efficiently developing it is critical. The remoteness of these frontier projects amplifies the consequences of any delays or issues. Risk prevention and mitigation is the object of particular attention in this new frontier area. Landing the first producer was a particularly sensitive operation, requiring a safe stop a few meters above the top of the reservoir to reduce the risk of landing the section within the reservoir gas cap bearing sandstone. A geometrical landing would be limited by a depth uncertainty of more than 10 m true vertical depth (TVD): relying on surface seismic information is subject to seismic time-to-depth conversion and the inherent limited resolution of seismic data. Taking these uncertainties into account normally requires setting the casing long in advance of the reservoir top, giving way to a much longer portion of the reservoir section exposed to the overburden shales, with consequent 8 ½’’well bore instability issues and risk of plugging the completion screens. For the Goliat well, the operator adopted a different approach to land the objective while preventing the risks of setting casing too soon or too late. A new ambitious objective was set: stopping and casing as close as possible to the reservoir, but no closer than 5 m TVD. This could only be done by using the latest generation of deep directional resistivity (DDR) logging-while-drilling tools in the 12 ¼" section, increasing both the precision and the accuracy of the landing by relying on a direct detection of the reservoir top before drilling into it. The DDR real-time automatic inversion of the subsurface layering revealed the top of the reservoir from 19 m TVD below the bottom hole assembly, a new record. By tracking the top boundary, even at a steep inclination near 70°, the operator confidently stopped drilling when the bit was 6 m TVD above the top of the reservoir, as planned, safely minimizing the distance to be drilled in shales before intersecting the reservoir. The distance to the reservoir was verified in the next section drilled. The use of DDR for landing wells accurately either above or just below a top reservoir is now a proven powerful option for drilling programs in which risk prevention is required at the top of the reservoir.

The new reservoir mapping-while-drilling technology provides enough data so that a real-time reservoir map can be created through inversion for a layered medium. These reservoir maps are used to optimize well placement and to improve reservoir understanding. Complex reservoirs can be imaged, but the assumption of a layered medium loses its validity when the reservoir cannot be approximated using 1D model locally, i.e., when the reservoir structure varies on the scale of the tool spacing. To improve reservoir mapping performance in such scenarios, an unbiased approximate 2D inversion is introduced that minimizes the error to the layer medium approximation of the reservoir. It is suited for any mildly 2D scenario in which the reservoir does not change abruptly. The method is validated on synthetic and field datasets.

International audience; Ultrathin c-Si solar cells have the potential to drastically reduce costs by saving raw material while maintaining good efficiencies thanks to the excellent quality of monocrystalline silicon. However, efficient light trapping strategies must be implemented to achieve high short-circuit currents. We report on the fabrication of both planar and patterned ultrathin c-Si solar cells on glass using low temperature (T < 275 °C), low-cost, and scalable techniques. Epitaxial c-Si layers are grown by PECVD at 160 °C and transferred on a glass substrate by anodic bonding and mechanical cleavage. A silver back mirror is combined with a front texturation based on an inverted nanopyramid array fabricated by nanoimprint lithography and wet etching. We demonstrate a short-circuit current density of 25.3 mA/cm2 for an equivalent thickness of only 2.75 μm. External quantum efficiency (EQE) measurements are in very good agreement with FDTD simulations. We infer an optical path enhancement of 10 in the long wavelength range. A simple propagation model reveals that the low photon escape probability of 25% is the key factor in the light trapping mechanism. The main limitations of our current technology and the potential efficiencies achievable with contact optimization are discussed.

We propose a new guide mode resonant photodiode demonstrating better sensitivity for the infrared imaging. This comprises a backside dielectric sub-wavelength periodic structure and an absorbing region as thin as 90 nm. In this study, electro-optical characterizations of individual InGaAs detector featuring focal-plane array-compatible geometries are fully explained by electro-magnetic simulations. In particular, we observe near perfect collection of the photo-carriers and external quantum efficiency of up to 71% around 1,55 µm.

We investigate a full-dielectric guided mode resonant photodiode. It has been designed to enhance the absorption by excitation of several resonances in the SWIR domain. The device consists of an InP/InGaAs/InP P-i-N heterojunction containing an active layer as thin as 90 nm on top of a subwavelength lamellar grating and a gold mirror. We successfully compared the electro-optical characterizations of individual pixels with electro-magnetic simulations. In particular, we observe near perfect collection of the photo-carriers and external quantum efficiency (EQE) of up to 71% around 1.55 μm. Moreover, compared with InGaAs resonator state-of-the-art detector, we show a broader spectral response in the 1.2-1.7 μm range, thus paving the way for SWIR low dark current imaging.

Effects of fluorine-based plasma treatment on the GaN-based HEMTs electrical properties have been investigated. Two structures have been studied and compared, one with AlGaN alloy barrier and another one with AlN/GaN super-lattice (SL) barrier. Firstly a large positive threshold voltage (Vth) shift in the structure with AlGaN alloy barrier is observed. Vth shift is due to the incorporation of fluorine into the barrier. As a consequence the 2D-electron gas density is lower and Vth enlarges. Secondly a small negative Vth shift is obtained in the structure with an AlN/GaN SL barrier. It has been attributed to fluorine n-type doping in the SL barrier (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In this paper we report the fabrication and characterization of single wall carbon nanotube film based devices. Carbon nanotubes (CNT) film is deposited on a silica substrate and usual clean room processes have been used to make Pt-electrodes on top of it and to pattern the CNT film. The obtained devices have been used to measure the evolution of the temperature coefficient of resistance (TCR) as a function of temperature. At room temperature the TCR is –0.2%K-1 and becomes even more important as the temperature goes down. Moreover the optical response in atmospheric band II and band III have been investigated at room temperature showing a variation of the device resistance up to 0.2% for an irradiance of ∼100 mW/cm2 in the 3–5 µm range. Such results are very promising for application of CNT films in bolometers for thermal infrared detection (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

International audience; We investigated the dark current components of thin planar InGaAs photodiodes grown by metalorganic vapor-phase epitaxy for optical nano-resonators. Owing to their high electric field enhancement, nano-resonators make it possible to substantially reduce the thickness of the active region to about 100 nm all the while maintaining high quantum efficiency. In the present study, to cover a broad spectral band, we combined several resonance peaks induced by guided-mode resonances in a given spectral range. This type of geometry allowed us to introduce InAlAs at the edge of a thin InGaAs active region in order to drastically reduce both the diffusion current and the generation/recombination current. We found that, in such devices, tunneling dark current components increase as the thickness of the active layer is reduced and dominate the reverse dark current. By optimizing the epitaxial stack, while keeping its total thickness constant (the optical properties of the nano-resonator remained unchanged), we showed that we are already able to achieve a specific detectivity of up to 1×10^13 cm√( Hz)W^−1 for λ=1.55 μm.

The data delivered by a new reservoir mapping while drilling (RMWD) tool provides more geological information than that from any other logging-while-drilling (LWD) technology previously available in the oil field. Its answer product images the surrounding formation structure, and the resulting maps can be used by the geoscientists to improve their understanding of the subsurface, the well placement and the reservoir. To take advantage of the richness of the measurements and deep depth of investigation across multiple formation boundaries, an automatic stochastic inversion has been developed that combines approximately a hundred phase and attenuation measurements at various frequencies and transmitter-to-receiver distances. This efficient Bayesian model-based stochastic inversion runs in parallel with multiple independent search instances that randomly sample hundreds of thousands of formation models using a Markov chain Monte Carlo method. All samples above a quality threshold over the solution space are used to generate the distribution of formation models that intrinsically contain the information for model uncertainties. RMWD is a highly nonlinear problem; inverting for a unique solution is analytically difficult due to the well-known local minima issue. The stochastic method addresses that by sampling thousands of possible formation models and outputting a distribution of layered models that are consistent with the measurements. Statistical distributions are displayed for formation resistivity, anisotropy and dip at each logging point. Additionally, the median formation models for resistivity are shown along the well trajectory as a curtain section plot. This provides an intuitive interpretation for the entire reservoir formation around the tool. The inversion curtain section plot can be overlaid with the seismic formation model for combined interpretation. Furthermore, the curtain plot provides graphical information for dip and distance to boundary, which are critical for field applications such as landing, geosteering, remote fluid contact identification, etc. The stochastic-sampling-based answer product has been intensively field tested and has proven to provide reliable estimation of the formation geometries and fluid distributions in many locations and geological environments worldwide. Field applications and simulated examples of the stochastic inversion include remote detection of the reservoir to enable accurate landing, navigating multilayered reservoirs, remote identification of fluid contacts and reservoir characterization in the presence of faults. The stochastic inversion samples the formation properties randomly and provides the distribution of formation properties based on a large number of samples, instead of providing only the most likely solution as is typical for deterministic inversions. A statistical method of presenting inversion results in formation space provides an instant and intuitive understanding of the formation surrounding the tool. Quantifying the non-uniqueness of the inverted formation models gives geologists a more robust insight into what the formation scenarios may be, and helps with the steering decision-making and reservoir mapping interpretation.

In 2014 ConocoPhillips (U.K) Ltd. drilled a third development well, a horizontal infill, in the Brodgar gas condensate field (central North Sea) to target a low relief structure 6,000 ft west of the existing production wells. A new deep resistivity tool was successfully used in this well to aid geosteering and mapping of the hydrocarbon envelope. A pilot well was originally proposed to reduce uncertainty around the hydrocarbon-water contact (HWC) and the top structure depth at the target location. However during data acquisition planning, extensive simulations of the response of the deep directional resistivity (DDR) logging-while-drilling (LWD) tool were carried out to evaluate its capability to reduce these uncertainties. The simulations gave confidence in the ability of the DDR tool to: (1) detect the reservoir 50 ft true vertical depth (TVD) away before wellbore arrives at top reservoir; and (2) effectively map the top and base of the entire reservoir zone. The decision was made to drop the pilot well and apply this new technology to mitigate the risks and meet the well plan and production objectives. This decision was supported by detailed reservoir simulation work and uncertainty modelling. The tool response showed the range of hydrocarbon column height upon landing at the initial target location to be between 70 and 110 ft (mid case predrill simulations predicted a column of 104 ft). Due to mechanical issues, this initial wellbore had to be abandoned and sidetracked at the 13 3/8-in shoe. As the sidetrack was a twin of the abandoned hole, the DDR LWD tool was not required for landing the sidetrack but was used for geosteering the horizontal section. The tool provided a real-time resistivity profile that could be interpreted up to 80 ft above and below the wellbore resulting in an accurate “map” of the hydrocarbon envelope. The tool has helped to significantly reduce uncertainty on top structure depth and on water encroachment behaviour, leading to re-interpretation of the seismic, static, and dynamic models. For ConocoPhillips (U.K) Ltd. this case study has demonstrated the value of applying new technology to reduce subsurface uncertainties and eliminate unnecessary well cost.

International audience; Degenerate two-photon absorption (TPA) is investigated in a 186 nm thick gallium arsenide (GaAs) p-in diode embedded in a resonant metallic nanostructure. The full device consists in the GaAs layer, a gold subwavelength grating on the illuminated side, and a gold mirror on the opposite side. For TM-polarized light, the structure exhibits a resonance close to 1.47 μm, with a confined electric field in the intrinsic region, far from the metallic interfaces. A 109 times increase in photocurrent compared to a non-resonant device is obtained experimentally, while numerical simulations suggest that both gain in TPA-photocurrent and angular dependence can be further improved. For optimized grating parameters, a maximum gain of 241 is demonstrated numerically and over incidence angle range of (−30°; +30°). This structure paves the way towards low-noise infrared detection, using non-degenerate TPA, involving two photons of vastly different energies in the same process of absorption in a large bandgap semiconductor material.

JUN 14-19, 2015; International audience; We report on the fabrication and characterization of both flat and patterned c-Si solar cells on glass. We use epitaxial layers grown by plasma enhanced chemical vapor deposition at low temperature (T

Statoil has played a key role in testing and development of the new ultra-deep directional resistivity (DDR) logging while drilling (LWD) measurements for high angle and horizontal wells the last 4 years. Inverted resistivity images provide an overview of geological structures and fluid contacts tens of meters around the wellbore. The ultra-deep look around measurements, sensitive to resistivity contrasts up to 30 m away or even more in favorable conditions, are a step change, when it comes to possibility to position the wellbore strategically in the reservoir and to characterize reservoir structure and properties. This paper will present how the new DDR measurements have been applied with success in an operating license on the Norwegian Continental Shelf (NCS). Long horizontal wells in the reservoir sections have been identified as a key strategy to increase recovery. The main benefits from the DDR measurements in the license have been to maximize reservoir exposure by active geosteering, to optimize well placement above oil-water contact, and to increase subsurface understanding which is important input for future well plans. The DDR measurements are already a commercial service with regard to well placement and reservoir landing. Statoil is however also actively pushing for improved reservoir characterization, by coupling geomodels and DDR modeling and inversion software. This paper will also present how standard LWD logs and images can be combined with the DDR inversion results, to build a near-wellbore 3D structural model supporting all available data. This is an important step towards an extended use of the new data not only for well placement, but also for increased subsurface understanding and geomodel update. Background The willingness to invest in R&D has been a key success factor for the development of the Norwegian petroleum industry since the very beginning. Operators on the NCS have pioneered innovative technology such as horizontal drilling, time lapse seismic surveying (4D), and subsea technology. The development of horizontal drilling and multilateral wells in the thin oil rim on Troll is an example of Norwegian technological excellence, which released reserves worth more than NOK 500 bn that would otherwise have been left in the ground (Mikkelsen et al. 2005). The development of horizontal drilling has been a key component of improved oil recovery on NCS. More than 50% of all production wells today on the NCS are highly deviated or horizontal. Global companies have used the NCS as a testing ground for new technology such as horizontal drilling and new LWD measurements to geosteer the long horizontals. Given the ability to drill with high angles there is also a considerable value in geosteering this type of wells for correct well placement with regard to formation boundaries and fluid contacts. Statoil, together with the former Hydro, has been pushing electromagnetic measurements (EM) while drilling for geosteering long horizontals with great success. Examples from Troll, Grane, Velsefrikk, Oseberg and Gullfaks fields demonstrate the added value from both non-directional and directional bed-boundary mapping tools in the past, where NCS has played a key role in development and testing of LWD EM-measurements (Iversen et al. 2003; Wiig et al. 2005; Constable et al. 2012).

International audience; The use of peptidic ligands is validated as a generic chemical platform allowing one to finely control the organization in solid phase of semiconductor nanorods originally dispersed in an aqueous media. An original method to generate, on a macroscopic scale and with the desired geometry, three-dimensional supracrystals composed of quantum rods is introduced. In a first step, nanorods are transferred in an aqueous phase thanks to the substitution of the original capping layer by peptidic ligands. Infrared and nuclear magnetic resonance spectroscopy data prove that the exchange is complete; fluorescence spectroscopy demonstrates that the emitter optical properties are not significantly altered; electrophoresis and dynamic light scattering experiments assess the good colloidal stability of the resulting aqueous suspension. In a second step, water evaporation in a microstructured environment yields superstructures with a chosen geometry and in which nanorods obey a smectic B arrangement, as shown by electron microscopy. Incidentally, bulk drying in a capillary tube generates a similar local order, as evidenced by small angle X-ray scattering.

We study light management in a 430 nm-thick GaAs p-i-n single junction solar cell with 10 InGaAs/GaAsP multiple quantum wells (MQWs). The epitaxial layer transfer on a gold mirror improves light absorption and increases the quantum efficiency in the MQW region by a factor of 4 through the excitation of Fabry-Perot resonances. We show a good agreement with optical simulation and achieve around 9% efficiency. This promising result can be further improved by anti-reflection layers and additional light-trapping solutions.

The design of metasurfaces able to efficiently control the polarization state of an electromagnetic wave is of importance for various applications. We demonstrate both theoretically and experimentally that plasmonic planar L-shaped antennas can induce a 90◦-rotation of the linear polarization of light with a nearly total efficiency in the infrared (3-5 µm). The nanoantenna geometry is engineered so that the polarization conversion occurs over a 1 μm-wide spectral band ([3.25-4.25] µm ) with a mean polarization conversion efficiency of 95 %. In order to validate a theoretical model describing the antenna behaviour, we investigate the polarization conversion effect as function of the incident and azimuthal angles.

Light trapping enhancement is a major research field in photovoltaics. Scarce and expensive resources for semiconductor material drive the research on light management in thin absorber layer. This paper reviews some of the known techniques, from back reflector to nanophotonic technologies such as nanowires or plasmonic-enhanced photovoltaic devices. Light trapping enhancement can reach ~100 fold and experimental demonstrations of device exceeding the ray optics limits have been reported.

Suzuki cross-coupling reactions between a range of aryl bromides and boronic acids using a water-soluble Pd(0)/TPPTS catalyst occur under mild conditions with high efficiency. The process tolerates electron-rich and electron-poor substituents and provides an efficient access to sterically hindered biaryls. Good turnovers are observed and the catalyst can be recycled three times without loss of activity.

Conventional light trapping techniques are inefficient at the sub-wavelength scale. This is the main limitation for the thickness reduction of thin-film solar cells below 500nm. We propose a novel architecture for broadband light absorption in ultra-thin active layers based on plasmonic nano-cavities and multi-resonant mechanism. Strong light enhancement will be shown numerically for photovoltaic materials such as CIGSe and GaAs. First experiments on ultrathin nano-patterned CIGSe solar cells will be presented.

Efficient intramolecular Heck-type cyclizations were carried out in aqueous medium using water-soluble Pd/TPPTS catalysts. Under these conditions, the generally observed exo process was reversed in favor of the regioselective formation of endo cyclized compounds.

The static earth model is the centrepiece of field development, from initial reserves evaluation to well planning to production and recovery optimization. Also, the static model is most often the main source of information into the well placement pre-job model. However, while it was always agreed that the findings of a well placement job should be used to refine the original model, up until now, enriching the static model was not offered as a mature service by the providers of geosteering solutions and interpretation. This paper and presentation introduces a new workflow combining LWD information from borehole images and deep boundary mapping services (possibly from several wells in an area) into a near-wellbore 3D structural model supporting all available data. The 3D near-wellbore structural model workflow is an important contribution to workflows closing the loop from horizontal logging and well placement back to the reservoir model update.

New technologies have been developed to achieve a higher degree of accuracy in well positioning as operators have been drilling increasingly challenging hydrocarbon pockets. The Nini East Field, Danish North Sea sector, represents a significant drilling challenge. The target is a postdepositionally remobilized sand reservoir of 2–15 meters thickness. Because of the reservoir's remobilized nature and its low resistivity, none of the standard well placement methods or the current bed-boundary mapping tools were suitable solutions for the well objectives. Previous wells drilled in this type of reservoir have been marginally economical due to sidetracks and net-pay ratios below 0.5. In view of these challenges, DONG E&P decided to collaborate to the field test of the next generation bed-boundary mapping tool to geosteer their two upcoming production wells. The technology currently in field test provides a real-time mapping of the reservoir several meters away from the wellbore. As the depth of investigation of the tool is within the same range as surface seismic measurements, the two data sources were integrated while drilling to provide look-ahead information. The two producers achieved an outstanding 0.99 and 0.96 net-pay ratio with no sidetracks or delays and were completed within budget. The inversion processing of deep directional resistivity measurements clearly shows the capability of this new generation tool to map the internal variations of the reservoir structure, enabling further understanding of its nature and depositional history and allowing optimization of the field development.

The last decade has shown a significant development in resistivity measurement technology providing directional resistivity at a larger scale than conventional logging tools. The latest development can identify resistivity contrasts ten's of meters around the wellbore. Statoil has tested deep look-around resistivity on a range of fields during the last 2 years and recorded data in more than 10 wells on the Norwegian Continental Shelf. The look-around images provides information at a scale that bridges the gap between conventional logging and seismic and adds important new pieces to the reservoir characterization puzzle. In good reservoir conditions, resistivity contrast up to 30 m away from the well-bore has been observed. This study will focus on results from the Visund and Åsgard fields, and will demonstrate how the device was used in a range of different applications in the geosteering operation: Detection of the reservoir boundary up to 20m TVD away. Detection of oil bearing reservoir from within underlying shale, through a water zone. Detection of Gas-Oil Contact (GOC). Detection of Oil-Water Contact (OWC) up to 20m TVD away. Detect faulting of the reservoir. These examples will highlight why deep look-around resistivity is a step change related to the possibility for doing pro-active well placement of highly deviated wellbores as well as for gaining a larger reservoir understanding. The imaged variation in resistivity contrasts can be related to geologic zonation and fluid content on the reservoir scale, which opens up a much better cross-disciplinary communication between geophysicists, geologists, petrophysicists and reservoir engineers. Finally, the deep resistivity images contribute in optimization of completion solutions when incorporating information on the reservoir scale.

International audience; We describe a method of controlled evaporation on a textured substrate for self-assembling and shaping gold-nanorod-based materials. Tridimensional wall features are formed over areas as large as several square millimeters. Furthermore, analyses by small-angle X-ray scattering and scanning electron microscopy techniques demonstrate that colloids are locally ordered as a smectic B phase. Such crystallization is in fact possible because we could finely adjust the nanoparticle charge, knowledge that additionally enables tuning the lattice parameters. In the future, the type of ordered self-assemblies of gold nanorods we have prepared could be used for amplifying optical signals.

The palladium-promoted deallylation of allylamines derived from primary and secondary amines is achieved with high to quantitative yield in the presence of 2-mercaptobenzoic acid as an allyl scavenger. This method was used for the sequential cleavage of diallylamines. A. synthetic application of this procedure is presented in the preparation of secondary amines from diallylamines.

Efficient intramolecular Heck-type cyclizations were carried out in aqueous medium using water-soluble Pd/TPPTS catalysts. Under these conditions, the generally observed exo process was reversed in favor of the regioselective formation of endo cyclized compounds.

Suzuki cross-coupling reactions between a range of aryl bromides and boronic acids using a water-soluble Pd(0)/TPPTS catalyst occur under mild conditions with high efficiency. The process tolerates electron-rich and electron-poor substituents and provides an efficient access to sterically hindered biaryls. Good turnovers are observed and the catalyst can be recycled three times without loss of activity.