D. Costantini

Bio: D. Costantini is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Laser & Plasmon. The author has an hindex of 11, co-authored 24 publications receiving 395 citations. Previous affiliations of D. Costantini include University of Paris-Sud & Saint-Gobain.

Plasmonic Metasurface for Directional and Frequency-Selective Thermal Emission

Abstract: Incandescent sources typically emit broadband light in all directions. Most of this radiation is lost for applications in the infrared region, such as spectroscopy or compositional analysis. Here the authors control both the spatial and temporal coherence of blackbody radiation with a plasmonic metasurface that emits a narrow band of frequencies in a small solid angle. This system operates reliably at 600 \ifmmode^\circ\else\textdegree\fi{}C using CMOS-compatible materials, inviting the development of compact, efficient, and cheap infrared sources and gas detectors.

Tunable loss filter based on metal-coated long-period fiber grating

Abstract: An all-fiber electrically tunable loss filter that is based on photoinduced long-period grating coated by Ti-Pt metal coating was developed and investigated. Maximum wavelength tuning of 11 nm with an applied power of 0.67 W was achieved for the HE17 cladding mode resonance peak.

In situ strain and temperature monitoring of adaptive composite materials

Abstract: An optical fiber sensor is designed to simultaneously measure strain and temperature in an adaptive composite material The sensor is formed by splicing two fiber Bragg gratings (FBGs) close to each other, which are written in optical fibers with different core dopants and concentrations Their temperature sensitivities are hence different The sensor is tested on an adaptive composite laminate made of unidirectional Kevlar-epoxy prepreg plies Several 150 μm diameter prestrained NiTiCu shape memory alloy (SMA) wires are embedded in the composite laminate together with one fiber sensor Simultaneous monitoring of strain and temperature during the curing process and activation in an oven is demonstrated

CMOS compatible metal-insulator-metal plasmonic perfect absorbers

Abstract: We report the design, fabrication and characterization of CMOS compatible metal-insulator-metal (MIM) plasmonic resonators made of tungsten and silicon nitride for the mid-infrared range. These structures give rise to spectrally selective emission/absorption, which is of particular interest in the field of non-dispersive infrared (NDIR) gas spectroscopy. In this paper, we demonstrate large scale fabrication on 200 mm silicon wafer of such devices, and show some of their main characteristics, such as tunability, multi-spectral sources, polarization-independance and consistency between reflectivity and emissivity measurements.

Fiber amplifiers for coherent space communication

Abstract: We report on the application of double-clad doped fiber amplifiers for coherent space communication systems using a master oscillator power amplifier (MOPA) design at 1.06 /spl mu/m. The master oscillator is either a single-frequency Nd:YAG solid-state laser or a distributed-feedback fiber laser. The power amplifier is a diode-laser-pumped double-clad Nd doped fiber with polarization control, 20 dB gain, and about 1.3 W output power. A dual stage configuration using a solid-state Nd:YAG amplifier as second stage is presented as well, increasing the output power to 3.5 W with 28 dB gain. We also report on the possibility to integrate a single-frequency fiber laser, an all-fiber phase modulator, and a fiber amplifier to build an all-fiber phase-modulated MOPA. Up to 1 W continuous-wave output phase-modulated with a bandwidth of 196 MHz has been achieved.

Optical fibre long-period grating sensors: characteristics and application

Abstract: Recent research on fibre optic long-period gratings (LPGs) is reviewed with emphasis placed upon the characteristics of LPGs that make them attractive for applications in sensing strain, temperature, bend radius and external index of refraction. The prospect of the development of multi-parameter sensors, capable of simultaneously monitoring a number of these measurands will be discussed.

Advances in Full Control of Electromagnetic Waves with Metasurfaces

Abstract: Metasurfaces, two-dimensional versions of metamaterials, retain the great capabilities of three-dimensional counterparts in manipulating electromagnetic wave behaviors, while reducing the challenges in fabrication. By judiciously engineering parameters of individual building blocks (such as geometry, size, and material) and selecting specific design algorithms, metasurfaces are promising to replace conventional electromagnetic elements in nanoplasmonic/photonic devices. Significantly, such concept can be readily promoted to other disciplines, such as acoustics, thermal physics, and seismology. In this article, the latest advances in full control of electromagnetic waves with metasurfaces are briefly reviewed from a functionality perspective. A broad avenue towards real-life applications of metamaterials has been opened up, although they are still at their infant stage. At the end, several promising approaches are suggested to extend the applications of metasurfaces.

Optical fiber long-period gratings with Langmuir–Blodgett thin-film overlays

Abstract: An overlay material was deposited by the Langmuir–Blodgett technique onto a single-mode optical fiber containing a long-period grating. The long-period grating exhibits characteristic attenuation bands in its transmission spectrum whose central wavelengths were observed to depend on the optical thickness of the overlay material, even for materials that have a refractive index higher than that of silica.

Review of long period fiber gratings written by CO2 laser

Abstract: This paper presents a systematic review of long period fiber gratings (LPFGs) written by the CO2 laser irradiation technique. First, various fabrication techniques based on CO2 laser irradiations are demonstrated to write LPFGs in different types of optical fibers such as conventional glass fibers, solid-core photonic crystal fibers, and air-core photonic bandgap fibers. Second, possible mechanisms, e.g., residual stress relaxation, glass structure changes, and physical deformation, of refractive index modulations in the CO2-laser-induced LPFGs are analyzed. Third, asymmetrical mode coupling, resulting from single-side laser irradiation, is discussed to understand unique optical properties of the CO2-laser-induced LPFGs. Fourthly, several pretreament and post-treatment techniques are proposed to enhance the efficiency of grating fabrications. Fifthly, sensing applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based temperature, strain, bend, torsion, pressure, and biochemical sensors. Finally, communication applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based band-rejection filters, gain equalizers, polarizers, and couplers.

Strain measurements of composite laminates with embedded fibre Bragg gratings : criticism and opportunities for research

Abstract: Embedded optical fibre sensors are considered for structural health monitoring purposes in numerous applications. In fibre reinforced plastics, embedded fibre Bragg gratings are found to be one of the most popular and reliable solutions for strain monitoring. Despite of their growing popularity, users should keep in mind their shortcomings, many of which are associated with the embedding process. This review paper starts with an overview of some of the technical issues to be considered when embedding fibre optics in fibrous composite materials. Next, a monitoring scheme is introduced which shows the different steps necessary to relate the output of an embedded FBG to the strain of the structure in which it is embedded. Each step of the process has already been addressed separately in literature without considering the complete cycle, from embedding of the sensor to the internal strain measurement of the structure. This review paper summarizes the work reported in literature and tries to fit it into the big picture of internal strain measurements with embedded fibre Bragg gratings. The last part of the paper focuses on temperature compensation methods which should not be ignored in terms of in-situ measurement of strains with fibre Bragg gratings. Throughout the paper criticism is given where appropriate, which should be regarded as opportunities for future research.