Centre National De La Recherche Scientifique

Office National D'etudes Et De Recherches Aerospatiales (onera)

Office National D'etudes Et De Recherches Aerospatiales

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Onera (office National D'etudes Et De Recherches Aerospatiales)

Office Nathional D'etudes Et De Recherches Aerospatiales—onera—chemie De La Huniere

Centre National De La Recherche Scientifique-cnrs

Riad Haidar

Jean-Luc Pelouard

Fabrice Pardo

Patrick Bouchon

Grégory Vincent

Sabrina Velghe

Stéphane Collin

Michaël Verdun

Jean-Jacques Yon

Nicolas Guerineau

Jerome Primot

Joël Deschamps

Jérôme Primot

Julien Jaeck

Stephane Collin

Mathilde Makhsiyan

Benjamin Portier

Quentin Levesque

Charlie Koechlin

Bruno Toulon

Antoine Bierret

Emilie Steveler

Nicolas Guérineau

Baptiste Fix

Paul Chevalier

Michel Tauvy

Gregory Vincent

Disclosed is a spectral filter including a plurality of Fabry-Perot structures which are collectively carried by a support, and coupled together so as to produce a coupling resonance that is distinct from individual resonances of each of the Fabry-Perot structures. The coupling resonance may have a higher quality factor than the quality factors of the individual resonances. Each Fabry-Perot structure includes two portions of metal surfaces which are parallel to a face of the substrate, so that electromagnetic radiation wave components propagating within each Fabry-Perot structure, and which contribute to the coupling resonance, have a direction of propagation that is parallel to the face of the substrate.

Spectral filter comprising at least two coupled Fabry-Perot structures

A device for multispectral imaging in the infrared, suitable for detecting at at least one first and one second detection wavelength is provided. It comprises a detection matrix array comprising a set of elementary detectors of preset dimensions forming an image field of given dimensions; and an image-forming optic having a given aperture number (N) and a given focal length (F), which aperture number and focal length are suitable for forming, at any point of the image field, an elementary focal spot covering a set of at least two juxtaposed elementary detectors. The device furthermore comprises a matrix array of elementary metal-dielectric guided-resonance filters, which matrix array is arranged in front of the detection matrix array at a distance smaller than a focal depth of the optic, the dimensions of the elementary filters being such that each elementary focal spot formed at each point of the image field covers at least two elementary filters; and the elementary filters are optimised for pass-band transmission in spectral bands centred on two different central wavelengths, equal to two of said detection wavelengths.

Device and method for multispectral imaging in the infrared

A photodetector includes a Helmholtz resonator and a photosensitive structure that is placed in an electric-field-concentrating interval forming part of the Helmholtz resonator. Such a photodetector is in particular suitable for imaging applications. The wavelength of the radiation to be detected is determined by dimensions of the Helmholtz resonator, within a detection spectral interval of the photosensitive structure.

Photodetector with helmholtz resonator

A spectral conversion element for electromagnetic radiation includes Terahertz antennas and infrared antennas which are distributed in pixel zones. The Terahertz antennas and the infrared antennas which are in one same pixel zone are thermally coupled, and those which are in different pixel zones are uncoupled. Such an element enables the capture of images which are formed with Terahertz radiation, by using an infrared image detector.

Spectral conversion element for electromagnetic radiation

According to one aspect, the invention relates to an element for quantum photodetection of an incident radiation in a spectral band centered around a central wavelength &#x3bb;, having a front surface intended for receiving said radiation, and including: a stack of layers of semiconductor material forming a PN or PIN junction and including at least one layer made of an absorbent semiconductor material having a cut-off wavelength &#x3bb;&#x3e;&#x3bb;, the stack of layers of semiconductor material forming a resonant optical cavity; and a structure for coupling the incident radiation with the optical cavity such as to form a resonance at the central wavelength &#x3bb;allowing the absorption of more than 80% in the layer of absorbent semiconductor material at said central wavelength, and an absence of resonance at the radiative wavelength &#x3bb;, wherein the radiative wavelength &#x3bb;is the wavelength for which, at operating temperature, the radiative recombination rate is the highest.

Quantum detection element with low noise and method for manufacturing such a photodetection element

According to one aspect, the invention relates to a device () for controlling the phase of an incident optical wavefront of wavelength comprised in a spectral band of given use, comprising a substrate () that is at least partially transparent in said spectral band and a set of strips () arranged substantially perpendicularly to the surface of the substrate, characterized in that: said set of strips comprises an alternation of juxtaposed strips respectively made of a metal (), of a first dielectric () and of at least one second dielectric () different from the first dielectric, such as to form juxtaposed metal/multi dielectric/metal (MmultiDM) structures (S) of subwavelength widths (w), each structure forming a cavity having one or more propagation modes&#x2014;the respective thicknesses of the strips made of the first dielectric and of the second dielectric(s) are adjusted in each of said MmultiDM structures to induce a local shift (&#x394;&#x3a6;) in the phase of the wavefront, the local phase shift being dependent on the effective index of the mode(s) able to propagate in said cavity.

Device for controlling the phase of an optical wavefront having juxtaposed metal-multidielectric-metal structures to induce a local shift

According to one aspect, the invention relates to a microbolometer array for thermal detection of light radiation in a given spectral band, comprising a supporting substrate and an array of microbolometers () of given dimensions, arranged in an array. Each of said microbolometers comprises a membrane () suspended above said supporting substrate, said membrane consisting of an element () for absorbing the incident radiation and a thermometric element () in thermal contact with the absorber, electrically insulated from said absorber element. The absorber element comprises at least one first metal/insulator/metal (MIM) structure comprising a multilayer of three superposed films of submicron-order thickness i.e. a first metallic film (), a dielectric film (), and a second metallic film (), said MIM structure being able to have a resonant absorption of said incident radiation at at least one wavelength in said spectral band. The area of the microbolometer pixel covered by said membrane () is less than or equal to half of the total area of the microbolometer pixel.

Microbolometer array with improved performance

According to one aspect, the invention relates a spectral band-pass filter, which is optimized for the transmission of an incident wave at at least a first given central wavelength &#x3bb;, and which includes: a metal grating having a thickness (t) greater than approximately &#x3bb;/50 and including at least a first set of substantially identical, parallel slots having a width (W) less than around &#x3bb;/10, and being spaced apart periodically or quasi-periodically according to a first period that is less than said first central wavelength, a layer of dielectric material having a thickness (h) and a given refractive index (n), which is coupled to the metal grating to form a waveguide for the waves diffracted by the grating, said first period of the grating being designed such that only orders 0 and &#xb1;1 of a wave having normal incidence and a wavelength &#x3bb;are diffracted in the layer of dielectric material, the assembly of the dielectric layer and grating being suspended, during use, in a fluid having a refractive index of close to 1.

Spectral band-pass filter having high selectivity and controlled polarization

The application relates to a method for analyzing the wave surface of a light beam from a source to the focus of a lens. The beam illuminates a sample on the analysis plane and having a defect. A diffraction grating of the plane is a conjugate of an analysis plane through a focal system. An image is formed in a plane at a distance from the grating plane and analyzed by processing means. The invention encodes this grating by a phase function resulting from the multiplication of two phase functions, a first exclusion function defining a meshing of useful zones transmitting the beam to be analyzed in the form of light pencil beams, and a second phase fundamental function which creates a phase opposition between two light pencil beams coming out of adjacent meshes of the exclusion grating.

Method, phase grating and device for analyzing a wave surface of a light beam

The method comprises positioning a diffraction grating with a two-dimensional meshing on the path of the beam to be analyzed and processing at least two interferograms of at least two different colors, each interferogram being obtained in a plane from two sub-beams with different diffraction orders. The invention can be used to analyze and correct divided wavefronts.

Wavefront analysis method involving multilateral interferometry with frequency difference

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Paris, France

Riad Haidar