Abstract: An optic fiber wavelength multiplexer-demultiplexer comprising a dispersing system (1) exhibiting a dispersing plane, at least one input fiber (2) with an output face, at least one output fiber (3) with an input face, and a device (4) for optic matching of the output face of the input fiber with the input face of the output fiber. The dispersing system and the matching means form an optic system with multiple transversal focuses (6) in the dispersing plane.

Abstract: A multiplexer, demultiplexer or router includes an input fiber and an output fiber, each fiber having a core and a sheath. At least one of the input fiber and the output fiber includes an intermediate ring having an optic index greater than the optic indexes of immediately adjacent portions of the core and the optic sheath and less than the optic index of the center axis of the core.

Abstract: An optic dispersing system, designed for usage in a wavelength field of a beam, includes a network or grating (1) carried by a support (2) with a dilatation coefficient .epsilon.. The system suggested is temperature-stabilized. To do so, it contains a front blade or optical element (3), or refractive index n.sub.1, transparent in the concerned wavelength field. .epsilon.+1/n.sub.1 .times.dn.sub.1 /dt is small and, advantageously, dn.sub.1 /dt and .epsilon. are of opposite signs. This device enables the manufacture of a multiplexer-demultiplexer or a fiber optic wavelength router, which is temperature-stabilized.

Abstract: A system for introducing a liquid sample (1) for analytical atomic spectrometry includes a nebulizer (20) and separator (27) at the exit (23) of the nebulizer. The system also includes at least one drain (30) fitted with evacuator (16, 17) for evacuating residual liquid (8) in a constricted and controlled flow, and reagent supplier (12, 13) for supplying drain (30) with a reagent (2) to generate hydride.

Abstract: A photodetection system that analyzes a luminous flux (15) received on a line (10). The photodetection system includes an opaque mask (4) provided with at least one aperture (6), placed in the vicinity of the line, driver (7) designed to rotate the mask, detector (8, 9) of an angular position of reference of the mask, a field lens (12) concentrating the luminous flux (16) crossing the line onto a photodetector (1), and a processing unit (3) connected to the photodetector, for analyzing the luminous flux to yield values for several points on the line.

Abstract: A luminous flux measuring device has a gain slaving circuit (10, 9), that receives an electrical output signal (m) produced by a photoreceiver (1) and includes a gain control circuit (9) and a comparator (10). The gain slaving circuit is connected to an A/D converter and a computer to record and evaluate the signal (m) and has a slave memory containing characteristic values (a,b) of a continuous function (f). The gain slaving circuit produces a slave signal (HT) according to the flux received (.PHI.) by the photoreceiver which signal is sent to the gain control circuit so that G=f(m).

Abstract: This invention relates to a method and a device for the ellipsometric measurement of physical parameters representative of a sample.The measured values I.sub.om, I.sub.sm and I.sub.cm are calculated (51, 52) from the signal (50) which represents the measured intensity I(t).In a first step (55, 57), initial theoretical values I.sub.st /I.sub.ot and I.sub.ct /I.sub.ot are produced from initial estimations (56) of the physical parameters. In a second step (58, 59) subsequent estimations (59) of physical parameters are determined from which subsequent theoretical values I.sub.st /I.sub.ot and I.sub.ct /I.sub.ot are deduced (55, 57). The second step is reiterated to an Nth estimation (59) of the physical parameters, so as to minimise the difference between the theoretical values and those measured.The physical parameters are evaluated (54) in the course of the Nth estimation.

Abstract: A diffraction grating, comprises a plurality of grooves formed by a plurality of first facets having a first set of propagative optical characteristics. All facets are generally positioned with a first orientation. A plurality of second facets have a second set of propagative optical characteristics and are generally positioned with a second orientation. The first facets are oriented to diffract light incident on them. The second facets are oriented and have propagative characteristics which prevent perturbation of the diffracted light.

Abstract: A double spectrograph system is disclosed. An entrance slit receives and passes light to be analyzed. A first focusing diffraction grating receives that light. A second focusing diffraction grating receives light reflected by the first focusing diffraction grating. The first and second focusing diffraction gratings both have the characteristic of forming planar substantially anastigmatic spectra. Mounting means keeps the first and second gratings at positions symmetrical about an imaginary plane and with their respective focal planes substantially coincident with each other and the imaginary plane. An exit slit receives the light after it has been reflected by the first grating to the second grating and from the second grating to the exit slit.

Abstract: The apparatus for local chemical analyses at the surface of solid materials by spectroscopy of X photoelectrons comprising an ultravacuum analysis chamber 1 wherein is housed the sample to be analyzed 2 which is connected to a manipulator 3 located outside said chamber 1, an analyzer 4 in the vicinity of the sample and an electron source 5 emitting an electron beam 10 is characterized in that it comprises between the electron beam 10 and the sample 2 which is a bulky solid material, a microsource of X photons 6 placed as close as possible to said bulky sample 2.

Abstract: A method of making a corrected plane holographic grating within one band of wavelengths, intended for use in a diffraction apparatus in which light emitted by an entry source (1) is collimated by a spherical mirror (2) to the grating (4), which reflects parallel pencils to another spherical mirror (7), a focusing mirror, is disclosed. An auxiliary holographic grating (25) is created by the interference on a spherical surface (15) of a parallel pencil of light produced by the spherical mirror (7) subsequent to reflection onto a plane mirror (12) and of a divergent pencil deriving from the center of the surface (15). The auxiliary grating, corrected by the interference on a plane surface (22) of a parallel pencil produced by the spherical mirror (2) and of another parallel pencil produced by the auxiliary grating (25) illuminated from the center of the spherical surface, is then recorded.

Abstract: Multiplexer-demultiplexer including:(a) a fiber-carrying element in which the entrance and exit fibers are embedded, with their ends in flush alignment in a plane surface of contact with the following element,(b) an element carrying the wavelength separation system, with a plane surface of contact with the fiber-carrying element and an opposite plane face of contact with the following element,(c) an intermediate element of the same index n as the element carrying the wavelength separation system, with a plane face of contact with the element carrying the wavelength separation system, and a spherical face of contact with the following element,(d) a mirror element with a spherical face of contact with the intermediate element and an opposite spherical face treated to form a concave spherical mirror towards the intermediate element.

Abstract: Multiplexer-demultiplexer device for wavelengths in an optical transmission fiber (6) for introducing therein a wavelength from an emitter (18) and for extracting wavelengths therefrom towards receivers (19), comprising several spherical mirrors (13-14) at least one of which (3) is a selective mirror with dielectric layers, selected to segregate by transmission or reflection a band containing only one of the wavelengths transmitted, or to be transmitted, by the fiber (6). The invention applies to telecommunications employing optical fibers.

Abstract: A multiplexer-demultiplexer for different wavelengths carried by optical fibers (10) the ends of which are disposed in the immediate vicinity of the focus of a concave mirror (18) associated with a plane diffraction grating (15) is disclosed.The multiplexer-demultiplexer consists of four elements that are adhesively attached to one another, namely, a fiber-carrying element (1); a grating-carrying element (15); an intermediary element (3) of the same index as the element (2); and a mirror element (4) having an index of refraction different from that of element (3) and selected to compensate for longitudinal spherical aberration of the mirror (18) for at least one of the wavelengths being utilized.

Abstract: Selector for separating at least two wavelength bands from a complex light introduced into the apparatus through the end of an optical fiber (12) arranged in the immediate vicinity of the focal point of a concave mirror (5) producing a parallel beam directed towards a plane reflecting device, the return beam being focused towards an output optical fiber. It comprises at least one plane multidielectric layer (8) interposed between the concave mirror (5) and the plane reflecting device (10) and forming, with the vertex axis (6) of the concave mirror, an angle which is slightly different from that of the plane reflecting device, each multidielectric layer having a discontinuity in the vicinity of the vertex axis of the concave mirror.

Abstract: Spectrometry device capable of splitting up, for analysis, polychromatic light, thus yielding a spectrum which extends into the ultraviolet, visible and near infra-red ranges. The device makes it possible to analyze the polychromatic light coming from an excitation source and comprises a polychromator provided with a concave grating, which receives the said polychromatic light through an inlet slit in order to diffract it into monochromatic bundles of the ultraviolet region, directed onto outlet slits that are associated with measuring detectors, the slits and grating being positioned on the Rowland circle, wherein, essentially, the order O bundle, which is symmetrical to the incident bundle, relative to the perpendicular on the grating (23), is taken up by a second optical device which disperses the said bundle into monochromatic bundles of the visible or near infra-red regions, at least one outlet slit (8) selecting one monochromatic bundle, measured by a measuring detector (28).

Abstract: Coupling-extracting device for an optical signal between an upstream fibre and a downstream fibre, with continuity of the signal from upstream to downstream and at the same time extraction of part of the signal to a detector and re-injection from an emitter.It comprises an entirely reflecting system placed only in the central part of the beam between the upstream fibre and downstream fibre. The same system is used to divert towards the downstream fibre the light coming from the emitter and to prevent the direct passage of light from the emitter to the detector.

Abstract: Method of concentrating a low-concentration element in a solution and removing other, high-concentration elements, using an ion exchange resin specific to the element to be concentrated.The resin is disposed in a mini-column less than 3 mm in diameter into which the solution is made to pass, the elution of the element from the resin is carried out by using a very small volume of elution liquid.The invention applies to quantitative analysis by emission spectrum in an inductive plasma, and in this case the whole of the small volume of elution liquid, previously nebulized, is simultaneously supplied to the plasma.

Abstract: High frequency inductive generator for the inductive coil of a plasma generator constituted by a head for inflow of gas into an inductive coil. The high frequency generator has a quarter wave anode resonant line oscillator circuit and a coupling circuit connected to the inductive coil. The quarter wave anode circuit is controlled from a single oscillator tube. One of the lines is connected to the anode of the tube, while the other is coupled exteriorly by capacitive coupling.The invention is used for analysis by emission spectrometry.

Abstract: In a dye laser comprising a cavity, one end of which is closed by an angular dispersion system, and which is provided with a separator for extracting the laser beam from the cavity, the separator is arranged so that the dispersive system and the system for application of the laser beam are on the same side relative to the separating face of the separator. An aperture isolates the reference wavelength from the extracted beam.Such a laser can have very good monochromaticity and is useful wherever there is a need for high spectral purity, in particular in Raman spectrometry.