EP2104871A1 - Device for sampling a plurality of parts of a light beam - Google Patents

Device for sampling a plurality of parts of a light beam

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Publication number
EP2104871A1
EP2104871A1 EP07858133A EP07858133A EP2104871A1 EP 2104871 A1 EP2104871 A1 EP 2104871A1 EP 07858133 A EP07858133 A EP 07858133A EP 07858133 A EP07858133 A EP 07858133A EP 2104871 A1 EP2104871 A1 EP 2104871A1
Authority
EP
European Patent Office
Prior art keywords
light beam
face
component
angle
sampling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP07858133A
Other languages
German (de)
French (fr)
Inventor
Eric Journot
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP2104871A1 publication Critical patent/EP2104871A1/en
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/14—Beam splitting or combining systems operating by reflection only
    • G02B27/145—Beam splitting or combining systems operating by reflection only having sequential partially reflecting surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/108—Beam splitting or combining systems for sampling a portion of a beam or combining a small beam in a larger one, e.g. wherein the area ratio or power ratio of the divided beams significantly differs from unity, without spectral selectivity
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/14—Beam splitting or combining systems operating by reflection only
    • G02B27/144—Beam splitting or combining systems operating by reflection only using partially transparent surfaces without spectral selectivity
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms

Definitions

  • the present invention relates to a device for sampling a plurality of parts of a light beam, in particular a laser beam.
  • This device comprises at least one optical component which is designed to generate two optical samples of a parallel ray light beam, without any parasitic image.
  • the invention is particularly applicable to the diagnosis of laser beams.
  • the above-mentioned component makes it possible to generate three diagnostic channels that are distinct, completely decoupled and without parasitic image.
  • the photometry of the channels can be managed in a conventional manner, by the type of semi-reflective treatment that is deposited on each side of the component.
  • a blade in English, flat 2 (FIG. 1) having two plane and parallel faces, or a prismatic plate 4 (FIG. 2), or a beam splitter cube (in English, beamsplitter cube) 6 (FIG. 3), or a diffractive component 8 (FIG. 4).
  • FIGS. 1 to 3 generate only one sampling channel 10 from an incident light beam 12, and the diffractive component 8 generates as many samples 14 as there are diffraction orders.
  • the blade with flat and parallel faces 2 generally generates several parasitic beams.
  • Figure 1 we see one of these, which is parallel to the beam 16 transmitted by the cube 2, and two other parasitic beams 18 which are parallel to the beam 10 reflected by this cube.
  • FIG. 2 shows that the parasitic beams 20 and 22 have directions which are respectively separated from that of the reflected beam 10 and that of the transmitted beam 24, but the separation is weak and the transmitted beam 24 is deflected, which complicates the mechanical integration of the analysis system (not shown) using the prismatic plate.
  • the beam splitter cube 6 solves the problem of parasitic imaging quite well. Indeed, we see in Figure 3 two parasitic beams 26 and 28 which are respectively parallel to the reflected beam 10 and the transmitted beam 30, and the maximum parasitic amplitude is typically one hundred times lower than that of the incident beam 12. But the cube 6 generates only a sample.
  • the diffractive component 8 generates, for its part, several samples 14 and perfectly solves the problem of parasitic imaging. However, it temporally alters a pulsed light beam and scatters a beam that is not perfectly monomode. It is then necessary to use two diffractive components to partially solve these problems of alteration and dispersion.
  • the object of the present invention is to overcome the above disadvantages by proposing a device which is capable of providing at least two samples devoid of parasitic images, from an incident light beam, and which allows the easy integration of a system. beam diagnostics using this device.
  • the present invention relates to a device for sampling a plurality of parts of a light beam, this device being characterized in that it comprises at least one optical component comprising a blade of material transparent to the light beam , this blade having first and second faces which are plane and parallel, and a third face which is flat and forms a dihedron with the first face, the angle of this dihedral being equal to ⁇ - ⁇ , with
  • n the refractive index of the material, so that by sending the light beam on the first face, at an angle of incidence equal to Arcsin (n.sin ( ⁇ )), recovering a first part taken and a second part removed and most of the light beam.
  • the third face is made reflective vis-à-vis the light beam.
  • the first and second faces can be processed so as to have reflection coefficients determined vis-à-vis the light beam.
  • the angle ⁇ may be equal to Arcsin (V2 / (2n)).
  • the device according to the invention may comprise at least two copies of said component, placed one after the other, so as to increase the number of parts removed.
  • the present invention also relates to a method of sampling a plurality of parts of a light beam, this method using the device object of the invention.
  • FIGS. 1 to 4 are schematic views of known beam picking devices and have already been described
  • FIG. 5 is a schematic top view of a particular embodiment; of the device which is the subject of the invention.
  • FIG. 6 is a schematic view of another device according to the invention.
  • the device according to the invention which is schematically represented in FIG. 5, comprises a single optical component 32.
  • This component is capable of producing two samples devoid of a parasitic image from an incident light beam 34 which is monochromatic and parallel, that is to say whose rays are parallel, such as for example a laser beam.
  • the component allows the easy integration of a diagnostic device comprising this component.
  • the component 32 is a prism that results from a flat-faced and parallel plate which has been truncated.
  • the prism 32 is made of a material that is transparent to the incident beam 34; and it has a first face 36 and a second face 38 which are flat and parallel to each other.
  • the prism has a third face 40 which forms a dihedron with the first face 34.
  • the faces 36, 38 and 40 are thus perpendicular to the plane of this figure 5.
  • the angle A of the dihedral is equal to ⁇ - ⁇ where ⁇ is the truncation angle of the blade, the truncated portion being delimited by dotted lines on FIG. 5. This angle ⁇ is such that:
  • n the refractive index of the material, at the wavelength of the beam 34.
  • a first portion 44 of the beam 34 is picked up by reflection on the face 36 but the bulk of the beam 34 leads to the refracted beam 46.
  • the latter emerges from the face 38 along a beam 48 which is parallel to the beam 34.
  • the latter is propagated towards the face 40 in a straight line which is perpendicular to this face 40, and is therefore reflected in part on it, following the same line, then emerges from the face 38 along a beam 52 which constitutes a second portion taken from the incident beam 34.
  • Each of the beams 48 and 52 forms an angle i. with a normal 54 to the face 38.
  • the major part 56 of the beam 50 emerges from the face 40, perpendicular to the latter, and can thus constitute a third sampling path. However, the existence of this part 56 would lead to a low intensity for the second part taken, constituted by the beam 52.
  • the face 40 is made reflective, for example by forming a metal layer 58 on this face, so as not to lose a signal on the sampling path 52.
  • the two samples formed by the beams 44 and 52 each carry between 2% and 8% of the incident energy, according to the polarization of the beam 34.
  • this incident beam 34 can perform a treatment of the faces 36 and 38 to adjust the value of the reflection coefficient of these faces, if necessary.
  • the two sampling channels 44 and 52 are perpendicular to the incident beam 34, which facilitates the mechanical integration of the other components (not shown) of the beam diagnostic system.
  • the angle ⁇ is equal to Arcsin (1 / (n S)).
  • the compact component 32 generates two samples 44 and 52 from the beam 34, without any parasitic image for the analysis system, which is very interesting for analyzing the beam 34. Moreover, this component is monobloc and very simple to manufacture. , and it can be serialized to multiply the number of channels.
  • Figure 6 shows two components 70 and 72 which are placed one after the other. These components are of the type of the component 32.
  • This beam 80 reaches the component 72 whose first face is facing the second face of the component 70 and parallel thereto.
  • the component 72 provides two samples 82 and 84.
  • the beam transmitted by the component 72 has the reference 85.
  • parasitic light beams 86, 88 and 90 which result from reflections of the light in the prism 32.
  • the beam 88 is directed towards the face 92 of the prism, face which connects the faces 36 and 38 as seen. This face 92 is unpolished to prevent specular reflection of the beam 88.
  • the single parasite return (beam 90) undergoes two reflections, and is therefore very weak; in addition, it returns to the source (not shown) of the beam 34, which does not disturb the measurement. If necessary, a slight modification of one of the angles i or ⁇ makes it possible to modify the direction of this parasitic return.
  • the component 32 laterally shifts the main beam: the beam 48 is shifted relative to the beam 34. But this can be corrected by a second component identical to the component 32 and mounted symmetrically. In this case, and repeating the notations of FIG. 6, the beam 85 emerges in the extension of the beams 74. It should also be noted that, like all the reflection sampling diagnostics, the component 34 can modify the state of polarization of a beam if the incident electromagnetic field is not TE or TM.
  • the device according to the invention can be used with any laser beam on which it is desired to make several samples.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

Abstract

The invention relates to a device for sampling a plurality of parts of a light beam, including at least one optical component (34) comprising a lamina which is made from a material that is transparent to the light beam and which has first and second flat, parallel faces (36, 38) and a third flat face (40) which forms a dihedral with the first face, the angle of said dihedral being equal to π-α, with 0 < α <_arcsin (1/n), wherein n is the refractive index of the material. In this way, when the light beam hits the first face at an angle of incidence equal to arcsin (n.sin(α)), a first sampled part (44) and a second sampled part (52) are recovered as well as the majority (48) of the light beam. The device is suitable for laser beam diagnostics.

Description

DISPOSITIF DE PRELEVEMENT D'UNE PLURALITE DE PARTIES D'UN FAISCEAU LUMINEUX DEVICE FOR COLLECTING A PLURALITY OF PARTS OF A BRIGHT BEAM
DESCRIPTION DOMAINE TECHNIQUEDESCRIPTION TECHNICAL FIELD
La présente invention concerne un dispositif de prélèvement d'une pluralité de parties d'un faisceau lumineux, en particulier d'un faisceau laser .The present invention relates to a device for sampling a plurality of parts of a light beam, in particular a laser beam.
Ce dispositif comprend au moins un composant optique qui est conçu pour engendrer deux prélèvements optiques d'un faisceau lumineux à rayons parallèles, sans aucune image parasite.This device comprises at least one optical component which is designed to generate two optical samples of a parallel ray light beam, without any parasitic image.
L'invention s'applique notamment au diagnostic des faisceaux lasers.The invention is particularly applicable to the diagnosis of laser beams.
Dans ce domaine, il est souvent nécessaire de disposer de plusieurs prélèvements distincts d'un faisceau pour caractériser complètement ce dernier.In this field, it is often necessary to have several separate samples of a beam to completely characterize it.
Indiquons dès à présent que le composant mentionné ci-dessus permet de générer trois voies de diagnostic qui sont distinctes, totalement découplées et sans image parasite. La photométrie des voies peut être gérée de manière classique, par le type de traitement semi-réfléchissant que l'on dépose sur chaque face du composant.Now let us indicate that the above-mentioned component makes it possible to generate three diagnostic channels that are distinct, completely decoupled and without parasitic image. The photometry of the channels can be managed in a conventional manner, by the type of semi-reflective treatment that is deposited on each side of the component.
ÉTAT DE LA TECHNIQUE ANTÉRIEURESTATE OF THE PRIOR ART
Pour prélever une ou plusieurs parties d'un faisceau lumineux, notamment d'un faisceau laser, il est connu d'utiliser une lame (en anglais, plate) 2 (figure 1) ayant deux faces planes et parallèles, ou une lame prismatique 4 (figure 2), ou un cube séparateur de faisceau (en anglais, beamsplitter cube) 6 (figure 3), ou un composant diffractif 8 (figure 4) .To collect one or more parts of a light beam, in particular a laser beam, it is known to use a blade (in English, flat) 2 (FIG. 1) having two plane and parallel faces, or a prismatic plate 4 (FIG. 2), or a beam splitter cube (in English, beamsplitter cube) 6 (FIG. 3), or a diffractive component 8 (FIG. 4).
Les composants représentés sur les figures 1 à 3 ne génèrent qu'une seule voie de prélèvement 10 à partir d'un faisceau lumineux incident 12, et le composant diffractif 8 génère autant de prélèvements 14 que d'ordres de diffraction.The components shown in FIGS. 1 to 3 generate only one sampling channel 10 from an incident light beam 12, and the diffractive component 8 generates as many samples 14 as there are diffraction orders.
En outre, en plus du prélèvement 10, la lame à faces planes et parallèles 2 engendre généralement plusieurs faisceaux parasites. Sur la figure 1, on voit l'un 15 de ces derniers, qui est parallèle au faisceau 16 transmis par le cube 2, et deux autres faisceaux parasites 18 qui sont parallèles au faisceau 10 réfléchi par ce cube.In addition, in addition to the sample 10, the blade with flat and parallel faces 2 generally generates several parasitic beams. In Figure 1, we see one of these, which is parallel to the beam 16 transmitted by the cube 2, and two other parasitic beams 18 which are parallel to the beam 10 reflected by this cube.
L'amplitude du plus important des faisceaux parasites vaut typiquement 10% du faisceau incident 12, ce qui peut s'avérer problématique avec un faisceau cohérent, à cause des interférences qui en résultent. La lame prismatique 4 résout partiellement ce problème : on voit sur la figure 2 que les faisceaux parasites 20 et 22 ont des directions qui sont respectivement séparées de celle du faisceau réfléchi 10 et de celle du faisceau transmis 24, mais la séparation est faible et le faisceau transmis 24 est dévié, ce qui complique l'intégration mécanique du système d' analyse (non représenté) utilisant la lame prismatique .The amplitude of the largest of the parasitic beams is typically 10% of the incident beam 12, which can be problematic with a coherent beam, because of interference resulting therefrom. The prismatic plate 4 partially solves this problem: FIG. 2 shows that the parasitic beams 20 and 22 have directions which are respectively separated from that of the reflected beam 10 and that of the transmitted beam 24, but the separation is weak and the transmitted beam 24 is deflected, which complicates the mechanical integration of the analysis system (not shown) using the prismatic plate.
Le cube séparateur de faisceau 6 résout assez bien le problème de l'imagerie parasite. En effet, on voit sur la figure 3 deux faisceaux parasites 26 et 28 qui sont respectivement parallèles au faisceau réfléchi 10 et au faisceau transmis 30, et l'amplitude parasite maximale est typiquement cent fois plus faible que celle du faisceau incident 12. Mais le cube 6 ne génère qu'un prélèvement.The beam splitter cube 6 solves the problem of parasitic imaging quite well. Indeed, we see in Figure 3 two parasitic beams 26 and 28 which are respectively parallel to the reflected beam 10 and the transmitted beam 30, and the maximum parasitic amplitude is typically one hundred times lower than that of the incident beam 12. But the cube 6 generates only a sample.
Le composant diffractif 8 génère, quant à lui, plusieurs prélèvements 14 et résout parfaitement le problème de l'imagerie parasite. Cependant, il altère temporellement un faisceau lumineux impulsionnel et disperse un faisceau qui n'est pas parfaitement monomode. Il faut alors utiliser deux composants diffractifs pour résoudre partiellement ces problèmes d'altération et de dispersion.The diffractive component 8 generates, for its part, several samples 14 and perfectly solves the problem of parasitic imaging. However, it temporally alters a pulsed light beam and scatters a beam that is not perfectly monomode. It is then necessary to use two diffractive components to partially solve these problems of alteration and dispersion.
EXPOSÉ DE L'INVENTIONSTATEMENT OF THE INVENTION
La présente invention a pour but de remédier aux inconvénients précédents en proposant un dispositif qui est apte à fournir au moins deux prélèvements dénués d'images parasites, à partir d'un faisceau lumineux incident, et qui permet l'intégration aisée d'un système de diagnostic de faisceau utilisant ce dispositif.The object of the present invention is to overcome the above disadvantages by proposing a device which is capable of providing at least two samples devoid of parasitic images, from an incident light beam, and which allows the easy integration of a system. beam diagnostics using this device.
De façon précise, la présente invention a pour objet un dispositif de prélèvement d'une pluralité de parties d'un faisceau lumineux, ce dispositif étant caractérisé en ce qu' il comprend au moins un composant optique comprenant une lame en matériau transparent au faisceau lumineux, cette lame ayant des première et deuxième faces qui sont planes et parallèles, et une troisième face qui est plane et forme un dièdre avec la première face, l'angle de ce dièdre étant égal à π-α, avecSpecifically, the present invention relates to a device for sampling a plurality of parts of a light beam, this device being characterized in that it comprises at least one optical component comprising a blade of material transparent to the light beam , this blade having first and second faces which are plane and parallel, and a third face which is flat and forms a dihedron with the first face, the angle of this dihedral being equal to π-α, with
0 < α < Arcsin (1/n) où n est l'indice de réfraction du matériau, de sorte qu'en envoyant le faisceau lumineux sur la première face, sous un angle d'incidence égal à Arcsin (n.sin(α) ) , on récupère une première partie prélevée et une deuxième partie prélevée ainsi que la majeure partie du faisceau lumineux .0 <α <Arcsin (1 / n) where n is the refractive index of the material, so that by sending the light beam on the first face, at an angle of incidence equal to Arcsin (n.sin (α )), recovering a first part taken and a second part removed and most of the light beam.
De préférence, la troisième face est rendue réfléchissante vis-à-vis du faisceau lumineux.Preferably, the third face is made reflective vis-à-vis the light beam.
Les première et deuxième faces peuvent être traitées de manière à avoir des coefficients de réflexion déterminés vis-à-vis du faisceau lumineux.The first and second faces can be processed so as to have reflection coefficients determined vis-à-vis the light beam.
L'angle α peut être égal à Arcsin (V2 / (2n) ). Le dispositif objet de l'invention peut comprendre au moins deux exemplaires dudit composant, placés l'un à la suite de l'autre, de manière à augmenter le nombre de parties prélevées.The angle α may be equal to Arcsin (V2 / (2n)). The device according to the invention may comprise at least two copies of said component, placed one after the other, so as to increase the number of parts removed.
La présente invention concerne aussi un procédé de prélèvement d'une pluralité de parties d'un faisceau lumineux, ce procédé utilisant le dispositif objet de l'invention.The present invention also relates to a method of sampling a plurality of parts of a light beam, this method using the device object of the invention.
BRÈVE DESCRIPTION DES DESSINSBRIEF DESCRIPTION OF THE DRAWINGS
La présente invention sera mieux comprise à la lecture de la description d'exemples de réalisation donnés ci-après, à titre purement indicatif et nullement limitatif, en faisant référence aux dessins annexés sur lesquels : les figures 1 à 4 sont des vues schématiques de dispositifs connus de prélèvement de faisceau et ont déjà été décrites, la figure 5 est une vue de dessus schématique d'un mode de réalisation particulier du dispositif objet de l'invention, etThe present invention will be better understood on reading the description of exemplary embodiments given below, for information only and in no way limiting, with reference to the accompanying drawings, in which: FIGS. 1 to 4 are schematic views of known beam picking devices and have already been described; FIG. 5 is a schematic top view of a particular embodiment; of the device which is the subject of the invention, and
- la figure 6 est une vue schématique d'un autre dispositif conforme à l'invention.- Figure 6 is a schematic view of another device according to the invention.
EXPOSÉ DÉTAILLÉ DE MODES DE RÉALISATION PARTICULIERSDETAILED PRESENTATION OF PARTICULAR EMBODIMENTS
Le dispositif conforme à l'invention, qui est schématiquement représenté sur la figure 5, comprend un seul composant optique 32.The device according to the invention, which is schematically represented in FIG. 5, comprises a single optical component 32.
Ce composant est apte à réaliser deux prélèvements dénués d'image parasite à partir d'un faisceau lumineux incident 34 qui est monochromatique et parallèle, c'est-à-dire dont les rayons sont parallèles, comme par exemple un faisceau laser. En outre, le composant permet l'intégration aisée d'un dispositif de diagnostic comportant ce composant.This component is capable of producing two samples devoid of a parasitic image from an incident light beam 34 which is monochromatic and parallel, that is to say whose rays are parallel, such as for example a laser beam. In addition, the component allows the easy integration of a diagnostic device comprising this component.
Le composant 32 est un prisme qui résulte d'une lame à faces planes et parallèles dont on a tronqué une partie.The component 32 is a prism that results from a flat-faced and parallel plate which has been truncated.
Plus précisément, le prisme 32 est fait d'un matériau qui est transparent au faisceau incident 34 ; et il comporte une première face 36 et une deuxième face 38 qui sont planes et parallèles l'une à l'autre. En outre, le prisme comporte une troisième face 40 qui forme un dièdre avec la première face 34. On voit la trace de ce dièdre ainsi que l'arête I de ce dernier sur la figure 5 qui est une vue de dessus du composant. Les faces 36, 38 et 40 sont ainsi perpendiculaires au plan de cette figure 5. L'angle A du dièdre est égal à π-α où α est l'angle de troncature de la lame, la partie tronquée étant délimitée par des pointillés sur la figure 5. Cet angle α est tel que :More specifically, the prism 32 is made of a material that is transparent to the incident beam 34; and it has a first face 36 and a second face 38 which are flat and parallel to each other. In addition, the prism has a third face 40 which forms a dihedron with the first face 34. We see the trace of this dihedral and the edge I of the latter in Figure 5 which is a top view of the component. The faces 36, 38 and 40 are thus perpendicular to the plane of this figure 5. The angle A of the dihedral is equal to π-α where α is the truncation angle of the blade, the truncated portion being delimited by dotted lines on FIG. 5. This angle α is such that:
0 < α < Arcsin (1/n) où n représente l'indice de réfraction du matériau, à la longueur d'onde du faisceau 34.0 <α <Arcsin (1 / n) where n represents the refractive index of the material, at the wavelength of the beam 34.
On précise que le composant 32 est utilisé en envoyant le faisceau 34 sur la première face 36 de façon que ce faisceau forme, avec une normale 42 à cette face, un angle d'incidence i. (0 < i £ π/2) tel que : sin(i) = n.sin(α) ou i = Arcsin (n . sin (α) ).It is specified that the component 32 is used by sending the beam 34 on the first face 36 so that this beam forms, with a normal 42 to this face, an angle of incidence i. (0 <i £ π / 2) such that: sin (i) = n.sin (α) or i = Arcsin (sin (α)).
Comme on le voit sur la figure 5, une première partie 44 du faisceau 34 est prélevée par réflexion sur la face 36 mais l'essentiel du faisceau 34 conduit au faisceau réfracté 46. Ce dernier émerge de la face 38 suivant un faisceau 48 qui est parallèle au faisceau 34.As can be seen in FIG. 5, a first portion 44 of the beam 34 is picked up by reflection on the face 36 but the bulk of the beam 34 leads to the refracted beam 46. The latter emerges from the face 38 along a beam 48 which is parallel to the beam 34.
Le faisceau réfracté 46, qui forme l'angle α avec la normale 42 (d'après la loi de Snell- Descartes, l'angle de réfraction est tel que sin(i) = n.sin(α) ) , se réfléchit également en partie sur la deuxième face 38 pour donner un faisceau réfléchi 50. Ce dernier se propage vers la face 40 suivant une ligne droite qui est perpendiculaire à cette face 40, et se réfléchit donc en partie sur celle-ci suivant la même ligne, puis émerge de la face 38 suivant un faisceau 52 qui constitue une deuxième partie prélevée du faisceau incident 34. Chacun des faisceaux 48 et 52 forme un angle i. avec une normale 54 à la face 38. Précisons en outre que la majeure partie 56 du faisceau 50 émerge de la face 40, perpendiculairement à cette dernière, et peut ainsi constituer une troisième voie de prélèvement. Cependant, l'existence de cette partie 56 conduirait à une faible intensité pour la deuxième partie prélevée, constituée par le faisceau 52.The refracted beam 46, which forms the angle α with the normal 42 (according to the Snell-Descartes law, the angle of refraction is such that sin (i) = n.sin (α)), is also reflected in part on the second face 38 to give a reflected beam 50. The latter is propagated towards the face 40 in a straight line which is perpendicular to this face 40, and is therefore reflected in part on it, following the same line, then emerges from the face 38 along a beam 52 which constitutes a second portion taken from the incident beam 34. Each of the beams 48 and 52 forms an angle i. with a normal 54 to the face 38. Note further that the major part 56 of the beam 50 emerges from the face 40, perpendicular to the latter, and can thus constitute a third sampling path. However, the existence of this part 56 would lead to a low intensity for the second part taken, constituted by the beam 52.
C'est pourquoi la face 40 est rendue réflectrice, par exemple en formant une couche métallique 58 sur cette face, pour ne pas perdre de signal sur la voie de prélèvement 52.This is why the face 40 is made reflective, for example by forming a metal layer 58 on this face, so as not to lose a signal on the sampling path 52.
Précisons en outre que si l'on ne traite pas les faces d'entrée et de sortie 36 et 38 du composant, les deux prélèvements constitués par les faisceaux 44 et 52 transportent chacun entre 2% et 8% de l'énergie incidente, selon la polarisation du faisceau 34.Note further that if the input and output faces 36 and 38 of the component are not treated, the two samples formed by the beams 44 and 52 each carry between 2% and 8% of the incident energy, according to the polarization of the beam 34.
Quelles que soient les caractéristiques de polarisation de ce faisceau incident 34, on peut réaliser un traitement des faces 36 et 38 pour adapter la valeur du coefficient de réflexion de ces faces, si cela est nécessaire.Whatever the polarization characteristics of this incident beam 34, one can perform a treatment of the faces 36 and 38 to adjust the value of the reflection coefficient of these faces, if necessary.
Dans le cas particulier où i vaut 45° (π/4 radians) les deux voies de prélèvement 44 et 52 sont perpendiculaires au faisceau incident 34, ce qui facilite l'intégration mécanique des autres composants (non représentés) du système de diagnostic de faisceau. Dans ce cas, l'angle α est égal à Arcsin (1/ (n S ) ) .In the particular case where i is equal to 45 ° (π / 4 radians), the two sampling channels 44 and 52 are perpendicular to the incident beam 34, which facilitates the mechanical integration of the other components (not shown) of the beam diagnostic system. . In this case, the angle α is equal to Arcsin (1 / (n S)).
Remarquons aussi un cas particulier peu intéressant : lorsque α est égal à la valeur-limite Arcsin (1/n), i. est égal à π/2.Note also a particular interesting case: when α is equal to the limit value Arcsin (1 / n), i. is equal to π / 2.
Le composant compact 32 génère deux prélèvements 44 et 52 à partir du faisceau 34, sans aucune image parasite pour le système d'analyse, ce qui est très intéressant pour analyser le faisceau 34. De plus, ce composant est monobloc et très simple à fabriquer, et il peut être mis en série pour multiplier le nombre de voies.The compact component 32 generates two samples 44 and 52 from the beam 34, without any parasitic image for the analysis system, which is very interesting for analyzing the beam 34. Moreover, this component is monobloc and very simple to manufacture. , and it can be serialized to multiply the number of channels.
La figure 6 montre deux composants 70 et 72 qui sont placés l'un à la suite de l'autre. Ces composants sont du genre du composant 32. On voit un faisceau laser incident 74 qui arrive sur la première face du composant 70 et les deux prélèvements 76 et 78 correspondant à ce composant 70. Le faisceau transmis a la référence 80. Ce faisceau 80 atteint le composant 72 dont la première face est en regard de la deuxième face du composant 70 et parallèle à celle-ci. Le composant 72 fournit deux prélèvements 82 et 84. Le faisceau transmis par le composant 72 a la référence 85. En revenant à la figure 5, on voit des faisceaux lumineux parasites 86, 88 et 90 qui résultent de réflexions de la lumière dans le prisme 32.Figure 6 shows two components 70 and 72 which are placed one after the other. These components are of the type of the component 32. We see an incident laser beam 74 which arrives on the first face of the component 70 and the two samples 76 and 78 corresponding to this component 70. The beam transmitted to the reference 80. This beam 80 reaches the component 72 whose first face is facing the second face of the component 70 and parallel thereto. The component 72 provides two samples 82 and 84. The beam transmitted by the component 72 has the reference 85. Returning to Figure 5, we see parasitic light beams 86, 88 and 90 which result from reflections of the light in the prism 32.
Le faisceau 88 se dirige vers la face 92 du prisme, face qui relie les faces 36 et 38 comme on le voit. Cette face 92 est non polie pour empêcher la réflexion spéculaire du faisceau 88. L'unique retour parasite (faisceau 90) subit deux réflexions, et il est donc très faible ; en outre, il retourne vers la source (non représentée) du faisceau 34, ce qui ne perturbe pas la mesure. Si nécessaire, une légère modification de l'un des angles i ou α permet de modifier la direction de ce retour parasite.The beam 88 is directed towards the face 92 of the prism, face which connects the faces 36 and 38 as seen. This face 92 is unpolished to prevent specular reflection of the beam 88. The single parasite return (beam 90) undergoes two reflections, and is therefore very weak; in addition, it returns to the source (not shown) of the beam 34, which does not disturb the measurement. If necessary, a slight modification of one of the angles i or α makes it possible to modify the direction of this parasitic return.
Remarquons que le composant 32 décale latéralement le faisceau principal : le faisceau 48 est décalé par rapport au faisceau 34. Mais cela peut être corrigé par un second composant identique au composant 32 et monté symétriquement. Dans ce cas, et en reprenant les notations de la figure 6, le faisceau 85 émerge dans le prolongement du faisceaux 74. Remarquons aussi que, comme tous les diagnostics de prélèvement à réflexion, le composant 34 peut modifier l'état de polarisation d'un faisceau si le champ électromagnétique incident n'est pas de type TE ou TM. Le dispositif objet de l'invention peut être utilisé avec n' importe quel faisceau laser sur lequel on souhaite faire plusieurs prélèvements. Note that the component 32 laterally shifts the main beam: the beam 48 is shifted relative to the beam 34. But this can be corrected by a second component identical to the component 32 and mounted symmetrically. In this case, and repeating the notations of FIG. 6, the beam 85 emerges in the extension of the beams 74. It should also be noted that, like all the reflection sampling diagnostics, the component 34 can modify the state of polarization of a beam if the incident electromagnetic field is not TE or TM. The device according to the invention can be used with any laser beam on which it is desired to make several samples.

Claims

REVENDICATIONS
1. Dispositif de prélèvement d'une pluralité de parties d'un faisceau lumineux (34), ce dispositif étant caractérisé en ce qu' il comprend au moins un composant optique (32, 70, 72) comprenant une lame en matériau transparent au faisceau lumineux, cette lame ayant des première et deuxième faces (36, 38) qui sont planes et parallèles, et une troisième face (40) qui est plane et forme un dièdre avec la première face, l'angle de ce dièdre étant égal à π-α, avec1. Device for sampling a plurality of parts of a light beam (34), this device being characterized in that it comprises at least one optical component (32, 70, 72) comprising a blade of material transparent to the beam bright, this blade having first and second faces (36, 38) which are flat and parallel, and a third face (40) which is plane and forms a dihedron with the first face, the angle of this dihedron being equal to π -α, with
0 < α < Arcsin (1/n) où n est l'indice de réfraction du matériau, de sorte qu'en envoyant le faisceau lumineux sur la première face, sous un angle d'incidence égal à Arcsin (n.sin(α) ) , on récupère une première partie prélevée (44) et une deuxième partie prélevée (52) ainsi que la majeure partie (48) du faisceau lumineux.0 <α <Arcsin (1 / n) where n is the refractive index of the material, so that by sending the light beam on the first face, at an angle of incidence equal to Arcsin (n.sin (α )), a first sampled portion (44) and a second sampled portion (52) and the major portion (48) of the light beam are recovered.
2. Dispositif selon la revendication 1, dans lequel la troisième face (40) est rendue réfléchissante vis-à-vis du faisceau lumineux (34) .2. Device according to claim 1, wherein the third face (40) is made reflective vis-à-vis the light beam (34).
3. Dispositif selon l'une quelconque des revendications 1 et 2, dans lequel les première et deuxième faces (36, 38) sont traitées de manière à avoir des coefficients de réflexion déterminés vis-à- vis du faisceau lumineux (34) . 3. Device according to any one of claims 1 and 2, wherein the first and second faces (36, 38) are treated so as to have determined reflection coefficients vis-à-vis the light beam (34).
4. Dispositif selon l'une quelconque des revendications 1 à 3, dans lequel l'angle α est égal à Arcsin(V2 / (2n) ) .4. Device according to any one of claims 1 to 3, wherein the angle α is equal to Arcsin (V2 / (2n)).
5. Dispositif selon l'une quelconque des revendications 1 à 4, comprenant au moins deux exemplaires (70, 72) dudit composant, qui sont placés l'un à la suite de l'autre, de manière à augmenter le nombre de parties prélevées.5. Device according to any one of claims 1 to 4, comprising at least two copies (70, 72) of said component, which are placed one after the other, so as to increase the number of parts removed .
6. Procédé de prélèvement d'une pluralité de parties d'un faisceau lumineux (34), ce procédé utilisant le dispositif selon l'une quelconque des revendications 1 à 5. 6. A method of sampling a plurality of portions of a light beam (34), said method using the device according to any one of claims 1 to 5.
EP07858133A 2006-12-28 2007-12-24 Device for sampling a plurality of parts of a light beam Ceased EP2104871A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0656021A FR2910979B1 (en) 2006-12-28 2006-12-28 DEVICE FOR COLLECTING A PLURALITY OF PARTS OF A BRIGHT BEAM
PCT/EP2007/064535 WO2008080915A1 (en) 2006-12-28 2007-12-24 Device for sampling a plurality of parts of a light beam

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EP2104871A1 true EP2104871A1 (en) 2009-09-30

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ES2803075T3 (en) * 2014-05-29 2021-01-22 Bae Systems Plc A beam splitter and a frequency monitoring system
EP2950066A1 (en) * 2014-05-29 2015-12-02 BAE Systems PLC A Beamsplitter and Frequency Monitoring System
GB201409504D0 (en) * 2014-05-29 2014-07-16 Bae Systems Plc A beamsplitter and frequency monitoring system

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GB1184080A (en) 1967-09-19 1970-03-11 Optomechanisms Inc Single Optical Block Interferometer Means
US4759616A (en) * 1985-08-26 1988-07-26 Eastman Kodak Company Method and apparatus for anamorphically shaping and deflecting electromagnetic beams
DE4128469C2 (en) * 1991-08-28 1997-12-18 Hell Ag Linotype Beam splitter device
FR2733601B1 (en) * 1995-04-28 1997-06-27 Thomson Multimedia Sa POLARIZATION SEPARATION DEVICE AND APPLICATION TO A LIQUID CRYSTAL SCREEN ILLUMINATION SYSTEM
GB2304923A (en) * 1995-09-02 1997-03-26 Renishaw Plc Detector system for an interferometric measuring apparatus
TW582551U (en) * 2002-10-04 2004-04-01 Quarton Inc Multi-light beam laser light splitting lens
JP2005106879A (en) * 2003-09-29 2005-04-21 Minolta Co Ltd Method for manufacturing prism having multilayer film on surface
US7006298B2 (en) * 2004-04-05 2006-02-28 Trimble Navigation Limited Optical system providing four beams from a single source
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WO2008080915A1 (en) 2008-07-10
FR2910979B1 (en) 2009-04-03
FR2910979A1 (en) 2008-07-04
US8120863B2 (en) 2012-02-21
US20100321807A1 (en) 2010-12-23

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