FR2719114A1 - Global spectral image analysing system for emission type optical and Raman diffusion or fluorescence spectrometer - Google Patents

Abstract

The system includes a primary monochromatic beam (6), a radiating source (4), a sample to be analysed (8), an illuminating means (12) designed so that the primary radiation (16) globally illuminates a chosen zone of the sample to be analysed. The system has an optical filtering unit (22,28) to receive the diffused secondary rays emitted by the sample and to produce a spectral image dispersed with this secondary radiation, and limited to a chosen spectral band. The illumination system (12) includes a fibre optic (100) having input and output sections (102,104). An optical unit (106) directs the primary rays into the input section (102) of the optic fibre. An optical system (14,110) optically combines the output section (104) of fibre optic and the zone of the sample to be analysed. A mixer unit (120,130,160) mixes the primary radiation introduced into the fibre optic so as to uniformly illuminate the zone of the sample to be analysed and to balance granularity of the primary radiation to the level of the zone.

Description

Spectral analysis device with global imaging The present invention

relates to an analysis device

spectral with global imagery.

  It finds general application in spectral analysis

  (micro) samples and in particular in the spectromet-

  optical sorting of emission, RAMAN or fluorescent type

  this. Spectral analysis devices with global imagery are already known which include: - a source suitable for generating primary monochromatic radiation, - a sample to be analyzed, - lighting means suitable for globally illuminating by said primary radiation a chosen area of the sample to be analyzed, and - optical filtering means suitable for receiving the secondary radiation scattered and / or emitted by the sample thus lit and characteristic of it, and for delivering a dispersed spectral image of this secondary radiation

  limited to at least one chosen spectral band.

  30. Global imagery is distinguished from point imagery by the fact that, in the first case, primary radiation,

  defocused, globally illuminates a selected area of the

  tillon, while, in the second case, the radiation

  primary, focused, illuminates a selected point of the sample.

  In point imaging, a linear scan of the ray-

  primary element allows, if necessary, to illuminate the exchange

line by line.

  In micro-analysis, the sample is a micro-sample placed on a stage of an optical microscope. The objective of the microscope is used, at full aperture, both to globally illuminate the entire field of the microscope and to collect the resulting secondary radiation. The sensitivity and quality of the images obtained by analysis

  spectral partly depend on the uniformity of the light-

  sample and light losses in the path

primary.

  A known solution for standardizing the illumination consists in using an annular objective coupled to an optical arrangement with two mirrors which rotate around the axis of the laser beam. Such a solution is not entirely satisfactory since it is difficult to implement

  implemented at the setting level. In addition, the intensity of the light-

  rement has radial variations and the aperture

digital is limited.

  Another known solution consists in defocusing the ray-

  primary, usually from a laser source. Nevertheless, the average illumination of the microscope field has a distribution

  at best Gaussian and often tainted with noise and an-

  diffraction grids. In addition, the local illumination at the level of the sample varies from 0 to 100%, due to the effect of laser granularity called "Speckle noise"

  which gives images in coherent light a granular appearance

  area making any measurement of local intensity imprecise.

  The object of the present invention is to remedy these drawbacks

  nients. Thus, it aims to provide a lighting device for

  the sample giving a uniform distribution of the ray-

  primary at the sample level.

  The invention relates to a spectral analysis device with

  global imagery of the type described above.

  According to a general definition of the invention, the lighting means comprise: - an optical fiber comprising an inlet section and an outlet section, - an optical element suitable for introducing the primary radiation into the inlet section of the optical fiber, - an optical arrangement suitable for optically combining the

  fiber optic output section and sample area

  tillon to be analyzed, and - means for mixing suitable for stirring the primary radiation introduced into the optical fiber in order to illuminate

  uniformly the area of the sample to be analyzed and uniform

  focus on the granularity of the primary radiation at

said area.

  Advantageously, the optical fiber is of the multimode type, in

  to improve the mixing of primary radiation.

  In practice, the diameter of the optical fiber is chosen as a function of the diameter of the desired illuminated field as well as of

the desired irradiation.

  According to a preferred embodiment of the invention, the stirring means comprise a mechanism disposed near the optical fiber and clean, on command and at a chosen rate, to change the curvature of the optical fiber. According to another embodiment of the invention, the stirring means comprise a clean internal modulator, on command and at a chosen rate, to modulate the index of

optical fiber refraction.

  According to another embodiment of the invention, the patching means comprise an external modulator, disposed upstream of the input section of the optical fiber, and suitable for modulating, at a chosen frequency, the polarization of the

primary radiation.

  The subject of the invention is also a spectral analysis apparatus with global imaging in which the optical filtering means comprise an entry slit illuminated by the secondary radiation to be analyzed and at least one dispersing stage. According to an important characteristic of the invention, the optical filtering means further comprise: - multi-spectral filtering means arranged downstream of the disperser stage, and suitable for filtering in parallel a plurality of spectral bands of the image dispersed, and - an optical arrangement suitable for optically combining the

  entry slit and multi-spectral filtering means.

  In practice, the multi-spectral filtering means include

  an optical mask comprising a plurality of absorbing, transparent or reflecting zones suitable for filtering the plurality of spectral bands, these zones

  can advantageously be switchable on command.

  The invention also relates to a spectral analysis apparatus with global imagery in which the means of

  optical filtering include a rectangular entry slit

  the area illuminated by the secondary radiation to be analyzed.

  According to yet another important characteristic of the invention

  tion, the optical filtering means comprise an arrangement-

  optically suitable for producing at the entrance slit an image of the secondary radiation of elliptical shape so as to

  optimizing the illumination of said entry slit.

  In practice, the optical arrangement is of the cylindrical afocal type. Other characteristics and advantages of the invention

  will appear in the light of the detailed description below.

  afterwards, and attached drawings, in which: - Figure 1 schematically shows a spectral analysis apparatus with global imaging of the prior art; - Figure 2 schematically shows an example of mixing means of the vibrator type according to the invention; - Figure 3 is a schematic representation of another example of modulator type patching means according to the invention; - Figure 4 is a schematic representation of another example of the magnetic field type stirring means according to the invention; - Figure 5 is a schematic representation of another embodiment of the modulator type patching means according to the invention;

  - Figure 6 is a schematic representation of the plan-

  practical tation of the stirring means in a spectral analysis apparatus with global imagery according to the invention; - Figure 7 schematically shows the multi-spectral filtering means according to the invention; FIG. 8 is another schematic representation of the multi-spectral filtering means; - Figures 9 to 11 schematically represent the image of the secondary radiation at an entry slit according to the prior art; - Figure 12 schematically shows an optical arrangement for optimizing the lighting of the entrance slot according to the invention; and - Figures 13 and 14 schematically represent the elliptical shape of the image of the secondary radiation at

  the entrance slot according to the invention.

  In FIG. 1, the reference 2 designates a spectral analysis apparatus with global imaging of the prior art. A laser source 4 generates primary monochromatic radiation 6. In spectral micro-analysis, the sample to be analyzed is a micro-sample 8 placed on a stage 10 of an optical microscope (not shown). Illumination means of the optical type 12 generally illuminate the sample 8 by the

primary radiation 6.

  The surface of the sample is thus illuminated in its

together.

  Advantageously, the plate 10 allows the precise positioning of the sample along orthogonal axes X, Y and Z. The image of the whole illuminated surface is obtained using a large aperture objective 14 (advantageously that microscope). This image thus obtained is then formed on a multichannel detector 20 through a monochromator 22 used as a bandpass filter which is adjusted for example on a RAMAN line (in RAMAN spectrometry) characteristic of one of the substances contained in

  the sample. An image is thus obtained giving the distribution

  tion of this substance. This image is displayed on a

  conventional display device 20.

  As a variant, the spatial image thus obtained is recorded,

  for example, using a pen recorder 26.

  In practice, the secondary radiation scattered and / or emitted 16 by the sample 8 thus illuminated is received by the objective 14 to be conveyed, via a transfer optic 18 and a

  input slot 28, in the monochromator 22.

  Monochromator 22 functions here as a spectrometer and serves

  spectral analysis of the scattered radiation.

  The Applicant has posed the problem of improving such a spectral analysis device, in particular by improving

  uniformity of illumination of the sample.

  For this, it proposes according to the invention to improve

  the illumination optics 12 described with reference to the figure

  re 1. With reference to FIG. 2, the lighting means according to the invention comprise an optical fiber 100 comprising an input section 102 and an output section 104. The optical fiber is of the multimode type like that sold by the

  SEDI company (French company).

  An optical element 106, for example of the converging lens type

  gente, introduces the primary radiation 6, coming from the source

  4, in the input section 102 of the optical fiber 100.

  An optical arrangement optically combines the section of

  output 104 of optical fiber 100 and the sample area

lon to analyze 8.

  In practice, the optical arrangement comprises a lens 110 disposed between the sample 8 and the input section 104, and the objective of the microscope 14 corrected for infinity in this particular case. Conventionally, an interposed separating blade 112

  between the lens 110 and the objective 14 reflects the ray-

  consistent primary towards sample 8 across

  objective 14 and transmits the incoherent secondary radiation

  rent diffused and / or emitted by the sample 8 thus lit, towards the monochromator spectrometer 22 via the optics of

transfer 18.

  Very advantageously, stirring means 120 stir the primary radiation 6 introduced into the optical fiber 100 in order to uniformly illuminate the area of the sample to be analyzed 8 and to standardize the granularity of the radiation

primary at the level of said zone.

  Referring to Figure 2, the stirring means 120 comprise a vibrating mechanism 121 arranged near the optical fiber. On command and at a chosen rate, the vibrator shakes the optical fiber to change its curvature. Surprisingly, the periodic modification of the curvature of the optical fiber, thanks to the vibrator powered at low frequency, makes it possible to eliminate the effect of granularity.

  (speckle noise) of the defocused laser beam.

  It should be noted that the arrangement of the two converging lenses 110 and 14 achieves the correct adaptation of the digital aperture, that is to say the optical conjugation of the output section 104 of the optical fiber and the sample

to analyze.

  As a variant, the variation in the curvature of the optical fiber

  is no longer periodic but pseudo-random.

  With reference to FIG. 3, another example has been shown.

  stirring means according to the invention.

  The stirring means here comprise an external modulator disposed upstream of the input section 102 of the optical fiber 100. The modulator 130 modulates the state of polarization of the incident beam 6 which is initially polarized. For example, the modulator 130 is of the POCKELS effect type or

KERR effect.

  In another exemplary embodiment, the modulator modulates the index of the medium, for example by ultrasonic waves generated by a piezoelectric device, or generated

  by creating a volume network by optical means.

  In practice, the modulator 130 is arranged between two

  converging lenses 106 and 140 to allow the introduction

  tion of the primary radiation 6 in the input section 102

fiber optic 100.

  Advantageously, a polarizing filter 152, or a half or quarter wave plate, is arranged between the output section 104 of the optical fiber and the converging lens 110, to depolarize the initially polarized laser beam 6 coming from

the optical fiber.

  In another exemplary embodiment (Figure 4), the fiber

  optical 100 is placed in an enclosure 150 with an electric field

that or variable magnetic.

  Preferably, the optical fiber is an optical fiber of the type

  solid or a hollow optical fiber filled with a liquid.

  The coherent monochromatic primary radiation 6 is initially polarized. The stirring means are static stirring means which make it possible, under the effect of a variable electric or magnetic field, to modify the optical properties of the medium constituting the optical fiber, for example the refractive index of the medium constituting the fiber

optical.

  We find in Figure 4 the polarizing filter 152 already

  described with reference to Figure 3.

  In another exemplary embodiment (FIG. 5), the stirring means comprise an internal modulator 160 capable of creating, in the medium constituting the optical fiber, a

  network of indices varying periodically or randomly.

  The internal modulation system 160 is driven by a

generator 170.

  It is clear that other stirring means can be used to modify the optical properties of the optical fiber in order to stir the primary radiation introduced into the optical fiber in order to obtain uniform illumination of the sample to be analyzed and standardize granularity

  primary radiation at said sample.

  In Figure 6, there is shown a spectral analysis apparatus with global imagery, using stirring means according to the invention described with reference to the figures

2 to 5.

  It is a device capable of both lighting

  overall the sample and perform a confo-

  wedge as described in the Patent Applications published in the name of the Applicant under No. FR-A-2 673 718 on September 11

  1991, and under No. EP-A-502 752 on September 9, 1992.

  This device advantageously uses the stirring means

described above.

  Switching means make it possible to pass from the confocal spectral mode to the global imaging mode. The confocal spectral part comprises in a known manner the following elements: means for routing the primary radiation 6 along an input axis 7; - First diaphragm means 9 comprising a first variable opening chosen to spatially filter the coherent excitation beam 6; separator means 112 described with reference to FIG. 2, capable of reflecting the coherent excitation beam 6

  to objective 14 of the microscope and to transmit the ray-

  inconsistent secondary ment 16 emitted, and / or diffused by the sample thus illuminated towards the spectrometer 22; - second diaphragm means 11, comprising a

  second variable opening combined with the first opening-

  re, and suitable for filtering the transmitted part 16 of the means

dividers 112.

  The means 9 and 11 are optically combined to allow confocal filtering of the image of the secondary radiation resulting from the illumination of the sample by the

primary radiation 6.

  Very advantageously, the device described in FIG. 6 also makes it possible to uniformly illuminate the sample by the

  brewing means described above.

  For this, there are provided separating means 190 capable of reflecting the coherent primary beam 6 along another input axis 13, perpendicular to the input axis 7, to route the primary radiation to the stirring means 120. On found, in the structure described with reference to Figure 6, the means described with reference to Figure 2, namely in particular an optical fiber 100 having an input face 102 and an output section 104. The converging lens 106 allows d '' introduce primary radiation

  6 in the input section 102 of the optical fiber 100.

  The converging lens 110 with the objective 14 of the microscope makes it possible to optically conjugate the output section 106 of

  the optical fiber and the area of the sample to be analyzed.

  Advantageously, positioners are provided for position-

  to precisely define the entry section in alignment with the primary radiation 6 and to align the section of

outlet 104 with lens 110.

  The primary radiation from the optical fiber 100 is then routed to the sample through separating plates and optical means such as those described in the Patent Application published in the name of the Applicant under the

No FR-A-2 681 941 April 2, 1993.

  The stirring means used to stir the primary radiation introduced into the optical fiber are here constituted

  by a mechanical vibrator capable of agitating the optical fiber.

  For example, the vibrator is driven by a micro-motor of the continuous type capable of agitating the optical fiber, at low frequency,

for example some Hertz.

  For example, the length of the optical fiber is around

a few decimeters.

  According to another aspect of the invention, the diameter of the optical fiber is chosen as a function of the diameter of the illuminated field

  desired, as well as desired irradiation.

  According to the invention, the use of a fiber

  optic having a diameter of 365 pm makes it possible to obtain respec-

  for X100, X50 and X10 lenses, a field diameter

  illuminated by 63 pm, 126 pm and 630 pm respectively.

  Furthermore, with an optical fiber with a diameter of 100 μm, one obtains respectively at objectives X100, X50 and X10, an illuminated field with a diameter of 17 μm, 34 μm and μm respectively. Finally, with an optical fiber with a diameter of 50 μm, an illuminated field with a diameter of 9 μm, 17 μm and μm respectively is obtained at objectives X100, X50 and X10. Thus, by changing the diameter of the optical fiber, it is possible to obtain different lighted zones, which makes it possible to adapt

  irradiation depending on the applications.

  It should be noted that the irradiation obtained with an optical fiber with a diameter of 365 pm is 13 times lower than that obtained with an optical fiber with 100 pm in diameter and 53 times lower than that obtained with an optical fiber.

50 µm in diameter.

  Under these conditions, a user chooses a fiber of a given diameter from a plurality of fibers of different diameters, depending on its application, i.e.

  desired illuminated field as well as desired irradiation.

  It should be noted that in optical mounting, according to

  the invention, the optical fibers are easily interchanged

  geables. It has been observed that, in this way, considerable advantages are obtained from the presence of the optical fiber in the lighting means of the spectral analysis device at

  global imagery, despite previous prejudices

  bles, without the attenuation provided by the optical fiber being prohibitive. The advantages obtained in terms of signal / noise ratio are in favor of the presence of optical fiber, compared to spectral analysis devices at

  previously known global imagery.

  Furthermore, to improve the faculty of discrimination and identification of a given substance in a heterogeneous mixture, the Applicant has proposed to isolate, in the spectrum, not a single spectral band or line as

  usually but a set of spectral bands or lines

  the characteristics of the chemical species chosen.

  Such multi-spectral filtering according to the invention makes it possible to increase the specificity of the spectral analysis on the one hand, to increase the intensity of the total signal measured by the detector on the other hand. These increases make it possible to choose a better spectral resolution, therefore to reduce

  the risk of analytical interference.

  Those skilled in the art know that the wavelengths or number of waves and the spectral intensities characteristic of the substances to be analyzed (emission lines for the elements, vibrational bands, or fluorescence bands for the compound molecules) are known, published and listed

  in spectra and databases catalogs.

  In addition, computer processing programs are available which allow automatic analysis based on the recognition of tapes and

  intensities observed in an experimental spectrum obtained-

  is lying. Surprisingly, the Applicant has found that these same data catalogs can be used by computer means to determine the most significant spectral bands with a view to producing according to the invention a filter

  multi-spectral suitable for imaging a given substance.

  With reference to FIG. 7, we find the essential elements

  tials of the secondary path of a specific analysis device

  global imaging line described with reference to FIG. 1 and in which the multi-spectral filtering means are placed

according to the invention.

  Thus, there is the secondary radiation 16 scattered and / or emitted by the sample 8 thus illuminated by the primary radiation. Said secondary radiation 16 lights up a slit

input 28.

  A disperser stage, most often a network 200, is used to eliminate the laser radiation, scattered or

  reflected without change in wavelength by the sample

  lon 8, with an extremely high relative intensity, while the radiation which has undergone a spectral shift by RAMAN effect is transmitted by said network 200. The selection of a characteristic radiation by this filtering makes it possible to observe

  a monochromatic image of the sample giving direct-

  ment the distribution of the molecular species chosen.

  The intensity of this image being very low, it can only be viewed and recorded thanks to multi-channel photoelectric detectors 20 coupled for example to a

  high sensitivity television system.

  Furthermore, the transfer optic 18 forms a real image of the sample 8 at the level of the disperser 200 and the objective 14 collects the polychromatic light 16 from

  sample 8 illuminated by primary radiation.

  According to the invention, an optical arrangement combines optical-

  the inlet slot 28 and the multi-filter means

  spectral 300 inserted between the network 200 and the detector

multichannel 20.

  This optical arrangement comprises a first optic 210, called collimator, arranged upstream of the disperser 200 and a second optic 220, called objective, arranged downstream

of the disperser 200.

  Finally, an optical system 230 disposed downstream of the multispectral filtering means 300 form a real image of the sample on the detector 20. This detector is of the two-dimensional multi-channel photoelectric type, for example

a CCD matrix.

  Furthermore, a conventional optical conjugation is provided between the sample 8 to be analyzed and the disperser 200. Another optical conjugation is provided between the disperser 200

and the detector 20.

  According to the invention, the multi-spectral filtering means 300 constitute an optical mask 300 which isolates the radiation

  characteristics in the spectrum plane.

  For example, the optical mask 300 comprises a plurality of absorbing zones individualized at A1 to A6 interspersed with

transparent areas T1 to T5.

  In FIG. 8, the multi-spectral filter mask 300 is

  likely to form two complementary images of the sample

  furrow. A first image is obtained on a first detection

  20-1. This first image constitutes a spectral filtering in the passbands I1, 12 and 13 which are

  characteristics of the substance chosen.

  The multiple bandwidths of the filter consist of reflective surfaces R1 to R3 which make it possible to return

  light to detector 20-1 via optics 230-1.

  The opaque or non-reflective areas A1 to A3 correspond to

  tooth to the parts of the spectra that we want to eliminate because they do not contain bands characteristic of the

chosen substance.

  The non-characteristic radiation 14 and 15 can, after passing through the mask 300, be used to form a

  second image of the sample on a second detector 20-

2 via optics 230-2.

  From an analytical point of view, this second image is complete

  of the first image giving the distribution of the chosen compound. It contains the spatial distribution of all other substances, excluding the selected substance. Computer processing of signals can advantageously benefit from the correlation between these two images for

  improve the selectivity of the analysis.

  It should be noted that to improve the accuracy of the passbands, the size of the spectrum projected on the mask can be increased at will by optical magnification. The mask

  is then defined by a homothetic relation.

  Alternatively, it is possible to interpose an appropriate optical system with variable magnification to adjust the dispersion

on the mask.

  According to the invention, each of the spectral masks can be produced from a network of fusible wires arranged according to the teeth of a comb. The electrical or optical control, by an appropriate addressing system, then causes the fusion of the wires corresponding to the chosen spectral bands. It should be noted that the spectral resolution

* is limited here only by the diameter of the wires. Alternatively, the network of wires is replaced by a network of tracks

  opaque formed by narrow parallel bands arranged

on a transparent support.

  In another variant, the mask is formed of a network of needles made of an opaque material and arranged according to the teeth of a comb. Advantageously, each of these needles is retractable by translation or rotation in a reversible manner. The retraction can be sequential or

simultaneous.

  In yet another variant, the mask is formed of ele

  modulating elements such as pixels of which an optical property (transmission or reflection) can be modified in a reversible manner under the action of a managed electrical signal

  by computer for example. These pixels can be

  killed by micro-mirror chips (DMD technology for DIGITAL

  MICRO-MIRROR DISPLAY, display by digital micro-mirrors

  ques). Furthermore, it should be noted that for the purposes of

  analysis, objective 14 of the microscope must be interchanged

  geable to adapt the magnification of the dimensions of the area to be analyzed of the sample 8. It follows that the dimension and the position of the pupil are not constant and can vary within wide proportions. The optical conjugation of this pupil on the entry slit 28 is obtained, in the prior art, only by compromise to the detriment either of the brightness, or of the spatial resolution or

  separating power, or spectral resolution.

  In fact, according to FIG. 9, in the plane of the slot 28, the image of the circular pupil P is superimposed on a slot

  rectangular 28 defined by lips 29 and 31.

  The entry slot 28, of width 1, is adapted to a resolution

  spectral averaging and causes a large obturation which reduces the useful surface of the pupil, which has two consequences: the reduction in luminosity and the loss of spatial resolution. Referring to Figure 10, the entrance slot 28 is wide open, with 1 equal to the diameter of the pupil image. Under these conditions, the brightness and the separating power are preserved, but the spectral resolution

becomes insufficient.

  A compromise is described with reference to FIG. 11 and provides for choosing a slot width equal to 70 or 80% of the

diameter of the pupil image.

  However, such a solution is not fully satisfied.

  health insofar as it is only a compromise.

  The Applicant proposes to provide a solution to this drawback. This object is achieved by using cylindrical or toric optics. With reference to FIG. 12, the optical assembly comprises

  the input objective 14 which remains spherical.

  According to the invention, provision is made to use a transfer optic 18 of the anamorphic type which will produce, at the entrance slit 28, an image of the pupil P of elliptical shape. The transfer optic 18 comprises, according to the invention, a first element 19 of the divergent cylindrical type, a second element 21 of the convergent cylindrical type, and a third

  element 23 of the converging spherical type.

  The choice of the anamorphosis ratio, defined as the ratio between the lengths of the two main axes A and B of ellipse 33, makes it possible to optimize the illumination of the rectangular slit while retaining the luminosity for a narrower slit, c is to say for a better spectral resolution

(figure 13).

  Correlatively, the use of a cylindrical optic causes

  in this case an anamorphosis of the beam at the level of the scatter-

  sor (figure 14), whose section is no longer circular but

  elliptical. The major axis of the ellipse A 'is directed parallel-

  Lement to the width of the slot, that is to say in the direction of the dispersion of the network 200. The width of the network 200 must

  be increased by a factor G, which improves advantageously-

  the intrinsic resolution of the network.

  To avoid the elliptical of the beam at the level of the disperser, it is advisable to use a rectangular network or else an optical arrangement which does not modify the characteristics

  of the image projected on the disperser.

  It should be noted that the interposition in the transfer optic 18 of a cylindrical afocal system of magnification G = B / A does not modify the height B of the image of the pupil P in the vertical direction, but contracts the width of this image by a factor G. The slit width 1 then becomes less than or equal to A, and the spectral resolution becomes

  G times better and this without loss of brightness.

  Furthermore, the final image of the sample formed through the spectral mask on the detector 20 is also anamorphic, but this is not disadvantageous because the presence of the disperser 200 already causes an anamorphosis in the spherical optic system which must be corrected by a

  signal processing during image reconstruction.

  The same type of correction by analog or digital processing of the detector signals thus makes it possible to restore

  an undistorted image of the object.

  Another solution consists in using a purely optical compensation by a second anamorphic system placed

  in the optics that form an image on the detector.

Claims (14)

Claims   1. Spectral analysis device comprising: - a source (4) capable of generating a primary monochromatic radiation (6), - a sample (8) to be analyzed,   - lighting means (12) suitable for global lighting -   ment by said primary radiation (16) a selected area of the sample to be analyzed, - optical filtering means (28, 22) suitable for receiving   secondary radiation scattered and / or emitted by the sample   thus illuminated and characteristic thereof, and in delivering a dispersed spectral image of this secondary radiation, limited to at least one chosen spectral band,   characterized in that the lighting means (12) comprise   nent: - an optical fiber (100) comprising an inlet section (102) and an outlet section (104), - an optical element (106) suitable for introducing the primary radiation into the inlet section (102) of the optical fiber,   - an optical arrangement (110,14) suitable for combining optical-   ment the output section (104) of the optical fiber and the area of the sample to be analyzed, and - stirring means (120, 130, 160) suitable for stirring the primary radiation introduced into the optical fiber in order to illuminate uniformly the area of the sample to be analyzed, and to standardize the granularity of the primary radiation to level of said area.   2. Apparatus according to claim 1, characterized in that   the optical fiber (100) is of the multimode type.   3. Apparatus according to claim 1, characterized in that the optical element (106) is a converging lens. 4. Apparatus according to claim 1, characterized in that the optical arrangement (110,14) comprises first (110) and   second (14) converging lenses.   5. Apparatus according to claim 1, characterized in that the diameter of the optical fiber is chosen according to the diameter of the desired illuminated field, as well as the desired irradiation. 6. Apparatus according to claim 5, characterized in that the stirring means comprise an external modulator (130) disposed upstream of the input section of the optical fiber and suitable for modulating at a selected frequency the   polarization of the primary radiation.   7. Apparatus according to claim 5, characterized in that the stirring means comprise a clean internal modulator (160), on command and at a chosen rate, at   modulate the refractive index of the optical fiber.   8. Apparatus according to claim 5, characterized in that the stirring means (120) comprise a mechanism (121) disposed near the optical fiber (100) and clean, on command and at a chosen rate, to change the curvature of the optical fiber.   9. Apparatus according to claim 1, characterized in that   the generator means (4) comprise a LASER source.   10. Apparatus according to claim 1, in which the optical filtering means comprise: - an entry slit (28) illuminated by the secondary radiation to be analyzed, and - at least one dispersing stage (200), characterized in that the optical filtering means further comprise: - multi-spectral filtering means (300) arranged downstream of the disperser stage (200), and suitable for filtering in parallel a plurality of spectral bands of the dispersed image, and - an optical arrangement (210, 220) suitable for optically combining the entry slit (28) and the filtering means multi-spectral (300).   11. Apparatus according to claim 10, characterized in that the multi-spectral filtering means (300) comprise an optical mask comprising a plurality of absorbing zones, transparent or reflective.   12. Apparatus according to claim 11, characterized in that the absorbent, transparent or reflective areas are switchable on command.   13. Apparatus according to claim 1, wherein the means   optical filters include a rectangular entry slot   area illuminated by the secondary radiation to be analyzed, characterized in that the optical filtering means comprise an optical arrangement (19,21,23) suitable for   produce an image of the rayon at the entry slit   secondary elliptical shape to optimize lighting entry slot.   14. Apparatus according to claim 13, characterized in that   the optical arrangement (19,21,23) is of the afocal cylindrical type than.