The way the diamonds detection using coherent anti-stokes raman spectroscopy and device for its implementation
(57) Abstract:The invention relates to the field of spectral analysis of diamonds. In the method of the analyzed particles is irradiated with laser radiation generated by the focus of many laser beams. At least two beams have frequencies that differ from one another in accordance with the characteristic of a diamond. In the focused beam at least some components of the laser beams must be coherently aligned in phase. The device provides a means for determining whether the scattering signal emitted by each particle, the characteristic signal of the coherent anti-Stokes Raman spectroscopy for the diamond. The technical result is increased efficiency. 2 C. and 17 C. p. F.-ly, 3 ill. The invention relates to a method for detecting diamonds using coherent anti-Stokes Raman spectroscopy (CARS) and device for implementing this method.There have been proposals to use Raman response for the detection and sorting of diamonds. In the known method intended for sorting particles illuminate the laser beam. For diamond the interaction of the laser beam with the oscillation modes of a crystal of diamond is much greater, than the incident laser beam. The corresponding frequency shift corresponds to the energy of oscillations, the value of which for diamonds is equal to the wave number 1332 cm-1.The so-called Raman shift does not depend on the frequency of the laser radiation, but the radiation intensity of the spontaneous Raman scattering depends on the frequency and in General small. Although at shorter excitation wavelengths is generated slightly stronger signals, such wavelengths are usually also excite diamonds fluorescence, which can suppress the characteristic Raman signal and extremely difficult reliable detection of diamonds.As noted above, CARS is a third option Raman method. In the known method CASRS simultaneously on a particle is directed by two laser beam, and the frequency of the two beams differ from one another in accordance with a quantitative characteristic of the material intended for the detection, that is, 1332 cm-1in the case of diamond. Coherence provides the fact that the two beams are at a certain angle to one another, thus ensuring the coordination phase. Rays interact with diamond or crystal lattice divest which is significantly greater than the spontaneous Raman signal has a higher frequency than the frequency of the lasers at the entrance. In the case of diamond, the shift towards higher frequencies equal 1332 cm-1in relation to one of the frequencies of excitation. The characteristic signal of a higher frequency is outside the frequency band of the fluorescence and, hence, can be detected without the presence therein of background fluorescence.As noted above, the problem of application of the known method CASRS for discovery of diamonds lies in the fact that the particles, which are presented for analysis, have rough surfaces that refract the laser beams so that it is impossible to provide the angular separation between the beams.The present invention is directed to solving this problem.According to one aspect of the present invention, a method for detecting diamonds, which consists in the fact that the particles are irradiated with a beam of laser radiation generated by focusing the two or more laser beams, at least two of which have frequencies that differ from one another on the characteristic of a diamond's value, at least some components of laser beams focused to permissione, emitted by each particle, and determine whether the signal characteristic signal CASRS for diamond.According to another aspect of the invention, an apparatus for detecting diamonds containing means for generating beams of laser radiation, at least two of which have frequencies that differ from one another on the characteristic of diamond value, means for focusing the laser beams for forming the irradiating beam of laser radiation, which is irradiated subjected to analysis of particles, and at least some components of the laser beams coherently aligned in phase by means of a focusing tool to collect scattering signal emitted by each particle, and a means for determining whether the signal characteristic signal CASRS for diamond.The invention is further described in more detail with reference to the accompanying drawings, in which Fig.1-3 depict first, second and third embodiments of the block diagram of the device for detection of diamond according to the invention.In the first embodiment, the laser sources (Fig.1) generate two lasers 12 and 14, the polarized relevant field is Chernoy for diamond frequency difference 1332 cm-1.The beam 12 reflects a mirror 20 and a dichroic plate mixing 22 and the beam 14 passes through the dichroic plate mixing 22. Beams 12 and 14 then combine to form a collinear beam 24 that is reflected by the mirror 26 and the focus lens 28 so as to receive the cone 30 of the laser radiation, which is irradiated with the particle 32, subjected to analysis.In the light cone 30 two laser frequencies, i.e. the frequencies of the beams 12 and 14, in fact, are in a certain range of angles with respect to each other, this range is determined by the angle limiting solution cone.Despite the fact that the particle 32 may have a rough and uneven surface, within this range of angles at least some of the intersecting components of the rays meet the criteria negotiation phases required for successful implementation of the method CASRS.The scattering signal CASRS from particles 32 has the shape of a cone and denoted by the numeral 34. The signal passes through the collecting lens 36, which restores the collimated beam. The signal passed through the filter 38 which removes all wavelengths different from the characteristic wavelength of 497 nm for diamond. Any signal that has passed through flectronic processor (not shown) carries out an assessment of indicates whether received by the spectrometer signal that particle 32 is a diamond.In Fig. 2 shows a second modified version of the embodiment of the invention. Dichroic plate mixing replaced by a mirror 23 which reflects the laser beam 12, and the laser beam 14 passes. So there is no gain collinear, summarized the laser beam, as in the first embodiment. The respective beams 12 and 14 are angled to one another and independently represent a mirror 26 on the focusing lens 28, forming a cone 30 of the laser radiation, which is irradiated subjected to analysis of particle 32.Beams 12 and 14 have the same frequency as in the first embodiment, therefore, the cone 30 is a similar effect, i.e., the corresponding frequencies are in a range of angles, which allows to obtain the consent of phases CARS at least for some components of the rays.The scattering signal CASRS collect the collimated beam focusing lens 36 and is passed through the filter 38 which removes all wavelengths different from the characteristic wavelength of 497 nm for diamond. The resulting signal reflect mirror 40 to the spectrometer 42, which in this is CASRS, the particle 32 can be identified as a diamond.In the third embodiment, and Fig.3 laser beams 12 and 14 with the same frequency as before, have in parallel to each other and reflect the prism 46 on the focusing lens 28, which forms a cone of 30 mixed laser radiation, which cover part 32. As in the first two implementation options available in the cone 30, the range of angles between the different frequencies allows to obtain the condition of coherence of the beam CARS for at least some component of the respective frequencies.The received signal scattering CASRS collect the focusing lens 36 in a collimated beam and filtered through filter 38, passing characteristic signal 497 nm, which is directed to the spectrometer 42 mirror 40, and produce an assessment, does this signal that the particle 32 is a diamond.Each of the above devices may form part of a sorting device that is used for analysis of the diamond particles from the associated gangue particles of rock. Online particle analysis can be carried out together with means for separating particles, which identified the th 28 carry out so, that limits the radiation intensity, which is subjected to the particles, thereby reducing the likelihood of damage to the diamond particles. 1. The discovery of diamonds, which consists in the fact that the particles are irradiated with a laser beam, generated by focusing the two or more laser beams, at least two of which have frequencies that differ from one another on the characteristic of a diamond's value, at least some components of laser beams focused to the formation of the irradiating beam of laser radiation, are coherently coordinated phase, collect the scattering signal emitted by each particle, and determine whether the signal characteristic signal of the coherent anti-Stokes Raman spectroscopy for the diamond.2. The method according to p. 1, characterized in that the particles of the light cone of the laser radiation generated by focusing two or more laser beams.3. The method according to p. 2, characterized in that the laser beams are collinear unite and focus for the formation of a cone of laser radiation.4. The method according to p. 3, characterized in that one reflect the laser beam from the dichroic plate daring with the reflected beam.5. The method according to p. 2, characterized in that the laser beams are tilted at an angle to one another and focus for the formation of a cone of laser radiation.6. The method according to p. 5, characterized in that one laser beam reflect mirror, and the other laser beam is directed into the bypass mirror at an acute angle to the reflected beam.7. The method according to p. 2, characterized in that the laser beams set parallel to one another and with spatial separation from one another and focus so as to form a cone of laser radiation.8. The method according to p. 7, characterized in that one laser beam reflect dichroic plate mixing, and the other laser beam so that it was parallel and spatially separated from the reflected beam, passed through a dichroic plate mixing.9. The method according to any of the preceding paragraphs, characterized in that the laser beams are polarized.10. The method according to any of the preceding paragraphs, characterized in that the scattering signal emitted by each particle, filtered to eliminate those wavelengths that are not characteristic for diamond, and analyze the filtered signal to predestin for diamond.11. The method according to p. 10, characterized in that the filtered signal is polarized.12. Device for the detection of diamond containing means for forming beams of laser radiation, at least two of which have frequencies that differ from one another on the characteristic of diamond value, means for focusing the laser beams for forming the irradiating beam of laser radiation, which is irradiated subjected to analysis of particles, and at least some components of the laser beams coherently aligned in phase with the aid of the focusing tool, a means to collect scattering signal emitted by each particle, and means for determining whether the signal characteristic signal of the coherent anti-Stokes Raman spectroscopy for the diamond.13. The device according to p. 12, characterized in that the means focusing focuses the laser beams so as to form a cone of laser radiation for irradiating particles.14. The device according to p. 13, characterized in that it comprises a dichroic plate mixing, which reflects a laser beam and transmits the other laser beam collinear reflected laser beam, and the lens f is the means for creating laser beams, inclined at an acute angle to one another, and a lens for focusing the tilted laser beams.16. The device according to p. 13, characterized in that it comprises a dichroic plate mixing, which reflects a laser beam and transmits the other laser beam parallel to the first, but with spatial diversity from the reflected beam, and a lens for focusing parallel rays.17. Device according to any one of paragraphs. 12-16, characterized in that it comprises polarizers for polarization of the laser beams.18. Device according to any one of the preceding paragraphs, characterized in that it further comprises a filter for filtering the scattering signal emitted by the signal of each particle, to eliminate those wavelengths that are not characteristic for diamond, and the analysis tool of the filtered signal to determine whether the signal of the coherent anti-Stokes Raman spectroscopy, characteristic for diamond.19. The device under item 18, characterized in that it comprises a polarizer to polarize the filtered signal.
FIELD: mining industry; minerals dressing and grading.
SUBSTANCE: the invention is pertaining to the field of upgrading and grading of minerals and may be used at dressing of the diamond-bearing ores and quality grading of the diamonds. The method provides for the optical rays irradiation of the minerals, registration of the scattered radiation in two spectral bands of the determined width, one of which contains the line of the Raman effect, the second band does not contain the line of the Raman effect, but envelops the first band from two sides, comparison of the signals in these two bands, identification and separation of the in compliance with the results of this comparison, in which the width of the spectral bands is regulated according to the condition: ▵ν1=ν0±δ,▵ν2= ν0±2δ-▵ν1, where: ▵ν1 - the bandwidth of the spectrum containing the line of the Raman effect;▵ν2 - the bandwidth of the spectrum, which does not contain the line of the Raman effect, but enveloping the first band from two sides; ν0 - the frequency of the maximum of the line of the Raman effect; δ - the band of the a frequencies of the selected line in the Raman effect spectrum. The device consists of: the storage hopper; the feeding mechanism; the source of the optical radiation; the inlet slit; the convergent lens; the dispersing component; the measuring channel with the outlet slit of the determined width, which outer surface is reflective; the reference channel receiving the light flux reflected from the outer surface of the exit slit of the measuring channel supplied with the outlet slit; imagers; the electronic unit; the executive actuating mechanism; recipients of the concentrate product and the tailings. At that the slits of the reference channel and the measuring channel are arranged coaxially and made adjustable. The technical result of the invention is the increased selectivity of the separation due to the more exact singling out of the Raman effect from the background noise.
EFFECT: the invention ensures the increased selectivity of the separation due to the more exact singling out of the Raman effect from the background noise.
3 cl, 5 dwg
FIELD: physics, measurement.
SUBSTANCE: invention is related to methods for investigation of quantitative-qualitative composition of different mixtures. In method investigated mixture is excited by laser radiation, afterwards spectrum of its Raman scattering is registered. When quantitative content of components is determined, basic value Ij of Raman scattering strip intensity is selected, which corresponds to j component of mixture, where j=1…N, and N is total number of mixture components, afterwards ratio of Raman scattering strips intensities is defined for every investigated component of mixture and specified basic value Ik/Ij, where k=1…N, k≠j. Afterwards ratio of every component concentration is calculated to concentration of basic j component, and then partial concentration pl is calculated for every component.
EFFECT: provision of partial concentrations of mixture components with specified extent of accuracy and possibility to control mixture samples directly in reservoirs installed at arbitrary distance from metering equipment both in zone of sight line and outside, using simple equipment.
4 cl, 1 dwg
FIELD: physics, measurements.
SUBSTANCE: invention relates to measurement of the surface plasmon resonance. The proposed method comprises placing the noble metal compound onto the prism lower face, irradiating aforesaid prism with the light to detect the reflected light. The said noble metal compound contains substituents on the side opposite to that in contact with the prism. Note that the specimen to be analysed is applied onto the side incorporating substituents in the noble metal compound.
EFFECT: ease of detecting phosphorylates peptide (protein) and verifying if peptide is phosphorylated or not.
8 cl, 8 dwg
FIELD: physics; measurement.
SUBSTANCE: invention pertains to measurement techniques. Invented are an optical sensor and a method of using it with a laser beam for stimulating visible light and a detector based on Raman spectroscopy, for detecting chemical groups in an analyte, deposited on the sensor. The sensor comprises a substrate, plasmon-resonance mirror, formed on the sensitive surface of the substrate, a layer of plasmon-resonance particles, put on top of the mirror, and a layer of optically transparent dielectric of thickness 2-40 nm, which separates the mirror and the layer of particles. The layer of particles is formed by a periodic matrix of plasmon-resonance particles, with (i) a coating, capable of bonding analyte molecules, (ii) essentially uniform dimensions and shapes of particles in a chosen range of dimensions 50-200 nm and (iii) regular periodic distance between particles, less than the wavelength of the stimulation laser beam. The device can detect an analyte with amplification factor of up to 1012-1014, i.e. detection of separate molecules of the analyte.
EFFECT: increased sensitivity of analysis.
16 cl, 16 dwg
SUBSTANCE: method involves use of Raman spectroscopy and active substrates which realise the gigantic Raman scattering effect for amplifying an optical signal from a complex of metal ions with an organic dye, wherein solutions, scrapings or wash-offs from solid surfaces are used to prepare the solution for analysis. A complexing organic dye is added to that solution, and several minutes after formation of a complex, a solid-state active substrate is placed into the solution. The time for adsorption of the analyte onto the surface of the material which amplifies the Raman scattering signal is equal to 1.5-2 hours. A dried sample is put into the measuring compartment of a Raman spectrometer. A Raman spectrum is obtained and then analysed for presence of lines associated with oscillations of the complex of metal ions with the organic dye.
EFFECT: invention increases sensitivity of determination and widens the range of methods of detecting and monitoring content of different metals in solutions.
1 dwg, 2 ex
SUBSTANCE: multipass optical system consists of two identical spherical mirrors whose centres lie at diametrically opposite points of the surface one imaginary sphere, having radius equal to the radius of curvature of the mirrors, as well as a laser and a focusing lens, lying on one optical axis which passes inside that sphere at a certain distance from its centre and cross the surface of the first mirror. The focus of the lens lies at about the distance of the radius of curvature of the mirror from that point of intersection. In the plane formed by the optical axis of the lens and the centre of the sphere, the optical axis of the second mirror makes an angle of γ=α2/[2(β-2α)] with the radius of the sphere extending to the centre of the second mirror, where α=arcsin(r/2R), β=arcsin(R0/R), wherein r is the radius of the laser beam, R0 is the size of the mirrors, R is the radius of curvature of the mirrors.
EFFECT: high intensity of the Raman scattering signal.
FIELD: instrument making.
SUBSTANCE: analysed gas medium is radiated with laser linearly polarised monochrome radiation, and two spectra of combination light scattering are recorded, J||(2) and J⊥(λ). For the first one the electric vector of scattered light is parallel to the electric vector of the exciting laser radiation, and for the second one - it is orthogonal. According to the isotrope spectrum of scattering produced from the condition J(λ)=J||(λ)-4/3·f(λ)·J⊥(λ), where f(λ) is the ratio of the spectral ratio of radiation transmission by equipment, the electric vector of which is parallel to the electric vector of the exciting laser radiation, to the identical coefficient of transmission for orthogonal polarisation, the composition of the analysed medium is defined.
EFFECT: possibility to identify larger quantity of components of analysed gas medium and increased validity of analysis.
FIELD: physics, optics.
SUBSTANCE: system can be used in investigating properties of gaseous media, including with chemical reactions, in small volumes by scattering spectroscopy or light absorption. The system includes assemblies of optical elements capable of moving towards a focal point, each having two flat swivel mirrors in an adjustment head which provides independent inclination of each mirror in two directions, or a lens in between, which is mounted at double the focal distance on the beam path from the measuring volume. The assemblies enable to focus a reflected beam at the same point. One assembly, having a lens and a flat mirror or only a concave mirror, directs the laser beam such that it travels its entire path in the reverse direction, wherein the number of passages is equal to or greater than 4 depending on the number of installed assemblies of optical elements.
EFFECT: high strength of the useful signal and reduced optical distortion of the laser beam due to multiple passage of the laser beam through the measuring volume.
2 cl, 2 dwg
SUBSTANCE: invention relates to optically active sensory technologies intended for detection of gas or fluid molecules, including those of toxic and explosive matters. Proposed method is implemented with the help of sensitive element based on slotted silicon microstructures with nano-structured porous ply of the surface of silicon walls. It consists in combination light dissipation in characteristic oscillatory modes of molecules amplified by partial light localisation in medium with periodically modulated reflective index (slotted silicon).
EFFECT: additional increase in probability of light interaction with molecules of detected gases or fluids results from availability of developed surface of porous ply which adds to sensitivity of gas sensor.
9 cl, 4 dwg, 1 tbl
FIELD: physics, optics.
SUBSTANCE: invention relates to optical analysis of the composition of a substance based on Raman and luminescence spectra and a spectral-selective portable Raman-luminescent analyser. The spectral-selective portable Raman-luminescent analyser further includes a microscope lens or a microscope and a one- or two-dimensional sample translator connected to a computer. The analyser is adapted to control a sample movement device and synchronise step-by-step sample scanning and identification of a substance at each step while focusing a laser beam by the microscope lens into a spot of micrometre or submicrometer dimensions.
EFFECT: high sensitivity and resolution and avoiding the need to decode complex spectra multi-component mixtures.