CA2418858A1 - Diamond detection using coherent anti-stokes raman spectroscopy - Google Patents
Diamond detection using coherent anti-stokes raman spectroscopy Download PDFInfo
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- CA2418858A1 CA2418858A1 CA002418858A CA2418858A CA2418858A1 CA 2418858 A1 CA2418858 A1 CA 2418858A1 CA 002418858 A CA002418858 A CA 002418858A CA 2418858 A CA2418858 A CA 2418858A CA 2418858 A1 CA2418858 A1 CA 2418858A1
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- particle
- diamond
- laser beams
- initial laser
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- 239000010432 diamond Substances 0.000 title claims abstract description 31
- 229910003460 diamond Inorganic materials 0.000 title claims abstract description 23
- 238000001514 detection method Methods 0.000 title claims description 7
- 238000002082 coherent anti-Stokes Raman spectroscopy Methods 0.000 title abstract description 16
- 239000002245 particle Substances 0.000 claims abstract description 44
- 230000001678 irradiating effect Effects 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 17
- 238000004458 analytical method Methods 0.000 abstract description 8
- 239000000523 sample Substances 0.000 description 6
- 230000004936 stimulating effect Effects 0.000 description 5
- CZTQRSPXKRZGAN-UHFFFAOYSA-N 2-chloro-n-(2,6-diethylphenyl)-n-(2-propoxyethyl)acetamide;4,6-dichloro-2-phenylpyrimidine Chemical compound ClC1=CC(Cl)=NC(C=2C=CC=CC=2)=N1.CCCOCCN(C(=O)CCl)C1=C(CC)C=CC=C1CC CZTQRSPXKRZGAN-UHFFFAOYSA-N 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/34—Sorting according to other particular properties
- B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
- B07C5/3425—Sorting according to other particular properties according to optical properties, e.g. colour of granular material, e.g. ore particles, grain
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/44—Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/65—Raman scattering
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/87—Investigating jewels
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/65—Raman scattering
- G01N2021/653—Coherent methods [CARS]
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Analytical Chemistry (AREA)
- Chemical & Material Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Abstract
The invention concerns a method and apparatus for detecting diamonds using the phenomenon of coherent anti-Stokes Raman spectroscopy (CARS). Each particle (46) which is to be analysed is irradiated by a focused particle irradiating beam (44) of laser light formed by combining initial laser beams (35, 36) having frequencies differing from one another by a value characteristic for diamond. Components of the initial laser beams are coherently phase-matched to produce, in diamond particles, a CARS signal characteristic of diamond. The scattered signal from the particle is then collected and analysed for the presence of the characteristic CARS signal. The irradiating beam and/or at least one of the initial laser beams is focused by a lens system including a cylindrical lens. This feature has been found to give an enhanced result compared to conventional CARS analysis.
Description
"DIAMOND DETECTION USING COHERENT ANTI-STOKES RAMAN
SPECTROSCOPY"
BACKGROUND TO THE INVENTION
THIS invention relates to a diamond detection using coherent anti-Stokes Raman spectroscopy (CARS).
ZA 98/5496, to which-reference should be made for the theory and details, describes a method of detecting diamonds in which particles suspected of containing diamond are irradiated in a beam of laser light formed by focusing multiple laser beams at least two of which have frequencies differing from one another by a value characteristic of diamond. The result is that at least some components of the laser beams which are focused to produce the irradiating beam are coherently phase-matched. The scattered signal emitted by a particle undergoing analysis is collected and analysed to determine whether a CARS signal characteristic of diamond is present.
As explained in the specification of the aforementioned reference, this technique was a development of the basic CARS detection technique in which particles are irradiated by laser beams at a specified angle to one another to ensure phase matching, but in which the problem was encountered that roughness of the particles presented for analysis led to difficulties in controlling beam direction in the particles.
The present invention seeks to provide an enhancement of the method described in ZA 98/5496.
CONFIRMATION COPY
_7_ SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a method ofi detecting diamonds in which each particle which is to be analysed is irradiated by a focused particle irradiating beam of laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched, and the scattered signal from the particle is collected and analysed for the presence of a CARS signal characteristic of diamond, wherein the particle irradiating beam and/or at least one of the initial laser beams is focused by a lens system including a cylindrical fens.
Various alternative arrangements are possible. For instance, the initial laser beams could first be combined with one another to form the irradiating beam which is then passed through a cylindrical lens, or an initial laser beam could be passed through a cylindrical lens before being combined with the other- initial laser beam. Preferably however the lens system is arranged to focus the irradiating beam to spaced apart focal points, thereby forming a "sofit focus" in a fiocal volume of relatively less intense laser light.
According to another aspect of the invention there is provided an apparatus for detecting diamonds, the apparatus comprising:
- particle irradiating means for irradiating each particle which is to be analysed by a focused particle irradiating beam ofi laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched; and - detection means fior collecting and analysing the scattered signal from the particle for the presence of a CARS signal characteristic of diamond, the particle irradiating means comprising a lens system, including a cylindrical lens, for focusing the particle irradiating beam and/or at least one of the initial laser beams.
The invention will now be described in more detail, by way of example only, with reference to the accompanying diagrammatic drawings in which Figures 1 and 2 illustrate different embodiments of the invention and Figures 3 shows a perspective view of a cylindrical lens as used in these embodiments.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
In Figure 1 a frequency doubled Nd:YAG laser 10 produces an initial laser beam 12 at a wavelength of 532nm. The beam 12 is expanded by a concave lens 14 and collected by a convex lens 16 which directs the resultant beam onto a beam splitter 18. A portion of the beam 12 is then directed by further mirrors 20 and 22 through a collimator consisting of a lens 24 and pinhole 26, and through an attenuator 28. The attenuator 28 is an optional component which, if present, is used to control the beam intensity and diameter. The beam is then reflected by a mirror 30 through a concave lens 31. The resultant, expanded beam is converged by a convex lens 32 onto a dichroic beam combiner 34. The beam 35 produced by the components 20, 22, 24, 26, 28 (if present) and 30 is referred to below as the stimulating beam.
The portion of the beam 12 which passes through the beam splitter 18 is absorbed by dye in a dye laser 38 which produces a second laser beam 36, referred to below as the probe beam, at a frequency of 572nm. The beam 36 is expanded by a concave lens 40 and the expanded beam is converged by a convex lens 42 onto the dichroic beam combiner 34.
The beam combiner combines the two initial laser beams to produce a combined particle irradiating beam 44 which is focused as a cone of laser light into a particle analysis zone in which each particle 46 undergoing analysis is presented. The lens system which achieves focusing includes a cylindrical lens 48 in accordance with this invention.
The scattered signal which is emitted by the particle is then collected and analysed for the presence of a CARS signal characteristic of diamond, as described in ZA 98/5496.
Compared to the technique described in ZA 98/5496, it has been observed that enhanced detection of a CARS signal characteristic of diamond is possible as a result of the use of the cylindrical lens 48 to focus the laser beam 44 by which the particle is irradiated.
The lens system described above is set up to produce two spaced apart focal points, referred to herein as a vertical and a horizontal focal point.
The vertical focal point is defined by light rays converged in a vertical plane inter alia by the cylindrical lens 48 and is indicated in Figure 3(a) by the numeral 54. The horizontal focal point is attributable to the convergence of the light rays in a horizontal plane by the lenses 32 and 42 and is indicated in Figure 3(b) by the numeral 55.
The use of the cylindrical lens 48 produces a beam comprising light rays at a range of angles. This, together with the fact that the two laser beams are individually refracted at slightly different angles on passing through a diamond surface, ensures that amongst all the angular deviations at least some light rays are still in a phase matching relationship to one another.
Compared to the technique described in ZA 98/5496, it is also believed that the technique described above will have the further advantage that there is less likelihood of damage to diamond particles presented for analysis. This is because the presence of two focal points creates, in effect, a three-dimensional focal volume in which the particle is positioned for analysis, compared to a single, well-defined, intense focal point in the technique of ZA 98/5496. In the latter technique, the particle is presented for analysis at a position close to the single, well defined focal point for effective emission of the required CARS signal, thereby creating the potential for possible graphitisation damage to the diamond. In the present technique the required signal can be emitted from the particle at any suitable position within the less intense focal volume provided by the spaced focal points, thereby reducing the chances of such damage to diamond. in this regard it is noted that within the focal volume defined by the spaced focal points of the cylindrical lens, it is not necessary for the phase matching to be exact or for the relevant light rays to be perfectly coincidental. In other words it is not necessary for the particle 46 to be perfectly positioned between the respective focal points.
The focal length of the cylindrical fens determines the extent of the cone of laser light coming to the focal points. The optimal angle between the combined beams in air for adequate phase matching to take place is estimated to be 3,5° in situations where the combined beam is presented at a near normal angle of incidence to the particle surface, but it is recognised that this angle may increase significantly as the angle of incidence on the particles moves away from a near normal value, for example towards the edges of most particles. As in the technique described in ZA 98/5496, it will be understood that the required angular relationships can exist between outer rays in the cone or between inner and outer rays.
In the illustrated embodiment, the combined irradiating beam 44 is focused towards the particle 46 by the lenses 32 and 42 and by the cylindrical lens 48. It is envisaged that advantageous results can also be obtained in alternative embodiments in which a cylindrical lens is placed in the path of the stimulating beam 35 between the mirror 30 and the lens 31, as indicated in broken outline in Figure 1 by the numeral 60, and/or in the path of the probe beam 36 between the dye laser 38 and the lens 40, as indicated in broken outline in Figure 1 by the numeral 62.
-G-Figure 2 illustrates another possibility in which the stimulating and probe beams are combined with one another before passing through the cylindrical lens. As shown, the cylindrical lens 64 is placed between a dichroic beam combiner 65 and a beam expander 66. It will be understood that the cylindrical lens 64 once again produces a vertical focal point while the beam expander 66 and subsequent beam focusing lens 68 produce the horizontal focal point.
In both embodiments described above, a dye laser is used to produce the probe beam at the appopriate frequency. The invention is not however limited to the use of dye lasers. For instance, it is envisaged that optical parametric oscillators could be used in other embodiments to produce the probe beam from the stimulating beam. Alternatively separate solid state diode lasers could be used to produce the stimulating and probe beams at the required frequencies.
SPECTROSCOPY"
BACKGROUND TO THE INVENTION
THIS invention relates to a diamond detection using coherent anti-Stokes Raman spectroscopy (CARS).
ZA 98/5496, to which-reference should be made for the theory and details, describes a method of detecting diamonds in which particles suspected of containing diamond are irradiated in a beam of laser light formed by focusing multiple laser beams at least two of which have frequencies differing from one another by a value characteristic of diamond. The result is that at least some components of the laser beams which are focused to produce the irradiating beam are coherently phase-matched. The scattered signal emitted by a particle undergoing analysis is collected and analysed to determine whether a CARS signal characteristic of diamond is present.
As explained in the specification of the aforementioned reference, this technique was a development of the basic CARS detection technique in which particles are irradiated by laser beams at a specified angle to one another to ensure phase matching, but in which the problem was encountered that roughness of the particles presented for analysis led to difficulties in controlling beam direction in the particles.
The present invention seeks to provide an enhancement of the method described in ZA 98/5496.
CONFIRMATION COPY
_7_ SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a method ofi detecting diamonds in which each particle which is to be analysed is irradiated by a focused particle irradiating beam of laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched, and the scattered signal from the particle is collected and analysed for the presence of a CARS signal characteristic of diamond, wherein the particle irradiating beam and/or at least one of the initial laser beams is focused by a lens system including a cylindrical fens.
Various alternative arrangements are possible. For instance, the initial laser beams could first be combined with one another to form the irradiating beam which is then passed through a cylindrical lens, or an initial laser beam could be passed through a cylindrical lens before being combined with the other- initial laser beam. Preferably however the lens system is arranged to focus the irradiating beam to spaced apart focal points, thereby forming a "sofit focus" in a fiocal volume of relatively less intense laser light.
According to another aspect of the invention there is provided an apparatus for detecting diamonds, the apparatus comprising:
- particle irradiating means for irradiating each particle which is to be analysed by a focused particle irradiating beam ofi laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched; and - detection means fior collecting and analysing the scattered signal from the particle for the presence of a CARS signal characteristic of diamond, the particle irradiating means comprising a lens system, including a cylindrical lens, for focusing the particle irradiating beam and/or at least one of the initial laser beams.
The invention will now be described in more detail, by way of example only, with reference to the accompanying diagrammatic drawings in which Figures 1 and 2 illustrate different embodiments of the invention and Figures 3 shows a perspective view of a cylindrical lens as used in these embodiments.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
In Figure 1 a frequency doubled Nd:YAG laser 10 produces an initial laser beam 12 at a wavelength of 532nm. The beam 12 is expanded by a concave lens 14 and collected by a convex lens 16 which directs the resultant beam onto a beam splitter 18. A portion of the beam 12 is then directed by further mirrors 20 and 22 through a collimator consisting of a lens 24 and pinhole 26, and through an attenuator 28. The attenuator 28 is an optional component which, if present, is used to control the beam intensity and diameter. The beam is then reflected by a mirror 30 through a concave lens 31. The resultant, expanded beam is converged by a convex lens 32 onto a dichroic beam combiner 34. The beam 35 produced by the components 20, 22, 24, 26, 28 (if present) and 30 is referred to below as the stimulating beam.
The portion of the beam 12 which passes through the beam splitter 18 is absorbed by dye in a dye laser 38 which produces a second laser beam 36, referred to below as the probe beam, at a frequency of 572nm. The beam 36 is expanded by a concave lens 40 and the expanded beam is converged by a convex lens 42 onto the dichroic beam combiner 34.
The beam combiner combines the two initial laser beams to produce a combined particle irradiating beam 44 which is focused as a cone of laser light into a particle analysis zone in which each particle 46 undergoing analysis is presented. The lens system which achieves focusing includes a cylindrical lens 48 in accordance with this invention.
The scattered signal which is emitted by the particle is then collected and analysed for the presence of a CARS signal characteristic of diamond, as described in ZA 98/5496.
Compared to the technique described in ZA 98/5496, it has been observed that enhanced detection of a CARS signal characteristic of diamond is possible as a result of the use of the cylindrical lens 48 to focus the laser beam 44 by which the particle is irradiated.
The lens system described above is set up to produce two spaced apart focal points, referred to herein as a vertical and a horizontal focal point.
The vertical focal point is defined by light rays converged in a vertical plane inter alia by the cylindrical lens 48 and is indicated in Figure 3(a) by the numeral 54. The horizontal focal point is attributable to the convergence of the light rays in a horizontal plane by the lenses 32 and 42 and is indicated in Figure 3(b) by the numeral 55.
The use of the cylindrical lens 48 produces a beam comprising light rays at a range of angles. This, together with the fact that the two laser beams are individually refracted at slightly different angles on passing through a diamond surface, ensures that amongst all the angular deviations at least some light rays are still in a phase matching relationship to one another.
Compared to the technique described in ZA 98/5496, it is also believed that the technique described above will have the further advantage that there is less likelihood of damage to diamond particles presented for analysis. This is because the presence of two focal points creates, in effect, a three-dimensional focal volume in which the particle is positioned for analysis, compared to a single, well-defined, intense focal point in the technique of ZA 98/5496. In the latter technique, the particle is presented for analysis at a position close to the single, well defined focal point for effective emission of the required CARS signal, thereby creating the potential for possible graphitisation damage to the diamond. In the present technique the required signal can be emitted from the particle at any suitable position within the less intense focal volume provided by the spaced focal points, thereby reducing the chances of such damage to diamond. in this regard it is noted that within the focal volume defined by the spaced focal points of the cylindrical lens, it is not necessary for the phase matching to be exact or for the relevant light rays to be perfectly coincidental. In other words it is not necessary for the particle 46 to be perfectly positioned between the respective focal points.
The focal length of the cylindrical fens determines the extent of the cone of laser light coming to the focal points. The optimal angle between the combined beams in air for adequate phase matching to take place is estimated to be 3,5° in situations where the combined beam is presented at a near normal angle of incidence to the particle surface, but it is recognised that this angle may increase significantly as the angle of incidence on the particles moves away from a near normal value, for example towards the edges of most particles. As in the technique described in ZA 98/5496, it will be understood that the required angular relationships can exist between outer rays in the cone or between inner and outer rays.
In the illustrated embodiment, the combined irradiating beam 44 is focused towards the particle 46 by the lenses 32 and 42 and by the cylindrical lens 48. It is envisaged that advantageous results can also be obtained in alternative embodiments in which a cylindrical lens is placed in the path of the stimulating beam 35 between the mirror 30 and the lens 31, as indicated in broken outline in Figure 1 by the numeral 60, and/or in the path of the probe beam 36 between the dye laser 38 and the lens 40, as indicated in broken outline in Figure 1 by the numeral 62.
-G-Figure 2 illustrates another possibility in which the stimulating and probe beams are combined with one another before passing through the cylindrical lens. As shown, the cylindrical lens 64 is placed between a dichroic beam combiner 65 and a beam expander 66. It will be understood that the cylindrical lens 64 once again produces a vertical focal point while the beam expander 66 and subsequent beam focusing lens 68 produce the horizontal focal point.
In both embodiments described above, a dye laser is used to produce the probe beam at the appopriate frequency. The invention is not however limited to the use of dye lasers. For instance, it is envisaged that optical parametric oscillators could be used in other embodiments to produce the probe beam from the stimulating beam. Alternatively separate solid state diode lasers could be used to produce the stimulating and probe beams at the required frequencies.
Claims (10)
1.
A method of detecting diamonds in which each particle which is to be analysed is irradiated by a focused particle irradiating beam of laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched, and the scattered signal from the particle is collected and analysed for the presence of a CARS signal characteristic of diamond, wherein the particle irradiating beam and/or at least one of the initial laser beams is focused by a lens system including a cylindrical lens.
A method of detecting diamonds in which each particle which is to be analysed is irradiated by a focused particle irradiating beam of laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched, and the scattered signal from the particle is collected and analysed for the presence of a CARS signal characteristic of diamond, wherein the particle irradiating beam and/or at least one of the initial laser beams is focused by a lens system including a cylindrical lens.
2.
A method according to claim 1 wherein the initial laser beams are first combined with one another to form the irradiating beam which is then passed through a cylindrical lens.
A method according to claim 1 wherein the initial laser beams are first combined with one another to form the irradiating beam which is then passed through a cylindrical lens.
3.
A method according to claim 1 or claim 2 wherein an initial laser beam is passed through a cylindrical lens before being combined with the other initial laser beam.
A method according to claim 1 or claim 2 wherein an initial laser beam is passed through a cylindrical lens before being combined with the other initial laser beam.
4.
A method according to any one of the preceding claims wherein the lens system is arranged to focus the irradiating beam to spaced apart focal points.
A method according to any one of the preceding claims wherein the lens system is arranged to focus the irradiating beam to spaced apart focal points.
5.
An apparatus for detecting diamonds, the apparatus comprising:
- particle irradiating means for irradiating each particle which is to be analysed by a focused particle irradiating beam of laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched; and - detection means for collecting and analysing the scattered signal from the particle for the presence of a CARS signal characteristic of diamond, the particle irradiating means comprising a lens system, including a cylindrical lens, for focusing the particle irradiating beam and/or at least one of the initial laser beams.
An apparatus for detecting diamonds, the apparatus comprising:
- particle irradiating means for irradiating each particle which is to be analysed by a focused particle irradiating beam of laser light formed by combining initial laser beams having frequencies differing from one another by a value characteristic for diamond, such that components of the initial laser beams are coherently phase-matched; and - detection means for collecting and analysing the scattered signal from the particle for the presence of a CARS signal characteristic of diamond, the particle irradiating means comprising a lens system, including a cylindrical lens, for focusing the particle irradiating beam and/or at least one of the initial laser beams.
6.
An apparatus according to claim 5 wherein the cylindrical lens is located in the path of the particle irradiating beam after combination of the initial beams.
An apparatus according to claim 5 wherein the cylindrical lens is located in the path of the particle irradiating beam after combination of the initial beams.
7.
An apparatus according to claim 5 wherein a cylindrical lens is located in the path of an initial beam before the initial beams are combined.
An apparatus according to claim 5 wherein a cylindrical lens is located in the path of an initial beam before the initial beams are combined.
8.
An apparatus according to any one of claims 5 to 7 wherein the lens system is arranged to focus the irradiating beam to spaced apart focal points.
An apparatus according to any one of claims 5 to 7 wherein the lens system is arranged to focus the irradiating beam to spaced apart focal points.
9.
A method of detecting diamonds substantially as herein described with reference to the accompanying drawings.
A method of detecting diamonds substantially as herein described with reference to the accompanying drawings.
10.
An apparatus for detecting diamonds substantially as herein described with reference to the accompanying drawings.
An apparatus for detecting diamonds substantially as herein described with reference to the accompanying drawings.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA200004111 | 2000-08-11 | ||
| ZA2000/4111 | 2000-08-11 | ||
| PCT/IB2001/001415 WO2002014837A2 (en) | 2000-08-11 | 2001-08-08 | Diamond detection using coherent anti-stokes raman spectroscopy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2418858A1 true CA2418858A1 (en) | 2002-02-21 |
Family
ID=25588860
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002418858A Abandoned CA2418858A1 (en) | 2000-08-11 | 2001-08-08 | Diamond detection using coherent anti-stokes raman spectroscopy |
Country Status (3)
| Country | Link |
|---|---|
| AU (2) | AU2001276600B2 (en) |
| CA (1) | CA2418858A1 (en) |
| WO (1) | WO2002014837A2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BR112012014789A2 (en) * | 2009-12-17 | 2019-09-24 | British Columbia Cancer Agency Branch | apparatus and method for tissue characterization, and computer readable media. |
| CN105642566B (en) * | 2016-03-03 | 2018-04-06 | 布勒索特克斯光电设备（合肥）有限公司 | A kind of color selector filter apparatus for automatic change |
| CN106053425A (en) * | 2016-05-10 | 2016-10-26 | 南京理工大学 | Raman spectrum gem and jade appraising device and method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4784275A (en) * | 1986-09-15 | 1988-11-15 | Vanzetti Systems Inc. | Verification systems for small objects |
| GB2280956B (en) * | 1991-02-20 | 1995-08-30 | Gersan Ets | Classifying or sorting |
| CA2241470C (en) * | 1997-06-26 | 2005-06-21 | De Beers Consolidated Mines Limited | Diamond detection using coherent anti-stokes raman spectroscopy |
| ZA985496B (en) * | 1997-06-26 | 1999-01-20 | De Beers Cons Mines Ltd | Diamond detection using coherent anti-stokes raman spectroscopy |
-
2001
- 2001-08-08 CA CA002418858A patent/CA2418858A1/en not_active Abandoned
- 2001-08-08 AU AU2001276600A patent/AU2001276600B2/en not_active Ceased
- 2001-08-08 AU AU7660001A patent/AU7660001A/en active Pending
- 2001-08-08 WO PCT/IB2001/001415 patent/WO2002014837A2/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| AU2001276600B2 (en) | 2005-05-19 |
| AU7660001A (en) | 2002-02-25 |
| WO2002014837A2 (en) | 2002-02-21 |
| WO2002014837A3 (en) | 2002-05-02 |
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