• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An apparatus for performing spatially shifted Raman spectroscopy on a sample, comprising a rotating prism (30) arranged such that a spatial shift between an input region and a collection region at a sample level depends on the angle of rotation of the prism.
    公开号:FR3038385A1
    申请号:FR1656336
    申请日:2016-07-01
    公开日:2017-01-06
    发明作者:William Parker
    申请人:COBALT LIGHT SYSTEMS Ltd；
    IPC主号:
    专利说明:

    The present invention relates to apparatuses and methods for performing spatially shifted Raman spectroscopy, for example a scanning unit for this purpose, and a method of operating a scanning unit of this type. Introduction
    Spatially shifted Raman spectroscopy is described in a number of prior art publications such as Matousek et al., Applied Spectroscopy, Volume 59, Number 4, 2005. This technique is used to extract Raman spectra from subsurface layers of a sample, for example in diffuse diffusing media. The technique involves applying probing light to one or more input surface regions of a sample, and collecting the scattered light scattered from one or more collection surface regions that are laterally spaced from the sample surface. / region (s) of entry. Raman spectral characteristics are then identified in the collected light. The depth profile of the Raman scattering that gives rise to the Raman spectral characteristics in the collected light then depends on the lateral spacing. A single spacing between input and collection may be used, or data from multiple spacings may be used to provide more accurate depth information.
    The technique is extensively discussed in WO2006 / 061565 and WO2006 / 061566, the contents of which are hereby fully mentioned for all purposes. In general, the probing light can be applied as a laser beam to form a laser spot on the sample surface to thereby define an input surface region, and the collection region can be defined by collection designed to collect backscattered light.
    The technique can be used with samples comprising highly diffusive materials such as powders, turbid liquids, opaque plastics and vitreous materials, paper and board-based materials, and with samples comprising low-diffusing materials. such as weakly diffusing and transparent liquids, plastics and transparent and colored glasses, etc. Samples may include layers of materials such as a pharmaceutical tablet inside a white plastic blister, a liquid in a glass or plastic bottle, a granulated material in a paper bag, etc. and in these cases, the technique can be very useful for determining Raman spectral characteristics of the contained material while eliminating the signature of the container or package.
    Equipment for performing spatially shifted Raman spectroscopy is sold in a variety of forms, but it remains necessary to have compact and robust equipment that is capable of obtaining more reliable and reproducible Raman spectral characteristics from a range of types and sample configurations. Summary of the invention
    Accordingly, the invention provides an apparatus for performing spatially shifted Raman spectroscopy on a sample, comprising: a light source adapted to form a sounding beam of light directed along an optical path to an input region on the sample; collection optics adapted to receive said probing light from a collection region on the sample following subsurface scattering of said probing light within the sample; a spectral analyzer adapted to detect Raman scattering spectral characteristics in the sounding light received through the collection optics; and a rotating prism disposed on the optical path, the rotating prism being arranged such that a spatial offset between the input region and the collection region depends on the rotation angle of the prism. The apparatus may be provided in the form of a scanning unit, for example a scanning unit of this type for portable use. In any case, the use of a rotating prism to control the spatial shift between the input and collection regions makes it possible to build a compact and reliable apparatus.
    In particular, the sounding light beam may be directed through opposite faces of the prism, for example the parallel or substantially parallel faces of such a prism. For this purpose, a square prism can be conveniently used, but other trapezoidal, rectangular shapes and still other shapes can be used. In any case, the prism can be configured and arranged so that the sample light beam reaching the sample is aligned substantially in the same direction relative to the apparatus, regardless of the spatial shift of the region of input and the corresponding rotational position of the prism. In other words, the apparatus may be arranged such that the angle between the sample beam of light reaching the sample and an optical axis of the collection optics is independent of the angle of rotation. prism is the spatial shift or both. Similarly, the apparatus may be arranged such that the angle of incidence of the sounding beam to the sample is independent of the spatial offset between the input region and the sample collection region.
    Such configurations provide more consistent illumination levels of the sample, minimizing variations in surface reflection and penetration into subsurface portions of the sample, thereby improving coherence of the relationship between spectral characteristics. determined for different spatial shifts®
    Although the prism may have substantially parallel opposite faces, other forms of prism may be used, for example such as a prism having non-parallel opposing faces, non-planar faces, etc. By way of example, a wedge prism can be used to reorient the sounding light beam and thus increase flexibility in the design of the apparatus in a compact form, and can also be used to provide anamorphic shaping of the beam. A translation of a wedge prism could also be used to control the spatial shift, instead of or simultaneously with the rotation of the prism. A curved prism face, for example a cylindrical face or another curve, can be used to create a focus and point size variation for a lateral axis of the beam, so that the shape and size of the point of the region input can be ordered. Such a curved face could be used to provide a different optical lens effect for different spatial shifts, for example between an offset equal to zero or zero and others
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    In general, the apparatus may be designed to rotate the prism within a range of less than ninety degrees, thereby providing a corresponding range of spatial offsets between the input region and the collection region. In general, a maximum spatial shift between the input and collection regions provided by the apparatus may be in the range of 5 mm to 25 mm. The minimum spatial shift that can be used to detect and / or isolate subsurface scattering can be only 1 mm or less. In general, to detect this subsurface scatter, the offset between the input and collection regions must be greater than about half the width of the input region, as determined by the width of the input beam. probing light reaching the sample. The apparatus may also be arranged so that the rotation of the prism gives rise to a negative spatial shift in a direction opposite to the direction of the maximum spatial shift. The apparatus is preferably also arranged so that a particular rotational position of the prism gives rise to a minimum spatial shift of zero mm between the input region and the collection region, i.e., wherein entry and collection regions coincide.
    It should be noted that, although the input and collection regions can generally be circular or ellipsoidal, being defined by the optics used to generate the regions, other forms and structures of regions may be used, among which regions consisting of a plurality of discrete and separated areas, regions comprising rings and loops, etc., and the term spatial shift must be correspondingly understood as being a relative positioning of regions which may or may not include a clearly defined offset equal to zero or zero at places where the regions coincide. The collection region may generally be elongated due to the input characteristics of the spectral analyzer, for example if the spectral analyzer comprises a spectrometer having an input slot. If the collection region is elongated, the apparatus can then also be arranged so that the entrance region is elongated along an axis parallel to the elongation of the collection region, to help maximize the signal collected for one of the negative and non-harmful spatial shifts or both.
    To control the rotation of the prism and therefore the spatial shift, the apparatus may further comprise an actuator adapted to control the rotation of the prism. The apparatus can then be designed, for each spatial offset, to receive said probing light from the sample, and to separately detect the Raman scattering spectral characteristics for each of these spatial shifts. The apparatus can then be designed to combine the detected Raman scattering spectral characteristics for each of the plurality of different spatial shifts to be selected preferentially for a depth or range of depths within the sample. The apparatus may also be designed to obtain characteristics of a sample surface subregion from the detected Raman scattering spectral characteristics, for example by identifying one or more chemical constituents of one or more subregions. surface, for example by identifying features such as depth profiles within the sample. This feature can be implemented by a control unit, analyzer, or other component of the device. The invention also provides methods corresponding to the aforementioned apparatus, for example spatially shifted Raman spectroscopy methods, such as providing a prism rotating on an optical path between a light source and a sample, the source light beam providing a sounding beam of light, and rotating said prism at different positions, so that the sounding beam of light is applied to each of a plurality of input regions on a sample, each region of input corresponding to a different position of the prism. Said probing light can then be received from a collection region on the sample, each input region being at a different spatial offset from the collection region, so that the Raman scattering spectral characteristics can be detected separately in the sounding light received for each spatial offset.
    The method may further include combining the detected spectral characteristics from the different spatial shifts to be selected preferentially for a particular depth or range of depths within the sample. The characteristic of a surface subregion of the sample can then be deduced from the Raman spectral characteristics detected for the different spatial shifts. The spectral characteristics detected from different offsets can be combined in this way using a control unit forming part of a scanning unit implementing the method, and the results of the analysis can be presented on a device. display of a scan unit of this type.
    Brief description of the drawings
    Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIG. 1 schematically represents, in a plan view, an apparatus for performing Raman spectroscopy; spatially shifted on a sample; and Figures 2a and 2b illustrate how the rotation of the prism of Figure 1 gives rise to spatial shift variations between the input and collection regions on the surface of the sample.
    Detailed description of embodiments
    Referring now to Figure 1, this schematically shows, in a plan view, an apparatus for performing spatially shifted Raman spectroscopy on a sample. The apparatus may conveniently be provided as a scanning unit for portable use. Some typical applications for a scanning unit of this type may be in the areas of homeland security, industrial production, agrochemistry, medicine, etc.
    In homeland security applications, the scanning unit could be used to test personal effects and baggage for the detection of illegal or dangerous substances such as explosives, narcotics and chemical precursors of these constituents, test samples being bottles, bags, tubes and other containers containing materials that potentially include such target substances, or various other types of samples. In the field of industrial production, a scanning unit of this type could be used to check the composition of raw materials and final chemicals contained in drums, bottles, bags, sachets, blister packs, tablets, etc. In agrochemicals, the samples could for example be sachets containing agrochemicals such as fertilizers, insecticides, and other substances. Various other applications of a scanning device of this type will be apparent to those skilled in the art, for example from the literature on spatially shifted Raman spectroscopy. The scanning unit 10 illustrated in FIG. 1 comprises a housing 12 inside which are housed a laser subassembly 14, a sounding beam conditioning optics 16, a collection optics 18, and a spectral analyzer. 20. The laser subassembly 14 comprises a laser (not shown) which generates a laser beam constituting a probing light beam 22 for testing a sample 100, which could for example be a bottle, drum or other container liquid to be analyzed, or a bag, a bag or other container of solid material to be analyzed. The laser can generally be a semiconductor diode laser operating in the near infrared, for example at 830 nm with a power of about 10 to 500 mW.
    The probing light beam 22 passes from the laser subsystem 14 through the sounding beam conditioning optic 16 to the sample 100. After diffusion within the sample 100, a portion probing light is collected by the collecting optics 18 which passes the collected probing light to the spectral analyzer 20 for the detection of one or more Raman scattering spectral characteristics in the collected probing light. The Raman scattering spectral characteristics can then be used as an indication of the chemical properties of subsurface regions of the sample, for example to identify particular chemical constituents and other properties of the sample.
    In Fig. 1, the scanning unit 10 is kept adjacent to the sample 100 by a spacer 24 which is also part of the scanning unit. The spacer 24 helps to ensure that the sample is stably maintained at a fixed and appropriate position relative to the scanning unit, for example by defining a plane S within which a surface is located. of the sample to be tested for scanning. The spacing member 24 which, in FIG. 1, is in the form of a truncated cone, has apertures suitable for allowing the probing beam 22 to pass to the sample 100, and to the scattered survey light. at the output of the sample 100 to be collected by the collecting optics 18. The probing beam conditioning optics 16 may comprise a defocus lens, or other suitable optical element or arrangement such as a diffuser, which causes the sounding beam to be slightly divergent, thereby reducing the risk of ocular injury for an operator or a person in the vicinity, and which also reduces the risk of burning of the sample 100. Beam conditioning optics probe 16 may also include an optical element, such as a magnifying prism, a wedge prism, a diffraction grating, or a holographic element, for anamorphic or modal magnification. Alternatively, probe the sounding beam to obtain a more appropriate configuration for use in a spatially shifted Rainan spectroscopy process. Simultaneously, the magnifying prism or other optical element may be used to deflect the beam toward the sample, to help produce a more compact configuration of the scanning unit.
    In accordance with prior art relating to spatially shifted Raman spectroscopy, it is known to use a range of offsets between an input region on the sample at locations where the probe beam 22 is incident on the sample, and a collection region. on the sample from which the collecting optics collects the scattered light scattered within the sample. This set of offsets can be used to ensure better selection of the depth within the sample, for example to help exclude Raman spectral characteristics due to surface layers of the sample, or to select a particular depth or depth range within the sample. Such techniques are described in WO2006 / 061565 and WO2006 / 061566, the contents of which are hereby incorporated by reference for all purposes, and elsewhere, for example in Loeffen et al., Proc. SPIE 8018, Chemical, Biological, Radiological, Nuclear, and Explosives (CERNE) Sensing XII, 80181E (June 03, 2011), "Chemical and explosive point detection through opaque containers using spatially offset Raman spectroscopy (SORS)". The range of offsets used in spatially shifted Raman spectroscopy should be understood to be the range of different distances or separations between the input and collection regions, or between the centers of these regions, although with more complex geometries of one or both regions, a mere distance may not always be an appropriate measure. Of course, some of the probing light reflected from the surface of the sample may be collected, especially at locations where the input collection regions are close to each other or overlap to some extent. At or near an offset of zero or zero at locations where the entrance and collection regions coincide or are colocalized, most of the light collected may result from surface scattering, but usually contains useful Raman spectral information relating for example to the surface of the sample. As discussed below, this surface scattering can be used to help correct the spectral data obtained from larger offsets.
    In FIG. 1, the position of this collection region is represented by an arrow B. The shape of the collection region may correspond to various shapes or configurations determined by the configuration of the collection optics 18, spectral analyzer 20, the optical coupling between these elements, and other factors. However, in the case of the apparatus of Fig. 1, the collection region may generally be an approximately circular point having a diameter of about 1 to 3 mm, or alternatively an elongated shape of about 1 at 3 mm on the main axis, with a dimension ratio greater than 1: 1, for example greater than 2: 1 or greater than 10: 1, and optionally up to about 40: 1. In some embodiments, for example, the collection region is defined by an image of a collection slot of the spectrometer, formed on the sample. In some embodiments, this image may have dimensions of the order of 1.8 mm x 0.08 mm, depending on the collection optics and the slot of the spectrometer. The apparatus (and in particular one or more of the probing beam conditioning optics 16, the prism 30 and the laser 14) can then be used to form an input region which is also elongate, with a main axis approximately aligned with the main axis of the collection region. In particular, the input region may be formed to have a shape and / or a ratio of dimensions similar to the collection region, thereby maximizing the collected signal. In some embodiments, this arrangement can also improve depth selection by minimizing the illumination distribution, for example by forming the input and collection regions so that they are elongated in a direction perpendicular to the offset direction. spatial.
    The position of the collection region on the sample, with respect to the scanning device, is approximately fixed because the optical axis of the collection optic X is perpendicular to the plane S of the sample surface held against the spacing element 24, although an oblique angle between X and S may be used, in which case the collection region would be typically elliptical.
    The input region illustrated in FIG. 1 is represented by an arrow A. According to the invention, the optical path starting from the laser sub-assembly 14, as it approaches the sample 100, can be laterally shifted without changing the direction or angle of incidence, by rotation of a prism 30 also mounted within the housing 12. The prism is therefore located on the optical path between the laser subassembly 14 and The extreme positions of the optical path between which the sounding beam can be adjusted using the rotation of the prism 30 are shown in Fig. 1 as paths 22a and 22c of the sounding beam. The collecting optics 18 shown in FIG. 1 is stationary with respect to the housing 12, so that by rotating the prism 30, a spatial offset at the sample surface S between the input region A and the region B collection can be directly ordered.
    The input region formed using the apparatus of FIG. 1 will generally be elliptical due to the oblique angle of incidence on the sample. An input region having a diameter or dimensions in the range of 0.5 mm to 3 mm may be used. A region of entry that is too small will tend to burn the sample, whereas too large a point size reduces the degree to which the scanner is able to distinguish different layers or depths within the sample at during the shift process.
    The range of spatial offsets that would be desirable to provide in a particular scanning unit may vary depending on the intended applications. For example, if the scanning unit is to be used with samples in which probing light can more easily penetrate, then the range of spacings can be increased in order to take advantage of this fact and the availability of a wider range of depths for a spatially shifted Raraan spectroscopy process. However, the scanning device can generally provide a range of offsets of the order of 0 mm to 10 mm, possibly up to 20 mm, 25 mm or more. From the point of view of the value of the range of offsets, or from the point of view of the value of the range of lateral displacements of the beam produced by the movement of the prism, for example measured near the prism or at the places where the beam goes out of the apparatus, this may for example be one of the following values: at least 10 mm, at least 20 mm, or at least 30 mm, and this range includes the position of a zero offset or zero offset if provided, and any negative offset if provided by the apparatus. A small negative offset can be provided at the assumed plane of the sample S, for example with a range of shifts of -2 mm to +10 mm, thereby ensuring an effective offset equal to zero when the sample is slightly larger. moved to the scanning unit as the sample plane S wanted.
    The process of varying the offset of the input region by means of the prism 30 is illustrated in greater detail in FIGS. 2a and 2b, which, for the sake of clarity, represent only the prism 30 with the associated optical paths of the Beam 22 and the geometric construction of the sample surface S for different rotations of the prism 30. The prism 30 of Figures 2a and 2b comprises first and second opposing faces 32 and 32 '. When these faces are perpendicular to the incoming bore light beam 22 (as illustrated by the position of the prism shown in solid lines in both figures), the beam passes through the prism without deviation or shift, and leaves along the path of the probing beam 22-b, to form an input region on the sample in Ab. When the prism is rotated so that the faces 32 and 32 'are no longer perpendicular to the incoming bore light beam 22, the beam passes through the prism with a gap or offset. In Fig. 2a, the rotation of the prism is clockwise from the viewpoint of the observer, so that the beam 22 exits along an offset sounding beam path 22-c, which is on the right and parallel to the undirected path 22-b, to form an input region on the Ac sample which is further away from the collection region B than Ab.
    The rotation in the opposite direction illustrated in Fig. 2b, causes an offset in the opposite direction to the path of the sounding beam 22-a, to form an input region on the sample at Aa which is closer to the region of collection B, and which may in fact coincide with the collection region B to provide an offset position equal to zero. For the "negative offset" discussed above, the input region A-a may be beyond the collection region B, so that the shifted position equal to zero would then be between A-a and A-b. The offset position equal to zero is in fact a coincidence between an input region Aa and the collection region B, for example to provide a null offset condition useful for the analysis and / or calibration of the spectroscopy results. Spatially shifted Raman.
    The prism shown in Figures 1, 2a and 2b is a square prism, although, since only the opposite faces 32 and 32 'are used in this example to direct the probe beam 22, a square shape is not strictly necessary. It would of course be possible to use all four sides of the square prism, or other configuration of the prism, for example to provide a prism that rotates continuously to produce a repeated scanning effect. This arrangement could also be used for a faster displacement between the extremes of the spatial shift, such as A-a and A-c in Figures 2a and 2b. The passage of the beam through one or two angles of the prism ensures the rapid transition between the extreme positions of the spatial shift. The size and refractive index of the prism can be selected according to a particular need and concept for a particular scanning unit. In one example, a square prism having sides 17 min in length and refractive index n = 1.763 to 830 nm is used (eg N-SF11 glass), giving a lateral beam shift of about 5.8 mm in each direction for prism rotation of 40 degrees in each opposite direction, therefore, a range of offsets of about 11.6 mm in all. A glass of lower refractive index provides a smaller range of offsets for the same prism size (an N-BK7 glass with η = 1.5102 at 830 nm provides a range of offsets of about 9.7 mm), and a glass of higher refractive index provides a larger set of offsets for the same prism size (an N-LASF79 glass with n = 1,9776 at 830 nm provides a range of offsets of about 13 mm). When designing a particular scanning unit, the space available for a larger prism, the increased weight of a larger prism and / or the heavier glass of higher refractive index, and the costs of different prisms and types of glass, can be taken into account.
    To provide space in the scanner for accommodating the various optical components, while providing an appropriate offset between the input and collection regions in a range of about 0 mm to 20 mm, it is generally desirable that the optical axis X of the collection optics and the angle of incidence of the sounding beam 22 on the sample are not parallel. In the figures, the optical axis of the collection optic X is perpendicular to the sample plane S, while the sounding light beam 22 is incident on the sample plane S at an oblique angle, but a reverse arrangement can be used in which the X axis is oblique and the sounding beam 22 is perpendicular, or both may be oblique. In the arrangement shown in the figures, the sounding beam reaches the sample plane S at an angle of about 15 to 45 degrees, or more preferably about 20 to 40 degrees, although other angles may be used, for example in the range of about zero to 45 degrees. In particular, an angle equal to zero may be used in designs in which the supply and collection paths to and from the sample, with respect to the apparatus, coincide or overlap or are coaxial, for example when a common lens is used for both supply and collection.
    In the figures, the axis of the rotation of the prism is shown known being generally perpendicular to the plane of the figure and perpendicular to both the direction of the probe beam 22 approximating the sample and the optical axis X, but this is not a requirement for obtaining an appropriate shifting of the sounding beam by means of the prism 30. The use of a prism 30 as described herein to effect shifting of the sounding beam without Significant change in direction allows the scanning unit to direct the sounding beam to the sample at the same angle of incidence for all offset spacings, or in the event of slight variations in the sample surface in the sample. shifts, at least at the same angle with respect to the optical axis X. Since the reflection of the probing light from the sample and the penetration of the light of its in the sample generally vary with the angle of incidence and / or the angle with respect to X, both because of the direction and shape of the input region, and because the The sounding behavior of the scattering light towards the collection region and the collecting optics also generally varies according to the angle of incidence on the input region, the use of prism 30 in this way leads to a more coherent instrument. The use of the prism as described also provides a compact arrangement that is robust in case of rough handling of the scanning unit, for example when it falls or in case of shock.
    The controlled rotation of the prism 30 can be performed in a variety of different ways. In Figure 1, the prism 30 is coupled to a co-rotating pinion 40, and a rack 42 is provided to couple a linear motion produced by an electric actuator 44 to the rotation of the pinion. This arrangement allows the prism actuator to be spaced apart to help form a more compact scanning unit, but it is clear that other arrangements for rotating the prism 30 can be used. For example, the electric actuator 44 may impart rotational movement to the prism without the use of a linear motion arrangement, for example by means of a motor producing a rotational movement coupled to the prism 30 by means of gears or by direct coupling. The spectral analyzer 20 can be provided in various forms, with the aim of detecting the Raman spectral characteristics in the collected light. In the arrangement of Figure 1, a spectrometer is used. It could be a dispersive spectrometer using a diffraction grating 52 such as a transmission grating, in association with a detector such as an image-forming detector 54, for example a 2D CCD-FFT grating. . However, other forms of spectrometer, including arrangements using one or more bandpass filters selected for particular spectral characteristics or regions of interest, can be used. If desired, the spectrometer could be coupled to the collection optic by means of a bundle of optical fibers, thereby better imaging the light collected on the spectrometer slot and improving the collection efficiency. The scanning unit 10 may be controlled by means of an electronic control unit 60 comprising electronics for controlling the laser subassembly 14 and the electric actuator 44, and receiving and analyzing spectral data from the Spectral analyzer 20. The control unit may also receive signals from the laser subsystem 14 (e.g., laser tuning or temperature), electric actuator (e.g. the position of the actuator or other control feedback), and can also control the signals supplied to the spectral analyzer 20. The control unit 60 generally comprises one or more microprocessors and an associated memory, as well as an interface electronics, such as A / D and N / A converters as required.
    With respect to controlling the electric actuator 44 for controlling the rotation of the prism 30 and thereby controlling the offset of the sounding beam 22, this can be done by the control unit 60 in accordance with various requirements. . For example, when testing a particular sample, the control unit 60 may first zero the offset between the input and collection regions, so that the regions coincide, and may collect data. spectral corresponding to this shift, before moving to a series of one, two or more different offsets (for example at 4 mm, 8 mm and 12 mm), collecting spectral data at each of these offsets. The spectral data corresponding to the various offsets can then be combined, compared, or otherwise analyzed by the controller 60, to generate an output that can be presented to a user of the scanning unit. This output would for example identify or confirm the presence or absence of one or more chemical constituents in the sample. If necessary, these outputs may be provided in the form of depth profiles within the sample, for example as discussed in more detail below. The scanning unit 10 therefore also preferably comprises a visual display unit 70 for presenting these outputs and other control and operational information to a user, a user input unit 72 such as a keyboard (which could be provided in the form of a touch function of the visual display unit) to allow a user to provide inputs and other commands to the unit (eg a selection specific scanning programs, sensitivities, etc.) and a wired and / or wireless interface 74 for digital communications with the scanner, e.g. to update firmware, download spectral data and other results, etc. The use of Raman spectral data obtained from different spatial shifts between the collection and input regions to determine subsurface characteristics of a sample is described in WO2006 / 061565 and WO2006 / 061566 mentioned above. , and the data and spectral processing techniques described therein are herein incorporated by reference. By way of example, it should be noted that the spectral data corresponding to each spatial shift are collected separately. In general, this is done using each different spatial offset for a separate time interval, in this case, by appropriate positioning of the rotating prism, and separately collecting and realizing spectral detection of the scattered Raman light for each of these offsets, although other techniques may be used.
    Since each spatial shift gives rise to a different Raman scattering depth profile resulting from the collected light, the spectral characteristics corresponding to the different spatial shifts can be combined to select a particular depth or range of depths within the beam. 'sample. Techniques for achieving this goal, described in WO02QQ6 / Q61565 and WO2006 / 061566, generally consist in deriving characteristics of a surface subregion of the sample from variations in intensity of the sample. one or more Raman spectral characteristics between different spatial shifts. These techniques include the subtraction of spectra or spectral characteristics corresponding to different spacings, for example in which a spectrum corresponding to a zero or low spatial shift is subtracted from a spectrum corresponding to a larger spatial shift, in order to reduce the contribution of layers in the spectrum obtained. Other techniques include multivariate data analysis, such as principal component analysis, to estimate a contribution to observed spectral data that results from a particular depth, range, or depth profile. inside the sample. The subtraction technique can be used with only two spatial shifts, for example a zero or low offset, and a larger offset. To be effective, multivariate techniques generally require spectral characteristics from a larger number of offsets to be combined, for example about ten different offsets.
    Such techniques allow the scanner to combine the detected spectral characteristics for each of a plurality of different spatial shifts to be selected preferentially for a depth or range or depth profile within the sample.
    In some cases, it may be appropriate to collect the scattered light from a single spatial shift, and to derive sample characteristics using only this shift, for example when the expected properties or Raman spectral characteristics of a container forming a surface of the sample are already known, or when the Raman spectral characteristics of such a container are weak or can be taken into account in another way, for example by separation or spectral analysis.
    These techniques and other similar techniques can be implemented by the control unit 60, or externally to the scanning device 10. The results of this analysis, for example the identification of the presence or concentration of a or more particular chemical substances in the sample, can then be presented on the display device 70.
    Although particular embodiments of the invention have been described, it will be apparent to those skilled in the art that various modifications and alterations can be made to it without departing from the scope of the invention.
    For example, although the arrangements described above use non-parallel and separate paths for applying probing light to the sample and collecting the backward-fired light to pass it to the spectral analyzer, supply and collection paths between the apparatus and the sample could coincide or be at least parallel and / or overlap and / or be coaxial. For example, if a common lens is used both for the provision and collection of the probing light, such a common lens could constitute all or part of the collection optics described 18. The use of a common lens for the supply and collection paths may be advantageous if a zero or low angle of incidence of the sample beam of light on the sample is required.
    Similarly, although Fig. 1 shows a sounding beam of light that is applied to the surface of the sample at an oblique angle, and that the collection optics has an axis perpendicular to the sample surface, they could both to be oblique, the sounding beam of light could be perpendicular and the axis of collection could be oblique, or various other options and combinations.
    Fig. 1 shows a spacer 24 used to hold the sample in a fixed position relative to the scanner while scanning is being performed, and this spacer 24 could be removable such that The scan may be used with or without the spacer 24, or simply omitted. Sampling of the sample without any such spacing unit being used may be advantageous when a contact with the sample is not desired, for example if the scanning suspects the presence of explosives, or materials that may adhere or stick to the scanner or otherwise damage it or affect it.
    权利要求:
    Claims (22)
    [1" id="c-fr-0001]
    An apparatus for performing spatially shifted Raman spectroscopy on a sample, comprising: a light source (14) arranged to form a sounding light beam directed along an optical path to an input region on the sample; a collection optics (18) adapted to receive said probing light from a collection region on the sample following subsurface scattering of said probing light into the sample; a spectral analyzer (20) designed to detect the Raman scattering spectral characteristics in the sounding light received through the collection optics; and a rotating prism (30) disposed on the optical path, the rotating prism being arranged such that a spatial offset between the input region and the collection region is dependent on the rotation angle of the prism.
    [2" id="c-fr-0002]
    An apparatus according to claim 1, wherein the prism comprises opposite faces, and the apparatus being arranged such that the sounding beam enters the rotating prism and leaves the opposite faces.
    [3" id="c-fr-0003]
    Apparatus according to claim 2, wherein the opposite faces are substantially parallel.
    [4" id="c-fr-0004]
    Apparatus according to claim 3, wherein the prism is a square prism.
    [5" id="c-fr-0005]
    An apparatus according to any of the preceding claims, adapted to rotate the prism on a child of less than ninety degrees to thereby provide a corresponding range of spatial offsets between the input region and the region of interest. collection
    [6" id="c-fr-0006]
    Apparatus according to any one of the preceding claims, arranged such that the angle between the sample light beam reaching the sample and an optical axis of the collection optics is independent of one or more two of the angle of rotation of the prism and the spatial shift.
    [7" id="c-fr-0007]
    An apparatus according to claim 6, wherein the angle between the sample light beam reaching the sample and an optical axis of the collection optics is in the range of 15 to 45 degrees.
    [8" id="c-fr-0008]
    An apparatus according to any one of the preceding claims, arranged so that the angle of incidence of the sounding beam on the sample is independent of the spatial shift between the input region and the collection region on the sample. sample.
    [9" id="c-fr-0009]
    Apparatus according to any one of the preceding claims, further comprising an actuator adapted to control the rotation of the prism so as to vary the spatial offset between the input region and the region of / *** II / "% 4 ™ / * "% Ly U ~ L -L. td vd *
    [10" id="c-fr-0010]
    Apparatus according to claim 9, arranged such that the rotation of the prism gives rise to a maximum spatial shift of between 5 mm and 25 mm between the input region and the collection region.
    [11" id="c-fr-0011]
    Apparatus according to claim 10, arranged such that the rotation of the prism gives rise to a negative spatial shift in a direction opposite to the direction of the maximum spatial shift.
    [12" id="c-fr-0012]
    Apparatus according to any one of claims 9 to 11, arranged in such a way that the rotation of the prism gives rise to a minimum spatial offset of zero between the input region and the collection region.
    [13" id="c-fr-0013]
    Apparatus according to any one of the preceding claims further adapted to control the rotation of the prism to receive said sample light from the sample for a plurality of different spatial shifts and to separately detect the spectral characteristics of the sample. Raman scattering for each of these spatial shifts.
    [14" id="c-fr-0014]
    The apparatus of claim 13, further adapted to combine the detected Raman scattering spectral characteristics for each of the plurality of different spatial shifts to be selected preferentially for a depth or range of depths within the sample.
    [15" id="c-fr-0015]
    Apparatus according to any one of the preceding claims, the apparatus being arranged to obtain characteristics of a surface subregion of the sample from the detected Raman scattering spectral characteristics.
    [16" id="c-fr-0016]
    A method for performing spatially shifted Raman spectroscopy, comprising: providing a prism rotating on an optical path between a light source and a sample, the light source providing a sounding beam of light; rotating said prism at different positions so that the sounding beam of light is applied to each of a plurality of input regions on a sample, each input region corresponding to a different position of the prism; receiving said probing light from a collection region on the sample, each input region being at a spatial offset different from the collection region; and detecting, for each of said spatial shifts, Raman scattering spectral characteristics in the received sounding light.
    [17" id="c-fr-0017]
    The method of claim 16, wherein the probing light is received from the collection region on the sample following subsurface scattering within the sample.
    [18" id="c-fr-0018]
    The method of claim 16 or 17, wherein, for each input region, the sample light beam reaching the sample is substantially parallel to the sounding beam for each other input region.
    [19" id="c-fr-0019]
    The method of any one of claims 16 to 18, wherein the prism comprises opposed parallel faces, and for each prism position, the sounding bore beam passes through the opposite parallel faces.
    [20" id="c-fr-0020]
    The method of any one of claims 16 to 19, further comprising combining the detected spectral characteristics from the different spatial shifts to be selected preferentially for a particular depth or range of depths within the sample. .
    [21" id="c-fr-0021]
    The method of any one of claims 16 to 20, further comprising detecting one or more characteristics of a sample surface subregion from the detected Raman spectral characteristics for the different spatial shifts.
    [22" id="c-fr-0022]
    The method of claim 21, wherein detecting one or more characteristics comprises identifying one or more chemical constituents of a surface subregion of the sample.
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    同族专利:
    公开号 | 公开日
    GB2541110A|2017-02-08|
    US9880099B2|2018-01-30|
    GB201511696D0|2015-08-19|
    US20170003226A1|2017-01-05|
    GB2541110B|2017-12-20|
    DE102016008084B4|2019-03-28|
    DE102016008084A1|2017-01-05|
    FR3038385B1|2020-03-20|
    GB201611283D0|2016-08-10|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20150131091A1|2013-11-14|2015-05-14|Malcolm Smith|Moving laser focus in a spectrometer|
    DE2952885C2|1978-06-20|1986-01-30|Sumitomo Metal Industries, Ltd., Osaka|Device for non-contact ultrasonic flaw testing|
    EP0633541A1|1993-07-06|1995-01-11|Opticon Sensors Europe B.V.|Scanning device|
    US7961235B2|2003-10-31|2011-06-14|Hewlett-Packard Development Company, L.P.|Imaging apparatuses, image data processing methods, and articles of manufacture|
    GB0426993D0|2004-12-09|2005-01-12|Council Cent Lab Res Councils|Apparatus for depth-selective raman spectroscopy|
    US8970838B2|2011-04-29|2015-03-03|Avolonte Health LLC|Method and apparatus for evaluating a sample through variable angle Raman spectroscopy|GB201511574D0|2015-07-01|2015-08-12|Stfc Science & Technology|Clinical thermometer|
    GB201618260D0|2016-10-28|2016-12-14|Science And Tech Facilities Council The|Detection of pH|
    CN107884389A|2017-12-26|2018-04-06|同方威视技术股份有限公司|Raman spectrum detection device and method|
    CN108489962B|2018-04-11|2021-01-29|中科凯利仪器设备有限公司|Biological tissue detection device based on spatial migration Raman spectroscopy|
    WO2019205052A1|2018-04-26|2019-10-31|深圳达闼科技控股有限公司|Substance detection method and detection terminal, and computer-readable storage medium|
    CN110687097A|2019-10-25|2020-01-14|北京华泰诺安探测技术有限公司|Raman spectrum system with tunable excitation light frequency and detection method thereof|
    CN110987898A|2019-12-06|2020-04-10|中国科学院合肥物质科学研究院|Spatial heterodyne offset Raman spectrum detection device and detection method thereof|
    GB202016873D0|2020-10-23|2020-12-09|Rsp Systems As|Apparatus and method for non-invasive in vivo measurements of analyte presence or concentration|
    CN113092446A|2021-05-21|2021-07-09|厦门大学|90-degree Raman signal collection plane optical path system based on dove prism|
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    2018-03-30| TP| Transmission of property|Owner name: AGILENT TECHNOLOGIES LDA UK LIMITED, GB Effective date: 20180219 |
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    优先权:
    申请号 | 申请日 | 专利标题
    GBGB1511696.5A|GB201511696D0|2015-07-03|2015-07-03|Scanner for spatially offset raman spectrscopy|
    GB1511696.5|2015-07-03|
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