A longitudinal modulus and shear modulus synchronous detection device based on Brillouin scattering

Abstract

The application discloses a longitudinal modulus and shear modulus synchronous detection device based on Brillouin scattering, which comprises a signal generating system, a signal receiving system, a double-channel spectrometer system and a signal collecting system in a multi-angle Brillouin imaging system; the signal receiving system receives Brillouin scattering signals of specific angles; the double-channel spectrometer system divides the scattering signals into shear Brillouin and longitudinal Brillouin by changing the polarization state of the scattering signals; the signal collecting system realizes the synchronous collection of the shear modulus and the longitudinal modulus of a sample placed on a multi-dimensional displacement table at the same position; the multi-dimensional displacement table is controlled to realize the three-dimensional longitudinal modulus and shear modulus detection of biological tissues; the Brillouin scattering of the longitudinal and shear phonons of the symmetry axis of the biological tissues is measured, the longitudinal modulus and the shear modulus at the same frequency are further obtained, and thus the complete stiffness tensor of the biological tissues is characterized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of imaging technology, and in particular to a longitudinal modulus and shear modulus synchronous detection device based on Brillouin scattering. BACKGROUND

[0002] The detection technology based on Brillouin scattering uses a low-power focused laser beam and a high-resolution confocal spectrometer to measure the Brillouin frequency shift and linewidth at the focal point, realizing the detection of the viscoelasticity of biological tissues. Although previous studies have shown that the longitudinal elastic modulus measured by Brillouin spectroscopy is related to the Young's modulus of cells and tissues, both the longitudinal elastic modulus and the Young's modulus of hydrated materials are affected by the water content. The current Brillouin detection system cannot directly measure the Young's modulus, and the measured is the longitudinal modulus at high frequency, while other elastic detection systems usually measure the Young's modulus and shear modulus at low frequency, so they cannot be compared.

[0003] Considering the huge difference between the longitudinal modulus and the Young's modulus and the lack of prior correlation between the longitudinal modulus and the shear modulus, the present application proposes a longitudinal modulus and shear modulus synchronous detection device based on Brillouin scattering. SUMMARY

[0004] The present application aims to solve the technical problems existing in the prior art and provide a longitudinal modulus and shear modulus synchronous detection device based on Brillouin scattering.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present application is: a longitudinal modulus and shear modulus synchronous detection device based on Brillouin scattering, comprising a signal generating system, a signal receiving system, a double-channel spectrometer system and a signal acquisition system in a multi-angle Brillouin imaging system; the signal receiving system receives Brillouin scattering signals at a specific angle, the double-channel spectrometer system divides the scattering signals into shear Brillouin and longitudinal Brillouin by changing the polarization state of the scattering signals, and realizes the synchronous acquisition of the shear modulus and the longitudinal modulus of the sample placed on the multi-dimensional displacement table at the same position through the signal acquisition system, and controls the multi-dimensional displacement table to realize the three-dimensional longitudinal modulus and shear modulus detection of biological tissues;

[0006] The double-channel spectrometer system is divided into two channels through a 1x2 optical fiber coupler; the first channel mainly comprises a first optical fiber collimator, a first cylindrical lens, a first virtual image phase array, a second cylindrical lens, a third mirror, a fourth mirror, a fifth plano-convex lens, a second virtual image phase array, a fifth mirror, and a sixth mirror; the second channel mainly comprises a second optical fiber collimator, a one-half wave plate, a first cylindrical lens, a first virtual image phase array, a second cylindrical lens, a seventh mirror, an eighth mirror, a sixth plano-convex lens, a third virtual image phase array, a ninth mirror, and a tenth mirror;

[0007] The first fiber collimator outputs 25% of the scattered light, and the second fiber collimator outputs 75% of the scattered light. After being compressed by the first cylindrical lens, the light is split by the first virtual image phase array. The split signal is collimated by the second cylindrical lens, and after passing through the third, fourth, and fifth plano-convex lenses, the longitudinal Brillouin signal is split by the second virtual image phase array. The sheared Brillouin signal passes through the seventh, eighth, and sixth plano-convex lenses, and is then split by the third virtual image phase array before finally being reflected to the signal acquisition system. By processing the longitudinal and sheared Brillouin spectra, the longitudinal and sheared Brillouin frequency shifts can be obtained, and the longitudinal modulus and shear modulus can be calculated.

[0008] Preferably, the signal generation system in the multi-angle Brillouin imaging system consists of a narrow-linewidth laser, a beam expander lens group, a first reflecting mirror, and a first microscope objective. The narrow-linewidth laser emits a laser beam, which is expanded by the beam expander lens group and then reflected by the first reflecting mirror to the first microscope objective, where it is focused onto the sample. The signal receiving system in the multi-angle Brillouin imaging system consists of a second microscope objective, a second reflecting mirror, a beam collimation system, and a spatial optical coupler. In the signal receiving system, the lateral Brillouin scattering signal light excited by the focused light at the sample is collected by the second microscope objective, reflected by the second reflecting mirror to the beam collimation system, and the collimated beam is coupled into an optical fiber by the spatial optical coupler.

[0009] Preferably, the beam expanding lens group includes a first plano-convex lens, a first aperture stop, and a second plano-convex lens; the beam collimation system includes a third plano-convex lens, a second aperture stop, and a fourth plano-convex lens.

[0010] Preferably, the narrow linewidth laser outputs a vertically polarized laser beam, and the generated scattered signal is mostly vertically polarized. The polarization state of the longitudinal phonons is consistent with the polarization state of the incident light. After the scattered light passes through the half-wave plate, the polarization state of the scattered light is orthogonal to the polarization state of the incident light, thereby detecting the Brillouin scattering signal caused by sheared phonons.

[0011] Preferably, the signal acquisition system consists of a large-aperture zoom lens and a CMOS camera; the large-aperture zoom lens is used to acquire longitudinal Brillouin signals and sheared Brillouin signals, and the optical path lengths of the two channels in the dual-channel spectrometer system are consistent to ensure that longitudinal Brillouin signals and sheared Brillouin scattering signals are acquired simultaneously.

[0012] Preferably, the first channel and the second channel share the first cylindrical lens, the first virtual image phase array, and the second cylindrical lens.

[0013] Preferably, the coupling ratio of the 1×2 fiber coupler is 75:25.

[0014] Preferably, the signal receiving system collects non-180° scattered signals because the Brillouin scattered signals at a backward 180° angle do not include Brillouin scattered signals caused by sheared phonons.

[0015] Beneficial effects of this invention:

[0016] This invention obtains the longitudinal modulus and shear modulus at the same frequency by measuring the longitudinal axis of symmetry of biological tissue and the Brillouin scattering of shear phonons, thereby characterizing the complete stiffness tensor of biological tissue. This breakthrough overcomes the problem that the longitudinal modulus of Brillouin detection technology cannot be mutually verified with other biomechanical parameters. Attached Figure Description

[0017] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the multi-angle Brillouin imaging system of the present invention;

[0019] Figure 2 This is a schematic diagram of the off-axis confocal Brillouin imaging system of the present invention;

[0020] Figure 3 This is a schematic diagram of the dual-channel spectrometer system of the present invention.

[0021] Attached image captions:

[0022] 1- Narrow linewidth laser, 2- First plano-convex lens, 3- First aperture, 4- Second plano-convex lens, 5- First reflecting mirror, 6- Second reflecting mirror, 7- Third plano-convex lens, 8- Second aperture, 9- Fourth plano-convex lens, 10- Spatial optical coupler, 11- Dual-channel spectrometer system, 12- Sample, 13- Multidimensional displacement stage, 14- First microscope objective, 15- Second microscope objective, 16- Third microscope objective, 17- 1×2 fiber optic coupler, 18- First fiber optic collimator, 19- Second fiber optic Collimator, 20-half-wave plate, 21-first cylindrical lens, 22-first virtual image phase array, 23-second cylindrical lens, 24-third reflecting mirror, 25-fourth reflecting mirror, 26-fifth plano-convex lens, 27-second virtual image phase array, 28-fifth reflecting mirror, 29-sixth reflecting mirror, 30-large aperture zoom lens, 31-CMOS camera, 32-seventh reflecting mirror, 33-eighth reflecting mirror, 34-sixth plano-convex lens, 35-third virtual image phase array, 36-tenth reflecting mirror. Detailed Implementation

[0023] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0024] In this invention, the multi-angle Brillouin imaging system can be replaced with an off-axis confocal Brillouin imaging system.

[0025] Example 1

[0026] Reference Figures 1-3 According to a preferred embodiment of the present invention, a device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering is provided. The device includes a signal generation system, a signal receiving system, and a dual-channel spectrometer system 11 in a multi-angle Brillouin imaging system. The signal receiving system receives Brillouin scattering signals at specific angles. The dual-channel spectrometer system 11 divides the scattering signals into shear Brillouin and longitudinal Brillouin by changing the polarization state of the scattering signals. The signal acquisition system realizes the simultaneous acquisition of shear modulus and longitudinal modulus at the same position of the sample 12 placed on the multi-dimensional displacement stage 13. The multi-dimensional displacement stage 13 is controlled to realize the detection of three-dimensional longitudinal modulus and shear modulus of biological tissue.

[0027] like Figure 1 and Figure 2 As shown, the signal generation system in the multi-angle Brillouin imaging system consists of a narrow-linewidth laser 1, a beam-expanding lens group (a first plano-convex lens 2, a first aperture 3, and a second plano-convex lens 4), a first reflecting mirror 5, and a first microscope objective 14. The narrow-linewidth laser 1 emits a laser beam, which is expanded by the beam-expanding lens group and reflected by the first reflecting mirror 5 to the first microscope objective 14, where it is focused onto the sample 12. The sample 12 is placed on a multi-dimensional displacement stage 13, and the multi-dimensional displacement stage 13 is controlled to detect the three-dimensional longitudinal modulus and shear modulus of the biological tissue.

[0028] The signal receiving system in the multi-angle Brillouin imaging system consists of a second microscope objective 15, a second mirror 6, a beam collimation system, and a spatial optical coupler 10. In the signal receiving system, the lateral Brillouin scattered signal light excited by the focused light at the sample 12 is collected by the second microscope objective 15 and reflected by the second mirror 6 to the beam collimation system. The collimated beam is then coupled into the optical fiber by the spatial optical coupler 10.

[0029] like Figure 3 As shown, Figure (b) is a top view of Figure (a). The dual-channel spectrometer system 11 is divided into two channels by a 1×2 fiber optic coupler 17; the coupling ratio of the 1×2 fiber optic coupler 17 is 75:25.

[0030] The first channel mainly comprises a first fiber collimator 18, a first cylindrical lens 21, a first virtual image phase array 22, a second cylindrical lens 23, a third reflecting mirror 24, a fourth reflecting mirror 25, a fifth plano-convex lens 26, a second virtual image phase array 27, a fifth reflecting mirror 28, and a sixth reflecting mirror 29; the second channel mainly comprises a second fiber collimator 19, a half-wave plate 20, a first cylindrical lens 21, a first virtual image phase array 22, a second cylindrical lens 23, a seventh reflecting mirror 32, an eighth reflecting mirror 33, a sixth plano-convex lens 34, a third virtual image phase array 35, a ninth reflecting mirror 36, and a tenth reflecting mirror 37.

[0031] The first fiber collimator 18 outputs 25% of the scattered light, and the second fiber collimator 19 outputs 75% of the scattered light. After being compressed by the first cylindrical lens 21, the light is split by the first virtual image phase array 22. The split signal is collimated by the second cylindrical lens 23, and after passing through the third mirror 24, the fourth mirror 25 and the fifth plano-convex lens 26, the longitudinal Brillouin signal is split by the second virtual image phase array 27, and the sheared Brillouin signal is split by the third virtual image phase array 35 after passing through the seventh mirror 32, the eighth mirror 33 and the sixth plano-convex lens 34, and finally reflected to the signal acquisition system. By processing the longitudinal Brillouin spectrum and the sheared Brillouin spectrum, the longitudinal and sheared Brillouin frequency shifts can be obtained, and the longitudinal modulus and shear modulus can be calculated.

[0032] In this embodiment, the narrow linewidth laser 1 outputs a laser beam with a vertical polarization state, and the generated scattered signal is mostly in a vertical polarization state. The polarization state of the longitudinal phonons is consistent with the polarization state of the incident light. After the scattered light passes through the half-wave plate 20, the polarization state of the scattered light is orthogonal to the polarization state of the incident light, thereby detecting the Brillouin scattering signal caused by sheared phonons.

[0033] In this embodiment, the first channel and the second channel share the first cylindrical lens 21, the first virtual image phase array 22, and the second cylindrical lens 23, reducing the number of components used and lowering costs.

[0034] In this embodiment, the signal acquisition system consists of a large-aperture zoom lens 30 and a CMOS camera 31. The large-aperture zoom lens 30 is used to acquire longitudinal Brillouin signals and sheared Brillouin signals. The optical path lengths of the two channels in the dual-channel spectrometer system 11 are consistent to ensure that longitudinal Brillouin signals and sheared Brillouin scattering signals are acquired simultaneously.

[0035] In this embodiment, the scattered signal collected by the signal receiving system is not 180° because the Brillouin scattering signal at a backward 180° angle does not include the Brillouin scattering signal caused by sheared phonons.

[0036] Specifically, the signal generation system excites a Brillouin scattering signal, the signal receiving system receives the Brillouin scattering signal at a specific angle, and the dual-channel spectrometer system 11 divides the scattered signal into shear Brillouin and longitudinal Brillouin by changing the polarization state of the scattered signal. The signal acquisition system then simultaneously acquires the shear modulus and longitudinal modulus of the sample 12 placed on the multidimensional displacement stage 13 at the same position. The polarization state of the scattered light from the shear phonons is orthogonal to the polarization state of the incident light, while the polarization state of the longitudinal phonons is consistent with the polarization state of the incident light.

[0037] The advantage of this invention is that by measuring the Brillouin scattering of longitudinal and shear phonons along the symmetry axis of biological tissue, the longitudinal modulus and shear modulus at the same frequency can be obtained, thereby characterizing the complete stiffness tensor of biological tissue. This invention improves the elasticity detection time of the Brillouin scattering elastography system, reduces the differences caused by tissue degeneration, and avoids potential damage to living biological tissues. It is of great significance for applying the Brillouin scattering elastography system to clinical elasticity detection.

[0038] Example 2

[0039] When the multi-angle Brillouin imaging system can be replaced by an off-axis confocal Brillouin imaging system, the signal generation system consists of a narrow-linewidth laser 1, a beam expander lens group (first plano-convex lens 2, first aperture 3, and second plano-convex lens 4), a first reflecting mirror 5, and a third microscope objective 16.

[0040] In the signal generation system, the narrow linewidth laser 1 emits a laser beam, which is expanded by the beam expanding lens group and reflected by the first reflecting mirror 5 to the third microscope objective 16, and then focused onto the sample 12 by the third microscope objective 16; the sample 12 is placed on the multidimensional displacement stage 13, and the multidimensional displacement stage 13 is controlled to realize the detection of the three-dimensional longitudinal modulus and shear modulus of biological tissue.

[0041] This invention obtains the longitudinal modulus and shear modulus at the same frequency by measuring the longitudinal axis of symmetry of biological tissue and the Brillouin scattering of shear phonons, thereby characterizing the complete stiffness tensor of biological tissue. This breakthrough overcomes the problem that the longitudinal modulus of Brillouin detection technology cannot be mutually verified with other biomechanical parameters.

[0042] Without causing conflict, those skilled in the art can freely combine and use the above-mentioned additional technical features.

[0043] The above description is only a preferred embodiment of the present invention. Any technical solution that achieves the purpose of the present invention by essentially the same means is within the protection scope of the present invention.

Claims

1. A device for simultaneously detecting longitudinal modulus and shear modulus based on Brillouin scattering, characterized in that: The system includes a signal generation system, a signal receiving system, a dual-channel spectrometer system (11), and a signal acquisition system in the multi-angle Brillouin imaging system. The signal receiving system receives Brillouin scattering signals at specific angles. The dual-channel spectrometer system (11) divides the scattering signals into shear Brillouin and longitudinal Brillouin by changing the polarization state of the scattering signals. The signal acquisition system enables the synchronous acquisition of shear modulus and longitudinal modulus at the same position of the sample (12) placed on the multi-dimensional displacement stage (13). The multi-dimensional displacement stage (13) is controlled to detect the three-dimensional longitudinal modulus and shear modulus of biological tissues. The dual-channel spectrometer system (11) is divided into two channels by a 1×2 fiber coupler (17); the first channel mainly consists of a first fiber collimator (18), a first cylindrical lens (21), a first virtual image phase array (22), a second cylindrical lens (23), a third mirror (24), a fourth mirror (25), a fifth plano-convex lens (26), a second virtual image phase array (27), a fifth mirror (28), and a sixth mirror (29); the second channel mainly consists of a second fiber collimator (19), a half-wave plate (20), a first cylindrical lens (21), a first virtual image phase array (22), a second cylindrical lens (23), a seventh mirror (32), an eighth mirror (33), a sixth plano-convex lens (34), a third virtual image phase array (35), a ninth mirror (36), and a tenth mirror (37); The first fiber collimator (18) outputs 25% of the scattered light, and the second fiber collimator (19) outputs 75% of the scattered light. After being compressed by the first cylindrical lens (21), the light is split by the first virtual image phase array (22). The split signal is collimated by the second cylindrical lens (23), and after passing through the third mirror (24), the fourth mirror (25) and the fifth plano-convex lens (26), the longitudinal Brillouin signal is split by the second virtual image phase array (27), and the sheared Brillouin signal is split by the third virtual image phase array (35) after passing through the seventh mirror (32), the eighth mirror (33) and the sixth plano-convex lens (34), and finally reflected to the signal acquisition system. By processing the longitudinal Brillouin spectrum and the sheared Brillouin spectrum, the longitudinal and sheared Brillouin frequency shifts can be obtained, and the longitudinal modulus and shear modulus can be calculated.

2. The device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering according to claim 1, characterized in that: The signal generation system in the multi-angle Brillouin imaging system consists of a narrow-linewidth laser (1), a beam expander lens group, a first reflecting mirror (5), and a first microscope objective (14). The narrow-linewidth laser (1) emits a laser beam, which is expanded by the beam expander lens group and then reflected by the first reflecting mirror (5) to the first microscope objective (14), which focuses the beam onto the sample (12). The signal receiving system in the multi-angle Brillouin imaging system consists of a second microscope objective (15), a second reflecting mirror (6), a beam collimation system, and a spatial optical coupler (10). In the signal receiving system, the lateral Brillouin scattering signal light excited by the focused light at the sample (12) is collected by the second microscope objective (15) and reflected by the second reflecting mirror (6) to the beam collimation system. The collimated beam is then coupled into the optical fiber by the spatial optical coupler (10).

3. The device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering according to claim 1, characterized in that: The beam expanding lens group includes a first plano-convex lens (2), a first aperture (3), and a second plano-convex lens (4); the beam collimation system includes a third plano-convex lens (7), a second aperture (8), and a fourth plano-convex lens (9).

4. The device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering according to claim 1, characterized in that: The narrow linewidth laser (1) outputs a laser beam with a vertical polarization state. Most of the scattered signals generated are in a vertical polarization state. The polarization state of the longitudinal phonons is consistent with the polarization state of the incident light. After the scattered light passes through the half-wave plate (20), the polarization state of the scattered light is orthogonal to the polarization state of the incident light, and then the Brillouin scattering signal caused by shearing phonons is detected.

5. The device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering according to claim 1, characterized in that: The signal acquisition system consists of a large-aperture zoom lens (30) and a CMOS camera (31). The large-aperture zoom lens (30) is used to acquire longitudinal Brillouin signals and sheared Brillouin signals. The optical path lengths of the two channels in the dual-channel spectrometer system are consistent to ensure that longitudinal Brillouin signals and sheared Brillouin scattering signals are acquired simultaneously.

6. The device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering according to claim 1, characterized in that: The coupling ratio of the 1×2 fiber coupler is 75:

25.

7. The device for simultaneous detection of longitudinal modulus and shear modulus based on Brillouin scattering according to claim 1, characterized in that: The reason why the signal receiving system collects non-180° scattered signals is that the Brillouin scattered signals at a back 180° angle do not include Brillouin scattered signals caused by sheared phonons.

Images