Optical wave full-transmission adaptive device suitable for biological tissue

Abstract

The present application belongs to the field of biomedicine, and relates to a wavefront shaping device for biological tissue, and particularly provides a light wave full-transmission adaptive device suitable for biological tissue, which is used to make a to-be-measured medium fully transmit detection laser. The present application comprises a holographic measurement system and a light modulation system. The holographic measurement system is used to measure a forward reflection matrix of the to-be-measured medium. The light modulation system comprises a spatial light modulator and a computer. The computer calculates a complementary medium forward transmission matrix according to the forward reflection matrix of the to-be-measured medium. The spatial light modulator loads the forward transmission matrix of the complementary medium under the control of the computer, forms a forward compensation matrix plate, and serves as an equivalent complementary medium of the to-be-measured medium, so that the to-be-measured medium fully transmits the detection laser. The present application can eliminate the loss caused by backward scattering during the propagation of light waves in biological tissue, and significantly improves the detection efficiency in the field of biological medical treatment.

Description

Technical Field

[0001] This invention belongs to the field of biomedicine and relates to a non-invasive detection technology for the concentration of specific components in human tissue fluid. It further relates to a wavefront shaping device for biological tissues to achieve full transmission of detection light waves to biological tissues. Specifically, it provides an adaptive device for full transmission of light waves suitable for biological tissues. Background Technology

[0002] In the biomedical field, optical detection technology has been widely used. For example, patent document CN 110811636 A discloses a photoacoustic non-invasive blood glucose meter that uses lasers to perform non-invasive measurements of blood glucose and blood pressure. However, these optical detection technologies all have a problem that cannot be ignored: due to the complex composition and irregular shape of biological tissues, biological tissues are usually regarded as strong chaotic scatterers in optics. This type of strong scatterer has a strong forward and backscattering effect on incident light. Especially in detection technologies that utilize the light absorption of biological tissues, the strong backscattering generated by biological tissues often reduces the detection depth of forward scattered light, resulting in a significant reduction in optical detection efficiency and interference with detection results.

[0003] To address the aforementioned problems, researchers have proposed several solutions, the core of which lies in reducing backscattering of light waves in biological tissues by modulating specific wavelengths. For example, patent document CN 113252613 B discloses a wavefront-shaping-based scattering medium absorption enhancement device and system. However, for most non-ex vivo biological tissues, their transmission matrix is ​​usually unavailable, thus limiting the widespread application of this technology for biological tissue information detection. Another example is the method for designing complementary media disclosed in the document "Anti-reflection structure for perfect transmission through complexmedia." This method searches for specific media materials as complementary media to the test medium, thereby eliminating backscattering of incident light waves by the test medium. However, not all test media have readily available complementary media, and this method is too costly and difficult to popularize. Therefore, this invention proposes an adaptive wavefront shaping system for biological tissues, specifically an adaptive device for full transmission of light waves in biological tissues, to achieve full transmission of detection light waves by biological tissues. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive light wave transmission device suitable for biological tissues, which serves as a wavefront shaping device for biological tissues. This device eliminates the loss caused by backscattering during the propagation of light waves in biological tissues, thereby achieving full transmission of detection light waves to biological tissues. In the field of biomedical optical detection technology for deep biological tissues, the adaptive light wave transmission device provided by this invention can significantly improve detection efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An adaptive optical wave transmission device suitable for biological tissues, comprising: a holographic measurement system and an optical modulation system; characterized in that:

[0007] The holographic measurement system is used to measure the forward reflection matrix r of the medium under test. R ;

[0008] The optical modulation system includes a spatial light modulator and a computer, wherein the computer determines the optical modulation based on the forward reflection matrix r of the medium under test. R The forward reflection matrix r of the complementary medium corresponding to the medium under test is calculated. L Then, the positive transmission matrix t of the complementary medium is obtained by using deep learning network inference. L The spatial light modulator, under computer control, loads the positive transmission matrix t of the complementary medium. L This forms a positive compensation matrix plate, which serves as an equivalent complementary medium to the medium under test, allowing the medium under test to be fully transmitted to the detection laser.

[0009] Furthermore, the holographic measurement system includes: a first collimating lens, a spatial filter, a second collimating lens, a planar beam splitter, a spatial light modulator, a third collimating lens, a fourth collimating lens, a prism-type beam splitter, a focusing lens, an objective lens, a first plane mirror, a second plane mirror, a CCD camera, and a computer. The measurement laser beam, after passing through the first collimating lens, the spatial filter, and the second collimating lens, is split into a probe beam and a reference beam by the planar beam splitter. The probe beam passes through the first and second plane mirrors, reaches the prism-type beam splitter, and then, after passing through the focusing lens and the objective lens, is incident directly onto the surface of the medium under test. The reflected light generated by the medium under test returns along its original path and propagates to the CCD camera via the prism-type beam splitter. The reference beam undergoes phase modulation by the spatial light modulator, then passes through the third and fourth collimating lenses, reaches the prism-type beam splitter, and propagates to the CCD camera. The reflected light and the reference light interfere during propagation, and the interference fringes are received by the CCD camera and transmitted to the computer.

[0010] The spatial light modulator modulates the phase of the reference light under computer control. The phase of the reference light is adjusted by the computer, and the measurement is repeated after each adjustment. After repeating 2 to 4 times, the forward reflection matrix r of the medium under test is reconstructed from the interference fringes using the phase-shifting method. R .

[0011] Furthermore, the optical modulation system also includes: a first collimating lens, a spatial filter, a second collimating lens, a third collimating lens, a fourth collimating lens, a focusing lens, and an objective lens. The detection laser passes through the first collimating lens, the spatial filter, and the second collimating lens before reaching the forward compensation matrix plate. After phase and amplitude compensation is performed by the forward compensation matrix plate, the laser passes through the third collimating lens, the fourth collimating lens, the focusing lens, and the objective lens before being incident directly onto the surface of the medium under test. The medium under test is fully transparent to the detection laser.

[0012] It should be noted that the holographic measurement system and the optical modulation system in this invention both include: a first collimating lens, a spatial filter, a second collimating lens, a spatial light modulator, a third collimating lens, a fourth collimating lens, a focusing lens, an objective lens, and a computer. The above devices can be reused or set up separately.

[0013] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0014] This invention provides an adaptive device for full transmission of light waves suitable for biological tissues. It serves as a wavefront shaping device for biological tissues, eliminating the loss caused by backscattering during the propagation of light waves in biological tissues and achieving full transmission of detection light waves to biological tissues. In the field of biomedical optical detection technology for deep biological tissues, especially in detection technology that utilizes the absorption of light by biological tissues, the adaptive device for full transmission of light waves can significantly improve detection efficiency.

[0015] Furthermore, the optical wave full transmission adaptive device provided by this invention also has the following advantages:

[0016] 1) Adaptability: For any medium under test, this invention obtains the forward reflection matrix r of the medium under test through a holographic measurement system. R Then, through calculation and reasoning, the positive transmission matrix t of the complementary medium is obtained. L And in the optical modulation system, a positive transmission matrix t of a complementary medium is used. L The spatial light modulator forms a positive compensation matrix plate and serves as an equivalent complementary medium, enabling the medium under test to be fully transparent to the detection laser. In this process, both the holographic measurement system and the optical modulation system are adaptively completed for the medium under test, which not only effectively improves the detection efficiency of optical detection technology and reduces the detection cost, but also significantly expands the application scope of optical detection technology.

[0017] 2) Versatility: In the optical modulation system of the present invention, the positive compensation matrix plate serves as a virtual complementary medium, enabling the optical wave full transmission adaptive device of the present invention to be applicable to any test medium, especially those test media for which a corresponding complementary medium cannot be found in reality, especially various biological tissues.

[0018] 3) Non-invasive: This invention does not alter the physicochemical properties or shape of the test medium, nor does it require invasive treatment of the medium. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of random matrix theory.

[0020] Figure 2 This is a schematic diagram of the working process of the adaptive light wave transmission device for biological tissues in this invention.

[0021] Figure 3 This is a schematic diagram of the measurement system in the optical wave full transmission adaptive device for biological tissues in this invention; wherein, 1 is the first collimating lens, 2 is the spatial filter, 3 is the second collimating lens, 4 is the plane beam splitter, 5 is the third collimating lens, 6 is the fourth collimating lens, 7 is the prism-type beam splitter, 8 is the focusing lens, 9 is the objective lens, 10 is the first plane mirror, and 11 is the second plane mirror.

[0022] Figure 4 This is a schematic diagram of the modulation system in the optical wave full transmission adaptive device for biological tissues in this invention.

[0023] Figure 5 This is a schematic diagram of the structure of the non-invasive detection device for human tissue component concentration based on the earlobe in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] This invention provides an adaptive device for full transmission of light waves to biological tissues. As a wavefront shaping device for biological tissues, it enables full transmission of detection light waves to biological tissues, eliminates the loss caused by backscattering of detection light waves during propagation in biological tissues, and thus significantly improves the detection depth.

[0026] In terms of working principle:

[0027] According to the theory of random matrices, the propagation of light waves in a non-absorbing medium can be divided into forward scattering (transmission) and backscattering (reflection). In this theory, the propagation of light waves in a non-absorbing medium can be represented by a scattering matrix S:

[0028]

[0029] like Figure 1 As shown, in matrix S, r represents the forward reflection matrix (i.e., the reflected light component when the light wave propagates forward (from left to right) in the medium), t represents the forward transmission matrix (i.e., the transmitted light component when the light wave propagates forward in the medium), r′ represents the reverse reflection matrix, and t′ represents the reverse transmission matrix. If the intensity of the input light wave is an identity matrix and the phase is a binary distribution of 0-π, then the four parameters contained in matrix S can directly reflect the relationship between the reflection and transmission components of the medium, and can be used as a basis to calculate the reflected and transmitted light components after any incident light wave exits through the medium. The corresponding components can be represented by the four sub-matrices in matrix S.

[0030] Based on flux conservation, the following relationships can be derived for r, t, r′, and t′ in the scattering matrix S:

[0031] tt + +r′r′ + =I,rt + +t′ + r′ + =0

[0032] Where I is the identity matrix, · + This indicates Hermetic conjugation.

[0033] Based on this, in order to achieve full transmission of light waves in the medium, two media with complementary optical properties are required, such as... Figure 1 As shown, the two media are tightly bonded, S L With S R Let represent the scattering matrices of the left and right media respectively, and let S represent the overall scattering matrix. Using the previously derived relationships within the scattering matrix S, we can deduce that when the left and right media satisfy the relationship... time (r) L ′ represents the back reflection matrix of the medium on the left, r R (representing the forward reflection matrix of the right-side medium). For the whole composed of the left and right media, the reflection component (forward reflection matrix) during forward propagation becomes 0; this means that the light wave passes through the entire medium without reflection, that is, the light wave achieves full transmission; furthermore, for media that can absorb light, the above theory still holds, and the left-side medium that satisfies this relationship can be called the fully transmission complementary medium of the right-side medium.

[0034] Based on the above principles, this invention proposes a fully transparent adaptive optical transmissivity device based on a spatial light modulator, comprising: a holographic measurement system and an optical modulation system, the principle of which is as follows: Figure 2As shown; wherein, the holographic measurement system is used to obtain the forward reflection matrix of the medium under test, and based on the forward reflection matrix, in conjunction with a deep learning network, to obtain the forward transmission matrix of the complementary medium. Then, the forward transmission matrix of the complementary medium is loaded onto the spatial light modulator of the optical modulation system, making it a forward compensation matrix plate (equivalent to the complementary medium of the medium under test), and then the modulation system enables the medium under test to fully transmit the detection light wave.

[0035] The specific process is as follows, wherein the medium to be tested is assumed to be a biological tissue-like medium with strong scattering and strong absorption;

[0036] 1. Measurement of the forward reflection matrix of the medium under test

[0037] The forward reflection matrix (r) of the medium under test R The measurement will be based on holography, in which light waves are regarded as complex functions consisting of amplitude and phase. Spatial light modulators can modulate the amplitude and phase of light respectively. It can be seen that holography is perfectly compatible with the modulation method of this invention.

[0038] The holographic measurement system used in this invention is as follows: Figure 3 As shown, the laser emitted by the laser is first collimated and denoised by collimating lens 1, spatial filter 2, and collimating lens 3. The obtained laser at this point can be considered as a plane wave. The collimated laser passes through plane beam splitter 4 to obtain probe light directed to plane mirror 10 and reference light directed to spatial light modulator 7. The probe light is reflected by plane mirrors 10 and 11 and reaches beam splitter 7. The probe light passes through beam splitter 7, focusing lens 8, and objective lens 9 and is incident directly onto the surface of the medium under test. Since the probe light is incident directly onto the surface of the medium under test, the reflected light generated by the medium under test (represented by dashed lines in the figure) will return along the same path and propagate to CCD through beam splitter 7. The reference light, after phase modulation by the spatial light modulator 7, passes through collimating lenses 5 and 6 to reach the beam splitter 7, and then propagates to the CCD. The reflected light and reference light interfere during propagation, and the interference fringes are received by the CCD. The interference fringes recorded by the CCD simultaneously record the amplitude and phase information of the forward reflected light wave of the test medium required by this invention. The interference fringes are transmitted to the computer and stored. This process is repeated 2 to 4 times to obtain interference fringes corresponding to reference lights with different phases. Finally, the amplitude and phase information of the forward reflected light wave of the test medium are reconstructed from the interference fringes using the phase-shifting method to obtain the forward reflection matrix r of the test medium. R .

[0039] Furthermore, the spatial light modulator, under computer control, performs phase modulation of the reference light, making the phase information of the reference light known a priori, and the objective lens 9 is used to expand the detection light area.

[0040] 2. Obtaining the forward transmission matrix of complementary media

[0041] The optical modulation system used in this invention is as follows: Figure 4 As shown, in the optical modulation device, a spatial light modulator is used as the forward compensation matrix plate, which, under computer control, can be equivalent to the complementary medium of the medium under test. Since the forward compensation matrix plate is not a true complementary medium, it can be regarded as a left-right symmetrical medium, that is, the forward and reverse propagation processes of light are completely consistent: r L =r L ′,t L =t′ L ;

[0042] Then, utilizing the complementary condition, the forward reflection matrix r of the medium under test is obtained. R The positive reflection matrix r of the complementary medium is obtained. L :

[0043] r L + =r R ;

[0044] Furthermore, in the theory of random matrices, there is a strong correlation between the reflection matrix *r* and the transmission matrix *t* in the same direction. Therefore, a deep learning network (CNN network) can be used to model the relationship between them, thereby inferring the transmission matrix in the corresponding direction from the reflection matrix. Thus, based on the positive reflection matrix *r* of the complementary medium... L The positive transmission matrix t of the complementary medium is obtained. L The specific process is well-known in the field and will not be described in detail here.

[0045] The positive transmission matrix t of the complementary medium L The light is loaded onto the spatial light modulator, which acts as a positive compensation matrix plate, allowing the medium under test to fully transmit the incident light wave.

[0046] It should also be noted that, on the one hand, light intensity is a linear unit, and the light intensity of any incident light wave can be expressed as a multiple of the light intensity used in the measurement system. For an incident light wave with a known intensity, this invention can linearly adjust the amplitude (without changing the phase) of the positive transmission matrix of the complementary medium loaded on the positive compensation matrix plate. Through modulation of the positive compensation matrix plate, the medium under test achieves full transparency to the incident light wave, thus realizing adaptive adjustment. On the other hand, for any medium under test, this invention only needs to measure the positive reflection matrix of the medium under test using the measurement system, correspondingly obtaining the positive transmission matrix of the complementary medium. Then, using the positive compensation matrix plate loaded with the positive transmission matrix of the complementary medium, the medium under test achieves full transparency to the incident light wave, again realizing adaptive adjustment. Furthermore, this invention uses the positive compensation matrix plate to equivalently form a complementary medium, not a real complementary medium, making the light wave full transmission adaptive device applicable to any medium under test, especially those media for which a corresponding complementary medium cannot be found in reality.

[0047] Finally, this embodiment applies the above-mentioned light wave full transmission adaptive device to a non-invasive photoacoustic detection device for human tissue component concentration based on the earlobe, and its structure is as follows: Figure 5 As shown, this enables blood glucose concentration measurement, effectively improving measurement accuracy.

[0048] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A light wave full-transmission adaptive device suitable for biological tissues, comprising: Holographic measurement system and optical modulation system; characterized in that: The holographic measurement system is used to measure the forward reflection matrix r of the medium under test. R ; The optical modulation system includes a spatial light modulator and a computer, wherein the computer determines the optical modulation based on the forward reflection matrix r of the medium under test. R The forward reflection matrix r of the complementary medium corresponding to the medium under test is calculated. L Then, the positive transmission matrix t of the complementary medium is obtained by using deep learning network inference. L The spatial light modulator, under computer control, loads the positive transmission matrix t of the complementary medium. L This forms a positive compensation matrix plate, which serves as an equivalent complementary medium to the medium under test, allowing the medium under test to be fully transmitted to the detection laser.

2. The adaptive light wave transmission device for biological tissues according to claim 1, characterized in that, The holographic measurement system includes: a first collimating lens, a spatial filter, a second collimating lens, a planar beam splitter, a spatial light modulator, a third collimating lens, a fourth collimating lens, a prism-type beam splitter, a focusing lens, an objective lens, a first plane mirror, a second plane mirror, a CCD camera, and a computer. The measurement laser beam, after passing through the first collimating lens, the spatial filter, and the second collimating lens, is split into a probe beam and a reference beam by the planar beam splitter. The probe beam passes through the first and second plane mirrors, reaches the prism-type beam splitter, and then passes through the focusing lens and the objective lens before being incident directly onto the surface of the medium under test. The reflected light generated by the medium under test returns along the same path and propagates through the prism-type beam splitter to the CCD camera. The reference beam undergoes phase modulation by the spatial light modulator, then passes through the third and fourth collimating lenses, reaches the prism-type beam splitter, and propagates to the CCD camera. The reflected light and the reference light interfere during propagation, and the interference fringes are received by the CCD camera and transmitted to the computer. The spatial light modulator modulates the phase of the reference light under computer control. The phase of the reference light is adjusted by the computer, and the measurement is repeated after each adjustment. After repeating 2 to 4 times, the forward reflection matrix r of the medium under test is reconstructed from the interference fringes using the phase-shifting method. R .

3. The adaptive light wave transmission device for biological tissues according to claim 1, characterized in that, The optical modulation system further includes: a first collimating lens, a spatial filter, a second collimating lens, a third collimating lens, a fourth collimating lens, a focusing lens, and an objective lens. The detection laser passes through the first collimating lens, the spatial filter, and the second collimating lens before reaching the forward compensation matrix plate. After phase and amplitude compensation is completed by the forward compensation matrix plate, the laser passes through the third collimating lens, the fourth collimating lens, the focusing lens, and the objective lens before being incident directly onto the surface of the medium under test. The medium under test is fully transparent to the detection laser.

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