Optical coherence tomography system

Abstract

The invention relates to the technical field of optical imaging, and discloses an optical coherence tomography system, which comprises a light emitting unit, a first optical fiber, a first single-mode coupling unit, a second optical fiber, a third optical fiber, a sample arm unit and a reference arm unit, the distance between the sorting unit and the first reflection unit is different from the distance between the sorting unit and the second reflection unit, so that the optical path of the reflected third light beam is different from the optical path of the reflected fourth light beam, and on the basis, the coherent frequency of a first interference light beam formed after interference of the reflected third light beam and the sample light beam is higher than the coherent frequency of a second interference light beam. The coherent frequency is different from the coherent frequency of a second interference light beam formed after interference of the reflected fourth light beam and the sample light beam, so that the situation that in the first interference light beam and the second interference light beam, light rays with similar coherent frequencies and orthogonal polarization directions are coupled, and artifacts appear in imaging of the optical coherence tomography system is avoided; according to the optical coherence tomography system, the technical effect of improving the imaging accuracy can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging, and in particular to an optical coherence tomography system. Background Art

[0002] Optical coherence tomography is a non-invasive, high-resolution cross-sectional tomographic optical imaging technology that obtains structural information inside biological tissue samples by analyzing optical interference signals. This technology has the advantages of being non-destructive, non-contact, high-resolution and fast imaging, and is therefore widely used in imaging and other fields.

[0003] Polarization optical coherence tomography is an important development direction of optical coherence tomography technology. It adds the specific presentation of the tissue distribution of the birefringence characteristics of the sample on the basis of traditional optical coherence tomography, thereby enhancing the accuracy of the imaging results. Among them, birefringence refers to the different refractive indices of the material for light in two orthogonal polarization directions. By detecting the changes in polarization direction at different depths after polarized light irradiates the sample, polarization optical coherence tomography can provide information about the polarization characteristics of the sample, such as phase delay and depolarization.

[0004] Polarization optical coherence tomography requires the use of optical interference signals with orthogonal polarization directions to interfere with the birefringence information inside the sample in order to obtain the image information of the sample. However, in this process, the two optical interference signals with similar coherence frequencies and orthogonal polarization directions often couple with each other. This coupling will cause artifacts in the reconstructed structural image, that is, erroneous signals appear in the image that are not caused by the structure inside the sample, causing image distortion. Summary of the invention

[0005] In view of this, the present invention provides an optical coherence tomography imaging system to solve the problem that artifacts exist in the structural image reconstructed by the existing polarization optical coherence tomography, resulting in image distortion.

[0006] The present invention provides an optical coherence tomography system, comprising:

[0007] A light emitting unit, used for emitting a laser beam;

[0008] A first optical fiber, one end of which is connected to the light-emitting unit;

[0009] a first single-mode coupling unit, the first single-mode coupling unit comprising a first end, a second end, a third end and a fourth end, the first end being connected to the other end of the first optical fiber, the first single-mode coupling unit being used to split the laser beam into a first beam and a second beam;

[0010] a second optical fiber, one end of which is connected to the second end and is used to transmit the first light beam;

[0011] a third optical fiber, one end of which is connected to the fourth end and is used to transmit the second light beam;

[0012] a sample arm unit connected to the other end of the third optical fiber, and used to transmit the second light beam to the surface of the sample to be imaged, and the sample light beam scattered back by the sample to be imaged is transmitted to the first single-mode coupling unit through the sample arm unit and the third optical fiber;

[0013] A reference arm unit connected to the other end of the second optical fiber, the reference arm unit comprising:

[0014] A sorting unit, one end of which is connected to the other end of the second optical fiber, and is used to split the first light beam into two light beams with orthogonal polarization directions, namely a third light beam and a fourth light beam;

[0015] a first reflecting unit, connected to the other end of the sorting unit, and configured to reflect the third light beam into the first single-mode coupling unit;

[0016] A second reflecting unit is connected to the other end of the sorting unit, and is used to reflect the fourth light beam into the first single-mode coupling unit. The distance between the second reflecting unit and the other end of the sorting unit is different from the distance between the first reflecting unit and the other end of the sorting unit, so that the optical path of the third light beam after reflection is different from the optical path of the fourth light beam after reflection.

[0017] Beneficial effect: By making the distance between the sorting unit and the first reflecting unit different from the distance between the sorting unit and the second reflecting unit, the optical path of the reflected third light beam is different from the optical path of the reflected fourth light beam. Based on this, when the coherence frequency of the first interference light beam formed after the interference of the reflected third light beam and the sample light beam is different from the coherence frequency of the second interference light beam formed after the interference of the reflected fourth light beam and the sample light beam, the coupling between the light beams with orthogonal polarization directions having similar coherence frequencies in the first interference light beam and the second interference light beam can be avoided, thereby preventing the occurrence of artifacts in the imaging of the optical coherence tomography system. The optical coherence tomography system of this embodiment can achieve the technical effect of improving the accuracy of imaging.

[0018] In an optional implementation, the first reflecting unit includes:

[0019] a fourth optical fiber, one end of which is connected to the sorting unit;

[0020] A first collimating structure, one side of which is connected to the other end of the fourth optical fiber;

[0021] a first reflecting structure, spaced apart at a side of the first collimating structure away from the sorting unit, the first reflecting structure being used to reflect the third light beam into the first single-mode coupling unit;

[0022] The second reflecting unit comprises:

[0023] a fifth optical fiber, one end of which is connected to the sorting unit;

[0024] A second collimating structure, one side of which is connected to the other end of the fifth optical fiber;

[0025] a second reflecting structure, spaced apart at a side of the second collimating structure away from the sorting unit, the second reflecting structure being used to reflect the fourth light beam into the first single-mode coupling unit;

[0026] The distance between the first collimating structure and the sorting unit is equal to the distance between the second collimating structure and the sorting unit, and the distance between the first collimating structure and the first reflecting structure is greater than or less than the distance between the second collimating structure and the second reflecting structure.

[0027] Beneficial effect: The third light beam is transmitted to the first collimating structure through the fourth optical fiber, and the first collimating structure can adjust the light in the third light beam along multiple transmission directions to be transmitted only along the direction perpendicular to the first collimating structure, which can reduce the divergence angle of the third light beam, so that the third light beam maintains good directionality during the transmission process, and can increase the amount of light of the third light beam entering the first reflecting structure, and further increase the amount of light of the third light beam reflected back to the first collimating structure and the first single-mode coupling unit by the first reflecting structure, so as to increase the light density of the first interference light beam, thereby achieving the technical effect of improving the accuracy of imaging.

[0028] Similarly, the fourth light beam is transmitted to the second collimating structure through the fifth optical fiber, and the light in the fourth light beam along multiple transmission directions is adjusted through the second collimating structure to be transmitted only along the direction perpendicular to the second collimating structure, which can reduce the divergence angle of the fourth light beam, so that the fourth light beam maintains good directionality during the transmission process, and can increase the amount of light of the fourth light beam entering the first reflection structure, and further increase the amount of light of the fourth light beam reflected back to the second collimating structure and the second single-mode coupling unit by the first reflection structure, so as to increase the light density of the second interference light beam, thereby achieving the technical effect of improving the accuracy of imaging.

[0029] Furthermore, by adjusting the distance between the first collimating structure and the first reflecting structure and the distance between the second collimating structure and the second reflecting structure, the optical path can be changed, which can not only improve the simplicity of the optical coherence tomography system structure, but also achieve the technical effect of cost saving.

[0030] In an optional embodiment, the sorting unit includes a first beam splitting structure, one end of which is connected to the second end, the other end of the first beam splitting structure is connected to both the first reflecting unit and the second reflecting unit, and the first beam splitting structure is used to split the first light beam into the third light beam and the fourth light beam.

[0031] Beneficial effect: The first beam splitting structure can split the first light beam into two linearly polarized lights with the same power and perpendicular polarization directions, namely the third light beam and the fourth light beam. By making the power of the third light beam and the fourth light beam the same, the phase shift between the third light beam and the fourth light beam caused by the power difference is reduced, thereby achieving the technical effect of improving the clarity of imaging and the measurement accuracy.

[0032] In an optional embodiment, the sorting unit includes a first control structure connected between the first single-mode coupling unit and the first beam splitting structure, and is used to adjust the angle between the linear polarization direction of the first light beam and the linear polarization direction of the third light beam, and the angle between the linear polarization direction of the first light beam and the linear polarization direction of the fourth light beam to be 45°.

[0033] Beneficial effect: Through the first control structure, the angle between the linear polarization direction of the first light beam and the linear polarization direction of the third light beam, and the angle between the linear polarization direction of the first light beam and the linear polarization direction of the fourth light beam can be set to 45°. Based on this, the first beam splitting structure can evenly divide the power and intensity of the first light beam into the third light beam with a horizontal polarization direction and the fourth light beam with a vertical polarization direction, and can improve the consistency between the power spectral density of the third light beam and the power spectral density of the fourth light beam, so as to further improve the balance of the intensity of the first interference light beam and the second interference light beam, thereby achieving the technical effect of improving imaging accuracy.

[0034] In an optional embodiment, the sample arm unit comprises:

[0035] An adjustment structure, provided on the light-emitting path of the second light beam, for adjusting the second light beam to circularly polarized light;

[0036] The scanning reflection structure is arranged on the light output path of the adjustment structure, and is used for reflecting the second light beam and driving the second light beam to scan the sample to be imaged.

[0037] Beneficial effects: By adjusting the structure, the second light beam can be adjusted to circularly polarized light. Based on this, the second light beam can reduce the glare caused by light scattering and the reflective points of the sample to be imaged, and can increase the contrast. When the circularly polarized light is transmitted inside the sample to be imaged, the evolution of the polarization optical characteristics of the circularly polarized light can improve the comprehensiveness of the distribution of the birefringence characteristics in the sample to be imaged, and can achieve the technical effect of improving the accuracy of imaging the object to be imaged. Furthermore, by applying a high and low dual-frequency triangular wave voltage to the scanning reflection structure, the scanning reflection structure can be orthogonally swung to achieve the surface scanning of the second light beam, thereby achieving the technical effect of improving the accuracy of scanning imaging of the sample to be imaged.

[0038] In an optional embodiment, the sample arm unit comprises:

[0039] a polarization-maintaining optical fiber, one end of which is connected to the other end of the third optical fiber, and the other end of which transmits the second light beam to the adjustment structure;

[0040] The second control structure is arranged on the third optical fiber, and the second control structure is used to adjust the polarization direction of the second light beam to be parallel to or perpendicular to the axial direction of the main axis of the polarization maintaining optical fiber.

[0041] Beneficial effect: The polarization-maintaining optical fiber can ensure that the polarization direction of the second light beam does not change during transmission. Even if the position of the polarization-maintaining optical fiber changes, such as curling, the polarization direction of the second light beam remains unchanged, thereby achieving the technical effect of improving the accuracy of the transmission direction of the second light beam. At the same time, the polarization-maintaining optical fiber can improve the consistency of the polarization direction of the second light beam, so that the polarization direction of all the light in the second light beam is at an angle of 45° with the adjustment structure, thereby achieving the technical effect of improving the transmission stability of the second light beam.

[0042] The direction of the second light beam is adjusted to be parallel to or perpendicular to the axial direction of the transmission axis of the polarization-maintaining optical fiber through the second control structure. Based on this, the polarization direction of the second light beam is first adjusted through the second control structure before entering the polarization-maintaining optical fiber, which can increase the amount of light of the second light beam entering the polarization-maintaining optical fiber, thereby achieving the technical effect of improving the light density in the second light beam and further enhancing the imaging accuracy.

[0043] In an optional embodiment, the sample arm unit comprises:

[0044] A third collimation structure is provided between the polarization maintaining optical fiber and the adjustment structure;

[0045] And / or, a focusing structure is provided between the scanning reflection structure and the sample to be imaged, and is used for focusing the second light beam.

[0046] Beneficial effect: The third collimating structure can adjust the light in the second light beam along multiple transmission directions to be transmitted only in the direction perpendicular to the third collimating structure, which can reduce the divergence angle of the second light beam, so that the second light beam maintains good directionality during transmission, and can increase the amount of light entering the adjustment structure of the second light beam, and increase the light density reflected by the second light beam to the sample to be imaged, so as to achieve the technical effect of improving the accuracy of imaging. Furthermore, the focusing structure can focus the second light beam on the sample to be imaged, avoiding the waste of the second light beam caused by the second light beam being transmitted outside the sample to be imaged, thereby achieving the technical effect of improving the utilization rate of the second light beam.

[0047] In an optional embodiment, the light beam formed after the interference of the third light beam and the sample light beam is a first interference light beam, and the light beam formed after the interference of the fourth light beam and the sample light beam is a second interference light beam;

[0048] The optical coherence tomography system includes an analysis unit connected to the third end and configured to analyze and integrate the spectrum of the first interference light beam and the spectrum of the second interference light beam.

[0049] Beneficial effect: The spectrum of the first interference light beam and the spectrum of the second interference light beam can be analyzed by the analysis unit without manual processing, thereby achieving the technical effect of improving the simplicity of spectral processing.

[0050] In an optional embodiment, the analysis unit includes:

[0051] A second beam splitting structure comprises a first input end, a first output end, and a second output end, wherein the first input end is connected to the third end and is used to split two lights with different polarization directions in the first interference light beam and the second interference light beam passing through the third end, wherein the two lights with different polarization directions are a fifth light beam and a sixth light beam;

[0052] a first detection structure, wherein a first interface and a second interface are provided at one end of the first detection structure, and the first interface is connected to the first output end and is used for analyzing and processing the fifth light beam;

[0053] A second detection structure, wherein a third interface and a fourth interface are provided at one end of the second detection structure, and the third interface is connected to the second output end and is used for analyzing and processing the sixth light beam;

[0054] A processing structure is connected to the other end of the first detection structure and the other end of the second detection structure, and is used to process the information fed back by the first detection structure and the second detection structure to form the spectrum.

[0055] Beneficial effect: The second beam splitting structure can split the light of two different polarization directions in the first interference beam, and split the light of two different polarization directions in the second interference beam, and the first detection structure and the second detection structure can detect the light of two different polarization directions separately, that is, the first detection structure can extract the light information in the fifth beam, and the second detection structure can extract the light information in the sixth beam, and the processing structure can realize the integration of the information fed back by the first detection structure and the second detection structure to form a spectrum.

[0056] In an optional embodiment, the optical coherence tomography system comprises:

[0057] A second single-mode coupling unit is connected between the light-emitting unit and the first single-mode coupling unit, the second single-mode coupling unit comprises a fifth end, a sixth end, a seventh end and an eighth end, the fifth end is connected to the light-emitting unit, the sixth end is connected to the first end, and the eighth end is idle;

[0058] The analysis unit comprises:

[0059] The third beam splitting structure includes a second input end, a third output end and a fourth output end. The second input end is connected to the seventh end and is used to split the two lights with different polarization directions in the first interference light beam and the second interference light beam passing through the seventh end to form a seventh light beam and an eighth light beam. The polarization direction of the seventh light beam is the same as that of the fifth light beam, and the polarization direction of the eighth light beam is the same as that of the sixth light beam. The third output end is connected to the second interface and is used to analyze and process the seventh light beam through the first detection structure. The fourth output end is connected to the fourth interface and is used to analyze and process the eighth light beam through the second detection structure.

[0060] Beneficial effect: Since the first detection structure is provided with a first interface and a second interface at one end, and the second detection structure is provided with a third interface and a fourth interface at one end, when the interfaces in the first detection structure and the second detection structure are idle, the analysis results of the first detection structure and the second detection structure will lack accuracy. In this application, by setting a second single-mode coupling unit, the second single-mode coupling unit divides the light of the light-emitting unit into two beams of equal power, one beam of light enters the first single-mode coupling unit, and the other beam of light is idle through the eighth end. When the first interference light beam and the second interference light beam return to the first single-mode coupling unit, a part of the first interference light beam and a part of the second interference light beam are transmitted through the third end, and the other part is transmitted through the first end to the sixth end, that is, enters the second single-mode coupling unit, so that the first interference light beam and the second interference light beam passing through the seventh end are divided into two lights with different polarization directions, a seventh light beam with the same polarization direction as the fifth light beam and an eighth light beam with the same polarization direction as the sixth light beam, and the seventh light beam is transmitted to the first detection structure through the second interface through the second single-mode coupling unit, and the eighth light beam is transmitted to the second detection structure through the fourth interface through the second single-mode coupling unit. Based on this, light enters the first interface and the second interface as well as the third interface and the fourth interface, thereby achieving the technical effect of the first detection structure and the second detection structure accurately analyzing the results of the first interference light beam and the second interference light beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 FIG. 4 is a schematic diagram of the structure of an optical coherence tomography system of this embodiment.

[0063] Description of reference numerals:

[0064] 1. Light-emitting unit; 2. First optical fiber;

[0065] 3. First single-mode coupling unit; 301. First end; 302. Second end; 303. Third end; 304. Fourth end;

[0066] 4. Second optical fiber; 5. Third optical fiber; 6. Reference arm unit;

[0067] 601, sorting unit; 6011, first beam splitting structure; 6012, first control structure;

[0068] 602, a first reflection unit; 6021, a first collimation structure; 6022, a first reflection structure;

[0069] 603, a second reflection unit; 6031, a second collimation structure; 6032, a second reflection structure;

[0070] 7. Sample arm unit; 701. Adjustment structure; 702. Scanning reflection structure; 703. Second control structure; 704. Polarization maintaining optical fiber; 705. Third collimation structure; 706. Focusing structure;

[0071] 8. Analysis unit; 801. Second beam splitting structure; 802. Third beam splitting structure; 803. First detection structure; 804. Second detection structure; 805. Processing structure;

[0072] 9. Second single-mode coupling unit; 901. Fifth end; 902. Sixth end; 903. Seventh end; 904. Eighth end. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0074] Combine the following Figure 1 , describing an embodiment of the present invention.

[0075] According to an embodiment of the present invention, there is provided an optical coherence tomography system, comprising:

[0076] A light emitting unit 1, used for emitting a laser beam;

[0077] A first optical fiber 2, one end of which is connected to the light-emitting unit 1;

[0078] A first single-mode coupling unit 3, the first single-mode coupling unit 3 comprises a first end 301, a second end 302, a third end 303 and a fourth end 304, the first end 301 is connected to the other end of the first optical fiber 2, and the first single-mode coupling unit 3 is used to split the laser beam into a first beam and a second beam;

[0079] A second optical fiber 4, one end of which is connected to the second end 302 and is used to transmit the first light beam;

[0080] A third optical fiber 5, one end of which is connected to the fourth end 304, for transmitting the second light beam;

[0081] The sample arm unit 7 is connected to the other end of the third optical fiber 5 and is used to transmit the second light beam to the surface of the sample to be imaged, and the sample light beam scattered back by the sample to be imaged is transmitted to the first single-mode coupling unit 3 through the sample arm unit 7 and the third optical fiber 5;

[0082] The reference arm unit 6 is connected to the other end of the second optical fiber 4, and the reference arm unit 6 includes:

[0083] A sorting unit 601, one end of which is connected to the other end of the second optical fiber 4, and is used to split the first light beam into two light beams with orthogonal polarization directions, namely a third light beam and a fourth light beam;

[0084] A first reflecting unit 602, connected to the other end of the sorting unit 601, and configured to reflect the third light beam into the first single-mode coupling unit 3;

[0085] The second reflecting unit 603 is connected to the other end of the sorting unit 601, and is used to reflect the fourth light beam into the first single-mode coupling unit 3. The distance between the second reflecting unit 603 and the other end of the sorting unit 601 is different from the distance between the first reflecting unit 602 and the other end of the sorting unit 601, so that the optical path of the reflected third light beam is different from the optical path of the reflected fourth light beam.

[0086] In the optical coherence tomography system of the present embodiment, the distance between the sorting unit 601 and the first reflecting unit 602 is different from the distance between the sorting unit 601 and the second reflecting unit 603, so that the optical path of the reflected third light beam is different from the optical path of the reflected fourth light beam. Based on this, when the coherence frequency of the first interference light beam formed after the interference of the reflected third light beam and the sample light beam is different from the coherence frequency of the second interference light beam formed after the interference of the reflected fourth light beam and the sample light beam, it is possible to avoid coupling between light beams with orthogonal polarization directions having similar coherence frequencies in the first interference light beam and the second interference light beam, thereby preventing the occurrence of artifacts in the imaging of the optical coherence tomography system. The optical coherence tomography system of the present embodiment can achieve the technical effect of improving the accuracy of imaging.

[0087] In this embodiment, the light emitting unit 1 may be a frequency-sweeping laser, and the central wavelength of the laser beam emitted by the light emitting unit 1 is 1060 nm.

[0088] As a convertible embodiment, the central wavelength of the laser beam emitted by the light emitting unit 1 is 1310 nm.

[0089] Of course, in other embodiments, the type of the light emitting unit 1 and the value of the central wavelength of the laser beam may be adjusted according to different designs of the optical coherence tomography system.

[0090] Preferably, the first single-mode coupling unit 3 divides the light beam into two equal-power first and second light beams. Of course, in other embodiments, depending on the design of the optical coherence tomography system, the powers of the first and second light beams may not be equal. Compared with other embodiments, this embodiment reduces the phase shift caused by the power difference by limiting the power of the first and second light beams to be equal, thereby achieving the technical effect of improving the clarity of imaging.

[0091] In addition, in this embodiment, combined with Figure 1 As shown, the first reflection unit 602 includes:

[0092] A fourth optical fiber, one end of which is connected to the sorting unit 601;

[0093] A first collimating structure 6021, one side of which is connected to the other end of the fourth optical fiber;

[0094] A first reflection structure 6022 is spaced apart from a side of the first collimating structure 6021 away from the sorting unit 601, and the first reflection structure 6022 is used to reflect the third light beam into the first single-mode coupling unit 3;

[0095] The second reflecting unit 603 includes:

[0096] A fifth optical fiber, one end of which is connected to the sorting unit 601;

[0097] A second collimating structure 6031, one side of which is connected to the other end of the fifth optical fiber;

[0098] A second reflection structure 6032 is spaced apart from the second collimating structure 6031 on a side away from the sorting unit 601 , and the second reflection structure 6032 is used to reflect the fourth light beam into the first single-mode coupling unit 3 ;

[0099] The distance between the first collimating structure 6021 and the sorting unit 601 is equal to the distance between the second collimating structure 6031 and the sorting unit 601 , and the distance between the first collimating structure 6021 and the first reflecting structure 6022 is greater than or less than the distance between the second collimating structure 6031 and the second reflecting structure 6032 .

[0100] The first collimating structure 6021 and the second collimating structure 6031 are both collimating mirrors, and the first reflecting structure 6022 and the second reflecting structure 6032 are both reflecting mirrors.

[0101] The third light beam is transmitted to the first collimating structure 6021 through the fourth optical fiber, and the first collimating structure 6021 can adjust the light along multiple transmission directions in the third light beam to be transmitted only along the direction perpendicular to the collimating surface of the first collimating structure 6021, which can reduce the divergence angle of the third light beam, so that the third light beam maintains good directionality during the transmission process, and can increase the amount of light of the third light beam entering the first reflecting structure 6022, and further increase the amount of light of the third light beam reflected back to the first collimating structure 6021 and the first single-mode coupling unit 3 by the first reflecting structure 6022, so as to increase the light density of the first interference light beam, thereby achieving the technical effect of improving the accuracy of imaging.

[0102] Similarly, the fourth light beam is transmitted to the second collimating structure 6031 through the fifth optical fiber, and the light along multiple transmission directions in the fourth light beam is adjusted through the second collimating structure 6031 to be transmitted only along the direction perpendicular to the collimating surface of the second collimating structure 6031, which can reduce the divergence angle of the fourth light beam, so that the fourth light beam maintains good directionality during the transmission process, and can increase the amount of light of the fourth light beam entering the first reflecting structure 6022, and further increase the amount of light of the fourth light beam reflected back to the second collimating structure 6031 and the second single-mode coupling unit 9 by the first reflecting structure 6022, so as to increase the light density of the second interference light beam, thereby achieving the technical effect of improving the accuracy of imaging.

[0103] Furthermore, in this embodiment, the distance between the first collimating structure 6021 and the sorting unit 601 is equal to the distance between the second collimating structure 6031 and the sorting unit 601, and the distance between the first collimating structure 6021 and the first reflecting structure 6022 is smaller than the distance between the second collimating structure 6031 and the second reflecting structure 6032, so that the optical path of the reflected third light beam is different from the optical path of the reflected fourth light beam.

[0104] As a convertible implementation, the distance between the first collimating structure 6021 and the first reflecting structure 6022 may be greater than the distance between the second collimating structure 6031 and the second reflecting structure 6032 .

[0105] Of course, in other embodiments, the fourth optical fiber can be a fiber delay line or the fifth optical fiber can be a fiber delay line on the basis that the distance between the first reflection unit 602 and the sorting unit 601 is equal to the distance between the second reflection unit 603 and the sorting unit 601, and the technical effect of changing the optical path of the third light beam and the fourth light beam can also be achieved. Compared with other embodiments, this embodiment can achieve the change of the optical path by only adjusting the distance between the first collimating structure 6021 and the first reflection structure 6022 and the distance between the second collimating structure 6031 and the second reflection structure 6032, which can not only improve the simplicity of the structure of the optical coherence tomography imaging system, but also achieve the technical effect of saving costs.

[0106] In other embodiments, the type of collimator and the type of reflector may be selected according to different designs of the optical coherence tomography system.

[0107] In addition, combined Figure 1 As shown, in this embodiment, the sorting unit 601 includes a first beam splitting structure 6011, one end of which is connected to the second end 302, and the other end of the first beam splitting structure 6011 is connected to both the first collimating structure 6021 and the second collimating structure 6031. The first beam splitting structure 6011 is used to split the first light beam into a third light beam and a fourth light beam.

[0108] The first beam splitting structure 6011 can be a light polarization beam splitter, which can split the first light beam into two linearly polarized lights with the same power and perpendicular polarization directions, namely the third light beam and the fourth light beam. By making the power of the third light beam and the fourth light beam the same, the phase shift between the third light beam and the fourth light beam caused by the power difference is reduced, thereby achieving the technical effect of improving the clarity of the imaging.

[0109] Furthermore, combined with Figure 1As shown, in this embodiment, the sorting unit 601 includes a first control structure 6012, which is connected between the first single-mode coupling unit 3 and the first beam splitting structure 6011, and is used to adjust the angle between the linear polarization direction of the first light beam and the linear polarization direction of the third light beam, and the angle between the linear polarization direction of the first light beam and the linear polarization direction of the fourth light beam to be 45°. Wherein, the first light beam is a linearly polarized light. Based on this, the angle between the linear polarization direction of the first light beam and the linear polarization direction of the third light beam, and the angle between the linear polarization direction of the first light beam and the linear polarization direction of the fourth light beam can be 45°. Based on this, the first beam splitting structure 6011 can evenly divide the power and intensity of the first light beam into the third light beam with a horizontal polarization direction and the fourth light beam with a vertical polarization direction, and can improve the consistency between the power spectral density of the third light beam and the power spectral density of the fourth light beam, so as to further improve the balance of the intensity of the first interference light beam and the second interference light beam, thereby achieving the technical effect of improving the imaging accuracy. Wherein, the first control structure 6012 is a polarization controller.

[0110] Of course, in other embodiments, the first control structure 6012 can adjust the first light beam to circularly polarized light, and then decompose it into two third and fourth light beams with orthogonal polarization directions and the same power through the first beam splitting structure 6011. Compared with other embodiments, this embodiment can directly adjust the linear polarization direction of the first light beam to 45° with the linear polarization direction of the third light beam and the linear polarization direction of the first light beam to the linear polarization direction of the fourth light beam through the first control structure 6012, which can reduce the difficulty of forming the polarization directions of the third and fourth light beams, thereby achieving the technical effect of improving the ease of use of the optical coherence tomography imaging system.

[0111] In other embodiments, the first control structure 6012 may not be provided.

[0112] Of course, in other embodiments, the types of the first beam splitting structure 6011 and the first control structure 6012 may be adjusted according to different designs of the optical coherence tomography system.

[0113] In addition, combined Figure 1 As shown, the sample arm unit 7 comprises:

[0114] An adjustment structure 701 is provided on the light-emitting path of the second light beam and is used to adjust the second light beam into circularly polarized light;

[0115] The scanning reflection structure 702 is disposed on the light output path of the adjustment structure 701, and is used to reflect the second light beam and drive the second light beam to scan the sample to be imaged.

[0116] By adjusting the structure 701, the second light beam can be adjusted to circularly polarized light. Based on this, the second light beam can reduce the glare caused by light scattering and the reflective points of the sample to be imaged, and can increase the contrast. When the circularly polarized light is transmitted inside the sample to be imaged, the evolution of the polarization optical characteristics of the circularly polarized light can improve the comprehensiveness of the distribution of the birefringence characteristics in the sample to be imaged, and can achieve the technical effect of improving the accuracy of imaging the object to be imaged. Further, by applying a high and low dual-frequency triangular wave voltage to the scanning reflection structure 702, the scanning reflection structure 702 can be orthogonally swung to achieve surface scanning of the second light beam, thereby achieving the technical effect of improving the accuracy of scanning imaging of the sample to be imaged.

[0117] In this embodiment, the adjustment structure 701 is a quarter wave plate, and the angle between the main axis of the adjustment structure 701 and the polarization direction of the light in the second light beam is 45°. The scanning reflection structure 702 is a pair of scanning galvanometers, which are specifically composed of two orthogonally placed electrically controlled reflectors, one large and one small. A low-frequency triangular wave voltage is applied to the large galvanometer to make the large galvanometer swing slowly within a certain angle range. At the same time, a high-frequency triangular wave voltage is applied to the small galvanometer to make the small galvanometer swing quickly within a certain angle range. The amplitude of the galvanometer swing angle is proportional to the amplitude of the triangular wave voltage. The high-frequency triangular wave and the low-frequency triangular wave are started synchronously, thereby realizing the surface scanning of the second light beam. Among them, the swing angles of the large galvanometer and the small galvanometer can be adjusted according to actual needs, and no excessive restrictions are made here.

[0118] Of course, in other embodiments, the types of the adjustment structure 701 and the scanning reflection structure 702 may be adjusted according to different designs of the optical coherence tomography system.

[0119] In addition, combined Figure 1 As shown, in this embodiment, the sample arm unit 7 includes:

[0120] Polarization-maintaining optical fiber 704, one end of which is connected to the other end of the third optical fiber 5, and the other end of the polarization-maintaining optical fiber 704 transmits the second light beam to the adjustment structure 701. The polarization-maintaining optical fiber 704 can ensure that the polarization direction of the second light beam does not change during transmission, and even if the position of the polarization-maintaining optical fiber 704 changes, such as curling, the polarization direction of the second light beam does not change, thereby achieving the technical effect of improving the accuracy of the transmission direction of the second light beam. At the same time, the polarization-maintaining optical fiber 704 can improve the consistency of the polarization direction of the second light beam, so that the polarization direction of all the light in the second light beam is at an angle of 45° with the adjustment structure 701, so as to achieve the technical effect of improving the transmission stability of the second light beam.

[0121] The second control structure 703 is arranged on the third optical fiber 5, and the second control structure 703 is used to adjust the polarization direction of the second light beam to be parallel to or perpendicular to the axial direction of the main axis of the polarization-maintaining optical fiber 704. Based on this, by first adjusting the polarization direction of the second light beam through the second control structure 703, and then entering the polarization-maintaining optical fiber 704, the amount of light of the second light beam entering the polarization-maintaining optical fiber 704 can be increased, thereby achieving the technical effect of improving the light density in the second light beam, and then enhancing the imaging accuracy. Among them, the polarization direction of the second light beam is parallel to the fast axis of the polarization-maintaining optical fiber 704, or the polarization direction of the second light beam is parallel to the slow axis of the polarization-maintaining optical fiber 704, or the polarization direction of the second light beam is perpendicular to the fast axis of the polarization-maintaining optical fiber 704, or the polarization direction of the second light beam is perpendicular to the slow axis of the polarization-maintaining optical fiber 704.

[0122] In this embodiment, the second control structure 703 is a light polarization controller. Of course, in other embodiments, the type of the second control structure 703 is adjusted according to different designs of the optical coherence tomography system.

[0123] In other embodiments, the polarization maintaining optical fiber 704 and the second control structure 703 may not be provided.

[0124] In addition, the sample arm unit 7 comprises:

[0125] A third collimating structure 705 is provided between the polarization maintaining optical fiber 704 and the adjustment structure 701;

[0126] The focusing structure 706 is disposed between the scanning reflective structure 702 and the sample to be imaged, and is used to focus the second light beam.

[0127] The third collimating structure 705 can adjust the light in the second light beam along multiple transmission directions to be transmitted only in the direction perpendicular to the third collimating structure 705, which can reduce the divergence angle of the second light beam, so that the second light beam maintains good directionality during transmission, and can increase the amount of light entering the adjustment structure 701 of the second light beam, and increase the light density of the second light beam reflected to the sample to be imaged, so as to achieve the technical effect of improving the accuracy of imaging. Furthermore, the focusing structure 706 can focus the second light beam on the sample to be imaged, avoiding the waste of the second light beam caused by the second light beam being transmitted outside the sample to be imaged, thereby achieving the technical effect of improving the utilization rate of the second light beam.

[0128] The third collimating structure 705 is a collimating lens, and the focusing structure 706 is a focusing lens. Of course, in other embodiments, the types of the third collimating structure 705 and the focusing structure 706 are adjusted according to different designs of the optical coherence tomography system.

[0129] In other embodiments, depending on the design of the optical coherence tomography system, only the third collimating structure 705 or only the focusing structure 706 may be provided.

[0130] In addition, combined Figure 1 As shown, the optical coherence tomography system includes an analysis unit 8, which is connected to the third end 303 and is used to analyze and integrate the spectrum of the first interference beam and the spectrum of the second interference beam. The analysis unit 8 can analyze the spectrum of the first interference beam and the spectrum of the second interference beam without manual processing, thereby achieving a technical effect of improving the simplicity of spectral processing.

[0131] Wherein, the analysis unit 8 comprises:

[0132] The second beam splitting structure 801 includes a first input end, a first output end, and a second output end. The first input end is connected to the third end 303 and is used to split the two lights with different polarization directions in the first interference light beam and the second interference light beam passing through the third end 303. The two lights with different polarization directions are the fifth light beam and the sixth light beam. That is, the light after the first interference light beam is split is divided into the first light with the first polarization direction and the second light with the second polarization direction. The light after the second interference light beam is split is divided into the third light with the first polarization direction and the fourth light with the second polarization direction. The first light and the third light are called the fifth light beam, and the second light and the fourth light are called the sixth light beam.

[0133] A first detection structure 803, wherein a first interface and a second interface are provided at one end of the first detection structure 803, wherein the first interface is connected to the first output end and is used for analyzing and processing the fifth light beam in the first polarization direction;

[0134] A second detection structure 804, wherein a third interface and a fourth interface are provided at one end of the second detection structure 804, and the third interface is connected to the second output end and is used for analyzing and processing a sixth light beam in a second polarization direction;

[0135] The processing structure 805 is connected to the other end of the first detection structure 803 and the other end of the second detection structure 804 , and is used to process the information fed back by the first detection structure 803 and the second detection structure 804 to form a spectrum.

[0136] The second beam splitting structure 801 can be used to split the light of two different polarization directions in the first interference beam, and the light of two different polarization directions in the second interference beam can be split at the same time. The first detection structure 803 and the second detection structure 804 can detect the light of two different polarization directions separately, that is, the first detection structure 803 can extract the light information in the fifth beam, and the second detection structure 804 can extract the light information in the sixth beam, and the processing structure 805 can be used to integrate the information fed back by the first detection structure 803 and the second detection structure 804 to form a spectrum.

[0137] Specifically, the processing structure 805 is a host computer, such as a computer. The first detection structure 803 and the second detection structure 804 can upload information to the processing structure 805 through an acquisition card. The acquisition card bundles the optical signals detected by the first detection structure 803 and the second detection structure 804 and transmits them to the processing structure 805. The processing structure 805 sequentially obtains the spectrum through processes such as data decomposition, resampling, Fourier transform, extraction of amplitude and phase information, and calculation of Stokes parameters representing polarization information, so as to obtain the structural information inside the sample to be imaged.

[0138] Furthermore, combined with Figure 1 As shown, the optical coherence tomography system comprises:

[0139] The second single-mode coupling unit 9 is connected between the light-emitting unit 1 and the first single-mode coupling unit 3. The second single-mode coupling unit 9 includes a fifth end 901, a sixth end 902, a seventh end 903 and an eighth end 904. The fifth end 901 is connected to the light-emitting unit 1, the sixth end 902 is connected to the first end 301, and the eighth end 904 is idle.

[0140] The analysis unit 8 comprises:

[0141] The third beam splitting structure 802 includes a second input end, a third output end and a fourth output end. The second input end is connected to the seventh end 903, and is used to split the two lights with different polarization directions in the first interference light beam and the second interference light beam passing through the seventh end 903 to form a seventh light beam and an eighth light beam, that is, the light after the first interference light beam is split is divided into a fifth light in the first polarization direction and a sixth light in the second polarization direction, and the light after the second interference light beam is split is divided into a seventh light in the first polarization direction and an eighth light in the second polarization direction. The fifth light and the seventh light are called the seventh light beam, and the sixth light and the eighth light are called the eighth light beam. The polarization directions of the seventh light beam and the fifth light beam are the same, and the polarization directions of the eighth light beam and the sixth light beam are the same. The third output end is connected to the second interface, and is used to analyze and process the seventh light beam through the first detection structure 803. The fourth output end is connected to the fourth interface, and is used to analyze and process the eighth light beam through the second detection structure 804.

[0142] Since the first detection structure 803 has a first interface and a second interface at one end, and the second detection structure 804 has a third interface and a fourth interface at one end, when one of the interfaces in the first detection structure 803 and the second detection structure 804 is idle, the analysis results of the first detection structure 803 and the second detection structure 804 will lack accuracy. In this embodiment, a second single-mode coupling unit 9 is provided, and the second single-mode coupling unit 9 divides the light of the light-emitting unit 1 into two beams of equal power. One beam of light enters the first single-mode coupling unit 3, and the other beam of light passes through the eighth end 904 and is idle. When the first interference beam and the second interference beam return to the first single-mode coupling unit 3, a part of the first interference beam and a part of the second interference beam are transmitted through the third end 303, and the other part is transmitted through the first end 301 to the sixth end 902, that is, enters the second single-mode coupling unit 9, so that the first interference beam and the second interference beam passing through the seventh end 903 are divided into two lights with different polarization directions, namely, the seventh beam with the same polarization direction as the fifth beam and the eighth beam with the same polarization direction as the sixth beam, and the seventh beam is transmitted to the first detection structure 803 through the second interface through the second single-mode coupling unit 9, and the eighth beam is transmitted to the second detection structure 804 through the fourth interface through the second single-mode coupling unit 9. Based on this, light enters the first interface and the second interface as well as the third interface and the fourth interface, so as to achieve the technical effect of the accuracy of the analysis results of the first interference beam and the second interference beam by the first detection structure 803 and the second detection structure 804.

[0143] In addition, in the present embodiment, both the first single-mode coupling unit 3 and the second single-mode coupling unit 9 use an X-type optical fiber coupler, that is, a 2×2 optical fiber coupler, that is, two connection ends are respectively provided at both ends of the first single-mode coupling unit 3 and the second single-mode coupling unit 9. At the same time, by limiting the two coupling units to single-mode coupling units, the probability of increasing imaging confusion by using coupling units of other modes can be avoided, and the single-mode coupling unit in the present embodiment can achieve the technical effect of improving the accuracy of imaging.

[0144] Of course, in other embodiments, the types of the first single-mode coupling unit 3 and the second single-mode coupling unit 9 may be adjusted according to different designs of the optical coherence tomography system.

[0145] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An optical coherence tomography system, characterized in that: include: A light emitting unit (1), used for emitting a laser beam; A first optical fiber (2), one end of which is connected to the light-emitting unit (1); a first single-mode coupling unit (3), the first single-mode coupling unit (3) comprising a first end (301), a second end (302), a third end (303) and a fourth end (304), the first end (301) being connected to the other end of the first optical fiber (2), the first single-mode coupling unit (3) being used for splitting the laser beam into a first beam and a second beam; a second optical fiber (4), one end of which is connected to the second end (302) and is used to transmit the first light beam; a third optical fiber (5), one end of which is connected to the fourth end (304) and is used to transmit the second light beam; A sample arm unit (7) is connected to the other end of the third optical fiber (5) and is used to transmit the second light beam to the surface of the sample to be imaged, and the sample light beam scattered back by the sample to be imaged is transmitted to the first single-mode coupling unit (3) through the sample arm unit (7) and the third optical fiber (5); A reference arm unit (6) is connected to the other end of the second optical fiber (4), and the reference arm unit (6) comprises: A sorting unit (601), one end of which is connected to the other end of the second optical fiber (4), and is used to split the first light beam into two light beams with orthogonal polarization directions, namely a third light beam and a fourth light beam; A first reflecting unit (602), connected to the other end of the sorting unit (601), and used for reflecting the third light beam into the first single-mode coupling unit (3); A second reflecting unit (603) is connected to the other end of the sorting unit (601) and is used to reflect the fourth light beam into the first single-mode coupling unit (3); the distance between the second reflecting unit (603) and the other end of the sorting unit (601) is different from the distance between the first reflecting unit (602) and the other end of the sorting unit (601), so that the optical path of the third light beam after reflection is different from the optical path of the fourth light beam after reflection.

2. The optical coherence tomography system according to claim 1, characterized in that: The first reflecting unit (602) comprises: a fourth optical fiber, one end of which is connected to the sorting unit (601); A first collimating structure (6021), one side of which is connected to the other end of the fourth optical fiber; a first reflection structure (6022), arranged at a distance from the first collimating structure (6021) on a side away from the sorting unit (601), the first reflection structure (6022) being used to reflect the third light beam into the first single-mode coupling unit (3); The second reflecting unit (603) comprises: a fifth optical fiber, one end of which is connected to the sorting unit (601); A second collimating structure (6031), one side of which is connected to the other end of the fifth optical fiber; a second reflection structure (6032), arranged at a distance from the second collimating structure (6031) on a side away from the sorting unit (601), the second reflection structure (6032) being used to reflect the fourth light beam into the first single-mode coupling unit (3); The distance between the first collimating structure (6021) and the sorting unit (601) is equal to the distance between the second collimating structure (6031) and the sorting unit (601), and the distance between the first collimating structure (6021) and the first reflecting structure (6022) is greater than or less than the distance between the second collimating structure (6031) and the second reflecting structure (6032).

3. The optical coherence tomography system according to claim 1, characterized in that: The sorting unit (601) comprises a first beam splitting structure (6011), one end of which is connected to the second end (302), and the other end of the first beam splitting structure (6011) is connected to both the first reflection unit (602) and the second reflection unit (603), and the first beam splitting structure (6011) is used to split the first light beam into the third light beam and the fourth light beam.

4. The optical coherence tomography system according to claim 3, characterized in that: The sorting unit (601) comprises a first control structure (6012) connected between the first single-mode coupling unit (3) and the first beam splitting structure (6011), and used for adjusting the angle between the linear polarization direction of the first light beam and the linear polarization direction of the third light beam, and the angle between the linear polarization direction of the first light beam and the linear polarization direction of the fourth light beam to be 45°.

5. The optical coherence tomography system according to any one of claims 1 to 4, characterized in that: The sample arm unit (7) comprises: An adjustment structure (701), arranged on the light exit path of the second light beam, for adjusting the second light beam into circularly polarized light; The scanning reflection structure (702) is arranged on the light output path of the adjustment structure (701) and is used to reflect the second light beam and drive the second light beam to scan the sample to be imaged.

6. The optical coherence tomography system according to claim 5, characterized in that: The sample arm unit (7) comprises: a polarization-maintaining optical fiber (704), one end of which is connected to the other end of the third optical fiber (5), and the other end of which transmits the second light beam to the adjustment structure (701); The second control structure (703) is arranged on the third optical fiber (5), and the second control structure (703) is used to adjust the polarization direction of the second light beam to be parallel to or perpendicular to the axial direction of the main axis of the polarization maintaining optical fiber (704).

7. The optical coherence tomography system according to claim 6, characterized in that: The sample arm unit (7) comprises: A third collimating structure (705) is provided between the polarization maintaining optical fiber (704) and the adjustment structure (701); And / or, a focusing structure (706) is provided between the scanning reflection structure (702) and the sample to be imaged, and is used to focus the second light beam.

8. The optical coherence tomography system according to claim 7, characterized in that: The light beam formed by the interference of the third light beam and the sample light beam is a first interference light beam, and the light beam formed by the interference of the fourth light beam and the sample light beam is a second interference light beam; The optical coherence tomography system comprises an analysis unit (8), which is connected to the third end (303) and is used to analyze and integrate the spectrum of the first interference light beam and the spectrum of the second interference light beam.

9. The optical coherence tomography system according to claim 8, characterized in that: The analysis unit (8) comprises: A second beam splitting structure (801) comprises a first input end, a first output end and a second output end, wherein the first input end is connected to the third end (303) and is used to split two lights with different polarization directions in the first interference light beam and the second interference light beam passing through the third end (303), wherein the two lights with different polarization directions are a fifth light beam and a sixth light beam; A first detection structure (803), wherein one end of the first detection structure (803) is provided with a first interface and a second interface, wherein the first interface is connected to the first output end and is used for analyzing and processing the fifth light beam; A second detection structure (804), wherein one end of the second detection structure (804) is provided with a third interface and a fourth interface, wherein the third interface is connected to the second output end and is used for analyzing and processing the sixth light beam; The processing structure (805) is connected to the other end of the first detection structure (803) and the other end of the second detection structure (804), and is used to process the information fed back by the first detection structure (803) and the second detection structure (804) to form the spectrum.

10. The optical coherence tomography system according to claim 9, characterized in that: The optical coherence tomography system comprises: a second single-mode coupling unit (9), connected between the light-emitting unit (1) and the first single-mode coupling unit (3), the second single-mode coupling unit (9) comprising a fifth end (901), a sixth end (902), a seventh end (903) and an eighth end (904), the fifth end (901) being connected to the light-emitting unit (1), the sixth end (902) being connected to the first end (301), and the eighth end (904) being idle; The analysis unit (8) comprises: The third beam splitting structure (802) comprises a second input end, a third output end and a fourth output end, wherein the second input end is connected to the seventh end (903) and is used to split the two lights with different polarization directions in the first interference light beam and the second interference light beam passing through the seventh end (903) to form a seventh light beam and an eighth light beam, wherein the polarization direction of the seventh light beam is the same as that of the fifth light beam, and the polarization direction of the eighth light beam is the same as that of the sixth light beam, wherein the third output end is connected to the second interface and is used to analyze and process the seventh light beam through the first detection structure (803), and wherein the fourth output end is connected to the fourth interface and is used to analyze and process the eighth light beam through the second detection structure (804).

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