A magnetic control optical fiber OCT probe and a preparation method and application thereof

Abstract

The application belongs to the technical field of micro-nano optics, and discloses a magnetic control fiber OCT probe and a preparation method thereof, which comprises: a transparent catheter; a single-mode optical fiber arranged in the interior of the transparent catheter; and an optical imaging assembly integrally formed on the end face of the single-mode optical fiber by means of a femtosecond laser two-photon polymerization technology, wherein the optical imaging assembly comprises a stator, a rotor and a focusing lens arranged in sequence, one end of the stator away from the rotor is fixedly connected with the single-mode optical fiber, the rotor rotates relative to the stator, one side of the focusing lens is provided with a reflecting surface, the reflecting surface is provided with a magnetic structure, and the magnetic structure is used for driving the rotor to rotate in response to an external magnetic field. The application can significantly reduce the diameter of the probe, improve the lateral resolution, and realize non-contact far-field magnetic control scanning, thereby directly serving the early diagnosis of microvascular lesions, intraoperative minimally invasive imaging and biological basic research.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano optics technology, and in particular relates to a magnetically controlled fiber optic OCT probe and its fabrication method. Background Technology

[0002] With the development of minimally invasive medicine and precision diagnosis and treatment, the demand for high-resolution imaging of microvascular vessels and microcavities is becoming increasingly urgent. Optical coherence tomography (OCT), with its micrometer-level axial / lateral resolution and non-invasive real-time imaging capabilities, has become an important tool for imaging intravascular vessels and cavities.

[0003] However, existing fiber optic OCT endoscopes suffer from the inability to image extremely narrow cavities. Specifically, traditional OCT probes are limited by probe diameter, scanning mechanism, and optical element size, making it difficult to achieve in-situ imaging of microvessels or extremely fine cavities with diameters much smaller than 1 mm. Therefore, developing a magnetically controllable microstructure fabricated on the fiber end face using femtosecond laser direct writing (Two-Photon Polymerization, TPP)—an OCT endoscope for magnetically controlled scanning—has significant medical and engineering value. Summary of the Invention

[0004] The purpose of this invention is to provide a magnetically controlled fiber optic OCT probe, its preparation method, and its application, aiming to solve the problem that existing fiber optic endoscopes cannot penetrate extremely narrow cavities for in-situ imaging.

[0005] In order to achieve the above objectives, the present invention provides a magnetically controlled fiber optic OCT probe, the specific structure of which includes an external transparent conduit, a single-mode fiber, a rotatable endoscope integrally processed on the fiber end face, and a magnetic structure processed in stages.

[0006] The single-mode optical fiber is disposed inside the transparent conduit; the optical imaging component is integrally formed on the end face of the single-mode optical fiber using femtosecond laser two-photon polymerization technology. The optical imaging component includes a stator, a rotor, and a focusing lens arranged in sequence. The end of the stator away from the rotor is fixedly connected to the single-mode optical fiber. The rotor rotates relative to the stator. A reflecting surface is provided on one side of the focusing lens. A magnetic structure is provided on the reflecting surface. The magnetic structure is used to respond to an external magnetic field to drive the rotor to rotate.

[0007] Optionally, the magnetic structure is a nickel layer deposited on the reflective surface by magnetron sputtering.

[0008] Optionally, the end face of the single-mode optical fiber is cut at an 8° angle.

[0009] Optionally, the stator and the rotor constitute a micro-bearing structure, and the interior of the micro-bearing structure is provided with free space for beam expansion.

[0010] Optionally, the reflective surface is an inclined surface, used to perform total internal reflection of the light emitted along the single-mode fiber, so as to change the direction of the optical path and achieve lateral emission.

[0011] Secondly, to achieve the above objectives, the present invention provides a method for fabricating a magnetically controlled fiber optic OCT probe, comprising:

[0012] S1: Cut the end face of the single-mode fiber at an 8° angle and clean it.

[0013] S2: Fix the cut single-mode fiber in the clamp;

[0014] S3: Using femtosecond laser two-photon polymerization technology, photoresist is polymerized on the end face of the single-mode fiber to prepare an optical imaging assembly including a stator, rotor, reflective surface and focusing lens;

[0015] S4: The formed optical imaging components are then developed.

[0016] S5: A magnetic material layer is deposited on the reflective surface to form a magnetic structure;

[0017] S6: The finished optical fiber and optical imaging components are encapsulated in a transparent conduit.

[0018] Optionally, step S2 specifically includes: inserting the cut single-mode fiber into a standard short-stem SC fiber ceramic ferrule with an inner diameter of 125 micrometers, and then placing the ceramic ferrule upside down on a cover glass after fitting it into a matching SC standard open sleeve.

[0019] Thirdly, to achieve the above objectives, the present invention provides an application of a magnetically controlled fiber optic OCT probe in imaging.

[0020] Optionally, imaging methods include:

[0021] S1: Transmit coherent light to the optical imaging component via a single-mode fiber;

[0022] S2: The coherent light is expanded in the free space between the stator and the rotor;

[0023] S3: After the expanded beam is totally reflected by the reflecting surface, the direction of the light changes and it exits laterally;

[0024] S4: Laterally emitted light rays are focused by a focusing lens and then pass through a transparent conduit to irradiate biological tissue;

[0025] S5: Backscattered and reflected light from biological tissues return along the original optical path to the single-mode fiber and are transmitted to the demodulation module of the OCT system to reconstruct the depth image of the biological tissue;

[0026] S6: Driven by an external rotating permanent magnet, the magnetic structure rotates, causing the rotor, reflective surface, and focusing lens to rotate, thereby achieving a circular scan of biological tissue and reconstructing a depth image of the entire cross-section of the biological tissue.

[0027] The technical effects of this invention are as follows:

[0028] This invention reduces the need for splicing multiple optical fibers, utilizing only single-mode fiber and employing integrated two-photon polymerization processing, significantly reducing manufacturing complexity. Furthermore, the introduction of magnetron splicing eliminates the need for complex torque coil drives, allowing the probe diameter to be reduced to within 200 micrometers. The wireless operation of the magnetron splicing also increases flexibility and safety. The extremely small probe diameter broadens application scenarios; even extremely narrow cavities previously accessible only through MRI and CT imaging can now be imaged in situ using OCT technology, offering significant value for imaging small blood vessels such as those in the brain.

[0029] This invention can significantly reduce the probe diameter, improve lateral resolution, and achieve non-contact far-field magnetic control scanning, directly serving the early diagnosis of microvascular lesions, minimally invasive intraoperative imaging, and basic biological research. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of the magnetically controlled fiber optic OCT probe in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram showing the position of the reflective surface in an embodiment of the present invention;

[0034] Figure 3 This is a flowchart illustrating the fabrication process of the magnetically controlled fiber optic OCT probe in an embodiment of the present invention.

[0035] Labeling explanation: 1. Stator; 2. Rotor; 3. Focusing lens; 4. Reflecting surface. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] To facilitate understanding of the present invention, a more comprehensive description of the invention will be given below with reference to the accompanying drawings, and several embodiments of the invention will be provided. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be more thorough and complete.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0039] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] Example 1

[0044] like Figures 1-2 As shown, this embodiment provides a magnetron-controlled fiber optic OCT probe based on femtosecond laser two-photon polymerization (TPP) technology. Femtosecond laser two-photon polymerization (TPP) technology is a 3D printing process that uses femtosecond lasers to induce nonlinear absorption in photosensitive materials. This process can achieve true three-dimensional processing and has very good processing accuracy, which is sufficient to meet the needs of processing high-precision micro-nano optical and mechanical structures.

[0045] The specific structure of the magnetically controlled fiber optic OCT probe described in this embodiment includes an external transparent conduit, a single-mode fiber, a rotatable endoscope integrally processed on the fiber end face, and a magnetic structure processed in stages.

[0046] The single-mode optical fiber is disposed inside the transparent conduit; the optical imaging component is integrally formed on the end face of the single-mode optical fiber using femtosecond laser two-photon polymerization technology. The optical imaging component includes a stator 1, a rotor 2, and a focusing lens 3 arranged sequentially. The end of the stator 1 away from the rotor 2 is fixedly connected to the single-mode optical fiber. The rotor 2 rotates relative to the stator 1. A reflecting surface 4 is provided on one side of the focusing lens 3. A magnetic structure is provided on the reflecting surface 4. The magnetic structure is used to respond to an external magnetic field to drive the rotor 2 to rotate.

[0047] It is feasible that the magnetic structure is a nickel layer deposited on the reflective surface 4 by a magnetron sputtering process.

[0048] It is feasible that the end face of the single-mode fiber is cut at an 8° angle.

[0049] It is feasible that the stator 1 and the rotor 2 constitute a miniature bearing structure, and the interior of the miniature bearing structure is provided with free space for beam expansion.

[0050] It is feasible that the reflective surface 4 is an inclined surface, used to perform total internal reflection of the light emitted along the single-mode fiber, so as to change the direction of the optical path and achieve lateral emission.

[0051] like Figure 3 As shown, this embodiment provides the manufacturing process of a magnetically controlled fiber optic OCT probe, specifically including:

[0052] S1: Cut the end face of the single-mode fiber at an 8° angle. This step is to avoid artifacts and obtain better optical imaging quality. Then, clean the end face with lens paper soaked in anhydrous ethanol. After that, place the fiber in a plasma cleaner to enhance its adhesion.

[0053] S2: The optical fiber is placed in a fixture, which is a standard short-stem SC fiber ceramic ferrule with an inner diameter of 125 micrometers. A matching SC standard open sleeve is fitted over it. Inverting it on a coverslip completes the fiber processing fixture. Femtosecond laser two-photon polymerization is used to polymerize SZ2080, IP-S, and other photoresists. The mixture is then developed in ethanol. The specific structure includes a stator 1 directly connected to the optical fiber, an outer rotor 2, and a reflective surface 4 and lens integrally machined with the rotor 2.

[0054] S3: Magnetron sputtering is performed on the four parts of its reflective surface to deposit a nickel layer, enabling it to be magnetron sputtered.

[0055] S4: The entire assembly is encapsulated in a transparent conduit.

[0056] The imaging process of the magnetically controlled fiber optic OCT probe described in this embodiment specifically includes:

[0057] Single-mode optical fiber is mainly used to transmit coherent light, that is, to transmit the light emitted from the light source to the focusing lens 3 for emission, and to receive the light signal containing biological tissue information scattered by the tissue to the demodulation system of the OCT system.

[0058] Light is emitted from the end face of a single-mode fiber. To achieve higher imaging resolution, i.e., a smaller spot size at the final convergence point, the effective light transmission area needs to be increased, necessitating beam expansion. Unlike traditional beam expansion by fusion splicing a section of coreless fiber, this embodiment utilizes the space created by a micro-bearing structure fabricated using femtosecond laser polymerization to allow the light to expand freely in free space. The expanded light then undergoes total internal reflection after passing through a specially designed and fabricated tilted reflective surface 4, resulting in lateral light emission. The nickel layer plated on reflective surface 4 not only enables magnetron splicing but also enhances its reflection effect, preventing light leakage. Finally, the light is focused by an integrally fabricated focusing lens 3 and passes through a transparent conduit to illuminate the biological tissue. Due to the reversibility of the optical path, the backscattered Rayleigh scattering and reflected light from the biological tissue returns along the original path and is ultimately collected by the single-mode fiber into the demodulation module of the OCT system. The reflected beam interferes with the beam of the reference arm, and the OCT signal demodulation system demodulates the interference signal to reflect the depth information of this biological tissue, thereby reconstructing a depth image. Then, an external rotating permanent magnet is used to make the rotor 2 drive the reflective surface 4 and the focusing lens to rotate, thereby achieving a circular scan and reconstructing the depth image of the entire cross section.

[0059] In summary, the probe device provided in this embodiment reduces the splicing process of multiple optical fibers, requiring only single-mode fiber. The integrated two-photon polymerization process significantly reduces manufacturing complexity. Furthermore, the introduction of magnetron splicing eliminates the need for complex torque coil drives, allowing the probe diameter to be reduced to within 200 micrometers. The wireless operation of the magnetron splicing also increases flexibility and safety. The extremely small probe diameter broadens application scenarios; even extremely narrow cavities previously accessible only through MRI and CT imaging can now be imaged in situ using OCT technology, offering significant value for imaging small blood vessels such as those in the brain.

[0060] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A magnetically controlled fiber optic OCT probe, characterized in that, include: Transparent catheter; A single-mode optical fiber, wherein the single-mode optical fiber is disposed inside the transparent conduit; An optical imaging assembly is integrally formed on the end face of the single-mode fiber using femtosecond laser two-photon polymerization technology. The optical imaging assembly includes a stator (1), a rotor (2), and a focusing lens (3) arranged in sequence. The end of the stator (1) away from the rotor (2) is fixedly connected to the single-mode fiber. The rotor (2) rotates relative to the stator (1). A reflecting surface (4) is provided on one side of the focusing lens (3). A magnetic structure is provided on the reflecting surface (4). The magnetic structure is used to respond to an external magnetic field to drive the rotor (2) to rotate.

2. The magnetically controlled fiber optic OCT probe according to claim 1, characterized in that, The magnetic structure is a nickel layer deposited on the reflective surface (4) by magnetron sputtering.

3. The magnetically controlled fiber optic OCT probe according to claim 1, characterized in that, The end face of the single-mode optical fiber is cut at an 8° angle.

4. The magnetically controlled fiber optic OCT probe according to claim 1, characterized in that, The stator (1) and the rotor (2) constitute a micro-bearing structure, and the interior of the micro-bearing structure is provided with a free space for beam expansion.

5. A magnetically controlled fiber optic OCT probe according to claim 1, characterized in that, The reflective surface (4) is an inclined surface, used to perform total internal reflection of the light emitted along the single-mode fiber, so as to change the direction of the optical path and achieve lateral emission.

6. The method for fabricating a magnetically controlled fiber optic OCT probe as described in claim 1, characterized in that, include: S1: Cut the end face of the single-mode fiber at an 8° angle and clean it. S2: Fix the cut single-mode fiber in the clamp; S3: Using femtosecond laser two-photon polymerization technology, photoresist is polymerized on the end face of the single-mode fiber to prepare an optical imaging assembly including a stator (1), a rotor (2), a reflective surface (4), and a focusing lens (3); S4: The formed optical imaging components are then developed. S5: A magnetic material layer is coated on the reflective surface (4) to form a magnetic structure; S6: The finished optical fiber and optical imaging components are encapsulated in a transparent conduit.

7. The preparation method according to claim 6, characterized in that, Step S2 specifically includes: inserting the cut single-mode fiber into a standard short-stem SC fiber ceramic ferrule with an inner diameter of 125 micrometers, and then placing the ceramic ferrule into a matching SC standard open sleeve and inverting it on a cover glass.

8. An application of a magnetically controlled fiber optic OCT probe in imaging.

9. The application according to claim 8, characterized in that, Imaging methods include: S1: Transmit coherent light to the optical imaging component via a single-mode fiber; S2: The coherent light expands in the free space between the stator (1) and the rotor (2); S3: After the expanded beam is totally reflected by the reflecting surface (4), the direction of the light changes and it is emitted laterally; S4: The light rays emitted from the side are focused by the focusing lens (3) and then pass through the transparent conduit to irradiate the biological tissue; S5: Backscattered and reflected light from biological tissues return along the original optical path to the single-mode fiber and are transmitted to the demodulation module of the OCT system to reconstruct the depth image of the biological tissue; S6: The magnetic structure is driven by an external rotating permanent magnet, which drives the rotor (2), the reflective surface (4) and the focusing lens (3) to rotate, so as to realize the ring scanning of biological tissue and the reconstruction of the depth image of the entire cross section of biological tissue.

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