Hand-held line field optical coherence tomography system and method of series interference architecture

Abstract

The invention provides a handheld line field optical coherence tomography system and method of a series interference framework, and belongs to the technical field of tomography. Comprising a light source module, a compensation interferometer, a handheld sensing interferometer, a middle beam splitter and a detection module. The compensation interferometer adopts a Michelson architecture, and a light source beam is split and reflected by the fixed reflector and the optical path adjustable reflector to obtain a front-end beam with a first optical path difference. The handheld sensing interferometer adopts a Mirau framework and comprises a scanning galvanometer and an immersed Mirau interference objective lens; the front-end light beam enters the objective lens after being adjusted by the galvanometer, is divided into second reference light and second sample light by the built-in beam splitter, and returns after being reflected by the reference surface of the objective lens and the sample respectively. And the returned light is guided to the detection module through the middle beam splitter. Through the series connection design, the probe is light and portable, the problems of volatilization and leakage of liquid immersed in a traditional Mirau objective lens are avoided through optical path compensation, the imaging quality is improved, the service life is prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of tomographic imaging technology, and more specifically to a handheld line-field optical coherence tomographic imaging system and method with a tandem interferometric architecture. Background Technology

[0002] In the field of optical coherence tomography (OCT), the interferometer architecture is the core for achieving high-resolution tomographic imaging. Currently, the mainstream interferometer architectures include the classic Michelson architecture, and the Mirau and Linnik architectures, which are specifically developed for microscopic imaging. (See appendix for details.) Figure 2 The Michelson architecture is clear and flexible in its adjustment, and is the basis of many systems; while the Mirau architecture achieves an extremely compact structure by integrating the reference plane inside the objective lens, which is conducive to integration; the Linnik architecture uses a pair of matching objectives to guide the reference arm and the sample arm respectively, which can achieve excellent imaging quality, but its structure determines its inherent size and weight.

[0003] The aforementioned architectures all have significant limitations when it comes to handheld, highly stable clinical diagnostic applications. Traditional Linnik interferometers, requiring two separate microscope objectives, result in a bulky and heavy system with high mechanical inertia, limiting scanning speed and making it difficult to design a lightweight probe that doctors can easily hold. While the compact Mirau architecture solves the size problem, its core immersion interferometer objective relies on an internal liquid layer for optical functionality. This liquid is prone to evaporation or leakage during long-term use. This not only directly leads to decreased image quality and signal attenuation but also introduces the need for frequent maintenance, calibration, and even objective replacement, significantly increasing operating costs and system instability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a handheld line-field optical coherence tomography system and method with a tandem interferometric architecture. This system solves the technical problems of the Linnik interferometer architecture being bulky and heavy, having high inertia, low scanning speed, and being inconvenient for doctors to hold, and the Mirau interferometer architecture, although compact in structure, having immersion objectives that are prone to evaporation and leakage during use, affecting image quality and incurring extremely high maintenance costs.

[0005] The technical solution adopted in this invention is a handheld line-field optical coherence tomography system and method with a tandem interference architecture.

[0006] Among them, the handheld line-field optical coherence tomography system with a tandem interferometric architecture includes: The light source module is used to emit a broadband, low-coherence line beam; The compensated interferometer, which adopts the Michelson architecture, includes: a compensated beam splitter, a fixed reflector, and an optically path-adjustable reflector. The light beam emitted by the light source module is split into two beams after passing through the compensated beam splitter. After being reflected by the fixed reflector and the optically path-adjustable reflector respectively, the beams return to the compensated beam splitter and generate a front-end beam. The front-end beam includes a first reference beam and a first sample beam with a first optical path difference, wherein the first optical path difference is greater than the coherence length of the light source. A handheld sensing interferometer, which adopts a Mirau architecture, includes a scanning galvanometer and a Mirau interferometer objective. The Mirau interferometer objective is an immersion objective. The scanning galvanometer is located at the entrance pupil of the Mirau interferometer objective. The front beam is oriented by the scanning galvanometer and then enters the Mirau interferometer objective. The front beam is split into a second reference beam and a second sample beam by a sensing beam splitter inside the objective and a second optical path difference is introduced. The second reference beam and the second sample beam pass through the objective reference plane and the test object, respectively, and then return to obtain the return beam. The system includes a detection module and an intermediate beam splitter located between the compensation interferometer and the handheld sensing interferometer. When the returned light passes through the intermediate beam splitter, it is separated into a new beam and received by the detection module.

[0007] Optionally, it also includes a piezoelectric ceramic displacement stage and an electric translation stage, wherein the piezoelectric ceramic displacement stage is disposed on the moving part of the electric translation stage, and the optical path adjustable reflector is disposed on the moving part of the piezoelectric ceramic displacement stage; Alternatively, it may include a rotatable optical wedge, which is arranged in pairs and positioned between the compensating beam splitter and the optical path adjustable mirror.

[0008] Optionally, the scanning galvanometer includes a reflector and a power source, wherein the power source can change the angle of the reflector, thereby changing the direction of the reflected light without changing the direction of the incident light.

[0009] Optionally, it also includes a relay lens group disposed between the optical paths of the compensated interferometer and the handheld sensing interferometer.

[0010] Optionally, the compensating beam splitter adopts a non-polarized beam splitting cube with a splitting ratio of 50:50.

[0011] Optionally, the detection module is a line scan camera, and a tube lens is provided between the line scan camera and the intermediate beam splitter.

[0012] Optionally, the contact window of the Mirau interference objective is made of sapphire.

[0013] Optionally, the light source module includes a linear light source and a collimating and shaping lens group.

[0014] The handheld line-field optical coherence tomography method with a tandem interferometric architecture, employing the handheld line-field optical coherence tomography system with the tandem interferometric architecture described above, includes the following steps: Optical path calibration: The objective lens of the handheld sensor interferometer is attached to the strong reflection module, the piezoelectric ceramic displacement stage and the scanning galvanometer remain stationary, the motorized translation stage moves the optical path adjustable reflector, the detection module scans the optical path difference, and when the optical path difference is zero, the position of the motorized translation stage is locked and calibration is completed.

[0015] Optionally, it also includes: two-dimensional tomography, wherein the piezoelectric ceramic displacement stage drives the piezoelectric ceramic displacement stage to oscillate back and forth, the light source module emits a light beam, and the detection module synchronously acquires the interference pattern; and three-dimensional volumetric imaging, wherein while performing the two-dimensional tomography, the scanning galvanometer deflects the light beam, causing it to move in a straight line on the sample surface.

[0016] As can be seen from the above technical solution, the beneficial technical effects of the present invention are as follows: By designing a tandem interferometric architecture, several significant and beneficial technical effects have been achieved. This scheme separates the bulky depth scanning mechanism and optical path adjustment function from the handheld probe and transfers them to the front-end compensation interferometer. This allows the handheld probe to consist only of a lightweight scanning galvanometer and a compact Mirau objective, greatly reducing the overall weight and size of the probe. This achieves true portability and ease of operation, overcoming the drawbacks of the traditional Linnik architecture, such as high inertia and difficulty in handheld operation. Simultaneously, the active optical path compensation mechanism can adjust the compensation interferometer in real time to counteract optical path drift caused by the evaporation of the immersion medium inside the Mirau objective or environmental changes. This fundamentally solves the problem of image quality degradation and failure caused by liquid leakage in traditional Mirau probes, greatly improving the long-term stability and reliability of the system, extending the lifespan of core optical components, and significantly reducing maintenance difficulty and cost. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0018] Figure 1 This is a schematic diagram of the tomographic imaging system architecture.

[0019] Figure 2 This is a schematic diagram comparing three interference architectures.

[0020] Figure reference numerals: Light source module 1, linear light source 11, collimating and shaping lens group 12, compensating interferometer 2, compensating beam splitter 21, fixed reflector 22, optical path adjustable reflector 23, handheld sensing interferometer 3, scanning galvanometer 31, interferometric objective lens 32, sensing beam splitter 33, reference plane 34, object under test 35, intermediate beam splitter 4, detection module 5, front beam 6, tube lens 7. Detailed Implementation

[0021] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0022] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] Before detailing the specific implementation methods, let's briefly introduce the principle of tomography: The core principle of tomography is to obtain depth information using light interference. The system splits the broadband light source beam into a reference beam and a probe beam. The probe beam is reflected by structures at different depths after entering the sample. Interference occurs only when the optical path difference between the returned probe beam and the reference beam is less than the extremely short coherence length of the light source, generating a signal. By continuously changing the reference optical path by moving the reference mirror, the system sequentially matches the interference conditions to each depth layer within the sample, thereby decoding the reflection intensity at different depths into time-varying interference signals. Ultimately, the peak time sequence of this signal corresponds to the depth position, and the peak amplitude corresponds to the structural reflectivity, reconstructing a one-dimensional depth profile.

[0024] Currently, there is a great demand for non-invasive, high-resolution 3D imaging of skin tissue in many scenarios, such as dermatological clinical diagnosis, cosmetic medicine, and biomedical research. Therefore, optical coherence tomography (OCT) is widely used. Line-field confocal optical coherence tomography (LC-OCT) is a high-resolution imaging technique that combines the OCT interferometry principle with confocal microscopy, featuring non-invasiveness and high resolution.

[0025] Currently, mainstream LC-OCT systems on the market are typically based on the Linnik interferometer architecture. Figure 2 c) A reference arm and a sample arm with identical structures are moved simultaneously or separately by a precision displacement stage to achieve optical path matching and depth scanning. Parallel detection is performed using a line scan camera, enabling the acquisition of vertical slices and 3D images of the skin at high speed. This technique, due to its Linnik architecture, is bulky and heavy, making it inconvenient for doctors to hold. Furthermore, during depth scanning, the mechanical movement of the entire interferometer is required, and its significant inertia limits the scanning speed.

[0026] Another type of interference structure is the Mirau interference structure ( Figure 2 (b) This structure integrates the beam splitter and reference mirror within the microscope objective, resulting in a compact design. To match the refractive index of biological tissue for high resolution and reduce surface reflection, water or silicone oil is typically used as the immersion medium. Existing Mirau objectives are usually designed for water or oil immersion to match the skin's refractive index, requiring the liquid medium to be encapsulated inside the lens or kept full during use. However, during long-term use, trace amounts of moisture or other liquid media inevitably evaporate or leak from the encapsulation, altering the optical path difference between the Mirau probe's sample arm and reference arm. This affects image quality, and users cannot calibrate it themselves. Typically, the entire expensive objective module must be scrapped or returned to the factory for complex liquid filling and encapsulation processes, resulting in extremely high maintenance costs and significantly limiting its commercial viability.

[0027] In this scheme, the handheld line-field optical coherence tomography system with a tandem interferometric architecture is described in the appendix. Figure 1 One possible implementation method is as follows: Light source module 1 is used to emit a broadband, low-coherence linear beam. Light source module 1 includes a linear light source 11 and a collimating and shaping lens group 12. Broadband refers to a wide spectral range, and its short coherence length determines the longitudinal resolution of the image. Low coherence means that the phase of the light wave changes rapidly and randomly, and interference can only occur within a very small optical path difference, thus achieving precise depth tomography (optical slicing). The linear beam shape facilitates lateral scanning. The combination of these three elements constitutes the light source foundation for high-resolution tomographic scanning in optical coherence tomography.

[0028] The compensating interferometer 2, employing a Michelson architecture, includes a compensating beam splitter 21, a fixed reflector 22, and an optically path-adjustable reflector 23. The beam emitted from the light source module 1 is split into two beams by the compensating beam splitter 21. After reflection by the fixed reflector 22 and the optically path-adjustable reflector 23 respectively, the beam returns to the compensating beam splitter 21, generating a front-end beam 6. The front-end beam 6 includes a first reference beam and a first sample beam with a first optical path difference greater than the coherence length of the light source. A controllable and interference-free optical path delay is pre-introduced to ensure the beam output from this stage is in a "collimated" state. This design ensures that the actual, effective interference signal is generated and determined solely by the subsequent handheld sensing interferometer 3, while the compensating interferometer 2 itself becomes an independent and precise optical path adjustment and compensation mechanism. By adjusting this optical path difference, optical path drift caused by liquid evaporation or environmental changes in the sensing probe can be actively compensated, thereby achieving long-term system stability and self-calibration, while ensuring that all scanning and imaging actions are ultimately reflected at the lightweight handheld probe end.

[0029] The handheld sensing interferometer 3 adopts a Mirau architecture and includes a scanning galvanometer 31 and a Mirau interferometer objective 32. The contact window of the Mirau interferometer objective 32 is made of sapphire. The Mirau interferometer objective 32 is an immersion objective. The scanning galvanometer 31 is located at the entrance pupil of the Mirau interferometer objective 32. The front beam 6 is oriented by the scanning galvanometer 31 before entering the Mirau interferometer objective 32. The scanning galvanometer 31 includes a reflector and a power source. The power source can change the angle of the reflector, thereby changing the direction of the reflected light while keeping the incident light direction unchanged, thus scanning the object under test. The front beam 6 is split into a second reference light and a second sample light by the sensing beam splitter 33 inside the objective, introducing a second optical path difference. The second reference light and the second sample light pass through the objective reference plane 34 and the object under test 35, respectively, and then return as return light. The second optical path difference is mainly determined by two factors: first, the difference in physical distance between the fixed reference plane inside the objective lens and the surface of the object under test; second, the equivalent optical path change caused by the difference in refractive index between the liquid and air when light passes through the immersion liquid layer (such as water or oil) inside the Mirau interference objective lens. The filling state of the liquid (such as thickness and refractive index) directly affects this part of the optical path value.

[0030] The system includes a detection module 5 and an intermediate beam splitter 4 positioned between the compensating interferometer 2 and the handheld sensing interferometer 3. When the returning light passes through the intermediate beam splitter 4, it is separated into new beams, which are then received by the detection module 5. To enable the compensating interferometer 2 and the handheld sensing interferometer 3 to operate relatively independently, a relay lens group is also included, positioned between the optical paths of the compensating interferometer 2 and the handheld sensing interferometer 3. The detection module 5 is a line scan camera, and a tube lens 7 is also provided between the line scan camera and the intermediate beam splitter 4.

[0031] The principle of the above embodiment is as follows: This scheme is based on the principle of series compensation. The low coherence light emitted by the linear light source 11 first passes through a collimating and shaping lens group 12 and then enters the Michelson architecture compensation interferometer 2, where it is split into two beams, introducing an initial optical path difference (OPD). Comp At this point, the optical path difference is greater than the coherence length of the light source, and the beam does not produce interference fringes upon exiting. Subsequently, the beam enters the handheld sensing interferometer 3 of the Mirau architecture, where it is again split into reference and sample beams, introducing a second optical path difference (OPD). Sens .

[0032] When the optical path difference introduced by the handheld sensor interferometer 3 is equal in magnitude but opposite in sign to the optical path difference of the compensating interferometer 2, OPD Comp =OPD Sens When the total optical path difference returns to the coherence length range of the light source, the detection module 5 will observe the interference signal. The evaporation of moisture within the Mirau interferometer objective 32 causes changes in refractive index or physical thickness, thus inducing OPD.Sens When a drift ΔL occurs, this scheme adjusts the reference arm length of the compensation interferometer 2 to make OPD... Comp By changing ΔL, the interference conditions are satisfied again, thereby eliminating the influence of environmental factors on imaging.

[0033] Furthermore, in one possible implementation, a piezoelectric ceramic displacement stage and an electric translation stage are also included. The piezoelectric ceramic displacement stage is mounted on the moving part of the electric translation stage, and the optically path-adjustable reflector 23 is mounted on the moving part of the piezoelectric ceramic displacement stage. The piezoelectric ceramic displacement stage is a precision driving device that utilizes the inverse piezoelectric effect of piezoelectric materials to produce precise microscopic deformation after applying voltage. It can achieve rapid linear displacement with nanometer-level resolution, fast response speed, and no mechanical backlash. In this system, it is typically used to drive the reflector of the compensation interferometer for high-frequency, short-stroke depth scanning. During normal imaging, the position of the optically path-adjustable reflector 23 is changed to rapidly modulate the optical path to correspond to different depths of the object being measured. The electric translation stage has a displacement at the millimeter level and can use a lead screw mechanism to compensate for the optical path after a small amount of water or other liquid medium in the Mirau interferometer objective lens 32 evaporates or leaks.

[0034] Alternatively, it may include rotatable optical wedges, arranged in pairs, positioned between the compensating beam splitter 21 and the optical path adjustable mirror 23. The optical path between the beam splitter 21 and the optical path adjustable mirror 23 is changed by rotating the optical wedges. An optical wedge is an optical element with a small wedge angle. When a beam passes through glass with a gradually varying thickness, an optical path delay is generated, which is related to the size and position of the wedge angle. By rotating a pair of optical wedges relative to each other, their combined thickness can be continuously and precisely adjusted, thereby achieving fine control of the optical path. In this system, it is used to compensate for optical path differences in the optical path.

[0035] In a more specific embodiment: The linear light source 11 of light source module 1 uses a high-power linear LED with a center wavelength of 750nm and a full width at half maximum (FWHM) of approximately 50nm. Compared to supercontinuum lasers, linear LEDs are less expensive and have no speckle noise. If higher axial resolution or deeper penetration is required, the linear LED can be replaced with a supercontinuum laser in conjunction with a cylindrical mirror to generate a line beam.

[0036] The compensating beam splitter 21 adopts a non-polarized cubic beam splitter with a splitting ratio of 50:50. The piezoelectric ceramic displacement stage has a stroke of 400μm and is superimposed on the motorized translation stage, which has a stroke of 25mm.

[0037] The Mirau interference objective 32 has a numerical aperture of 0.5, and the lens is pre-sealed with distilled water or silicone oil and sealed with a sapphire window.

[0038] The scanning speed of the line scan camera is matched with that of the piezoelectric ceramic displacement stage, and the line frequency of the optional piezoelectric ceramic displacement stage is 20kHz-100kHz.

[0039] Simultaneously, control software can be developed based on LabVIEW or C++, employing a four-step phase-shift extraction method to extract the interference envelope. Furthermore, by combining image acquisition cards and FPGA / PC workstations, the system synchronizes the oscillation of the piezoelectric ceramic displacement stage, the deflection of the galvanometer, and the camera exposure; it receives camera data, demodulates interference fringes using an envelope extraction algorithm, and reconstructs the image.

[0040] One possible implementation of the handheld line-field optical coherence tomography method with a tandem interferometric architecture is as follows: The handheld line-field optical coherence tomography system employing the above-mentioned tandem interferometric architecture includes the following steps: For optical path calibration, the objective lens of the handheld sensor interferometer 3 is attached to the strong reflection module (such as a plane mirror), and the system enters the "calibration mode". The piezoelectric ceramic displacement stage and scanning galvanometer 31 remain stationary, while the motorized translation stage moves the optical path adjustable mirror 23. The detection module 5 scans the optical path difference. When the optical path difference is zero, the camera will detect the strongest interference fringe signal. This position is the new zero optical path point. The position of the motorized translation stage is locked and the calibration is completed.

[0041] In one possible implementation, it further includes: two-dimensional tomography, in which a piezoelectric ceramic displacement stage drives the piezoelectric ceramic displacement stage to oscillate back and forth, a light source module 1 emits a light beam, and a detection module 5 synchronously acquires interference patterns. The images are then demodulated in real time via an FPGA to obtain a longitudinal section image of the skin. Because the depth scanning component is located in the compensation interferometer section, the handheld probe remains stationary, avoiding the inertial effects caused by hand tremors. Three-dimensional volumetric imaging involves performing two-dimensional tomography while simultaneously deflecting the beam using a scanning galvanometer 31, causing it to move linearly across the sample surface. The system continuously acquires a series of images, which are then stacked in spatial order by the software to reconstruct the three-dimensional microstructure inside the sample.

[0042] In summary, this solution has the following advantages over existing technologies: Traditional immersion Mirau interferometer objectives are susceptible to optical path drift caused by medium evaporation or leakage. Even a small amount of evaporation or leakage of the internal encapsulated liquid can alter the optical path of the reference arm, leading to the disappearance of interference fringes and preventing imaging. This solution utilizes a tandem interferometer architecture and the large-stroke adjustment capability of the host-side compensating interferometer to actively compensate for optical path drift caused by medium evaporation at the probe end.

[0043] This design moves the heavy and bulky depth scanning components into the compensation interferometer. The handheld probe only needs to retain the lightweight scanning galvanometer and objective lens, thus significantly reducing the probe's weight.

[0044] In terms of light source cost, using linear LEDs as the light source significantly reduces the hardware cost of the system compared to the commonly used expensive supercontinuum lasers, while eliminating laser speckle noise and improving image quality.

[0045] In terms of precision assembly and adjustment costs, the tandem interference architecture allows the Mirau interferometer to be physically separated from the compensation interferometer, and the optical path matching accuracy requirements of the probe can be appropriately relaxed, thereby reducing the difficulty of precision manufacturing and assembly of the probe.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A handheld line-field optical coherence tomography system with a tandem interferometric architecture, characterized in that, include: The light source module (1) is used to emit a broadband, low-coherence line beam; The compensation interferometer (2) adopts the Michelson architecture and includes: a compensation beam splitter (21), a fixed mirror (22) and an optical path adjustable mirror (23). The light beam emitted by the light source module (1) is split into two beams after passing through the compensation beam splitter (21) and is reflected by the fixed mirror (22) and the optical path adjustable mirror (23) respectively. The beam returns to the compensation beam splitter (21) and generates a front beam (6). The front beam (6) includes a first reference light and a first sample light with a first optical path difference. The first optical path difference is greater than the coherence length of the light source. A handheld sensing interferometer (3) is provided. The handheld sensing interferometer (3) adopts the Mirau architecture and includes a scanning galvanometer (31) and a Mirau interferometer objective (32). The Mirau interferometer objective (32) is an immersion objective. The scanning galvanometer (31) is located at the entrance pupil of the Mirau interferometer objective (32). The front beam (6) is adjusted in direction by the scanning galvanometer (31) and then enters the Mirau interferometer objective (32). The front beam (6) is split into a second reference beam and a second sample beam by the sensing beam splitter (33) inside the objective and a second optical path difference is introduced. The second reference beam and the second sample beam pass through the objective reference surface (34) and the object under test (35) respectively and then return to obtain the return beam. The return light is separated into a new beam when it passes through the intermediate beam splitter (4) and is received by the detection module (5) and the intermediate beam splitter (4) between the compensation interferometer (2) and the handheld sensing interferometer (3).

2. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: It also includes a piezoelectric ceramic displacement stage and an electric translation stage, wherein the piezoelectric ceramic displacement stage is disposed on the moving part of the electric translation stage, and the optical path adjustable reflector (23) is disposed on the moving part of the piezoelectric ceramic displacement stage; Alternatively, it may also include a rotatable optical wedge, which is arranged in pairs and positioned between the compensating beam splitter (21) and the optical path adjustable reflector (23).

3. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: The scanning galvanometer (31) includes a reflector and a power source. The power source can change the angle of the reflector, thereby changing the direction of the reflected light without changing the direction of the incident light.

4. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: It also includes a relay lens group, which is located between the optical paths of the compensation interferometer (2) and the handheld sensing interferometer (3).

5. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: The compensation beam splitter (21) adopts a non-polarized beam splitting cube with a splitting ratio of 50:

50.

6. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: The detection module (5) is a line scan camera, and a tube lens (7) is provided between the line scan camera and the intermediate beam splitter (4).

7. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: The contact window of the Mirau interference objective (32) is made of sapphire.

8. The handheld line-field optical coherence tomography system with a tandem interferometric architecture as described in claim 1, characterized in that: The light source module (1) includes a linear light source (11) and a collimating and shaping lens group (12).

9. A handheld line-field optical coherence tomography method with a tandem interferometric architecture, characterized in that, The handheld line-field optical coherence tomography system employing the tandem interferometric architecture as described in claim 2 includes the following steps: Optical path calibration: The objective lens of the handheld sensor interferometer (3) is attached to the strong reflection module. The piezoelectric ceramic displacement stage and the scanning galvanometer (31) remain stationary. The electric translation stage moves the optical path adjustable reflector (23). The detection module (5) scans the optical path difference. When the optical path difference is zero, the position of the electric translation stage is locked and calibration is completed.

10. The handheld line-field optical coherence tomography method with a tandem interferometric architecture as described in claim 9, characterized in that, Also includes: Two-dimensional tomography, the piezoelectric ceramic displacement stage drives the piezoelectric ceramic displacement stage to oscillate back and forth, the light source module (1) emits a light beam, and the detection module (5) synchronously acquires the interference pattern; In three-dimensional volumetric imaging, while performing the two-dimensional tomographic imaging, the scanning galvanometer (31) deflects the light beam, causing it to move in a straight line on the sample surface.

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