A method for shaping a fiber-optic microbubble probe and apparatus therefor

Abstract

The application discloses a shaping method and device of a fiber microbubble probe. The method comprises the following steps: obtaining a fiber microbubble probe initial product with structural deformity, wherein the structural deformity comprises at least one of the following: a skew of a handle or a probe, and a collapse of a microbubble cavity; fixing the initial product and filling a gas with a predetermined pressure into the cavity of the initial product; performing local thermal shaping on the deformed part by using unilateral laser heating; and driving the deformed part to return to a preset geometric shape by using surface tension difference or internal gas pressure expansion force generated by material heating. The application solves the problem that the fiber microbubble probe cannot be sensed due to structural skew or collapse caused by uneven thermal field in the preparation of the fiber microbubble probe, realizes non-contact and non-destructive repair, improves the yield, guarantees the coaxiality and symmetry of the device, and can stably support optical resonance or interference.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing technology, and in particular to a method and apparatus for shaping fiber optic microbubble probes. Background Technology

[0002] Fiber optic microbubble probes are micro- and nano-scale optical sensing elements that can convert physical quantities such as pressure and displacement into optical signals for high-precision detection based on the principles of interference or whispering-gallery mode resonance. They have important applications in microsystem assembly, materials testing, and biological sample analysis. Carbon dioxide laser processing is one of the main techniques for fabricating these devices.

[0003] In fiber optic microcavity fabrication technology, the method of using carbon dioxide laser thermal melting tapering combined with internal gas filling is widely used to manufacture fiber optic microbubble probes. Specifically, this technique typically involves using dual-channel carbon dioxide lasers to symmetrically irradiate and heat the sample from both sides, causing localized melting of the quartz fiber, and then blowing it under internal gas pressure to form a microsphere or microbubble cavity structure. Based on this, by precisely controlling the laser power and gas pressure, a probe structure for mechanical sensing can be formed at one end of the microbubble, thus constituting a fiber optic microbubble probe that can be used for microforce or microdisplacement measurement. This probe structure typically includes a connecting fiber, a hollow shank, a microbubble cavity, and a probe tip at the end, and its fabrication process depends on the delicate interaction between the laser heat source and the quartz material.

[0004] However, in actual fabrication, factors such as instantaneous fluctuations in laser power, alignment errors in dual-path optical systems, or the precision of the displacement stage control often make it difficult to maintain an ideal symmetrical thermal field in the heating area. This uneven distribution of the thermal field leads to tension imbalance on the surface of the fused silica, resulting in severe structural deformities, mainly manifested as skewed bending of the shank and probe, or microbubble collapse due to localized overheating / underheating. Skewed probes cannot guarantee perpendicular contact with the surface to be measured, leading to mechanical measurement failure; collapsed or asymmetrical microbubbles will disrupt the optical path resonance conditions, causing the sensor to malfunction. Due to the extreme fragility of micro- and nano-devices, there is currently a lack of effective non-contact repair methods. Once the above deformities occur, the device usually has to be scrapped, which greatly limits the yield and application of fiber optic microbubble probes. Summary of the Invention

[0005] This invention provides a method and apparatus for shaping fiber optic microbubble probes, which solves the problem of structural deformities such as skeletal or probe misalignment and microbubble cavity collapse caused by factors such as uneven thermal field during the fabrication of fiber optic microbubble probes. These deformities prevent the device from forming effective interference or resonance and thus lose their sensing function. The invention achieves non-contact repair of various deformities through a combination of unilateral laser heating and internal air pressure control. The repaired device has a skeletal coaxiality with the optical fiber, a probe pointing towards the center of the microbubble, and a circumferentially uniform microbubble wall thickness, which can stably support optical resonance or interference, thereby improving the yield and measurement reliability.

[0006] This invention provides a method for shaping an optical fiber microbubble probe, the method comprising: Obtain a preliminary fiber optic microbubble probe with structural deformities, the structural deformities including at least one of the following: skeletal or probe misalignment and collapse of the microbubble cavity. The fiber optic microbubble probe prototype is fixed, and gas at a predetermined pressure is injected into the cavity of the fiber optic microbubble probe prototype. For the location of the structural deformity, a unilateral laser heating method is used to perform local thermal reshaping of the deformed area. The surface tension difference or internal air pressure expansion force generated by the heating of the material in the heated area is used to drive the deformed area to restore it to the preset geometric shape.

[0007] Optionally, before the step of performing localized thermal reshaping of the deformed area using unilateral laser heating, the method further includes: The image of the initial fiber microbubble probe is acquired and compared with a preset standard geometric model to determine the type of deformity and the position coordinates of the deformity in three-dimensional space. Based on the stated position coordinates, the laser spot is controlled to align with the back side of the deformed area.

[0008] Optionally, when the structural deformity is a misalignment of the handle or probe, the step of locally heating and reshaping the deformed area using unilateral laser heating includes: Identify the bending direction of the handle or probe to determine the back side of the bend; The laser beam is controlled to be focused on the curved back side and irradiated using a stepped heating strategy; As the temperature on the curved back side increases, the increased surface tension of the material on that side pulls the handle or probe back to the optical fiber axis.

[0009] Optionally, the step of irradiation using a stepped heating strategy includes: Gradually increase the laser power while observing the morphological changes of the deformed area in real time; When the initial observation shows that the malformed area begins to shift axially, it is determined that the current laser power has reached the material melting threshold, and the power is stopped from being increased.

[0010] Optionally, when the structural deformity is the collapse of a microbubble cavity, the step of locally heating and reshaping the deformed area using unilateral laser heating includes: Adjust the air pressure inside the fiber optic microbubble probe prototype to a pressure value that allows the collapsed cavity wall to expand and recover. The laser beam is controlled to heat the cavity wall of the collapsed area, so that the cavity wall of the collapsed area is in a molten and softened state; Under the expansion force of the internal air pressure, the collapsed part in the molten and softened state is pushed outward, restoring it to a spherical or near-spherical symmetrical structure.

[0011] Optionally, before the step of local heating and reshaping the deformed area, the method further includes: The laser power is controlled to be maintained at a preset power value below the material melting threshold of the deformed area, and the deformed area is pre-irradiated to eliminate thermal stress concentration.

[0012] Optionally, the step of using unilateral laser heating to perform localized thermal reshaping of the deformed area includes: Verify from at least two different observation angles whether the deformed area has been restored to the preset geometric shape; If the deformity is still observed at any angle, repeat the laser alignment, heating, and recovery steps until recovery is confirmed at all angles.

[0013] Optionally, when the fiber optic microbubble probe prototype simultaneously exhibits stem misalignment and microbubble collapse, the execution sequence of the shaping method includes: First, the skewed handle is shaped, the laser spot is aligned with the curved back side of the handle, the first air pressure is injected into the microbubble probe to prevent the hollow structure of the handle from collapsing, and the laser power is gradually increased until the axis of the handle coincides with the axis of the optical fiber. After the axis of the handle is restored, the internal air pressure is increased to the second air pressure, and the laser spot is aimed at the collapsed part to heat it, so that the collapsed part is restored to a spherical or near-spherical symmetrical structure under the action of air pressure. The second air pressure is greater than the first air pressure and can cause the collapsed cavity wall to expand outward.

[0014] Optionally, when the structural deformity is a probe tilt, the gas pressure filled into the cavity of the fiber microbubble probe prototype before using unilateral laser heating is set to be slightly higher than atmospheric pressure to prevent the microbubble tip connected to the probe from collapsing during the shaping process.

[0015] Furthermore, to achieve the above objectives, embodiments of the present invention also provide a shaping device for an optical fiber microbubble probe, comprising: A fixing unit is used to fix the initial fiber optic microbubble probe with structural deformities. A pressure control unit is used to fill the cavity of the fiber optic microbubble probe sample with gas at a predetermined pressure. The laser heating unit is used to perform localized thermal reshaping of deformed areas using unilateral laser heating. A controller, connected to the fixing unit, the air pressure control unit and the laser heating unit, is used to execute the method described in any one of the above-mentioned embodiments.

[0016] Optionally, the device further includes an image acquisition and processing unit, used to acquire an image of the fiber microbubble probe prototype, and compare the image with a preset standard geometric model to determine the type of deformity and the position coordinates of the deformity in three-dimensional space; the controller controls the laser heating unit to align the laser spot with the back side of the deformed part according to the position coordinates.

[0017] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: 1. By heating the back side of the deformed area with a single laser, the surface tension of the material on the heated side is increased after softening, while the back side maintains a low tension. This drives the tilted handle or probe to automatically return to the correct position, achieving non-contact and non-destructive morphological repair at the micro-nano scale without the need for additional correction structures.

[0018] 2. By filling the collapsed microbubble with gas at a pressure higher than normal and combining it with local laser heating to soften the cavity wall, the collapsed part is pushed outward by the uniform expansion force of the internal gas pressure. This can restore the spherical symmetry structure without mechanical contact, ensuring the circumferential uniformity of the wall thickness at the equatorial surface of the microbubble, thereby restoring stable optical resonance or interference performance.

[0019] 3. By eliminating thermal stress through pre-irradiation below the melting threshold, step-by-step heating and real-time observation of morphological changes to accurately determine the melting initiation point, and verifying the shaping effect from at least two orthogonal angles and iteratively repairing, it is possible to overcome the spatial blind zone of single-view monitoring and the artifact of gravity sag, avoid secondary damage, and enable the repaired device to meet the requirements of coaxiality and symmetry in three-dimensional space. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the shaping method of the fiber optic microbubble probe of the present invention. Figure 2 This is a schematic diagram of the repair process for probe misalignment in the fiber optic microbubble probe shaping method of the present invention; Figure 3 This is a schematic diagram of the repair process of microbubble collapse in the shaping method of the fiber optic microbubble probe of the present invention. Figure 4 This is a schematic diagram of the shaping device for the fiber optic microbubble probe of the present invention. Detailed Implementation

[0021] During the fabrication of fiber optic microbubble probes, factors such as laser power fluctuations and uneven thermal fields can lead to structural deformities such as probe or shank misalignment and microbubble cavity collapse. These deformities prevent the device from forming effective interference or resonance, thus losing its sensing function. To address this, this invention provides a method for shaping fiber optic microbubble probes: A preliminary microbubble probe with structural deformities is obtained; a gas at a predetermined pressure is injected into the internal cavity; then, the back side of the deformed location is heated using a unilateral laser. The surface tension difference generated by the heated material drives the misaligned portion back to its correct position, or the internal gas pressure expansion force pushes out the collapsed portion, thereby restoring the deformed portion to a preset geometric shape. This method can repair various deformities non-contactly without causing secondary damage, improving device yield. The repaired probe shank is coaxial with the fiber, the probe points towards the center of the microbubble, and the microbubble wall thickness is uniformly distributed along the equatorial plane, enabling stable support for whispering-gallery mode resonance or Fabry-Perot interferometry, ensuring the accuracy and reliability of mechanical measurements.

[0022] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0023] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0024] Example 1 In this embodiment, a method for shaping an optical fiber microbubble probe is provided to repair structural deformities that occur during the fabrication process, including shank misalignment, probe misalignment, or microbubble cavity collapse.

[0025] Reference Figure 1 The shaping method for the fiber optic microbubble probe in this embodiment includes the following steps: Step S1: Obtain a preliminary fiber microbubble probe with structural deformities, wherein the structural deformities include at least one of the following: skeletal or probe misalignment and collapse of the microbubble cavity. In this embodiment, the fiber optic microbubble probe refers to a complete device composed of an optical fiber, a hollow shank, a microbubble cavity, and a probe section. The shaping object includes at least one part of the shank, probe tip, or microbubble cavity of the device. A preliminary fiber optic microbubble probe refers to a semi-finished or finished microbubble probe that has undergone preliminary preparation but is not yet complete, or is already completed and may contain structural defects. These structural deformities include, but are not limited to: skewness or bending of the shank relative to the fiber axis, skewness or bending of the probe relative to the fiber axis, and local collapse or asymmetry of the microbubble cavity. These deformities will prevent the device from generating stable interference or resonant signals, rendering it unusable for mechanical measurements.

[0026] Alternatively, the fiber optic microbubble probe can be made of quartz, borosilicate glass, or other transparent dielectric materials that can be softened by laser heating.

[0027] As an alternative implementation, microscopic observation or an automated image recognition system can be used to screen out at least one of the aforementioned deformities from a batch of prepared microbubble probes, which can then be used as the initial samples to be reshaped.

[0028] Optionally, the screening process includes placing the microbubble probe on an inverted microscope stage equipped with a three-dimensional motorized displacement stage. Real-time images of the microbubble probe are acquired from two orthogonal angles, top and side, using a high-resolution CCD camera. The acquired images are transmitted to a computer, where image processing algorithms are used to extract the central axis of the stem and the contour of the microbubble cavity, and compared with a pre-stored standard geometric model. If the deviation exceeds the tolerance range, the deformity type of the probe and its coordinate deviation in three-dimensional space are automatically marked, serving as the initial sample to be corrected. For the standard geometric model, the stem bending angle can be set to be less than 0.5°, and the microbubble cavity roundness error to be less than 2%.

[0029] Optionally, the central axis of the handle and the microbubble cavity contour are extracted by real-time images from a high-resolution CCD camera and computer. The microbubble cavity contour on one side is selected as a reference contour, and the other side reference contour is formed by axial flipping. When the error between the microbubble cavity contour on the other side and the other side reference contour is greater than 2%, the fiber optic microbubble probe prototype is automatically marked as microbubble deformed.

[0030] Step S2: Fix the fiber optic microbubble probe prototype and fill the cavity of the fiber optic microbubble probe prototype with gas at a predetermined pressure. In this embodiment, the selected initial sample is fixed on a displacement stage to maintain its spatial stability. Gas is introduced into the internal cavity of the microbubble probe to prevent the hollow structure from collapsing due to melting during subsequent laser heating, or to allow for active expansion and restoration of its shape using gas pressure when dealing with collapsed deformities.

[0031] Optionally, the initial fiber optic microbubble probe is a capillary fiber structure with one open end, or has a pre-drilled gas filling micropore at the shank. The open end is sealed and connected to a pressure-resistant gas tube, the other end of which is connected to a pressure controller. Gas is introduced into the cavity; the gas can be nitrogen or an inert gas to prevent oxidation of the fiber optic material at high temperatures.

[0032] Optionally, the predetermined pressure setting depends on subsequent shaping requirements. If only thermal collapse needs to be prevented, the predetermined pressure is set higher than standard atmospheric pressure, such as 150k-200kPa; if active repair of microbubble collapse is required, a higher pressure is needed, such as 200k-600kPa. During the shaping process, the pressure controller monitors and provides feedback on the intracavitary pressure in real time, maintaining pressure fluctuations within ±5kPa through closed-loop control to ensure the stability of the shaping force.

[0033] Optionally, when the structural deformity is probe skew, before using unilateral laser heating, the gas pressure filled into the cavity of the fiber microbubble probe prototype is set to be slightly higher than atmospheric pressure, such as 150k-200kPa, to prevent the microbubble tip connected to the probe from softening and collapsing due to heat conduction during the shaping process.

[0034] Step S3: For the location of the structural deformity, a unilateral laser heating method is used to perform local thermal shaping on the deformed part. The surface tension difference or internal air pressure expansion force generated by the heating of the material in the heated area is used to drive the deformed part to restore to the preset geometric shape.

[0035] In this embodiment, unilateral laser heating refers to applying laser irradiation only from one side of the deformed area, i.e., the back side in the bending direction. This step utilizes the physical property that the viscosity of the fiber optic microbubble probe decreases after heating and that surface tension drives it towards a minimum surface energy state. The side directly irradiated by the laser heats up faster, and the material softens first, entering a viscous flow state. Under the contraction of surface tension, a positive tensile force is generated, thereby driving the deformed area to restore the preset geometric shape. For microbubble collapse, the high-pressure gas inside expands outward as the cavity wall softens, pushing the collapsed area out and restoring the spherical shape. By generating a controllable surface tension difference through unilateral heating, the skew can be accurately corrected while avoiding thermal damage to other parts of the device; for collapse, the high pressure and heating work together to achieve non-destructive restoration to a round shape.

[0036] For example, based on the deformed location determined in step S1, the displacement stage is controlled to align the laser spot with the deformed area to be measured. The carbon dioxide laser is turned on, and the power is gradually increased from a low value. Simultaneously, the morphological changes are observed in real time through a microscope. When the deformed area begins to slowly recover, the current power is maintained or fine-tuned until the morphology returns to the target geometry. During the heating process, the internal air pressure is continuously maintained to prevent the hollow structure from collapsing. The diameter of the laser spot can be adjusted according to the size of the deformed area to ensure that the spot accurately covers the deformed region without damaging the surrounding intact structure.

[0037] Optionally, a carbon dioxide laser can be used, which can be effectively absorbed by common materials of fiber optic microbubble probes, achieving efficient local heating and melting. Other types of lasers that can be absorbed by fiber optic microbubble probe materials and produce local thermal effects, such as femtosecond lasers or continuous-wave infrared lasers, can also be used to achieve the shaping operation described in this method, as long as their wavelength and power are sufficient to soften the material without causing vaporization or ablation.

[0038] As an optional implementation, before performing local thermal reshaping on the deformed area, an image of the initial fiber microbubble probe can be acquired, and the image can be compared with a preset standard geometric model to determine the type of deformity and the position coordinates of the deformity in three-dimensional space; based on the position coordinates, the laser spot is controlled to be aligned with the back side of the deformed area.

[0039] Specifically, machine vision is used to automatically identify the location and type of deformities, enabling automatic alignment of the laser spot. An image acquisition module acquires an image of the initial fiber optic microbubble probe. An edge detection algorithm extracts the contours of the shank, probe tip, and microbubble cavity, which are then matched with a preset standard geometric model to calculate the type of deformity and its coordinates in three-dimensional space. Then, a three-dimensional displacement stage is controlled to automatically move the laser spot to the coordinates on the back side of the deformed area.

[0040] As an alternative implementation, when performing unilateral heating to reshape a misaligned shank or probe, the bending direction of the shank or probe is identified to determine the back side of the bend. The laser beam is focused on the back side of the bend, and a stepped heating strategy is used for irradiation. As the temperature of the back side of the bend increases, the increased surface tension of the material on that side pulls the shank or probe back to the optical fiber axis. By combining stepped heating with real-time observation, the critical point of material softening can be accurately captured, effectively avoiding excessive melting or burning of the optical fiber material due to excessive laser power. It also solves the problem of thermal shock cracks easily caused by single-heating, improving the structural strength and yield of the probe shank. The probe misalignment repair process can be found in [reference needed]. Figure 2The repair process for a misaligned shank is similar to that for a misaligned probe. After the above steps, the shank is basically aligned with the fiber axis, and the misalignment is significantly improved.

[0041] Specifically, when the deformity is a misalignment of the shank or probe tip, it is necessary to accurately identify the bending direction and heat the back side. A stepped heating method can be used to avoid secondary damage caused by thermal shock and to facilitate observation of the starting point of morphological change. For example, after determining the bending direction of the shank or probe tip, mark the bent back side; focus the laser beam on this back side, set the initial power to a value below the material melting threshold, increase the power in steps of 0.05W, maintain each step for more than 1 second, and observe the morphological change of the deformed area in real time. When the deformed area is first observed to begin to shift axially, it is determined that the current laser power has reached the material melting threshold, and the power increase is stopped. Thereafter, maintain this power or make fine adjustments until the deformed area is completely straightened, and then turn off the laser. Stepped heating gradually softens the material, avoiding local overheating that could lead to bubbles or deformation; real-time observation and stopping the power increase at the starting point of the shift ensures precise control at the first moment when the melting threshold is reached, avoiding overheating.

[0042] Optionally, when the deformed part is a probe misalignment, gas can be injected into the microbubble probe before heating to prevent the microbubble tip in contact with the probe from collapsing.

[0043] Optionally, when the deformed area is due to probe misalignment, during the gradual increase of power, after each or multiple power increases, the heated area is moved away from the microbubble cavity but remains on the probe. Because the effective laser heating area expands with increasing power, to reduce the impact of the heated area on the microbubble cavity and prevent the collapse of the microbubble tip in contact with the probe, the heated area can be gradually moved away from the microbubble cavity. This distance can be 0-50 micrometers, adjusted according to the laser power.

[0044] As another optional implementation, when the deformity type is microbubble collapse, the gas pressure inside the fiber optic microbubble probe prototype can be adjusted to a pressure value sufficient to allow the collapsed cavity wall to expand and recover. A laser beam is controlled to heat the cavity wall of the collapsed area, causing it to melt and soften. Under the expansion force of the internal gas pressure, the melted and softened collapsed area is pushed outward, restoring it to a spherical or near-spherical symmetrical structure. Through the synergistic effect of high-pressure gas and local softening, and utilizing the internal gas pressure as a uniform expansion driving force, the collapsed area can overcome the tendency of spontaneous contraction due to glass surface tension, achieving isotropic recovery of the microbubble cavity from local depression to a spherical shape. This ensures the uniformity of the wall thickness at the equatorial surface of the microbubble cavity, thereby improving the signal-to-noise ratio of subsequent optical interference signals. The repair process can be found in [reference needed]. Figure 3 .

[0045] Specifically, microbubble collapse typically manifests as localized depressions at the equatorial plane or overall asymmetry. Repair requires raising the internal pressure to a level sufficient to overcome surface tension, while simultaneously heating the collapsed area to soften it. The expanding gas pushes the cavity walls outwards. For example, the internal pressure of the microbubble is increased to a preset high-pressure value, such as 600 kPa, using a pressure controller. This pressure value can be adjusted according to the microbubble size. Then, the laser spot is adjusted to cover the collapsed area, the laser is turned on, and the power is gradually increased until the collapsed area begins to bulge and gradually regains its spherical shape. During heating, the internal high pressure is maintained constant. After recovery, the laser is turned off, and the area is allowed to cool naturally to room temperature before the internal pressure is slowly released. The simultaneous action of high pressure and heating ensures uniform expansion of the collapsed area, restoring symmetry, while preventing microbubble rupture due to excessive pressure.

[0046] As an alternative implementation, before local heating the deformed area, thermal stress can be eliminated by pre-irradiation. That is, the laser power is controlled to be maintained at a preset power value lower than the material melting threshold of the deformed area, and the deformed area is pre-irradiated to eliminate thermal stress concentration.

[0047] Specifically, before formal heating and shaping, the deformed area is pre-irradiated with a power lower than the material's melting threshold. The purpose is to slowly raise the temperature, eliminate residual localized thermal stress within the device from the earlier fabrication process, and prevent uncontrollable deformation or cracking during subsequent heating. For example, before activating the laser for thermal shaping, the laser power is set to a fixed value below the melting threshold, such as 0.2-1W, and the deformed area is irradiated for several seconds to ensure a uniform temperature rise without softening. After pre-irradiation, heating and shaping are then performed according to the specific type of deformity. Pre-irradiation serves to preheat and release stress, reducing the risk of secondary deformities.

[0048] As an alternative implementation, during local shaping, multi-angle verification and iterative repair can be performed. This involves verifying from at least two different observation angles whether the deformed area has been restored to the preset geometric shape. If the deformity is still observed from any angle, the laser alignment, heating, and restoration steps are repeated until restoration is confirmed from all angles. This multi-angle verification and iterative repair mechanism overcomes the spatial blind spot problem inherent in traditional monocular vision inspection, eliminates shaping errors caused by gravity or viewing angle obstruction, and ensures the geometric accuracy of the final fabricated fiber microbubble probe in three-dimensional space.

[0049] Specifically, since laser processing typically involves only one field of view, and gravity can cause the probe tip or microbubble of the cantilever structure to appear to droop, it is necessary to change the viewing angle to confirm the shaping effect. If deformities still exist, the shaping steps are repeated.

[0050] For example, after one laser shaping is completed, the device is kept fixed, and the deformed part is observed from at least two mutually perpendicular directions, such as the front side and the side, by rotating the displacement stage or moving the microscope lens. If it is shown from all angles that the shank is coaxial with the optical fiber, the probe tip has no bending, and the microbubble is symmetrical, the product is determined to be qualified; if deviation is observed from any angle, the process returns to step S2 or S3, re-aligns with the current dorsal side of the deformed part, and performs laser heating again until all angle verifications are qualified. Multi-angle verification avoids misjudgment in a single view, and iterative repair ensures the high yield of the final product.

[0051] As an optional implementation, if the initial optical fiber microbubble probe has both shank skew and microbubble collapse, shaping is performed in the following order: shaping the shank skew first, aligning the laser spot to the dorsal side of the bent shank, filling the interior of the microbubble probe with a first air pressure to prevent the hollow structure of the shank from collapsing, and gradually increasing the laser power until the axis of the shank coincides with the axis of the optical fiber; after the axis of the shank is restored, increasing the internal air pressure to a second air pressure, aligning the laser spot to the collapsed part for heating, so that the collapsed part recovers to a symmetrical spherical or nearly spherical structure under the action of air pressure, wherein the second air pressure is greater than the first air pressure and can make the collapsed cavity wall expand outward. When the initial microbubble probe has both shank skew and microbubble collapse, the processing sequence affects the final effect. Processing shank skew first can ensure that the axis of the supporting structure is correct during subsequent microbubble shaping, and avoid new asymmetry caused by uneven force on microbubble expansion due to shank bending. Wherein, the specific values of the first air pressure and the second air pressure are calibrated in advance according to the device size and material properties.

[0052] The optical fiber microbubble probe shaping method of this embodiment can realize non-contact, local and controllable shape repair for various structural deformations such as shank skew, probe tip skew and microbubble cavity collapse occurring in the preparation process. After repair, the shank of the device is coaxial with the optical fiber, the probe tip is perpendicular to the equatorial plane of the microbubble and points to the geometric center, and the wall thickness of the microbubble cavity is evenly distributed along the circumferential direction of the equatorial plane, which ensures that the probe can vertically press the surface to be measured during mechanical measurement, the stress deformation of the microbubble cavity is symmetrical, and can stably support whispering gallery mode resonance or Fabry-Perot interference. The whole shaping process eliminates thermal stress through pre-irradiation, avoids secondary damage through stepwise temperature rise, and ensures the repair effect through multi-angle verification.

[0053] Based on the same inventive concept, the embodiment of the present invention also provides a shaping device corresponding to the method in embodiment one, which can be found in embodiment two.

[0054] Embodiment Two Based on Embodiment One, another embodiment of the present invention is proposed, referring to Figure 4 , the optical fiber microbubble probe shaping device of this embodiment includes: a fixing unit, an air pressure control unit, a laser heating unit and a controller.

[0055] A fixing unit is used to fix the fiber optic microbubble probe prototype with structural deformities. Specifically, the fixing unit may include a three-dimensional motorized displacement stage and a fiber optic clamp. The fiber optic clamp holds and fixes the fiber end of the probe prototype, and the three-dimensional displacement stage can drive the probe prototype to translate and rotate in the X, Y, and Z directions to adjust its spatial position so that the deformed part is aligned with the laser spot.

[0056] The pressure control unit is used to fill the cavity of the fiber optic microbubble probe prototype with gas at a predetermined pressure. Specifically, the pressure control unit includes a gas source, a precision pressure controller, and a pressure sensor. The pressure controller receives instructions from the controller, sets the target pressure value, and adjusts the inflation flow rate through a proportional valve. Simultaneously, the pressure sensor monitors the internal pressure in real time and feeds it back to the controller, forming a closed-loop control to ensure that the internal pressure remains stable during the shaping process.

[0057] The laser heating unit is used to perform localized thermal reshaping of deformed areas using unilateral laser heating. Specifically, the laser heating unit includes a laser, a focusing optical path, and a spot position adjustment mechanism. The laser emitted by the laser is focused to form a micron-sized spot, and the spot position adjustment mechanism aligns the spot with the back side of the deformed area according to the controller's instructions.

[0058] The controller, connected to the fixing unit, the air pressure control unit, and the laser heating unit, is used to execute the method in Embodiment 1. The controller can be a PLC, an industrial computer, or an embedded microprocessor, and its internal memory stores executable instructions, enabling it to control operations such as moving the displacement stage, adjusting laser power, setting air pressure, and image acquisition and processing according to a preset program.

[0059] The shaping device also includes an image acquisition and processing unit. This unit comprises a high-resolution CCD camera and an image processor, used to acquire images of the initial fiber microbubble probe and compare the images with a preset standard geometric model to determine the type of deformity and its position coordinates in three-dimensional space. The controller, based on the position coordinates, controls the laser heating unit to align the laser spot with the back side of the deformed area. The image acquisition and processing unit may include two orthogonally arranged cameras, simultaneously acquiring images from the front and side views to eliminate blind spots from a single viewpoint.

[0060] The shaping device of this embodiment can automatically or semi-automatically execute the method described in Embodiment 1 to achieve precise and non-destructive repair of structural deformities of fiber optic microbubble probes. It has the advantages of automated operation, high shaping accuracy, and high yield.

[0061] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0062] This invention is described with reference to flowchart illustrations and / or line drawings of methods and products according to embodiments of the invention. It should be understood that each step in the flowchart can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the process. Figure 1 A device for a function specified by one or more processes.

[0063] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0064] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0065] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, third, etc., does not indicate any order. These words can be interpreted as names.

[0066] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for shaping an optical fiber microbubble probe, characterized in that, The method includes: Obtain a preliminary fiber optic microbubble probe with structural deformities, the structural deformities including at least one of the following: skeletal or probe misalignment and collapse of the microbubble cavity. The fiber optic microbubble probe prototype is fixed, and gas at a predetermined pressure is injected into the cavity of the fiber optic microbubble probe prototype. For the location of the structural deformity, a unilateral laser heating method is used to perform local thermal shaping on the deformed area. The surface tension difference or internal air pressure expansion force generated by the heating of the material in the heated area is used to drive the deformed area to restore it to the preset geometric shape. Wherein, when the structural deformity is a skewed handle or probe, the method of using unilateral laser heating to perform local thermal reshaping of the deformed area includes: Identify the bending direction of the handle or probe to determine the back side of the bend; The laser beam is controlled to be focused on the curved back side and irradiated using a stepped heating strategy. The stepped heating strategy includes gradually increasing the laser power while observing the morphological changes of the deformed part in real time. When the deformed part is first observed to begin to shift axially, it is determined that the current laser power has reached the material melting threshold, and the power is stopped from being increased. As the temperature on the curved back side increases, the increased surface tension of the material on that side pulls the handle or probe back to the optical fiber axis. When the fiber optic microbubble probe prototype simultaneously exhibits stem misalignment and microbubble collapse, the execution sequence of the shaping method includes: First, the skewed handle is shaped, the laser spot is aligned with the curved back side of the handle, the first air pressure is injected into the microbubble probe to prevent the hollow structure of the handle from collapsing, and the laser power is gradually increased until the axis of the handle coincides with the axis of the optical fiber. After the axis of the handle is restored, the internal air pressure is increased to the second air pressure, and the laser spot is aimed at the collapsed part to heat it, so that the collapsed part is restored to a spherical or near-spherical symmetrical structure under the action of air pressure. The second air pressure is greater than the first air pressure and can cause the collapsed cavity wall to expand outward.

2. The method as described in claim 1, characterized in that, Before the step of performing localized thermal reshaping of the deformed area using unilateral laser heating, the method further includes: The image of the initial fiber microbubble probe is acquired and compared with a preset standard geometric model to determine the type of deformity and the position coordinates of the deformity in three-dimensional space. Based on the stated position coordinates, the laser spot is controlled to align with the back side of the deformed area.

3. The method as described in claim 2, characterized in that, When the structural deformity is the collapse of a microbubble cavity, the step of using unilateral laser heating to locally heat and reshape the deformed area includes: Adjust the air pressure inside the fiber optic microbubble probe prototype to a pressure value that allows the collapsed cavity wall to expand and recover. The laser beam is controlled to heat the cavity wall of the collapsed area, so that the cavity wall of the collapsed area is in a molten and softened state; Under the expansion force of the internal air pressure, the collapsed part in the molten and softened state is pushed outward, restoring it to a spherical or near-spherical symmetrical structure.

4. The method according to any one of claims 1-3, characterized in that, Before the step of localizing the deformed area with heat, the procedure further includes: The laser power is controlled to be maintained at a preset power value below the material melting threshold of the deformed area, and the deformed area is pre-irradiated to eliminate thermal stress concentration.

5. The method as described in claim 2, characterized in that, The steps for localized thermal reshaping of deformed areas using unilateral laser heating include: Verify from at least two different observation angles whether the deformed area has been restored to the preset geometric shape; If the deformity is still observed at any angle, repeat the laser alignment, heating, and recovery steps until recovery is confirmed at all angles.

6. The method as described in claim 1, characterized in that, When the structural deformity is a probe tilt, before using unilateral laser heating, the gas pressure filled into the cavity of the fiber microbubble probe prototype is greater than the standard atmospheric pressure to prevent the microbubble tip connected to the probe from collapsing during the shaping process.

7. The method as described in claim 1, characterized in that, When the structural deformity is a probe tilt, during the irradiation process using a stepped heating strategy, after each or multiple increases in laser power, the laser-heated area is moved away from the microbubble cavity, but remains on the probe.

8. A shaping device for an optical fiber microbubble probe, characterized in that, The device includes: A fixing unit is used to fix the initial fiber optic microbubble probe with structural deformities. A pressure control unit is used to fill the cavity of the fiber optic microbubble probe sample with gas at a predetermined pressure. The laser heating unit is used to perform localized thermal reshaping of deformed areas using unilateral laser heating. A controller, connected to the fixing unit, the air pressure control unit and the laser heating unit, for performing the method according to any one of claims 1 to 7.

9. The apparatus as claimed in claim 8, characterized in that, The device further includes an image acquisition and processing unit, used to acquire an image of the fiber microbubble probe prototype, and compare the image with a preset standard geometric model to determine the type of deformity and the position coordinates of the deformity in three-dimensional space; the controller controls the laser heating unit to align the laser spot with the back side of the deformed part according to the position coordinates.

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