A laser micro-ablation optical fiber bundle device for a laser micro-thruster

Abstract

The present invention discloses a fiber-optic bundle ablation device for laser micro-ablation, comprising an optical fiber, an anti-reflection glass sheet, a solid working fluid target strip, a substrate, and a laser. The present invention changes the concept of existing optical lens installation and debugging in laser thrusters, utilizes optical fiber coupling to output the laser, utilizes a grooved substrate to achieve laser bundle output, and utilizes the known parameters of the optical fiber divergence angle, the position of the anti-reflection lens, and the refractive index to accurately arrange the working fluid ablation position and achieve efficient ablation of the working fluid; the present invention has a simple structure and higher space utilization, greatly reducing the structural complexity of the laser micro-thruster and extending the service life of the laser thruster; the grooved substrate of the present invention uses micro-machining technology to minimize the cumulative error caused by multiple processing, achieving a high-precision, high-density fiber-optic bundle arrangement effect. The laser micro-ablation achieved by the present invention has the effects of low cost, miniaturization, and high efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of optics, and in particular, relates to a laser micro-ablation fiber bundle ablation device for a laser micro-thruster, which is used in scenarios where laser ablates a propulsion medium in a space laser micro-thruster. Background Art

[0002] A laser microthruster is a space micropropulsion system that generates microthrust by laser ablation of a propellant. Because the laser ablation spot on the propellant is typically on the order of hundreds of microns, a micro-ablation process, its thrust is relatively low, typically in the micronewton to millinewton range. It is primarily used for attitude and orbit control and orbit maintenance for micro- and nanosatellites. Existing laser microthrusters suffer from complex ablation light sources, large size, and dispersed beam distribution in the ablation spot area, making them incapable of efficiently ablating the propellant. This, in turn, limits the miniaturization and low-power requirements of space laser microthrusters.

[0003] In addition, the key to improving the performance of space laser microthrusters lies in the high or low laser power density and the efficient ablation of the working fluid to reduce the "dead weight" and thus meet the high total impulse requirements. This requires that the laser of the laser microthruster has good focusing performance and a densely packed beam arrangement. However, the existing method is to achieve the focusing of the laser beam through the use of a single or multiple lenses. However, the use of lenses not only increases the difficulty of debugging the optical path, but also brings complexity to the system. At the same time, in order to achieve efficient ablation of the target belt-type solid working fluid, a single lens must be able to reciprocate in a certain dimension, which in turn requires the addition of motion actuators such as motors and guide rails, increasing the additional power of the thruster. There are also existing technical methods that use a combination of multiple lenses to achieve efficient ablation of the working fluid, which in turn increases the system volume and the complexity of debugging. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to reduce the complexity of the laser microthruster structure, reduce the volume of the laser microthruster, reduce the energy consumption and debugging difficulty of the laser microthruster structure, and achieve low cost, miniaturization and high efficiency of laser microablation.

[0005] To achieve the above-mentioned object, the present invention provides a fiber-bundling ablation device for laser micro-ablation, comprising an optical fiber, a substrate, a glass sheet, a solid working fluid target tape, a substrate and a laser;

[0006] There are multiple diode lasers, each of which is connected to an optical fiber. The laser light emitted by the diode laser is output through the optical fiber. The substrate is used to fix the output end of the optical fiber and make the directions of the optical fiber output ends parallel to each other.

[0007] The glass sheet is arranged between the optical fiber output end and the solid working medium target belt;

[0008] The solid working fluid target strip is placed on the laser target surface outputted from the output end of the optical fiber. The solid working fluid target strip is ablated under the action of the laser beam. The ablation spots on the solid working fluid target strip are circular spots and are tangent to each other.

[0009] Furthermore, the glass sheet is an anti-reflection glass sheet, and both sides of the anti-reflection glass sheet are coated with an anti-reflection film with the same wavelength as the diode laser.

[0010] Furthermore, the material of the glass sheet is quartz glass.

[0011] Furthermore, the substrate is a single-body structure or a top-bottom combination structure; when the substrate is a single-body structure, a through hole for accommodating the output end of the optical fiber is provided inside the substrate, or a through groove for accommodating the optical fiber is provided on the substrate; when the substrate is a top-bottom combination structure, the substrate includes an upper substrate and a lower substrate stacked up and down, and a through groove for accommodating the output end of the optical fiber is provided on the opposite surfaces of the upper and lower substrates, or a through groove for accommodating the output end of the optical fiber is provided on the upper surface of the lower substrate or only on the lower surface of the upper substrate; the optical fiber is fixed in the through groove or through hole.

[0012] Furthermore, the optical fiber bundling and ablation device further comprises a bundling shell, which is provided with a through groove, and the substrate and the glass sheet with the optical fiber output end fixed thereon are fixed in the through groove.

[0013] Furthermore, the optical fiber output ends are parallel to each other and are equally spaced, the optical fiber output ends are on a straight line, and the spacing between the optical fiber output ends is p. Wherein, w is the width of the solid working fluid target band, and n is the number of optical fibers.

[0014] Furthermore, the optical fiber bundle composed of multiple optical fibers fixed in the substrate is fixed in position with the glass sheet and the solid working medium belt, wherein the distance between the output end of the optical fiber bundle and the glass sheet is L1; the distance between the glass sheet and the solid working medium belt is L2, wherein Where D is the ablation spot size on the target band; d is the fiber core diameter; θ1 is the divergence angle of a single fiber; θ2 is m is the refractive index of the glass sheet, and L is the thickness of the glass sheet.

[0015] Furthermore, the distance L1 between the output end of the optical fiber bundle and the glass sheet is ≤5 mm.

[0016] Furthermore, the diode laser is connected to the optical fiber via an FC interface.

[0017] Furthermore, the solid working fluid target belt includes a transparent base layer and a propulsion working fluid layer. The transparent base layer is placed on a side close to the output end of the optical fiber, and the propulsion working fluid layer is placed on a side away from the output end of the optical fiber.

[0018] The beneficial effects of the present invention are as follows: 1) The fiber optic bundling device for laser micro-ablation of the present invention changes the concept of optical lens installation and debugging in the existing technical solutions, uses fiber optic coupling to output the laser, uses a substrate with square grooves to achieve laser beam output, and uses the known parameters of fiber divergence angle, lens position and refractive index to accurately arrange the working fluid ablation position and achieve efficient ablation of the working fluid; 2) The structure of the present invention is simple and the space utilization rate is higher, which can greatly reduce the structural complexity of the laser micro-thruster and extend the service life of the laser thruster; 3) The grooved substrate of the present invention uses micro-machining technology to minimize the cumulative error caused by multiple processing and achieve a high-precision, high-density fiber optic bundling arrangement effect. Therefore, the laser micro-ablation achieved by the present invention has the effects of low cost, miniaturization and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of light spot distribution when optical fiber is bundled in the present invention;

[0020] Figure 2 This is a schematic diagram of the distribution of optical fibers on the target band after passing through the multiplier lens during the bundling of the optical fibers according to the present invention;

[0021] Figure 3 This is a schematic diagram of an optical fiber connected to a diode laser according to the present invention;

[0022] Figure 4 Schematic diagram of optical fiber bundling on a substrate with square grooves according to the present invention;

[0023] Figure 5 Schematic diagram of optical fiber bundling in two substrates with square grooves according to the present invention;

[0024] Figure 6 A schematic diagram of the optical fiber bundle of the present invention being placed on a substrate with square grooves and then fixed by a metal mounting housing;

[0025] Figure 7 Diagram of the fiber bundling module discovered by this study.

[0026] The reference numerals are as follows:

[0027] 1-optical fiber; 2-glass sheet; 3-solid working fluid target belt; 4-substrate; 5-housing; 6-diode laser. DETAILED DESCRIPTION

[0028] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0031] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0032] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0033] The fiber bundler for laser micro-ablation in the specific embodiment of the present invention uses multiple low-cost small diode lasers and multi-channel fiber coupling output to achieve the bundle combination of multiple laser beams, thereby meeting the ablation effect on the working medium. Figures 1-6 A specific embodiment of the optical fiber bundling device for laser microablation according to the present invention will be described.

[0034] The fiber bundling device for laser micro-ablation of the present invention comprises an optical fiber 1, a glass sheet 2, a solid working fluid target tape 3, a substrate 4 and a laser 6, wherein the laser 6 is a low-cost small diode laser.

[0035] In some specific embodiments of the present invention, the substrate 4 comprises two pieces, an upper substrate and a lower substrate, with through linear grooves being formed on the opposing surfaces of the upper and lower substrates, with the grooves spaced evenly apart. The optical fiber is placed and fixed in the grooves. The grooves can be square, which facilitates processing and manufacturing and makes it easy to make the inner wall of the square groove of the substrate tangent to the circular cross-section of the outer diameter of the optical fiber, thereby controlling the position of the laser as a solid working fluid target band. A second method of grooving is to form through linear grooves only on the lower surface of the upper substrate or the upper surface of the lower substrate, leaving the other substrate ungrooved. Alternatively, a through hole can be directly formed in the substrate.

[0036] The glass sheet 2 is arranged in front of the end face of the optical fiber output end of the substrate 4, and the solid working fluid target strip 3 is placed in front of the glass sheet 2. The input end of the optical fiber 1 is connected to the diode laser 6 through the FC interface. The laser emitted by the diode laser 6 acts on the solid working fluid target strip 3 after passing through the optical fiber 1 and the glass sheet 2. The solid working fluid target strip 3 is ablated under the action of the laser beam. The ablation spots on the solid working fluid target strip 3 are circular spots and are tangent to each other. The solid working fluid target strip 3 includes a transparent base layer and a propulsion working fluid layer. The transparent base layer faces the glass sheet 2, and the propulsion working fluid layer is on the outside away from the glass sheet 2.

[0037] like Figure 1 As shown, in some specific embodiments of the present invention, in the optical fiber bundling device for laser micro-ablation, the arrangement spacing between the optical fibers 1 is p, where Wherein w is the width of the solid working fluid target band, and n is the number of optical fibers. In front of the optical fiber bundle is a glass sheet 2, and the thickness of the glass sheet is L. Preferably, the glass sheet is an anti-reflection glass sheet, and both sides of the anti-reflection glass sheet are coated with an anti-reflection film with the same wavelength as the diode laser, and the selected material is quartz glass. The use of the anti-reflection glass sheet not only prevents the contamination of the optical fiber core diameter by the ejected material, but also increases the transmittance of the specific wavelength laser emitted by the diode laser, filters out part of the light of other wavelengths, and makes the laser passing through the anti-reflection glass sheet purer.

[0038] A solid working fluid target strip 3 is placed in front of the anti-reflection glass sheet. The solid working fluid target strip has a double-layer structure. The layer close to the anti-reflection glass sheet is a transparent substrate, and the other layer is a propulsion working fluid. The laser light emitted by the diode laser is output through optical fiber coupling, passes through the anti-reflection glass sheet, and passes through the transparent substrate on the working fluid target strip, eventually forming an ablation spot on the working fluid, generating an ablation effect. The ablation spots are tangent to each other, thereby making full use of the working fluid and reducing "dead weight". Since ejected substances are generated during the ablation process, the obstruction of the glass sheet 2 can also avoid contamination of the optical fiber core diameter. Furthermore, in order to prevent the optical fiber core diameter from being contaminated, facilitate manufacturing, and increase reliability during use, as shown in FIG. Figure 7 As shown, the substrate 4 and the glass sheet 2 with the optical fibers fixed thereon are fixed in a cluster housing 5 with a through groove, and the transparent glass sheet 2 is placed at one end of the groove of the cluster housing 5.

[0039] See also Figure 2 In some specific embodiments of the present invention, a fiber bundle consisting of multiple optical fibers 1 fixed in a substrate 4 is placed in sequence with a glass sheet 2 and a solid working medium belt, wherein the distance between the emitting end of the fiber bundle and the glass sheet 2 is L1, which is usually ≤ 5 mm; the distance between the glass sheet 2 and the solid working medium belt 3 is L2, wherein Where D is the ablation spot size on the target band; d is the fiber core diameter; θ1 is the divergence angle of a single fiber; θ2 is m is the refractive index of the anti-reflection glass, and L is the thickness of the anti-reflection glass. Figure 2 It can be seen that for the same spot size, the refraction of the anti-reflection glass sheet in the solution of setting the anti-reflection glass sheet shortens the distance between the optical fiber output end and the solid working fluid target band, which is conducive to simplifying the structural design and reducing the volume of the entire device.

[0040] See also Figure 3 In the present invention, the input end of the optical fiber 1 is connected to the diode laser 6 through the FC interface, and the output end of the optical fiber is placed on the substrate with a square groove, and the output end of the optical fiber is used to emit a laser beam.

[0041] See also Figure 4-Figure 7 In one embodiment of the present invention, a method for manufacturing a fiber-optic bundle ablation device for laser micro-ablation comprises the following steps:

[0042] Step S100: The step of making grooves on the substrate. In this step, micromachining technology is used to make grooves on the substrate. Grooves can be made on both the upper and lower substrates, or only on the lower substrate. Alternatively, only one substrate with through grooves can be made. Generally, the cross section of the groove is square to facilitate processing and control the accuracy of optical fiber spacing. Depending on the processing conditions, it can also be other shapes, such as circular. The grooves are arranged parallel to each other and are equally spaced. The arrangement interval is p, where Where w is the width of the solid working fluid target band, and n is the number of optical fibers.

[0043] Step S200: Place the optical fiber on a lower substrate with square grooves, and then place an upper substrate above the optical fiber. The optical fiber is clamped between the two substrates, and the number of optical fibers is consistent with the number of grooves on the substrates; the output end of the optical fiber is flush with the end surface of the substrate with the grooves; preferably, the grooves on the substrates have the same size; the size of the grooves matches the outer diameter of the optical fiber; the inner wall of the groove on the substrate is tangent to the circular cross-section of the outer diameter of the optical fiber.

[0044] Step S300: injecting adhesive between the optical fiber and the groove wall of the substrate and curing;

[0045] Step S400: placing an anti-reflection glass sheet at position L1 in front of the end surface of the substrate. Preferably, both sides of the anti-reflection glass sheet are coated with an anti-reflection film with the same wavelength as the diode laser. The selected material is quartz glass, and L1 is usually ≤ 5mm;

[0046] Step S500: placing the upper and lower substrates with the optical fibers installed and the anti-reflection glass sheet in a metal mounting housing;

[0047] Step S600: placing the target strip at a distance L2 in front of the anti-reflection glass sheet, wherein Where D is the ablation spot size on the target band; d is the fiber core diameter; θ1 is the divergence angle of the fiber; θ2 is m is the refractive index of the antireflection glass, and L is the thickness of the antireflection glass.

[0048] In one embodiment of the present invention, an eight-way fiber bundle is fabricated using a substrate with square grooves. 105 / 125 multimode optical fibers are used. The fibers are arranged on a substrate with equally spaced square grooves. The substrate has eight square grooves, each 125μm in side length, and is spaced 750mm apart. Micromachining techniques are used to minimize the cumulative error caused by multiple machining operations, thereby achieving a high-precision, high-density fiber bundle arrangement. The eight optical fibers are placed within the square grooves, ensuring that the groove dimensions match the fiber outer diameters, with the inner walls of the substrate's square grooves tangent to the circular cross-section of the fiber's outer diameter. A second substrate with eight square grooves is manufactured. The two substrates are combined and placed, with optical fibers placed within them. Adhesive is injected and cured between the optical fibers and the square groove walls of the two substrates, thus forming a fiber bundle. A 2mm thick antireflective glass sheet is placed in front of the substrate, 4mm away. Because the diode laser wavelength used is 976nm, both sides of the glass sheet are coated with a 976nm wavelength antireflection coating. The fiber bundle and antireflective glass sheet are placed in a fixed metal housing to form a fiber bundle device. Finally, the position of the working fluid target band is determined.

[0049] The fiber-optic bundle-collecting device for laser micro-ablation of the present invention changes the concept of optical lens installation and debugging in the existing technical solutions. It uses fiber coupling to output the laser and uses a substrate with square grooves to realize laser bundle output. By using the known parameters of the fiber divergence angle, the position of the multiplier lens and the refractive index, the working fluid ablation position can be accurately arranged to achieve efficient ablation of the working fluid.

[0050] The present invention has a simple structure and higher space utilization, can greatly reduce the structural complexity of the laser micro-thruster, and extend the service life of the laser thruster.

[0051] The grooved substrate of the present invention utilizes microfabrication technology to minimize the cumulative errors caused by multiple machining operations, achieving high-precision, high-density fiber bundle arrangement. Therefore, the laser microablation achieved by the present invention is low-cost, miniaturized, and highly efficient.

[0052] This application is not limited to the contents defined in the description and claims. Any modifications and changes known in the art fall within the scope of this application. The specific embodiments of the description are only illustrative of the present invention and are not specific limitations of the present invention.

Claims

1. A fiber-optic bundle ablation device for laser micro-ablation, characterized in that: It includes optical fiber, substrate, glass sheet, solid working fluid target belt, substrate and diode laser; There are multiple diode lasers, each of which is connected to an optical fiber. The laser light emitted by the diode laser is output through the optical fiber. The substrate is used to fix the output end of the optical fiber and make the directions of the optical fiber output ends parallel to each other. The glass sheet is arranged between the optical fiber output end and the solid working medium target belt; The solid working fluid target strip is placed on the laser target surface outputted by the output end of the optical fiber. The solid working fluid target strip is ablated under the action of the laser beam. The ablation spots on the solid working fluid target strip are circular spots and are tangent to each other. The optical fiber bundle composed of multiple optical fibers fixed in the substrate is fixed in the positions of the glass sheet and the solid working medium belt in sequence, wherein the distance between the output end of the optical fiber bundle and the glass sheet is L1; the distance between the glass sheet and the solid working medium belt is L2, wherein , where D is the ablation spot size on the target band; d is the fiber core diameter; θ1 is the divergence angle of a single fiber; θ2 is , m is the refractive index of the glass sheet, and L is the thickness of the glass sheet.

2. The optical fiber bundle ablation device for laser micro-ablation according to claim 1, characterized in that: The glass sheet is an anti-reflection glass sheet, and both sides of the anti-reflection glass sheet are coated with an anti-reflection film with the same wavelength as the diode laser.

3. The optical fiber bundle ablation device for laser micro-ablation according to claim 1, characterized in that: The material of the glass sheet is quartz glass.

4. The optical fiber bundle ablation device for laser micro-ablation according to claim 1, characterized in that: The substrate is a single-body structure or a top-bottom combination structure; when the substrate is a single-body structure, a through hole for accommodating the output end of the optical fiber is provided inside the substrate, or a through groove for accommodating the optical fiber is provided on the substrate; when the substrate is a top-bottom combination structure, the substrate includes an upper substrate and a lower substrate stacked up and down, and the through groove for accommodating the output end of the optical fiber is provided on the opposing surfaces of the upper and lower substrates, or the through groove for accommodating the output end of the optical fiber is provided on the upper surface of the lower substrate or only on the lower surface of the upper substrate; the optical fiber is fixed in the through groove or through hole.

5. The optical fiber bundle ablation device for laser micro-ablation according to any one of claim 4, characterized in that: The optical fiber bundling and ablation device further comprises a bundling shell, which is provided with a through groove, and the substrate and the glass sheet with the optical fiber output end fixed thereon are fixed in the through groove.

6. The optical fiber bundle ablation device for laser micro-ablation according to any one of claims 1 to 5, characterized in that: The output ends of the optical fibers are parallel to each other and are equally spaced. The ends of the optical fibers are in a straight line. The spacing between the output ends of the optical fibers is Wherein, w is the width of the solid working fluid target band, and n is the number of optical fibers.

7. The optical fiber bundle ablation device for laser micro-ablation according to claim 1, characterized in that: The distance L1 between the output end of the optical fiber bundle and the glass sheet is ≤5 mm.

8. The optical fiber bundle ablation device for laser micro-ablation according to any one of claims 1 to 5, characterized in that: The diode laser is connected to the optical fiber through the FC interface.

9. The optical fiber bundle ablation device for laser micro-ablation according to any one of claims 1 to 5, characterized in that: The solid working fluid target belt comprises a transparent base layer and a propulsion working fluid layer. The transparent base layer is arranged on a side close to the output end of the optical fiber, and the propulsion working fluid layer is arranged on a side away from the output end of the optical fiber.

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