AU2020102409A4 - Optical fiber end face microcantilever sensor and fabrication method thereof - Google Patents
Optical fiber end face microcantilever sensor and fabrication method thereof Download PDFInfo
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- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
- G01N2021/458—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods using interferential sensor, e.g. sensor fibre, possibly on optical waveguide
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Abstract
The present invention discloses an optical fiber end face microcantilever sensor and a
fabrication method thereof. The optical fiber end face microcantilever sensor includes an optical
5 fiber and a cantilever structure, polymerized on an end face of the optical fiber by virtue of a
femtosecond laser induced two-photon polymerization technology; the cantilever structure is of a
polymer structure and includes a base and a microcantilever; and the microcantilever is parallel to
the end face of the optical fiber. An optical fiber end face microcantilever fabricated by using the
femtosecond laser induced two-photon polymerization technology is made of a polymer material
0 which has greater elasticity than a silicon-based material, so that detection sensitivity can be
greatly improved; the fabrication method belongs to additive fabrication, integration of the
optical fiber with a cantilever is achieved, and structure is compact; the optical fiber self is not
damaged or broken; and meanwhile, processing time is saved, and the mode of fabrication is
flexible. The optical fiber end face microcantilever cured by the femtosecond laser induced
5 two-photon polymerization technology in the present invention has characteristics of small size
and high elasticity, and is applicable to multiple fields.
1/5
LCladdg
20 Base
30. Microcantilever
12. Fiber core
FIG1
20pn
MicrocantLiever
20 Base 30pm
12- Fibe1 cor e
FIG 2
Description
1/5
LCladdg
20 Base 30. Microcantilever
12. Fiber core
FIG1
20pn
MicrocantLiever 20 Base 30pm
12- Fibe1 cor e
FIG 2
Field
[0001] The present invention relates to an optical fiber end face microcantilever sensor and a fabrication method thereof, and belongs to the technical field of sensors.
Background
[0002] An optical fiber type sensor has outstanding advantages of high sensitivity, high precision, strong anti-interference ability, large dynamic response range, high pressure resistance, corrosion resistance, and the like.
[0003] An existing optical fiber type sensor is generally fabricated by using methods as follows:
[0004] femtosecond laser ablation, namely subtractive fabricating is directly performed on an end face of an optical fiber through a femtosecond laser ultrashort pulse. In the case of incidence of a laser pulse, energy which is generated by absorption of a photon by an optical fiber material is rapidly accumulated in an absorption layer of merely a few nanometers in thickness, the temperature value of an electron generated instantaneously is far higher than the melting point of the optical fiber material, an optical fiber appointed area finally achieves a plasma state of superheat, high pressure and high density, and thus non-hot melting ablation of the optical fiber is achieved. A cantilever structure of a hydrogen sensor fabricated by using the method is made of the optical fiber material self, is large in rigidity and is not beneficial to cantilever deformation. In addition, the method is large in workload, a processed structure has a rough surface, and thus the resolution ratio of a sensor is low.
[0005] Focused ion beam milling, namely an ion beam which is emitted from an ion source and is subjected to accelerated focusing is adopted as an incident beam, an optical fiber material is subjected to sputtering peeling in the process where ions of high energy collide with atoms of the surface of an optical fiber, and thus subtractive fabricating of an appointed area on an end face of the optical fiber is achieved. A cantilever structure of a hydrogen sensor fabricated by using the o method is also made of the optical fiber material self, is large in rigidity and is not beneficial to cantilever deformation. In addition, the method of fabrication is long in time and low in efficiency.
[0006] A silicon cantilever adhering method, namely a commercial silicon cantilever is directly adhered to an end face of an optical fiber by using ultraviolet curing glue, or the silicon cantilever is adhered to an end face of a packaging pipe and the optical fiber is packaged later. The fabrication method of adhesion needs a high-precision micro manipulator, dissociation is likely to be caused, the straightness of the cantilever is hard to control, and a silicon-based material is large in rigidity and is not beneficial to cantilever deformation.
Summary
[0007] To overcome problems in the prior art, the present invention discloses a fabrication method of an optical fiber end face microcantilever sensor. The fabrication method includes the following steps:
[0008] Si, flatly cleaving one end of an optical fiber; parallelly placing and fixing the optical fiber to a glass slide; setting support parts on the glass slide at both sides of the optical fiber so as to prevent a cover glass from pressing the optical fiber; dropping a photoresist to the cleaved end face of the optical fiber to immerse the end face of the optical fiber into the photoresist; and covering the glass slide with the cover glass;
[0009] S2, forming a polymer cantilever structure on the end face of the optical fiber by using a 3D lithography machine by virtue of a femtosecond laser induced two-photon polymerization technology, so as to obtain a sample of the optical fiber with a cantilever structure;
[0010] S3, performing developing, namely taking down the cover glass after curing is completed, immersing the sample together with the glass slide into a developing solution; dissolving unexposed photoresist in the solution; and retaining the cured polymer cantilever structure;
[0011] the cantilever structure includes a base and a microcantilever; a first end of the base is combined with a cladding of the end face of the optical fiber; the microcantilever is parallel to the end face of the optical fiber; one end of the microcantilever is fixed to a second end of the base; and the other end of the microcantilever is suspended above a fiber core to form a cantilever.
[0012] Further, the step S2 of forming the polymer cantilever structure on the end face of the !5 optical fiber by using the femtosecond laser induced two-photon polymerization technology includes: fixing a sample to a three-dimensional precise displacement platform; controlling the three-dimensional precise displacement platform to move in three directions such as X, Y and Z through a computer; and enabling a femtosecond laser beam to perform writing in the photoresist after passing through a processing optical path system.
[0013] Further, the step of enabling the femtosecond laser beam to perform writing in the photoresist after passing through the processing optical path system includes:
[0014] passing the femtosecond laser beam through an attenuator and a power meter after beam expansion by a beam expander; after passing through reflectors, reflecting a near-infrared band light beam in the laser beam by a dichroic mirror to enter an objective lens; further focusing the near-infrared band light beam into the photoresist to perform processing; and enabling a visible light part in the laser beam to penetrate through the dichroic mirror, pass through a filter and further enter a charge coupled device (CCD) to perform imaging.
[0015] Further, the thickness of the support parts in the step Sl is 150-300m; and in the step S3, the support parts are removed after curing is completed and the cover glass is taken down.
[0016] Further, the fabrication method further includes the following step after the step S3:
[0017] S4, coating the surface of the microcantilever with a hydrogen sensitive film by using a magnetron sputtering coating apparatus.
[0018] Further, in the step S2, after the sample isfixed to the three-dimensional precise displacement platform, the three-dimensional precise displacement platform is moved to position the sample in an initial processing point position on an initial processing plane, and to position a light spot focus of the femtosecond laser beam at an initial processing point; and the laser beam is enabled to start polymerizing the microcantilever in a lateral direction from the end face of the optical fiber by controlling on/off of a shutter and the drive of the three-dimensional precise displacement platform.
[0019] The present invention further provides an optical fiber end face microcantilever sensor, including:
[0020] an optical fiber, including a fiber core and a cladding;
[0021] a cantilever structure, polymerized at one end face of the optical fiber by virtue of a femtosecond laser induced two-photon polymerization technology; wherein
[0022] the cantilever structure is of a polymer structure, and the cantilever structure includes a base and a microcantilever;
[0023] a first end of the base is combined with the cladding of the end face of the optical fiber; one end of the microcantilever is fixed to a second end of the base; the other end of the microcantilever is suspended above the fiber core to form a cantilever; the microcantilever is !5 parallel to the end face of the optical fiber; in a direction perpendicular to the end face of the optical fiber, a projection of the cantilever on the end face of the optical fiber covers thefiber core; and
[0024] the optical fiber end face microcantilever sensor is fabricated by using any one of the fabrication methods.
[0025] Further, the thickness of the microcantilever is of a micron order, and the width is of a micron order; and the height of the base is of a micron order.
[0026] Further, the optical fiber end face microcantilever sensor is a hydrogen sensor; the surface of the microcantilever is coated with a palladium film; and the thickness of the palladium film is smaller than 1 m.
[0027] Further, the thickness of the palladium film is 50-150nm.
[0028] Further, the thickness of the microcantilever of the hydrogen sensor is not greater than 10Om; the width is not greater than 100m; and the height of the base is not greater than 200[tm.
[0029] According to the optical fiber end face microcantilever sensor disclosed by the present invention, an optical fiber end face microcantilever fabricated by using the femtosecond laser induced two-photon polymerization technology is made of a polymer material which has greater elasticity than a silicon-based material, so that detection sensitivity is greatly improved under a condition that reaction time is not prolonged. The fabrication method belongs to additive fabrication, integration of an optical fiber with a cantilever is achieved, and a compact structure is achieved. The optical fiber self is not damaged or broken, so that completeness of the optical fiber is protected. Meanwhile, processing time is greatly saved, structural design is flexible, the mode of fabrication is flexible, and a great guarantee is provided to meet requirements of different environments.
[0030] The optical fiber end face microcantilever cured by the femtosecond laser induced two-photon polymerization technology in the present invention has the features of small size and high elasticity, and is applicable to multiple fields.
Brief Description of the Drawings
[0031] Fig. 1 is a structural schematic diagram of an opticalfiber end face microcantilever hydrogen sensor according to an embodiment of the present invention;
[0032] Fig. 2 is a scanning electron microscope image I of an optical fiber end face microcantilever hydrogen sensor according to an embodiment of the present invention;
[0033] Fig. 3 is a scanning electron microscope image II of an optical fiber end face microcantilever hydrogen sensor according to an embodiment of the present invention;
[0034] Fig. 4 is a processing optical path system for fabricating an optical fiber end face !5 microcantilever hydrogen sensor by virtue of a femtosecond laser induced two-photon polymerization technology according to an embodiment of the present invention;
[0035] Fig. 5 is a reflection spectrum of an opticalfiber end face microcantilever Fabry-Perot interferometer of a hydrogen sensor according to an embodiment of the present invention;
[0036] Fig. 6 is a spectrum drift of a reflection spectrum along with hydrogen concentration changes in hydrogen detection according to an embodiment of the present invention; and
[0037] Fig. 7 is an index relation curve of some interference valley value wavelength along with hydrogen concentration drift in hydrogen detection according to an embodiment of the present invention.
[0038] Reference symbols:
[0039] 10-optical fiber, 12-fiber core, 11-cladding, 20-base, and 30-microcantilever
Detailed Description of the Embodiments
[0040] Technical solutions of the present invention are further described in detail in combination of drawings and embodiments.
[0041] Fig. 1 is a structural schematic diagram of an opticalfiber end face microcantilever sensor according to an embodiment of the present invention.
[0042] The optical fiber end face microcantilever sensor includes an optical fiber 10 and a cantilever structure, wherein the optical fiber 10 includes a fiber core 12 inside and a cladding 11 for cladding the fiber core 12. The cantilever structure disclosed by the present invention is formed on an end face of the optical fiber 10 by virtue of a femtosecond laser induced two-photon polymerization technology.
[0043] The cantilever structure includes a base 20 and a microcantilever 30, wherein a first end of the base 20 is combined with the end face of the optical fiber 10. One end of the microcantilever 30 is fixed to a second end of the base 20. The other end of the microcantilever 30 is suspended to form a cantilever. The microcantilever is parallel to the end face of the optical fiber. A gap is formed between the fiber core 12 and the microcantilever 30. The distance of the gap is the height of the base 20.
[0044] Due to adoption of the femtosecond laser induced two-photon polymerization technology, the surface of the fabricated microcantilever is relatively smooth and has good parallelism to the end face of the optical fiber, and a non-intrinsic Fabry-Perot interferometer is formed. The cantilever formed by using the femtosecond laser induced two-photon polymerization technology is made of a polymer material, and a polymer has greater elasticity than a silicon-based material, so that after the cantilever is coated with a palladium film, the hydrogen detection sensitivity is greatly improved under a condition that reaction time is not !5 prolonged.
[0045] According to scanning electron microscope images shown in Fig. 2 and Fig. 3, a polymer microcantilever 30 can be clearly distinguished, and the cantilever structure is tightly combined with the end face of the optical fiber 10. In the scanning electron microscope image shown in Fig. 2, the position of the fiber core 12 is circled with a dotted line in the figure so as to clearly indicate the position of the fiber core 12.
[0046] According to the embodiment of the present invention, the base 20 avoids the position of the fiber core 12, and the base 20 is combined with the cladding of the end face of the optical fiber and is staggered with the fiber core 12. The microantilever 30 is suspended above the fiber core 12 (see Fig. 2), and the cantilever covers the fiber core in a direction parallel to the end face. In a direction perpendicular to the end face of the optical fiber, a projection of the cantilever on the end face of the optical fiber covers the fiber core.
[0047] According to the embodiment of the present invention, the thickness of the microcantilever 30 is of a micron order, and the width is of a micron order. The height of the base 20 is of a micron order. As a preferable solution, a thickness range of the microcantilever 30 is smaller than 10hm, and a width range is smaller than 100m. Performance and reliability of the optical fiber end face microcantilever sensor are affected by thickness and width dimensions of the microcantilever 30.
[0048] A cavity length of the non-intrinsic Fabry-Perot interferometer is the distance of gap between the fiber core 12 and the microcantilever 30. The distance of the gap is the height of the base 20. Preferably, the height of the base 20 is not greater than 200[tm.
[0049] Specific dimensions, of the thickness and width dimensions of the microcantilever 30 and the height dimension of the base 20, are determined by specific application fields of the optical fiber end face microcantilever sensor.
[0050] The base serves as a support. In one specific embodiment, the length of the base 20 is 5-50[tm, and the width is 5-100 m. It is understandable that length and width dimensions of the base are not limited by this.
[0051] When the optical fiber end face microcantilever sensor according to the embodiment serves as a hydrogen sensor, the thickness of the microcantilever 30 is not greater than 5[m, the width range is 5-30[tm, and the height of the base 20 is 20-80tm. As a preferable solution, the thickness of the microcantilever 30 is 3[m, the width is 20jm, and the height of the base 20 is 60jm. The dimensions of the first end of the base 20 that is tightly combined with the end face of the optical fiber 10 are as follows: the length is 30m, and the width is 30[m.
[0052] According to the embodiment of the present invention, the optical fiber 10 may be a single-mode optical fiber or a multimode optical fiber, which is not specifically limited. !5 According to one specific embodiment, the diameter of the optical fiber 10 is 125am, and the length of the cantilever of the microcantilever 30 is 30[m.
[0053] When the optical fiber end face microcantilever sensor according to the embodiment serves as the hydrogen sensor, the surface of the microcantilever 30 is additionally coated with a hydrogen sensitive film. The thickness of the hydrogen sensitive film is not greater than I m.
[0054] Preferably, the hydrogen sensitive film is a palladium film. As a further improvement solution, the thickness of the palladium film is 50-150nm.
[0055] The embodiment of the present invention further provides a fabrication method of a optical fiber end face microcantilever sensor, including the following steps:
[0056] SI, flatly cleaving one end of an optical fiber 10, parallelly placing andfixing the optical fiber 10 to a glass slide, dropping a photoresist to an end face of the optical fiber 10 to immerse the cleaved end face of the optical fiber 10 into the photoresist, and covering the glass slide with a cover glass.
[0057] Specifically, in the step, a single-mode optical fiber 10 maybe flatly cleaved by using an optical fiber cutter. After the optical fiber 10 is parallelly placed and fixed to the glass slide, support parts are set on the glass slide at both sides of the optical fiber 10. The cover glass is supported by the support parts, so as to prevent the cover glass from pressing the optical fiber 10.
[0058] Parallelly placing of the optical fiber 10 refers to the case that the axis of the optical fiber 10 is parallel to the glass slide.
[0059] The support parts may be in multiple forms, e.g., adhesive tapes may be adhered to or stacked on the glass slide at both sides of the optical fiber 10. In order to meet thickness requirements of the support parts, multiple layers (two layers or more) of the adhesive tapes may be employed, or glass pieces or plastic blocks may also be arranged as the support parts. It is understandable that specific forms of the support parts are not limited by this. Preferably, the thicknesses of the support parts are 150-300m, and due to the setting, a good molding effect is obtained in femtosecond laser induced two-photon polymerization.
[0060] S2, forming a polymer cantilever structure on the end face of the optical fiber 10 by using a 3D lithography machine by virtue of a femtosecond laser induced two-photon polymerization technology, so as to obtain a sample of the optical fiber 10 with a cantilever structure.
[0061] In the step, the step of forming the polymer cantilever structure on the end face of the optical fiber 10 by using the femtosecond laser induced two-photon polymerization technology includes: fixing the glass slide so as to fix the sample to a three-dimensional precise displacement platform; controlling the three-dimensional precise displacement platform to move in three directions such as X, Y and Z through a computer; and enabling a femtosecond laser beam to !5 perform writing in the photoresist after passing through a processing optical path system.
[0062] Fig. 4 is a processing optical path system for fabricating the optical fiber end face microcantilever 30 by using the femtosecond laser induced two-photon polymerization technology disclosed by the present invention. A femtosecond laser beam is subjected to beam expansion by a beam expander, and a light spot of the femtosecond laser beam is expanded for 2-3 times and passes through an attenuator and a power meter in sequence. The attenuator is used for adjusting a laser power value, and the power meter is used for detecting a laser power value. After multiple times of reflection of reflectors, the laser beam reaches a dichroic mirror, a near-infrared band light beam in the laser beam is reflected by the dichroic mirror, enters an objective lens and is focused into the photoresist to perform processing, and a visible light part in the laser beam penetrates through the dichroic mirror, passes through a filter and further enters a charge coupled device (CCD) to perform imaging, so that a curing phenomenon is conveniently observed in real time.
[0063] In the step, the glass slide may be fixed through vacuum adsorption of a 3D air-bearing moving platform. After the sample is fixed to the three-dimensional precise displacement platform, the three-dimensional precise displacement platform is moved to position the sample in an initial processing point position on an initial processing plane, and to position a light spot focus of the femtosecond laser beam at an initial processing point. By controlling the on/off of the shutter and the drive of the three-dimensional precise displacement platform, the laser beam is enabled to start polymerizing the microcantilever 30 in a lateral direction from the end face of the optical fiber 10.
[0064] In the step, an appropriate cantilever structure may be designed through computer aided design (CAD) software programming, a reasonable moving route is adjusted, an interlayer distance and a line distance are optimized into appropriate distances, and polymerization processing is implemented according to a designed route.
[0065] In the polymerization process, if the precise displacement platform serves as reference, relatively speaking, the laser beam performs scanning. The moving route is designed according to the shape of the cantilever structure, and then the laser beam performs planar layer-by-layer scanning from the end face of the optical fiber 10 from bottom to top, and performs optical grating scanning on each layer. In order to shorten processing time, line scanning in layers is performed in a back and forth scanning mode. According to a focal depth of the selected objective lens, the interlayer distance is appropriately set as 0.25-1jm, and the line distance is 0.25-1m.
[0066] In the step, a high numerical aperture objective lens is adopted as a processing objective lens, e.g., a 50x (NA = 0.7) objective lens is used. The power of femtosecond laser at the wavelength of 1026nm is set as appropriate power, and a displacement speed matched with the selected objective lens is set, e.g., according to the specific embodiment, the power of !5 femtosecond laser is 0.5-4mw, and the displacement speed is 0.05-1mm/s.
[0067] S3, performing developing, namely after curing is completed, taking down the cover glass on the sample; taking down adhesive tapes at both sides; immersing the sample together with the glass slide into a developing solution; dissolving unexposed photoresist in the solution; and retaining the cured polymer cantilever structure, so as to obtain a cured polymer microcantilever 30 on the end face of the optical fiber 10.
[0068] In the step, the developing solution is a mixed solution prepared by mixing acetone with isopropanol according to a certain ratio (proportions), and the sample is immersed into the mixed solution for minutes.
[0069] According to the method, the optical fiber end face microcantilever sensor may be fabricated.
[0070] As the photoresist is polymerized through the femtosecond laser beam, the formed cantilever is made of a polymer material, and a polymer has greater elasticity than a silicon-based material, so that the detection sensitivity is greatly improved.
[0071] If the optical fiber end face microcantilever sensor serves as a hydrogen sensor, a following step after step S3 is also performed:
[0072] S4, sputtering a palladium film, namely placing the sample into a magnetron sputtering coating apparatus, and coating the surface of the microcantilever 30 with a hydrogen sensitive film by using the magnetron sputtering coating apparatus, so as to prepare the hydrogen sensor.
[0073] In the step, the hydrogen sensitive film is the palladium film. In process of film coating, the end face of the optical fiber 10 faces a palladium target, a substrate is rotated, and thus uniform sputtering of a film layer is achieved. A palladium film layer which is not greater than 1 m in thickness is obtained on the surface of the microcantilever 30 by controlling sputtering time.
[0074] Fig. 5 is a reflection spectrum of an opticalfiber end face microcantilever Fabry-Perot interferometer. Near a wavelength of 1550nm, the free spectral range is about 20nm, the cavity length of the interferometer is 60km, and a relationship of the free spectral range and the cavity length is met, namely FSR=X 2/2nL.
[0075] Hydrogen detection is implemented after the optical fiber end face microcantilever hydrogen sensor is fabricated, and a hydrogen detection method includes:
[0076] inserting the optical fiber end face microcantilever sensor into a micro channel with a hydrogen-nitrogen mixed gas; connecting a broadband light source and a spectrum analyzer through a 3dB coupler to measure the reflection spectrum; adjusting the concentration of hydrogen in the hydrogen-nitrogen mixed gas; and tracking the drift of the reflection spectrum along with the concentration change of the hydrogen by using the spectrum analyzer.
[0077] In hydrogen detection, flows of pure hydrogen generated by a hydrogen generator and pure nitrogen released from a nitrogen cylinder are controlled by using two flowmeters, respectively, gases are mixed by using a three-port connector, finally a mixed gas is output from a plastic micro channel, and the dimension of the plastic micro channel is, for example, about 500pm. In detection, the concentration of hydrogen in the hydrogen-nitrogen mixed gas is adjusted by adjusting the flowmeters. Fig. 6 shows a drift of the reflection spectrum of the sensor along with hydrogen concentration changes. Along with increase of hydrogen concentration, the spectrum has conspicuous blue shift. Fig. 7 summarizes an index relation curve of some interference valley value wavelength along with hydrogen concentration drift.
[0078] According to the optical fiber end face microcantilever sensor disclosed by the present invention, an optical fiber end face microcantilever fabricated by using the femtosecond laser induced two-photon polymerization technology is made of the polymer material which has greater elasticity than the silicon-based material, so that the detection sensitivity may be greatly improved under a condition that reaction time is not prolonged. The fabrication method belongs to additive fabrication, integration of an optical fiber with a cantilever is achieved, and structure is compact. The optical fiber self is not damaged or broken, so that completeness of the optical fiber is protected. Meanwhile, processing time is greatly saved, structural design is flexible, the mode of fabrication is flexible, and a great guarantee is provided to meet requirements of different environments.
[0079] The optical fiber end face microcantilever fabricated by using the femtosecond laser induced two-photon polymerization technology through curing, disclosed by the present invention, has the characteristics of being small in size and high in elasticity, and is applicable to multiple fields. After being coated with palladium, the microcantilever may be used as the hydrogen sensor. Since the polymer has a high thermo-optical coefficient, the microcantilever may be used for temperature sensing and serves as a temperature sensor with high sensitivity. Since a cavity between the microcantilever and the end face of the optical fiber is opened, the microcantilever may be used for refractive index sensing. Due to water swelling of the polymer, the microcantilever may be used for humidity measurement. The microcantilever may also be applied to measurement of some vibration signals such as acoustic waves and vibration according to vibration properties of the microcantilever. The microcantilever may be used as a magnetic field sensor by changing magnetic photoresists. After bio-modification, the microcantilever may be used as a bio-sensor.
[0080] The specific embodiments are only for further describing the objectives, technical solutions and beneficial effects of the present invention in detail. It shall be understood that, the above descriptions are merely specific embodiments of the present invention, and not intended to limit the scope of protection of the present invention. Modifications, equivalent replacements, !5 improvements and the like made within the spirit and principle of the present invention shall fall within the scope of protection of the present invention.
Claims (10)
1. A fabrication method of an optical fiber end face microcantilever sensor, comprising the following steps:
Sl, flatly cleaving one end of an optical fiber; parallelly placing and fixing the optical fiber to a glass slide; setting support parts on the glass slide at both sides of the optical fiber so as to prevent a cover glass from pressing the optical fiber; dropping a photoresist to an end face of the optical fiber to immerse the end face of the optical fiber into the photoresist; and covering the glass slide with the cover glass;
S2, forming a polymer cantilever structure on the end face of the optical fiber by using a 3D lithography machine by virtue of a femtosecond laser induced two-photon polymerization technology, so as to obtain an optical fiber sample with a cantilever structure; and
S3, performing developing, namely taking down the cover glass after curing is completed; immersing the sample together with the glass slide into a developing solution; dissolving unexposed photoresist in the solution; and retaining the cured polymer cantilever structure; wherein,
the structure comprises a base and a microcantilever; a first end of the base is combined with a cladding of the end face of the optical fiber; the microcantilever is parallel to the end face of the optical fiber; one end of the microcantilever is fixed to a second end of the base; and the other end of the microcantilever is suspended above a fiber core to form a cantilever.
2. The fabrication method of the optical fiber end face microcantilever sensor of claim 1, wherein the step S2 of forming the polymer cantilever structure on the end face of the optical fiber by using the femtosecond laser induced two-photon polymerization technology comprises: fixing a sample to a three-dimensional precise displacement platform; controlling the three-dimensional precise !5 displacement platform to move in three directions such as X, Y and Z through a computer; and enabling a femtosecond laser beam to perform writing in the photoresist after passing through a processing optical path system.
3. The fabrication method of the optical fiber end face microcantilever sensor of claim 2, wherein the step of enabling the femtosecond laser beam to perform writing in the photoresist after passing through the processing optical path system comprises:
passing the femtosecond laser beam through an attenuator and a power meter after beam expansion by a beam expander; after passing through reflectors, reflecting a near-infrared band light beam in the laser beam by a dichroic mirror to enter an objective lens; further focusing the near-infrared band light beam into the photoresist to perform processing; and enabling a visible light part in the laser beam to penetrate through the dichroic mirror, pass through a filter and further enter a charge coupled device (CCD) to perform imaging.
4. The fabrication method of the optical fiber end face microcantilever sensor of claim 1, wherein a thickness of the support parts in the step S is 150-300m; and in the step S3, the support parts are removed after curing is completed and the cover glass is taken down.
5. The fabrication method of the optical fiber end face microcantilever sensor of claim 1, further comprising the following step after the step S3:
S4, coating a surface of the microcantilever with a hydrogen sensitive film by using a magnetron sputtering coating apparatus.
6. The fabrication method of the optical fiber end face microcantilever sensor of claim 1, wherein
in the step S2, after the sample is fixed to the three-dimensional precise displacement platform, the three-dimensional precise displacement platform is moved to position the sample in an initial processing point position on an initial processing plane, and to position a light spot focus of the femtosecond laser beam at an initial processing point; and the laser beam is enabled to start polymerizing the microcantilever in a lateral direction from the end face of the optical fiber by controlling on/off of a shutter and drive of the three-dimensional precise displacement platform.
7. An optical fiber end face microcantilever sensor, comprising:
an optical fiber, comprising a fiber core and a cladding;
a cantilever structure, polymerized at one end face of the optical fiber by virtue of a femtosecond laser induced two-photon polymerization technology; wherein,
the cantilever structure is of a polymer structure, and the cantilever structure comprises a base and a microcantilever;
a first end of the base is combined with the cladding of the end face of the optical fiber; one !5 end of the microcantilever is fixed to a second end of the base; the other end of the microcantilever is suspended above the fiber core to form a cantilever; the microcantilever is parallel to the end face of the optical fiber; in a direction perpendicular to the end face of the optical fiber, a projection of the cantilever on the end face of the optical fiber covers the fiber core; and
the optical fiber end face microcantilever sensor is fabricated by using the fabrication method of any one of claims 1-6.
8. The optical fiber end face microcantilever sensor of claim 7, wherein the optical fiber end face microcantilever sensor is a hydrogen sensor; a surface of the microcantilever is coated with a hydrogen sensitive film; and a thickness of the hydrogen sensitive film is smaller than 1 m.
9. The optical fiber end face microcantilever sensor of claim 8, wherein the hydrogen sensitive film is a palladium film; and a thickness of the palladium film is 50-150nm.
10. The optical fiber end face microcantilever sensor of claim 8, wherein a thickness of the microcantilever of the hydrogen sensor is not greater than1I0m; a width is not greater than1I00m; and a height of the base is not greater than 200[tm.
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| CN201911294643.0A CN111077113A (en) | 2019-12-16 | 2019-12-16 | Optical fiber end surface micro-cantilever sensor and preparation method thereof |
| CN2019112946430 | 2019-12-16 |
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|---|---|---|---|---|
| NL2032418A (en) * | 2022-01-14 | 2023-07-21 | Zhuhai Must Science And Tech Research Institute | Probe-type hydrogen concentration sensor for f-p interferometers based on hollow-core fibers |
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| CN112326077B (en) * | 2020-09-18 | 2022-05-06 | 桂林电子科技大学 | Micro contact force optical fiber sensing probe based on polymer hollow microtube and preparation method thereof |
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| CN103134636B (en) * | 2013-01-22 | 2016-05-18 | 中国计量学院 | Optical fiber harmonic oscillator vacuum transducer |
| CN104865192B (en) * | 2015-05-12 | 2018-01-05 | 中国科学院合肥物质科学研究院 | A kind of optic fibre cantilev microphone and preparation method for optoacoustic spectroscopy detection |
| CN107015024A (en) * | 2017-04-19 | 2017-08-04 | 李俊 | A kind of highly sensitive optical fiber micro-cantilever beam sensor and processing method for detecting acceleration |
| CN207096273U (en) * | 2017-04-19 | 2018-03-13 | 李俊 | A kind of highly sensitive optical fiber micro-cantilever beam sensor for detecting acceleration |
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| NL2032418A (en) * | 2022-01-14 | 2023-07-21 | Zhuhai Must Science And Tech Research Institute | Probe-type hydrogen concentration sensor for f-p interferometers based on hollow-core fibers |
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