CN115753705A - Light sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining - Google Patents

Abstract

The application discloses light sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining relates to food safety detection technical field to solve the problem that the detection process of the existing detection equipment in the aspect of food safety detection is relatively complicated. The method comprises the following steps: a housing; a laser source disposed within the housing and configured to output laser light; the collimator is arranged in the shell, the input end of the collimator is connected with the output end of the laser source, and the collimator is used for converting output laser into parallel laser; the compressor is arranged in the shell, the input end of the compressor is connected with the output end of the collimator, and the compressor is used for enabling the parallel laser to form an optical sheet at a focus; and the multimode coreless optical fiber is arranged on the shell and positioned at one side of the compressor, and when output laser of the laser source enters the multimode coreless optical fiber through the collimator and the compressor, the output laser enters the multimode coreless optical fiber at a preset inclination angle.

Description

Light sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining

Technical Field

The application relates to the technical field of food safety detection, in particular to an optical sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining.

Background

In the aspect of food safety detection, the official standard detection methods are liquid chromatography, gas chromatography and mass spectrometry in laboratories, and the three methods need to evaluate collected spectral data and establish a model to estimate the food safety quality. However, these methods all require special personnel to take samples, because the detection equipment used is expensive and heavy, the samples and the detection equipment are often not located in one place, and the samples after sampling need to be additionally transferred to the detection equipment for detection, that is, the detection process of the existing detection equipment in food safety detection is tedious.

Thus, there is a need for improvement and development of the prior art.

Disclosure of Invention

The technical problem that this application will be solved lies in, to prior art's not enough, provides the slide slope light ray fluorescence chemical sensor based on femto second laser micromachining to solve the comparatively loaded down with trivial details problem of testing process of current check out test set in the aspect of to food safety inspection.

In order to solve the above technical problems, the present application provides an optical sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining, including:

a housing;

a laser source disposed within the housing and configured to output laser light;

the collimator is arranged in the shell, the input end of the collimator is connected with the output end of the laser source, and the collimator is used for converting output laser into parallel laser;

the compressor is arranged in the shell, the input end of the compressor is connected with the output end of the collimator, and the compressor is used for enabling the parallel laser to form an optical sheet at a focus;

a multimode coreless fiber disposed on the housing at a side of the compressor, wherein when an output laser of the laser source enters the multimode coreless fiber through the collimator and the compressor, the output laser enters the multimode coreless fiber at a predetermined tilt angle;

the multimode coreless optical fiber comprises an induction area which consists of a plurality of sections of cavities, wherein the diameters of the induction area and the sections of cavities are different, the induction area is provided with a plurality of nano cavities, a metal nano particle layer is filled in each nano cavity, and a fluorescent material layer covers the outer layer of each metal nano particle layer;

and the power detector is arranged on the shell, is connected with the multimode coreless optical fiber and is used for detecting the fluorescence power.

In one implementation manner, the sensing region is a tapered sensing region, wherein the tapered sensing region includes a first column, a first tapered column, a second tapered column, and a third column, which are connected in sequence.

In one implementation, the sensing region is a cylindrical sensing region, wherein the cylindrical sensing region includes a fourth cylinder, a fifth cylinder and a sixth cylinder that are connected in sequence, and a diameter of the fifth cylinder is greater than the fourth cylinder and the sixth cylinder.

In one implementation, the induction area is a microbubble induction area, wherein the microbubble induction area includes a seventh column, an annular body, and an eighth column that are connected in sequence, and the diameter of the annular body is greater than the seventh column and the eighth column.

In one implementation, the light sheet oblique light ray fluorescence chemical sensor further includes:

the polarizer is arranged in the shell, the input end of the polarizer is connected with the output end of the collimator, the output end of the polarizer is connected with the input end of the compressor, and the polarizer is used for dividing the output laser into two parts.

In one implementation, the light sheet inclined light ray fluorescence chemical sensor further includes:

and the photoelectric detector is arranged in the shell, the input end of the photoelectric detector is connected with the output end of the collimator, and the photoelectric detector is used for correcting the drift of the output laser power.

In one implementation, the light sheet oblique light ray fluorescence chemical sensor further includes:

the rotator is arranged in the shell, the input end of the rotator is connected with the output end of the collimator, the output end of the rotator is connected with the input end of the compressor, and the rotator is used for changing the polarization state of the output laser.

In one implementation, the light sheet oblique light ray fluorescence chemical sensor further includes:

and the dimming mechanical platform is arranged on the shell and used for controlling the incident angle of the optical sheet transmitted into the multimode coreless optical fiber, and the multimode coreless optical fiber is arranged on the dimming mechanical platform.

In one implementation, the light sheet oblique light ray fluorescence chemical sensor further includes:

the long-pass filter is arranged in the shell and positioned on one side, close to the induction area, of the multimode coreless optical fiber, the output end of the long-pass filter is connected with the input end of the power detector, and the long-pass filter is used for enabling energy received by the power detector to come from fluorescence.

In one implementation, the light sheet oblique light ray fluorescence chemical sensor further includes:

and the integrating sphere is arranged in the shell, the output end of the integrating sphere is connected with the input end of the power detector, and the integrating sphere is used for enabling the power detector to receive all the fluorescence.

Has the advantages that: the utility model provides a laser source, the collimator, the compressor, multimode coreless optic fibre and power detector structure size are less, with foretell laser source, the collimator, the compressor, multimode coreless optic fibre and power detector dress back to the casing, the concrete size that forms slide slope light ray fluorescence chemical sensor is similar to some instruments of hand-held type, compare in current expensive and bulky check out test set, this embodiment simple structure, and convenient carry, need not that the special personnel take a sample and sample shift, and can realize the detection of the equal effect with current check out test set, can realize carrying out quick, the efficient screening detection effect to on-the-spot video pollutant, additionally, the slide slope light ray fluorescence chemical sensor of this application is the novel optic fibre chemistry sensing system that produces the high strength evanescent field on inhomogeneous multimode coreless optic fibre's surface, the excitation and the transmission of slide slope light ray in multimode coreless optic fibre, in order to improve sensitivity and the tightness of sensor, the local surface plasmon resonance that metal nanoparticle formed, further strengthen fluorescence intensity, adopt femto second laser micromachining technique to carry out nanometer cavity structure processing to the optic fibre surface, protect metal nanoparticle from the external influence, improve sensor's long-term stability and reusability.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings may be obtained according to the drawings without any inventive work.

Fig. 1 is a schematic diagram of an overall device of an optical sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining provided by the application.

Fig. 2 is a schematic diagram of a light path of an optical sheet oblique light ray entering a multimode coreless fiber in the optical sheet oblique light ray fluorescence chemical sensor based on femtosecond laser micromachining provided by the application.

Fig. 3 is a schematic structural diagram of a sensing area in a femtosecond laser micromachining-based optical sheet oblique light ray fluorescence chemical sensor, wherein fig. a is a schematic diagram of excitation of optical sheet oblique light rays in the sensing area; FIG. b is a schematic diagram of the propagation of the oblique light ray of the light sheet in the sensing region as a spiral light ray; figure c is a schematic light path diagram of the oblique light rays of the light sheet and the meridian light rays transmitted in the sensing area; and d is a structural schematic diagram of the metal nanoparticle layer, the fluorescent material layer and the nano cavity in the sensing region.

Fig. 4 is a schematic structural diagram of a sensing region in an optical sheet oblique light ray fluorescence chemical sensor based on femtosecond laser micromachining provided by the application.

Fig. 5 is another schematic structural diagram of a sensing area in an optical sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining provided by the application.

Fig. 6 is a schematic structural diagram of a sensing area in an optical sheet inclined optical ray fluorescence chemical sensor based on femtosecond laser micromachining provided by the application.

Fig. 7 is a schematic structural diagram of an original region in the light sheet oblique light ray fluorescence chemical sensor based on femtosecond laser micromachining provided by the application.

In the figure: 1. a laser source; 2. a collimator; 3. a compressor; 4. a multimode coreless fiber; 41. a sensing region; 42. a metal nanoparticle layer; 43. a layer of phosphor material; 44. a nano-cavity; 5. a power detector; 6. a polarizer; 7. a photodetector; 8. a rotator; 9. a long pass filter; 10. an integrating sphere; 11. an electrically driven rotary stage; 12. three-axis electric translation stage.

Detailed Description

The present application provides a femtosecond laser micromachining-based optical sheet inclined light ray fluorescence chemical sensor, and in order to make the purpose, technical scheme, and effect of the present application clearer and clearer, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad application.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The following further describes the content of the application by describing the embodiments with reference to the attached drawings.

In the aspect of food safety detection, the official standard detection methods are liquid chromatography, gas chromatography and mass spectrometry in laboratories, and the three methods need to evaluate collected spectral data and establish a model to estimate the food safety quality. However, these methods all require special personnel to take samples, because the detection equipment used is expensive and heavy, the samples and the detection equipment are often not located in one place, and the samples after sampling need to be additionally transferred to the detection equipment for detection, that is, the detection process of the existing detection equipment for food safety detection equipment is tedious.

Fiber optic sensing has many advantages over other technologies, including resistance to electromagnetic interference, durability at high pressures and temperatures, high sensitivity, and high specificity.

Therefore, as shown in fig. 1, the present embodiment provides a light-sheet inclined optical-ray fluorescence chemical sensor based on femtosecond laser micromachining, which can perform fast and efficient screening detection on a field food pollutant, the light-sheet inclined optical-ray fluorescence chemical sensor of the present embodiment is used for detecting a liquid or water-soluble food, the detected pollutant index is the pollutant concentration, the higher the pollutant concentration is, the lower the fluorescence power is, that is, the pollutant concentration can be determined by detecting the fluorescence power, so as to determine the food safety quality; the detection of the fluorescence power is actually the detection of the fluorescence intensity excited, and the enhancement of the fluorescence intensity is beneficial to the detection of the fluorescence power; in order to enhance the fluorescence intensity to facilitate the detection of fluorescence power and the screening detection of food pollutants on site, the optical sheet inclined light ray fluorescence chemical sensor comprises a shell (not shown in the figure), a laser source 1, a collimator 2, a compressor 3, a multi-mode coreless optical fiber 4 and a power detector 5, wherein the laser source 1, the collimator 2 and the compressor 3 are all arranged in the shell, the multi-mode coreless optical fiber 4 and the power detector 5 are arranged on the shell, the output end of the laser source 1 is connected with the input end of the collimator 2, and the output end of the collimator 2 is connected with the input end of the compressor 3; when the output laser of the laser source 1 enters the multimode coreless fiber 4 through the collimator 2 and the compressor 3, the output laser forms a light sheet through the compressor 3, enters the multimode coreless fiber 4 at a preset inclination angle by controlling the incident angle of the light sheet on the fiber end face of the multimode coreless fiber 4, and is transmitted in the multimode coreless fiber 4 by inclining the light ray with the light sheet; the multimode coreless fiber 4 includes an induction area 41 composed of a plurality of sections of cavities, and the diameters of the sections of cavities are different from each other, for example, if the plurality of sections of cavities are assumed to be three sections of cavities, the diameter of the cavity in the middle is different from the diameters of the cavities at the front and rear ends; in the embodiment, the sensing area 41 which is composed of a plurality of sections of cavities and has different corresponding diameters among the plurality of sections of cavities is arranged in the multimode coreless fiber 4, so that more light penetrates through the core cladding layer boundary due to sudden change of the waveguide geometric shape in the plurality of sections of cavities (for example, the waveguide diameter becomes smaller), and interacts with the outside in the form of an evanescent field, the smaller the waveguide diameter is, the more evanescent fields are generated, which is similar to water pipe resistance, and the stronger evanescent field means more pump light (when laser is used for exciting fluorescence, it is called pump light) to pump a fluorophore to excite fluorescence, thereby enhancing the fluorescence intensity; referring to a diagram of fig. 3, a plurality of metal nanoparticle layers 42 are disposed on the sensing region 41, a fluorescent material layer 43 is disposed on an outer layer of the metal nanoparticle layers 42, for example, the metal nanoparticle layers 42 are coated with the fluorescent material layer 43 such as a monoclonal antibody (FB 1 molecule, FB1-FITC molecule) and the metal nanoparticles of the metal nanoparticle layers 42 are kept at a distance from the fluorescent molecules of the fluorescent material layer 43, so that the fluorescence intensity can be further enhanced, and since the photo inclined light ray fluorescence chemical sensor is washed each time the liquid to be detected is detected, the influence on the next detection result is prevented; in order to prevent the metal nanoparticles of the metal nanoparticle layer 42 from being washed away, the present embodiment precisely modifies the surface of the multimode coreless fiber 4 using a femtosecond laser micromachining system to create an array of nanocavities 44, and it can be understood that the sensing region 41 is provided with a plurality of nanocavities 44 by femtosecond laser micromachining, each nanocavity 44 is filled with the metal nanoparticle layer 42, which are used to physically protect the metal nanoparticle layer 42 after the metal nanoparticle layer 42 is attached in the nanocavities 44, provide a perfect solution to the problem that the metal nanoparticle layer 42 is easily washed away, protect the metal nanoparticle layer 42 from external influences, improve the long-term stability and the repeatable practicality of the optical sheet inclined light ray fluorescence chemical sensor, and the nanoparticle layer filled in the nanocavities 44 may generate localized surface plasmon resonance, and can further enhance the fluorescence intensity, wherein the type and the shape size of the used metal nanoparticle layer 42 may be changed, for example, the type may be a gold nanoparticle layer or a silver nanoparticle layer, and the like, and the shape may be a spherical particle layer or a rod-like; when the optical sheet inclined light ray fluorescence chemical sensor of the embodiment is required to be used for detecting liquid to be detected, the sensing area 41 of the multimode coreless fiber 4 is firstly placed into the liquid to be detected, stable output laser is output through the laser source 1 of the embodiment, the output laser is changed into parallel laser after passing through the collimator 2, the parallel laser passes through the compressor 3 to form an optical sheet at a focal point, the incident angle of the optical sheet on the fiber end face of the multimode coreless fiber 4 is controlled, a preset inclined optical sheet inclined light ray is formed to be transmitted in the multimode coreless fiber 4, fluorescence is absorbed in the sensing area 41 of the multimode coreless fiber 4 through a fluorescent material, the fluorescence power of the liquid to be detected is specifically detected through the power detector 5, the concentration of pollutants is determined through the fluorescence power, and the food safety quality of the liquid to be detected is further determined; the laser source 1 is a polarized laser source 1, the collimator 2 is a plano-convex lens collimator 2, and the compressor 3 is a cylindrical plano-convex lens; the laser source 1, the collimator 2, the compressor 3, multimode centreless optic fibre 4 and power detector 5 structure size of this embodiment are less, with foretell laser source 1, the collimator 2, the compressor 3, multimode centreless optic fibre 4 and power detector 5 dress back to the casing, the concrete size that forms light piece slope light ray fluorescence chemical sensor is similar to some instruments of hand-held type, can understand, compare in current expensive and heavy check out test set, this embodiment simple structure, conveniently carry, need not the special staff and take a sample and the sample shifts, and can realize the detection with current check out test set equivalent effect, can realize carrying out quick, efficient screening detection effect to the on-the-spot video pollutant.

In one embodiment, the present embodiment uses a multimode coreless fiber 4 as the sensing main waveguide, and the sensing region utilizes a sensing region 41 to improve sensitivity, as shown in FIG. 1, where the sensing region 41 is located at the middle section of the multimode coreless fiber 3. It is understood that the multimode coreless fiber 4 includes not only the sensing region 41 but also original regions (not shown) located at both ends of the sensing region 41, where the original regions are uniform unmodified multimode coreless fibers, and the light propagation along the uniform unmodified multimode coreless fiber can be described simply by ray-optical approximation, as shown in FIG. 7, which is the advancing path of the light sheet in the original region of the multimode coreless fiber 4, but wave optics (Maxwell's equation) is required if the waveguide diameter (which can be directly considered as the fiber diameter) is comparable to or smaller than the wavelength of light. The design significance of the light sheet of the present embodiment entering the multimode coreless fiber 4 at a preset inclined angle and propagating the inclined light ray of the light sheet in the multimode coreless fiber 4 is as follows: as shown in fig. 2, the light sheet oblique rays do not intersect the axis of the waveguide, they can be given a predetermined skew when they are reflected from the curved waveguide interface, the resulting light sheet oblique rays can be described mathematically using two angles relative to the waveguide-outer interface as viewed from the longitudinal and transverse angles, and after propagating a distance, the light sheet oblique rays will expand radially and form helical rays, as shown in fig. 3; the sensing system injects an inclined optical sheet (thin rectangular section excited by light on the end face of the input optical fiber) to the incident end face of a section of multimode coreless optical fiber 4 (see diagram a in fig. 3) by using a linearly polarized laser source 1 and a collimator 2 and a compressor 3, the inclined optical sheet can generate a narrower range of spiral optical ray angles, and the spiral optical ray used as pump light greatly increases the number of total internal reflections (see diagram b and diagram c in fig. 3), so that the overlapping area between the pump light evanescent field and the fluorescent material layer 43 is increased, and the fluorescence intensity is enhanced; the optical sheet enters the multimode coreless fiber 4 at a preset inclination angle, and an optimal angle at which an inclined optical ray of the optical sheet enters the multimode coreless fiber can be adjusted and determined through experiments, and then the adjusted and determined inclined optical ray of the optical sheet enters the multimode coreless fiber at a fixed angle, so that each time the optical sheet inclined optical ray fluorescence chemical sensor of the present embodiment is used for detecting a liquid to be detected, the inclined optical ray of the optical sheet can enter the multimode coreless fiber 4 at the adjusted and determined angle, of course, in order to facilitate the entry of the optical sheet into the multimode coreless fiber 4 at the preset inclination angle, the present embodiment is further provided with a dimming mechanical platform, the dimming mechanical platform is arranged on the housing and located at one side of the compressor 3, specifically, the dimming mechanical platform is located behind the compressor 3 as seen in the propagation direction of the laser source 1, in the present embodiment, the incident angle of the optical sheet on the fiber end face of the multimode coreless fiber 4 can be controlled through the dimming mechanical platform, so that the inclined optical ray of the optical sheet can be propagated in the multimode coreless fiber 4, and the dimming mechanical platform can include an electric rotary stage 11 and a triaxial electric translation stage 12.

In an embodiment, for the sensing regions 41 composed of multiple segments of cavities and having different respective corresponding diameters, three structures of the sensing regions 41 are specifically developed in this embodiment, wherein the sensing region 41 may be a tapered sensing region 41, as shown in fig. 4, the tapered sensing region 41 is implemented by heating and stretching the multimode coreless fiber 4, wherein the tapered sensing region 41 includes a first cylinder, a first tapered cylinder, a second tapered cylinder and a third cylinder, which are connected in sequence, wherein one end of the first tapered cylinder having a larger area is connected to the first cylinder, the other end is connected to the second cylinder, one end of the second tapered cylinder having a smaller area is connected to the second cylinder, and the other end is connected to the third cylinder, and the diameter of the second cylinder is smaller than the diameter of the first cylinder and the diameter of the third cylinder. Coherent light sources will be used to achieve good spectral overlap and minimize unnecessary interference; the sensing region 41 may also be a cylindrical sensing region 41, as shown in fig. 5, wherein the cylindrical sensing region 41 includes a fourth cylinder, a fifth cylinder and a sixth cylinder connected in sequence, the diameter of the fifth cylinder is larger than that of the fourth cylinder and that of the sixth cylinder, and on the basis of the shape, the diameter and length of the central section of the multimode coreless fiber 4 may also be controlled to find the optimal conditions for fluorescence enhancement and collection; the sensing region 41 may also be a microbubble sensing region 41, as shown in fig. 6, wherein the microbubble sensing region 41 includes a seventh cylinder, an annular body, and an eighth cylinder, which are connected in sequence, the annular body is an annular hollow waveguide structure, the diameter of the annular body is larger than that of the seventh cylinder and the eighth cylinder, and the annular hollow waveguide structure confines light in a narrow channel, thereby enhancing the intensity of an evanescent field.

In an embodiment, the light sheet inclined light ray fluorescence chemical sensor further includes a polarizer 6, as shown in fig. 1, the polarizer 6 is a polarization beam splitter, and is disposed in the housing, an input end of the polarizer 6 is connected to an output end of the collimator 2, an output end of the polarizer 6 is connected to an input end of the compressor 3, the polarizer 6 is configured to divide the output laser light into two, one beam is used for sensing, and the other beam is used for reference, so as to ensure that the recorded signal data is the same as the output power of the laser light recorded at any time point.

In an embodiment, the optical sheet inclined optical ray fluorescence chemical sensor further includes a photodetector 7, as shown in fig. 1, the photodetector 7 is a reference photodetector 7, and is disposed in the housing, an input end of the photodetector 7 is connected to an output end of the polarizer 6, so as to be connected to an output end of the collimator 2, and since an output power of output laser of the laser has a certain drift, the present embodiment corrects the output power of output laser of the laser by disposing the photodetector 7, so as to maintain stability of the output power of the output laser.

In an embodiment, the light sheet inclined light ray fluorescence chemical sensor further includes a rotator 8, as shown in fig. 1, the rotator 8 is a half-wave plate, the rotator 8 is disposed in the housing, an input end of the rotator 8 is connected to an output end of the collimator 2, an output end of the rotator 8 is connected to an input end of the compressor 3, the rotator 8 of this embodiment is used in a situation where the output laser of the laser has a specific polarization state, for example, linearly polarized light, the rotator 8 is required to change the polarization state of the output laser, and if the output laser has polarization states in all directions, the rotator 8 of this embodiment is not required.

In one embodiment, the light sheet inclined light ray fluorescence chemical sensor further comprises a long-pass filter 9, as shown in fig. 1, the long-pass filter 9 is disposed in the housing and located at a side of the multimode coreless fiber 4 close to the sensing area 41, an output end of the long-pass filter 9 is connected to an input end of the power detector 5, the long-pass filter 9 is used for fluorescence power detection, and since a wavelength of generated fluorescence is greater than a laser output laser wavelength, the long-pass filter 9 is used for enabling energy received by the power detector 5 to come from fluorescence.

In one embodiment, the light sheet inclined light ray fluorescence chemical sensor further comprises an integrating sphere 10, as shown in fig. 1, the integrating sphere 10 is disposed in the housing, an input end of the integrating sphere 10 is connected to an output end of the long pass filter 9, an output end of the integrating sphere 10 is connected to an input end of the power detector 5, and the integrating sphere is used for enabling the power detector 5 to receive all fluorescence, so as to reduce fluorescence loss as much as possible.

In one embodiment, femtosecond laser micromachining techniques can be applied to the fabrication of arrays of fiber surface nanocavities 44 for carrying metal nanoparticles. Each nonlinear absorption in the interaction of the femtosecond laser with the transparent glass material and the rapid ionization inside the bulk material leads to thermally induced defect formation, material densification/thinning, or material ablation. The extent of such processing is determined by many factors, such as wavelength, pulse energy, focal spot size, intensity/phase distribution, pulse width, pulse repetition rate, translation speed, writing direction, writing depth and polarization.

The probability of each nonlinear absorption process (multiphoton absorption and tunnel ionization) in the interaction of the femtosecond laser with the transparent material can be determined from the Keldysh parameter:

where ω is the laser frequency, I is the laser intensity, me is the electron effective mass, e is the fundamental electron charge, c is the speed of light, n is the linear refractive index,. Epsilon.0 is the dielectric constant of free space, and Eg is the band gap of the material. When γ is much greater or less than 1, multiphoton absorption (tunnel ionization) predominates. For γ ≈ 1, absorption (photoionization) is due to a combination of two processes. For the waveguide in glass, γ is typically about 1.

In summary, the present embodiment provides a light sheet inclined optical ray fluorescence chemical sensor based on femtosecond laser micromachining, the light sheet inclined optical ray fluorescence chemical sensor includes a housing, a laser source 1, a collimator 2, a compressor 3, a multimode coreless fiber 4 and a power detector 5, the laser source 1, the collimator 2 and the compressor 3 are all disposed in the housing, the multimode coreless fiber 4 and the power detector 5 are disposed on the housing, an output end of the laser source 1 is connected to an input end of the collimator 2, and an output end of the collimator 2 is connected to an input end of the compressor 3; when the output laser of the laser source 1 enters the multimode coreless fiber 4 through the collimator 2 and the compressor 3, the output laser forms a light sheet through the compressor 3, and enters the multimode coreless fiber 4 at a preset inclination angle by controlling the incident angle of the light sheet on the fiber end face of the multimode coreless fiber 4, and the light ray is propagated in the multimode coreless fiber 4 by inclining the light sheet; the multimode coreless fiber 4 includes an induction area 41 composed of a plurality of sections of cavities, and the diameters of the sections of cavities are different from each other, for example, if the sections of cavities are assumed to be three sections of cavities, the diameter of the cavity in the middle is different from the diameters of the cavities at the front and rear ends; in the embodiment, the sensing area 41 which is composed of a plurality of sections of cavities and has different corresponding diameters among the plurality of sections of cavities is arranged in the multimode coreless optical fiber 4, so that the inclined light ray of the optical sheet entering the sensing area 41 penetrates through the boundary of the core cladding layer due to the sudden change of the geometric shape of the waveguide in the plurality of sections of cavities (for example, the waveguide diameter becomes smaller), more light penetrates through the boundary of the core cladding layer and interacts with the outside in the form of an evanescent field, the smaller the waveguide diameter is, the more evanescent fields are generated, which is similar to water pipe resistance, and the stronger evanescent field means more pump light (when laser is used for exciting fluorescence, the laser is called as pump light) to pump the fluorophore to excite the fluorescence, thereby enhancing the fluorescence intensity; referring to a diagram of fig. 3, a plurality of metal nanoparticle layers 42 are disposed on the sensing region 41, a fluorescent material layer 43 is disposed on an outer layer of the metal nanoparticle layers 42, for example, the metal nanoparticle layers 42 are coated with the fluorescent material layer 43 such as a monoclonal antibody (FB 1 molecule, FB1-FITC molecule) and the metal nanoparticles of the metal nanoparticle layers 42 are kept at a distance from the fluorescent molecules of the fluorescent material layer 43, so that the fluorescence intensity can be further enhanced, and since the photo inclined light ray fluorescence chemical sensor is washed each time the liquid to be detected is detected, the influence on the next detection result is prevented; in order to prevent the metal nanoparticles of the metal nanoparticle layer 42 from being washed away, the present embodiment precisely modifies the surface of the multimode coreless fiber 4 using a femtosecond laser micromachining system to create an array of nanocavities 44, and it can be understood that the sensing region 41 is provided with a plurality of nanocavities 44 by femtosecond laser micromachining, each nanocavity 44 is filled with the metal nanoparticle layer 42, which are used to physically protect the metal nanoparticle layer 42 after the metal nanoparticle layer 42 is attached in the nanocavities 44, provide a perfect solution to the problem that the metal nanoparticle layer 42 is easily washed away, protect the metal nanoparticle layer 42 from external influences, improve the long-term stability and the repeatable practicality of the optical sheet inclined light ray fluorescence chemical sensor, and the nanoparticle layer filled in the nanocavities 44 may generate localized surface plasmon resonance, and can further enhance the fluorescence intensity, wherein the type and the shape size of the used metal nanoparticle layer 42 may be changed, for example, the type may be a gold nanoparticle layer or a silver nanoparticle layer, and the like, and the shape may be a spherical particle layer or a rod-like; when the optical sheet inclined light ray fluorescence chemical sensor of the embodiment is required to be used for detecting liquid to be detected, the sensing area 41 of the multimode coreless fiber 4 is firstly placed into the liquid to be detected, stable output laser is output through the laser source 1 of the embodiment, the output laser is changed into parallel laser after passing through the collimator 2, the parallel laser passes through the compressor 3 to form an optical sheet at a focal point, the incident angle of the optical sheet on the fiber end face of the multimode coreless fiber 4 is controlled, a preset inclined optical sheet inclined light ray is formed to be transmitted in the multimode coreless fiber 4, fluorescence is absorbed in the sensing area 41 of the multimode coreless fiber 4 through a fluorescent material, the fluorescence power of the liquid to be detected is specifically detected through the power detector 5, the concentration of pollutants is determined through the fluorescence power, and the food safety quality of the liquid to be detected is further determined; the laser source 1 is a polarized laser source 1, the collimator 2 is a plano-convex lens collimator 2, and the compressor 3 is a cylindrical plano-convex lens; the laser source 1 of this embodiment, collimator 2, compressor 3, multimode centreless optic fibre 4 and power detector 5 structure size are less, with foretell laser source 1, collimator 2, compressor 3, multimode centreless optic fibre 4 and power detector 5 dress back to the casing, the concrete size that forms light piece slope light ray fluorescence chemical sensor is similar to some instruments of hand-held type, can understand, compare in current expensive and bulky check out test set, this embodiment simple structure, conveniently carry, need not the special staff and take a sample and the sample shifts, and can realize the detection with current check out test set equal effect, can realize carrying out quick, the efficient screening detection effect to on-the-spot video pollutant.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims (10)

1. An optical sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining is characterized by comprising:

a housing;

a laser source disposed within the housing and configured to output laser light;

the collimator is arranged in the shell, the input end of the collimator is connected with the output end of the laser source, and the collimator is used for converting output laser into parallel laser;

the compressor is arranged in the shell, the input end of the compressor is connected with the output end of the collimator, and the compressor is used for enabling the parallel laser to form a light sheet at a focus;

the multimode coreless optical fiber is arranged on the shell and positioned on one side of the compressor, wherein when output laser of the laser source enters the multimode coreless optical fiber through the collimator and the compressor, the output laser enters the multimode coreless optical fiber at a preset inclination angle;

the multimode coreless optical fiber comprises an induction area which consists of a plurality of sections of cavities, wherein the diameters of the induction area and the sections of cavities are different, the induction area is provided with a plurality of nano cavities, a metal nano particle layer is filled in each nano cavity, and a fluorescent material layer covers the outer layer of each metal nano particle layer;

and the power detector is arranged on the shell, is connected with the multimode coreless optical fiber and is used for detecting the fluorescence power.

2. The optical sheet inclination optical ray fluorescence chemical sensor based on femtosecond laser micromachining as claimed in claim 1, wherein the sensing region is a tapered sensing region, wherein the tapered sensing region comprises a first cylinder, a first tapered cylinder, a second tapered cylinder and a third cylinder which are connected in sequence.

3. The femtosecond laser micromachining-based light-sheet inclined-ray fluorescence chemical sensor according to claim 1, wherein the sensing area is a cylindrical sensing area, wherein the cylindrical sensing area includes a fourth cylinder, a fifth cylinder and a sixth cylinder which are connected in sequence, and the diameter of the fifth cylinder is larger than that of the fourth cylinder and that of the sixth cylinder.

4. The optical sheet inclination optical ray fluorescence chemical sensor based on femtosecond laser micromachining according to claim 1, wherein the sensing region is a micro-bubble sensing region, wherein the micro-bubble sensing region comprises a seventh column, an annular body and an eighth column which are connected in sequence, and the diameter of the annular body is larger than that of the seventh column and that of the eighth column.

5. The optical sheet inclined optical ray fluorescence chemical sensor based on femtosecond laser micro-machining according to claim 1, wherein the optical sheet inclined optical ray fluorescence chemical sensor further comprises:

the polarizer is arranged in the shell, the input end of the polarizer is connected with the output end of the collimator, the output end of the polarizer is connected with the input end of the compressor, and the polarizer is used for dividing the output laser into two parts.

6. The light sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining according to claim 5, wherein the light sheet inclined light ray fluorescence chemical sensor further comprises:

and the photoelectric detector is arranged in the shell, the input end of the photoelectric detector is connected with the output end of the collimator, and the photoelectric detector is used for correcting the drift of the output laser power.

7. The optical sheet inclined optical ray fluorescence chemical sensor based on femtosecond laser micro-machining according to claim 1, wherein the optical sheet inclined optical ray fluorescence chemical sensor further comprises:

the rotator is arranged in the shell, the input end of the rotator is connected with the output end of the collimator, the output end of the rotator is connected with the input end of the compressor, and the rotator is used for changing the polarization state of the output laser.

8. The light sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining according to claim 1, wherein the light sheet inclined light ray fluorescence chemical sensor further comprises:

and the dimming mechanical platform is arranged on the shell and used for controlling the incident angle of the optical sheet transmitted into the multimode coreless optical fiber, and the multimode coreless optical fiber is arranged on the dimming mechanical platform.

9. The light sheet inclined light ray fluorescence chemical sensor based on femtosecond laser micromachining according to claim 1, wherein the light sheet inclined light ray fluorescence chemical sensor further comprises:

the long-pass filter is arranged in the shell and positioned on one side, close to the induction area, of the multimode coreless optical fiber, the output end of the long-pass filter is connected with the input end of the power detector, and the long-pass filter is used for enabling energy received by the power detector to come from fluorescence.

10. The optical sheet inclined optical ray fluorescence chemical sensor based on femtosecond laser micro-machining according to claim 1, wherein the optical sheet inclined optical ray fluorescence chemical sensor further comprises:

and the integrating sphere is arranged in the shell, the output end of the integrating sphere is connected with the input end of the power detector, and the integrating sphere is used for enabling the power detector to receive all the fluorescence.

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