Alumina surface waveguide and surface sensor based on structural deformation and method of manufacture

Abstract

The application discloses an alumina surface waveguide and surface sensor based on structural deformation and a preparation method, and comprises the following steps: performing structural deformation on an alumina internal waveguide with a circular ring-shaped end face composed of a linear modification zone, specifically moving the alumina internal waveguide to the alumina surface, removing the linear modification zone above the alumina surface in the circular ring-shaped alumina internal waveguide, and forming a U-shaped ring structure on the alumina surface as the alumina surface waveguide, wherein the end face is perpendicular to the alumina surface, and the inner radius of the circular ring is 10-25 um; the distance from the top of the U-shaped ring structure to the alumina surface is 1-10 um, and when the U-shaped ring structure is formed by removing the linear modification zone above the alumina surface, the distance from the bottom of the U-shaped ring structure to the alumina surface is 1 / 2-3 / 2 of the inner radius of the circular ring. By optimizing the laser parameters and process conditions of laser direct writing, the preparation of the alumina surface light waveguide with high precision and high stability is realized, and a new technical means is provided for the integration and miniaturization of photonic devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical devices and laser processing, and particularly relates to an alumina surface waveguide and surface sensor based on structural deformation and a preparation method. BACKGROUND

[0002] Optical waveguide is an important basic component in optical devices, and its preparation technology and performance optimization have attracted widespread attention and play a key role in the application fields of optical communication and integrated optics. In recent years, laser direct writing technology has become an efficient method for preparing optical waveguides due to its high precision, flexible controllability, and non-contact processing advantages. Especially in the field where traditional micro-nano processing technology cannot achieve ideal results, laser direct writing technology can be used as an effective alternative. Laser direct writing technology uses objective focusing and other methods to focus high-energy density laser beams on the target material to achieve local modification near the laser beam focus. By designing the modified region, the expected waveguide structure is formed. This technology can accurately and controllably realize patterning and structuring on a micro-nano scale, and is suitable for a variety of materials, thus having a wide application prospect.

[0003] According to the classification of materials, optical waveguides prepared by laser direct writing technology can be divided into three categories: glass, polymer, and crystal. The effects of laser interaction with different materials are fundamentally different. For glass and polymer materials, as amorphous materials, their modification laser power threshold is small. Laser focusing modifies the material, and the refractive index of the modified region changes positively (i.e., the refractive index increases). At the same time, these two types of materials are easily affected by external conditions, and their stability is poor under high temperature, corrosion, and other environmental changes. For the third category: crystal materials, due to their lattice structure, the power threshold for laser modification is relatively large, and the refractive index of the modified region changes negatively (i.e., the refractive index decreases). The advantage of crystal materials is that they have better material stability and more reliable stability in the face of temperature, corrosion, and other environments, and some crystal materials also have better hardness and wear resistance. The disadvantage is that when using laser direct writing technology to prepare optical waveguides and other micro-nano optical components, crystal materials are prone to cracking. Since the crystal has hard and brittle material properties, it requires precise control of laser optical parameters, mechanical parameters included in the processing conditions, and special structural design during laser processing, so as to ultimately prepare optical waveguide components with excellent performance and achieve applications in different fields.

[0004] When using laser direct writing technology to prepare optical waveguide for crystal materials, it is also distinguished according to the position of the optical waveguide, including the inside and the surface of the crystal material. In the existing inventions and literature reports, laser direct writing technology can realize waveguide structure inside the crystal, but cannot directly modify the material on the surface of the crystal. This is because the laser power threshold for laser modification of the crystal surface is low, and as the interface between the crystal and the environment (such as air), it is more susceptible to heat. Therefore, when the laser modifies the surface of the crystal, cracks will inevitably occur, which is the difficulty of preparing the surface waveguide of the crystal.

[0005] Aluminum oxide is a typical crystal material with high melting point, high temperature environment, excellent mechanical properties of high hardness and chemical stability of corrosion resistance, and high transmittance in a wide spectrum covering ultraviolet, visible, near-infrared and mid-infrared, which is a multifunctional material with excellent performance. In the process of processing aluminum oxide, traditional methods mainly include ion beam etching, lithography and other micro-nano processing technologies. Although these methods can realize the preparation of optical waveguide to some extent, they have the disadvantages of complex process, high cost and long preparation period, which limits their popularization in practical application. Correspondingly, laser direct writing as a new technology can provide an accurate and efficient preparation method to realize the waveguide structure in aluminum oxide crystal. At present, there are still problems to be solved in the research of preparing aluminum oxide surface waveguide based on laser direct writing, including laser parameter optimization, waveguide structure design, surface quality control, etc. Therefore, it is of great significance to develop an efficient and controllable method for preparing aluminum oxide waveguide based on laser direct writing, especially for aluminum oxide surface waveguide, to promote the development of photonic integration technology. SUMMARY

[0006] In view of the above, the purpose of the present application is to provide an aluminum oxide surface waveguide and surface sensor based on structural deformation and a preparation method. By designing a special structure of the aluminum oxide surface waveguide based on structural deformation and optimizing the laser parameters and process conditions of laser direct writing, high-precision and high-stability aluminum oxide surface optical waveguide preparation is realized, which provides a new technical means for the integration and miniaturization of photonic devices.

[0007] To achieve the above-mentioned purpose of the application, an aluminum oxide surface waveguide based on structural deformation provided by the embodiment comprises:

[0008] The internal waveguide of the aluminum oxide with a circular ring-shaped end face composed of linear modification zones is subjected to structural deformation, specifically the internal waveguide of the aluminum oxide is moved to the surface of the aluminum oxide, and the linear modification zones close to or above the surface of the aluminum oxide are removed in the circular ring-shaped internal waveguide of the aluminum oxide to form a U-shaped ring structure as the aluminum oxide surface waveguide, wherein the end face is perpendicular to the surface of the aluminum oxide, and the inner radius of the circular ring is 10-25 um;

[0009] The distance from the top of the U-shaped ring structure to the surface of the aluminum oxide is 1-10 um, and when the linear modification zone above the surface of the aluminum oxide is removed to form the U-shaped ring structure, the distance from the bottom of the U-shaped ring structure to the surface of the aluminum oxide is 1 / 2-3 / 2 of the inner radius of the ring.

[0010] In order to realize the laser direct writing of the surface waveguide of the aluminum oxide, the surface waveguide of the aluminum oxide is designed based on structural deformation, specifically, waveguides are prepared at different depths from the surface in the crystal, the distance between the structure and the surface is reduced until the waveguide structure is close to the surface, and the above-mentioned U-shaped ring structure is formed as the surface waveguide of the aluminum oxide, so that when the laser direct writing technology is implemented, the linear modification zone directly on the surface of the crystal is cancelled, and the crack is avoided, but since the designed U-shaped ring structure is composed of the linear modification zone, the effect of confining the mode field during light transmission can be achieved, thereby serving as the surface waveguide of the crystal.

[0011] In order to realize the above-mentioned object of the application, the embodiment of the present application further provides a preparation method of a surface waveguide of aluminum oxide, the surface waveguide of aluminum oxide is the above-mentioned U-shaped ring structure formed on the surface of the aluminum oxide, and the preparation method comprises the following steps:

[0012] The U-shaped ring structure is processed on the surface of the aluminum oxide by using the laser direct writing processing mode, the focusing depth of the laser beam which determines the shape of the structure in the aluminum oxide, the laser repetition frequency and the transverse moving speed of the displacement table, and the laser single pulse energy which determines the modification degree are controlled during processing.

[0013] The laser repetition frequency and the transverse moving speed of the displacement table determine the shape of the U-shaped ring structure at the same time, the laser repetition frequency is set to be adjustable at 1 Hz-2 MHz, the transverse moving speed of the displacement table is set to be 1 um / s-2000 um / s, and a plurality of laser pulse points form a linear modification zone along the moving direction of the displacement table at a certain interval distance, since the interval distance between the laser pulse points directly affects the modification performance of the laser on the aluminum oxide, in order to improve the modification performance of the laser on the aluminum oxide, when the laser repetition frequency is kept at 5 kHz, the acceptable transverse moving speed is 500-1500 um / s, and the interval distance of the laser pulse is required to be 0.1-0.3 um. In the experimental exploration, the stability of the displacement table movement and the laser processing efficiency are comprehensively considered, the laser repetition frequency f of 5 kHz and the transverse moving speed v of the displacement table of 900 um / s can be used, and the interval distance x of the laser pulse points is v / f=0.18 um, when the spot diameter D after focusing through the objective lens is estimated to be 2 um, the number of times of the laser pulse acting on the spot coverage area is about N=D / x=11 times, and it can be considered that the modification of the laser on the aluminum oxide is realized by multiple pulses.

[0014] The laser single pulse energy determines the modification degree of the aluminum oxide, and specifically corresponds to the length and width of the linear modification area. After focusing by the objective lens, it is found that the laser pulse energy reaching the aluminum oxide position can well realize the modification of the aluminum oxide when the laser pulse energy is in the order of hundreds of nJ. The specific laser single pulse energy value floats within a certain range, and is determined according to the modification depth and modification effect of the laser on the aluminum oxide. It is also found through research that the deeper the internal waveguide depth, the greater the laser single pulse energy required for material modification. When the laser single pulse energy is the same and the depth is greater, the laser single pulse energy does not reach the modification threshold, which will result in an incomplete waveguide structure. For the surface waveguide, the laser single pulse energy needs to be reduced, because the material near the crystal surface is prone to cracking. Cracking is also the biggest problem and difficulty in preparing the surface waveguide. Therefore, when preparing the aluminum oxide surface waveguide, the laser single pulse energy is in the order of hundreds of nJ, and the shorter the distance from the linear modification area to the surface of the aluminum oxide, the smaller the laser single pulse energy used, so as to ensure the modification and also ensure that the U-shaped ring structure aluminum oxide surface waveguide does not have cracks.

[0015] According to the distance from each linear modification area in the U-shaped ring structure to the surface of the aluminum oxide, the focusing depth of the laser beam in the aluminum oxide is controlled to realize the modification of the aluminum oxide at different depths and form each linear modification area.

[0016] The laser wavelength can realize the effect of modifying the aluminum oxide crystal. When the U-shaped ring structure is processed on the surface of the aluminum oxide by using the laser direct writing processing method, the laser wavelength range is limited to visible to near infrared. Combined with the commonly used laser wavelength and the use of frequency multiplication accessories, the wavelength range includes 515 nm, 532 nm, 635 nm, 808 nm, 1030 nm, 1064 nm, etc.

[0017] The laser pulse width preferably uses fs laser, because the time scale of fs is shorter than the time scale (ps) of the heat affected zone generated by the absorption of the laser by the aluminum oxide. Therefore, when the aluminum oxide is modified by using the fs laser, the heat affected zone can be avoided or limited to the maximum extent. The heat affected zone will cause uneven stress distribution in the aluminum oxide, thereby affecting the performance of the prepared waveguide. Specifically, when the U-shaped ring structure is processed on the surface of the aluminum oxide by using the laser direct writing processing method, the laser pulse width is limited to 130 fs-1 ps. In order to avoid the heat affected zone to the maximum extent, the laser pulse width is controlled to be below 1 ps, and further, the laser pulse width is limited to 130 fs.

[0018] To achieve the above-mentioned object of the application, an embodiment of the present application further provides a surface sensor, which adopts the aluminum oxide surface waveguide based on structural deformation.

[0019] To achieve the above-mentioned object of the application, an embodiment of the present application further provides a surface sensor, which adopts the aluminum oxide surface waveguide prepared by the above-mentioned method.

[0020] Compared with the prior art, the present application has the beneficial effects at least including:

[0021] The present application adopts ultrafast laser focusing into the incident alumina crystal to realize local modification of the alumina, and the refractive index of the modified region is reduced. By adjusting the optical parameters in the ultrafast laser, including laser pulse width, laser wavelength, laser single pulse energy, etc., the material modification caused by the effect of the focused laser on the alumina is realized. At the same time, the mechanical parameters such as the transverse movement speed of the displacement table and the laser repetition frequency are adjusted, so that the relative displacement between the laser beam and the alumina sample is generated, and then the laser beam can form a modified region with a specific track inside and / or on the surface of the alumina sample. By synergistically adjusting the optical parameters and the mechanical parameters, a controllable modification result is formed on the alumina crystal, while cracks are avoided. By controlling the focusing depth of the laser beam in the alumina, different depths of modification of the alumina are realized, forming each straight-line modified region, which constitutes a U-shaped ring structure on the surface of the alumina, and then an alumina surface waveguide that prevents cracks is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is a structural schematic diagram of the alumina surface waveguide based on structural deformation provided by the embodiments;

[0024] Figure 2 is a light field simulation diagram of the alumina surface waveguide based on structural deformation provided by the embodiments;

[0025] Figure 3 is a cross-sectional view of the experimentally prepared alumina surface waveguide provided by the embodiments;

[0026] Figure 4 is a light field simulation diagram of the surface sensor provided by the embodiments. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the protection scope of the present application.

[0028] The inventive concept of the present application is that: for the preparation of waveguide on crystal material by using laser direct writing technology, due to the material properties of the crystal, cracks are easily generated, and it is difficult to obtain an optical device with good performance. At the same time, since cracks are inevitably generated when the laser modifies the surface of the crystal, the surface waveguide of the crystal cannot be directly prepared, and the present application provides an alumina surface waveguide based on structural deformation and a preparation method thereof. By optimizing the laser optical parameters and the mechanical condition parameters during processing, the modification effect of the laser on the alumina crystal is controlled, and the laser modification of the alumina is realized without cracks. By designing a special waveguide structure to prepare the alumina surface optical waveguide, and testing the optical performance, the alumina surface waveguide obtained can realize device application in extreme environments, such as surface sensors in high-temperature environments and corrosive gas environments.

[0029] The alumina surface waveguide provided by the embodiment is obtained by structural deformation based on the alumina internal waveguide, that is, the structural deformation is performed on the alumina internal waveguide with a circular ring-shaped end face composed of straight-line modification regions, and specifically, the alumina internal waveguide is moved to the alumina surface, and the straight-line modification regions close to the alumina surface in the circular ring-shaped alumina internal waveguide are removed, as shown in the left part of FIG. Figure 1 , or the straight-line modification regions above the alumina surface are removed, as shown in the middle and right parts of FIG. Figure 1 , to form a U-shaped ring structure as the alumina surface waveguide, wherein the end face is perpendicular to the alumina surface.

[0030] In the U-shaped ring structure as shown in FIG. Figure 1 , it is found through simulation research as shown in FIG. Figure 2 that for any form of U-shaped ring structure in FIG. Figure 1 , the clamping region of the U-shaped ring structure can form a bound optical field, which plays a waveguide role for surface transmission of light. By limiting the distance from the top of the U-shaped ring structure to the alumina surface to 1-10 um, specifically 2 um, the bound optical field formed by the obtained U-shaped ring structure has surface waveguide characteristics, and the alumina surface will not be cracked. At the same time, it is also limited that the inner radius of the circular ring is 10-25 um, specifically 15 um, so that the bound optical field formed by the obtained U-shaped ring structure has stronger confinement and stronger waveguide characteristics.

[0031] In the embodiment, it is also explored that when the straight-line modification regions above the alumina surface are removed to form the U-shaped ring structure, the distance from the bottom of the U-shaped ring structure to the alumina surface is also limited to 1 / 2-3 / 2 of the inner radius of the circular ring, so that the bound optical field formed has the transmission characteristics of the surface waveguide. When the distance exceeds this distance, the U-shaped ring structure can no longer transmit light on the surface, and the central region of the U-shaped ring structure can no longer bind the optical field.

[0032] The alumina surface waveguide of the above structure cancels the direct modification of the crystal surface by laser during preparation, avoids cracks, and still maintains the integrity of the waveguide and the property of efficient transmission of light.

[0033] The embodiment also provides a preparation method of the above structure deformation-based alumina surface waveguide, which specifically adopts a laser direct writing processing mode to process a U-shaped ring structure in alumina, and controls the laser repetition frequency and the transverse moving speed of the displacement table which determine the shape of the structure, the laser single pulse energy, the focusing depth of the laser beam in alumina, the laser wavelength, and the laser pulse width which determine the modification degree.

[0034] Specifically, the method comprises the following steps:

[0035] S1, optical parameters and platform processing parameters are set. The optical parameters specifically include a laser wavelength of 1030 nm, a laser pulse width of 130 fs, a repetition frequency f = 5 kHz, and a single pulse energy E = 192 nJ; and the platform processing parameters specifically include a transverse moving speed v = 900 um / s of the displacement table and an initial focusing depth Z = 0 of the laser beam.

[0036] S2, a U-shaped ring structure to be processed and size parameters are confirmed. The structure refers to a 1 / 2 circular U-shaped ring structure, and in addition, structures close to a complete circular ring and a 3 / 4 circular U-shaped ring structure are also included; the size parameters of the U-shaped ring include an inner radius r = 15 um of the circular ring, a total number N = 11 of straight lines constituting a 1 / 2 circular ring of the modified region, and a distance Z0 = 2 um from the top of the U-shaped ring structure to the surface of the alumina.

[0037] S3, processing is started from the straight line with the largest depth of the U-shaped ring in the alumina material, and the straight lines are sequentially processed in the order of gradually decreasing depth. The specific operation comprises the following steps.

[0038] S3-1, first, the focusing depth of the laser beam is set as Z1 = Z0 + r, that is, the straight line with the largest depth in the alumina is processed as the target. The laser is turned on, and the displacement table is transversely moved by a certain distance (5 mm) at the same time. Then, the laser is turned off, and the first straight line is completed.

[0039] S3-2, then, the focusing depth of the laser beam is set as Z2 = Z0 + r, that is, the two straight lines with the second largest depth in the U-shaped ring are processed. Since the U-shaped ring is a symmetrical circular ring structure from the cross-sectional view, there are two straight lines with the same depth except for the straight line with the largest depth. The left straight line with the same depth is processed first. The laser is turned on, and the displacement table is transversely moved by a certain distance (5 mm) at the same time. Then, the laser is turned off. The right straight line with the same depth is processed.

[0040] S3-3, then, the focusing depth of the laser beam is set as Z3 = Z0 + r, that is, the two straight lines with the third largest depth in the U-shaped ring are processed. The two straight lines corresponding to the third largest depth in the U-shaped ring. First, process the left straight line at this depth, turn on the laser, and move the displacement table horizontally by a certain distance (5 mm), turn off the laser. Then process the right straight line at this depth.

[0041] S3-4, then set the focusing depth of the laser beam to Z4=Z0+ The two straight lines corresponding to the fourth largest depth in the U-shaped ring. First, process the left straight line at this depth, turn on the laser, and move the displacement table horizontally by a certain distance (5 mm), turn off the laser. Then process the right straight line at this depth.

[0042] S3-5, then set the focusing depth of the laser beam to Z5=Z0+ The two straight lines corresponding to the fifth largest depth in the U-shaped ring. First, process the left straight line at this depth, turn on the laser, and move the displacement table horizontally by a certain distance (5 mm), turn off the laser. Then process the right straight line at this depth.

[0043] S3-6, set the focusing depth of the laser beam to Z6=Z0, the two straight lines corresponding to the closest to the surface of the alumina. First, process the left straight line at this depth, turn on the laser, and move the displacement table horizontally by a certain distance (5 mm), turn off the laser. Then process the right straight line at this depth.

[0044] Through the above steps, the alumina surface waveguide shown in Figure 3 is obtained.

[0045] The embodiment also provides a surface sensor based on the above-mentioned alumina surface waveguide. In the surface sensor, based on the surface waveguide structure designed by the application, the waveguide core layer binds the light mode field of the transmission light, and the transmission light is close to the interface between the alumina material and the environment. Based on the difference in the interaction between the environment and the transmission light, the results of the waveguide transmission light can be obviously compared.

[0046] For example, the environment is set as air and water, and the transmission light is set as a middle infrared wavelength of 2.85um. At this wavelength, water has strong absorption, and air has weak absorption. When the input light is in TM mode, the electric field of the TM mode has a longitudinal component (E z ), which can more strongly pass through the interface between the waveguide and the environment, and enhance the interaction between the light and the environment. As a result, when the environment is water, the transmission light in the waveguide is more easily absorbed by the environment, and it is difficult to detect at the output end; when the environment is air, the transmission light in the waveguide is not easily affected by the environment, and the transmission light can be detected at the output end.

[0047] The simulation is also carried out in the embodiment, the inner ring radius of the waveguide structure is 15 um, the outer ring radius is 28 um, the transmission light wavelength is 2.85 um, and the TM mode is transmitted. The mode field distribution of the transmission light under the environment water (unable to transmit) and air (transmissible) is respectively shown on the left and right. The simulation result is shown in Figure 4 The simulation result is shown in Figure 4 The alumina surface waveguide of the present application has a binding effect on light.

[0048] The above detailed description of the specific embodiments has described the technical solutions and beneficial effects of the present application. It should be understood that the above description is only the most preferred embodiment of the present application and is not used to limit the present application. Any modification, supplement and equivalent replacement within the principle range of the present application should be included in the protection range of the present application.

Claims

1. A structure deformation based aluminum oxide surface waveguide, characterized by, Comprise: The structure of the annular end surface aluminum oxide internal waveguide composed of straight line modification zone is deformed, specifically the aluminum oxide internal waveguide is moved to the surface of the aluminum oxide, the straight line modification zone near or above the surface of the aluminum oxide is removed in the annular aluminum oxide internal waveguide, and the formed U-shaped ring structure is used as the aluminum oxide surface waveguide, wherein the end surface is perpendicular to the surface of the aluminum oxide, and the inner radius of the annular ring is 10-25um; Wherein, the focusing depth of the control laser beam in the aluminum oxide is controlled to modify the aluminum oxide at different depths to form each straight line modification zone; The distance from the top of the U-shaped ring structure to the surface of the aluminum oxide is 1-10um, and when the straight line modification zone above the surface of the aluminum oxide is removed to form the U-shaped ring structure, the distance from the bottom of the U-shaped ring structure to the surface of the aluminum oxide is limited to 1 / 2-3 / 2 of the inner radius of the annular ring.

2. A method of fabricating an alumina surface waveguide, characterized by, The preparation method of the aluminum oxide surface waveguide comprises the following steps: The U-shaped ring structure is processed in the aluminum oxide by using a laser direct writing processing method, and the focusing depth of the laser beam in the aluminum oxide, the laser repetition frequency and the transverse moving speed of the displacement table, and the laser single pulse energy which determines the modification degree are controlled during processing.

3. The method of claim 2, wherein the alumina surface waveguide is formed by sintering a green body of a mixture of alumina powder and a binder. The laser repetition frequency is 1Hz-2MHz, the transverse moving speed of the displacement table is 1um / s-2000um / s, and the interval distance of the laser pulse is 0.1-0.3um.

4. The method of claim 2, wherein the alumina surface waveguide is formed by sintering a green body of a mixture of alumina powder and a binder. The laser single pulse energy is in the order of hundreds of nJ, and the shorter the distance from the straight line modification zone to the surface of the aluminum oxide, the smaller the laser single pulse energy used, which ensures the modification and also ensures that the U-shaped ring structure of the aluminum oxide surface waveguide does not appear cracks.

5. The method of claim 2, wherein the alumina surface waveguide is formed by sintering a green body of a mixture of alumina powder and a binder. According to the distance from each straight line modification zone in the U-shaped ring structure to the surface of the aluminum oxide, the focusing depth of the laser beam in the aluminum oxide is controlled to modify the aluminum oxide at different depths to form each straight line modification zone.

6. The method of claim 2, wherein the alumina surface waveguide is formed by sintering a green body of a mixture of alumina powder and a binder. When the U-shaped ring structure is processed on the surface of the aluminum oxide by using the laser direct writing processing method, the laser wavelength range is limited to visible to near infrared, and the specific wavelength range includes 515nm, 532nm, 635nm, 808nm, 1030nm, and 1064nm.

7. The method of claim 2, wherein the alumina surface waveguide is formed by sintering a green body of a mixture of alumina powder and a binder. When the U-shaped ring structure is processed on the surface of the aluminum oxide by using the laser direct writing processing method, the laser pulse width is limited to 130fs-1ps.

8. A surface sensor, characterized by The surface sensor uses the aluminum oxide surface waveguide based on structural deformation according to claim 1.

9. A surface sensor, characterized by The surface sensor uses the aluminum oxide surface waveguide prepared by the method according to any one of claims 2-7.

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