Glass waveguide surface plasma resonance sensor

Abstract

The invention discloses a glass waveguide surface plasma resonance sensor. The sensor comprises a glass substrate with a cylindrical waveguide core layer and two grooves, wherein the two grooves are respectively positioned on two symmetrical sides of the cylindrical waveguide core layer and are respectively provided with a nano metal film. The manufacturing method of the sensor is simple, the dual-channel nano metal film generates a surface plasma resonance effect along with the change of an external environment, and different metal films absorb light with different specific wavelengths. The sensor is small in crosstalk and high in practicability, measurement of multiple environmental parameters can be achieved, high-sensitivity rapid measurement of the environmental temperature and the environmental refractive index is achieved through high-sensitivity response of the characteristic absorption peak wavelength of the transmission spectrum trough to external environmental refractive index disturbance, and a good sensing effect is achieved.

Description

Technical Field

[0001] The present invention relates to a surface plasmon resonance sensor, belonging to the field of optical waveguide sensors, and particularly to a glass waveguide surface plasmon resonance sensor. Background Art

[0002] Surface plasmon resonance (SPR) is a special optical phenomenon occurring at the metal-dielectric interface. When incident light of a specific wavelength irradiates the metal surface, it can excite surface plasmon waves, resulting in a significant change in light intensity under specific conditions. This phenomenon is highly sensitive to the environmental refractive index. By introducing temperature-sensitive materials around the glass waveguide, the temperature sensing performance can also be significantly improved. Currently, traditional surface plasmon resonance sensors have problems such as poor stability and easy interference of the measured parameters. Summary of the Invention

[0003] In order to solve the problems in the background art, the present invention provides a glass waveguide surface plasmon resonance sensor. The dual-channel surface plasmon resonance (SPR) sensor proposed by the present invention exhibits advantages such as small crosstalk between two parameters and strong practicability. The multi-parameter waveguide sensor is based on a glass-based graded waveguide and can simultaneously measure the environmental temperature and the environmental refractive index.

[0004] The technical solution adopted by the present invention is as follows:

[0005] The glass waveguide surface plasmon resonance sensor of the present invention includes a glass substrate with a cylindrical waveguide core layer, a first groove, and a second groove. The cylindrical waveguide core layer is arranged parallel to the length direction of the glass substrate. The two grooves are respectively located symmetrically on both sides of the cylindrical waveguide core layer at parallel intervals and are respectively provided with nano-metal films. The cylindrical waveguide core layer receives an optical signal through an externally connected optical fiber, and thus measures the change in the external environment by measuring the change in the optical signal.

[0006] The cylindrical waveguide core layer is formed at the top center of the glass substrate, and there is a gap between the top surface and the top surface of the glass substrate to form a cladding. The two grooves are rectangular grooves, and the lengths of the cylindrical waveguide core layer and the two grooves are equal to the length of the glass substrate.

[0007] A layer of nano-gold film is plated on one side of the first groove close to the cylindrical waveguide core layer, and a polydimethylsiloxane (PDMS) block is provided in the groove of the first groove on the side of the nano-gold film.

[0008] The thickness of the nano-gold film is 30 - 80 nm.

[0009] First, the groove of the first groove on the side of the nanogold film is filled with polydimethylsiloxane (PDMS) material and completely filled, and then a polydimethylsiloxane (PDMS) block is obtained after curing.

[0010] A layer of silver nanofilms is plated on the side surface of the second groove close to the cylindrical waveguide core layer, and a layer of iron oxide nanofilms is plated on the silver nanofilms.

[0011] The thickness of the silver nanofilms is 30 - 80 nm, and the thickness of the iron oxide nanofilms is 20 - 50 nm.

[0012] The refractive indices of the circular cross-sections of the cylindrical optical waveguide core layer are all Gaussian distributions. The refractive index of the cylindrical waveguide core layer is greater than that of other parts of the glass substrate. The refractive index difference between the maximum refractive index of the cylindrical optical waveguide core layer and the refractive index of other parts of the glass substrate is 0.005 - 0.02.

[0013] The radius of the cylindrical optical waveguide core layer is 3.0 - 5.0 μm, the length is 100 - 2500 μm; the cladding thickness is 0 - 2 μm.

[0014] The spacing distances between the cylindrical optical waveguide core layer and the two grooves are both 0.1 - 2 μm; the widths of the two grooves are 10 - 100 μm, the depths are 10 - 100 μm, and the lengths are 100 - 2500 μm.

[0015] The sensor of the present invention is a sensor that can simultaneously measure temperature changes and refractive index changes. Its working principle is to create grooves on both sides of the glass waveguide and coat different metal films on the grooves. Different metal films will absorb light of different specific wavelengths, thereby realizing the measurement of multiple environmental parameters. The spectrum can be obtained through measurement, and then the wavelength and frequency changes of the optical signal can be obtained, and further environmental measurement can be carried out. With the change of the external environment, the surface plasmon resonance effect will occur on the metal film. Different metal films will absorb light of different specific wavelengths, thereby realizing the measurement of multiple environmental parameters, and the temperature and substances such as liquids and gases can also be monitored.

[0016] The beneficial effects of the present invention are:

[0017] The present invention adopts a waveguide structure that can excite the surface plasmon resonance effect. The optical waveguide structure can realize further functional integration, can realize the measurement of multiple environmental parameters, the sensor has high sensitivity, and the manufacturing method is simple. Different environmental parameters can be measured by plating different metal films and sensitive films. The characteristic absorption peak wavelength of the transmission spectrum valley is used for the highly sensitive response to the refractive index perturbation of the external environment, realizing the highly sensitive and rapid measurement of the environmental temperature and the environmental refractive index. The manufacturing method of the sensor of the present invention is simple, the manufacturing cost is relatively low, and it can simultaneously monitor the temperature and substances with a refractive index below 1.4 and has a good sensing effect. Brief Description of the Drawings

[0018] Figure 1 is a schematic cross-sectional view of the surface plasmon resonance sensor of the glass waveguide of the present invention;

[0019] Figure 2 is a schematic structural view of the surface plasmon resonance sensor of the glass waveguide of the present invention;

[0020] Figure 3 is a transmission spectrum diagram when the environmental refractive index is 1 - 1.02 under a 45nm gold nanomembrane, a 45nm silver nanomembrane, and a 45nm iron oxide nanomembrane;

[0021] Figure 4 is a transmission spectrum diagram when the environmental temperature is 20 - 80°C under a 45nm gold nanomembrane, a 45nm silver nanomembrane, and a 45nm iron oxide nanomembrane;

[0022] Figure 5 is a transmission spectrum diagram when the environmental refractive index is 1.15 - 1.25 under a 45nm gold nanomembrane, a 45nm silver nanomembrane, and a 30nm iron oxide nanomembrane;

[0023] Figure 6 is a transmission spectrum diagram when the environmental temperature is 20 - 80°C under a 45nm gold nanomembrane, a 45nm silver nanomembrane, and a 30nm iron oxide nanomembrane;

[0024] Figure 7 is a transmission spectrum diagram when the environmental refractive index is 1.3 - 1.37 under a 40nm gold nanomembrane, a 40nm silver nanomembrane, and a 20nm iron oxide nanomembrane;

[0025] Figure 8 is a transmission spectrum diagram when the environmental temperature is 20 - 80°C under a 40nm gold nanomembrane, a 40nm silver nanomembrane, and a 20nm iron oxide nanomembrane;

[0026] In the figure: 1. Glass substrate, 2. Cladding, 3. Cylindrical waveguide core layer, 4. First groove, 5. Gold nanomembrane, 6. Polydimethylsiloxane PDMS block, 7. Second groove, 8. Silver nanomembrane, 9. Iron oxide nanomembrane. Detailed Embodiments

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] As Figure 1 and Figure 2As shown in the figure, the glass waveguide surface plasmon resonance sensor of the present invention includes a glass substrate 1 with a cylindrical waveguide core layer 3, a first groove 4 and a second groove 7. The cylindrical waveguide core layer 3 is arranged parallel to the length direction of the glass substrate 1. The two grooves 4 and 7 are respectively located on the symmetric sides of the cylindrical waveguide core layer 3 at parallel intervals and are respectively provided with nano-metal films. The cylindrical waveguide core layer 3 receives an optical signal through an externally connected optical fiber, so as to measure the change of the external environment by measuring the change of the optical signal. The cylindrical waveguide core layer 3 is fabricated by electron beam lithography, laser direct writing or ion exchange process. The two grooves 4 and 7 are fabricated by femtosecond laser lithography and wet etching process. A layer of nano-gold film 5 is deposited on one side of the first groove 4 close to the cylindrical waveguide core layer 3, and a polydimethylsiloxane (PDMS) block 6 is provided in the groove of the first groove 4 on the side of the nano-gold film 5. The thickness of the nano-gold film 5 is 30 - 80 nm. First, the polydimethylsiloxane (PDMS) material is added and completely filled in the groove of the first groove 4 on the side of the nano-gold film 5, and then the polydimethylsiloxane (PDMS) block 6 is obtained after curing. A layer of nano-silver film 8 is deposited on one side of the second groove 7 close to the cylindrical waveguide core layer 3, and a layer of nano-iron oxide film 9 is deposited on the nano-silver film 8. The thickness of the nano-silver film 8 is 30 - 80 nm, and the thickness of the nano-iron oxide film 9 is 20 - 50 nm. The nano-metal film is realized by coating methods such as atomic layer deposition during coating.

[0029] A cylindrical waveguide core layer 3 is formed at the top center of the glass substrate 1, and there is a gap between the top surface of the core layer and the top surface of the glass substrate 1 to form a cladding layer 2; the two grooves 4 and 7 are rectangular grooves, and the lengths of the cylindrical waveguide core layer 3 and the two grooves 4 and 7 are equal to the length of the glass substrate 1. When the cylindrical waveguide core layer 3 is formed, film coating, photolithography, and etching are performed on the upper surface of the glass substrate 1, followed by thermal ion exchange and electro-assisted exchange processes. Then, the optical waveguide is buried into the glass substrate 1 under the action of an electric field to form a buried cylindrical waveguide core layer 3. The glass substrate 1 left above the cylindrical waveguide core layer 3 due to burial constitutes the cladding layer 2. Then, two grooves 4 and 7 are processed on both sides of the cylindrical waveguide core layer 3, and then film coating and filling of PDMS material are performed on the grooves to obtain an optical waveguide chip with a sensing effect. The refractive indices of the circular cross-section of the cylindrical optical waveguide core layer 3 are all Gaussian distributed. The refractive index of the cylindrical waveguide core layer 3 is greater than that of other parts of the glass substrate 1, and the refractive index difference between the maximum refractive index of the cylindrical optical waveguide core layer 3 and the refractive index of other parts of the glass substrate 1 is 0.005 - 0.02. The radius of the cylindrical optical waveguide core layer 3 is 3.0 - 5.0 μm, and the length is 100 - 2500 μm; the thickness of the cladding layer 2 is 0 - 2 μm. The spacing between the cylindrical waveguide core layer 3 and the two grooves 4 and 7 is 0.1 - 2 μm; the widths of the two grooves 4 and 7 are 10 - 100 μm, the depths are 10 - 100 μm, and the lengths are 100 - 2500 μm.

[0030] When fabricating a glass waveguide surface plasmon resonance sensor, the following fabrication steps are included:

[0031] Waveguide mask fabrication: Transfer the designed waveguide pattern onto the mask on the glass substrate 1, which is used as a blocking film for the optical waveguide during the ion exchange process.

[0032] Thermal ion exchange: Immerse the glass substrate 1 with the mask into a silver ion exchange molten salt with a concentration lower than the preset concentration to fabricate a surface optical waveguide, and remove the mask on the glass substrate 1.

[0033] Electro-assisted ion exchange: Place the glass substrate 1 that has undergone the second thermal ion exchange into the exchange molten salt, add a first electrode and a second electrode on both sides of the glass substrate 1, and perform electro-assisted exchange processing to bury the optical waveguide into the glass substrate 1 under the action of an electric field to form a buried cylindrical optical waveguide core layer 3. The glass substrate 1 left above the cylindrical optical waveguide core layer 3 due to burial constitutes the cladding layer 2.

[0034] Fabrication of grooves 4 and 7: Use femtosecond laser etching and wet etching processes to fabricate microfluidic groove channels along both sides of the cylindrical optical waveguide core layer 3.

[0035] Film coating: The nano-metal film is coated using the atomic layer deposition coating method.

[0036] Specific embodiments of the present invention are as follows:

[0037] Example 1:

[0038] The radius of the cylindrical waveguide core layer 3 of the glass waveguide surface plasmon resonance sensor is 4 μm, and the length is 1000 μm; the refractive index difference between the maximum refractive index of the cylindrical optical waveguide core layer 3 and other parts of the glass substrate 1 is 0.008; the cladding thickness 2 is 2.0 μm; the widths of the two grooves 4 and 7 are 50 μm, the depths are 50 μm, and the lengths are 1000 μm; a 45-nm nano-gold film 5 is attached to the first groove 4 by atomic layer deposition coating, a 45-nm nano-silver film 8 is attached to the second groove 7 by atomic layer deposition coating, and a 45-nm iron oxide film 9 is attached to the nano-silver film 8 by atomic layer deposition coating.

[0039] As Figure 3 and Figure 4 shown, the present invention is simulated by Comsol simulation software. The input light source is a broadband light source with a wavelength range of 500 - 1000 nm. The simulation is carried out in the range of environmental refractive index 1.00 - 1.02 and temperature 20 - 80 °C to obtain different environmental transmission spectra. The simulation results show that the sensor with the structure of the present invention can achieve good sensing effects within the gas refractive index range. The refractive index sensitivity can reach 550 nm / RIU, and the temperature sensitivity can reach 1.45 nm / °C.

[0040] Example 2:

[0041] The radius of the cylindrical waveguide core layer 3 of the glass waveguide surface plasmon resonance sensor is 3 μm, and the length is 1500 μm; the refractive index difference between the maximum refractive index of the cylindrical optical waveguide core layer 3 and other parts of the glass substrate 1 is 0.006; the cladding thickness 2 is 1.0 μm; the widths of the two grooves 4 and 7 are 50 μm, the depths are 50 μm, and the lengths are 1000 μm; a 45-nm nano-gold film 5 is attached to the first groove 4 by atomic layer deposition coating, a 45-nm nano-silver film 8 is attached to the second groove 7 by atomic layer deposition coating, and a 30-nm iron oxide film 9 is attached to the nano-silver film 8 by atomic layer deposition coating.

[0042] As Figure 5 and Figure 6As shown, the present invention is simulated by Comsol simulation software. The input light source is a broadband light source with a wavelength range of 500 - 1000 nm. The simulation is carried out in the range of environmental refractive index of 1.15 - 1.25 and temperature of 20 - 80 degrees Celsius to obtain different environmental transmission spectra. The simulation results show that this structure sensor can achieve good sensing effects in the refractive index range of 1.15 - 1.25. The refractive index sensitivity can reach 890 nm / RIU, and the temperature sensitivity can reach 1.41 nm / °C.

[0043] Example 3:

[0044] The radius of the cylindrical waveguide core layer 3 of the glass waveguide surface plasmon resonance sensor is 4 μm, and the length is 1000 μm; the refractive index difference between the maximum refractive index of the cylindrical optical waveguide core layer 3 and the refractive index of other parts of the glass substrate 1 is 0.007; the cladding thickness 2 is 2.0 μm; the widths of the two grooves 4 and 7 are 50 μm, the depths are 50 μm, and the lengths are 1000 μm; a 40-nm nanogold film 5 is attached to the first groove 4 by atomic layer deposition coating method, a 40-nm nanosilver film 8 is attached to the second groove 7 by atomic layer deposition coating method, and a 20-nm iron oxide film 9 is attached to the nanosilver film 8 by atomic layer deposition coating method.

[0045] As Figure 7 and Figure 8 As shown, the present invention is simulated by Comsol simulation software. The input light source is a broadband light source with a wavelength range of 500 - 1000 nm. The simulation is carried out in the range of environmental refractive index of 1.30 - 1.37 and temperature of 20 - 80 degrees Celsius to obtain different environmental transmission spectra. The simulation results show that this structure sensor can achieve good sensing effects in the refractive index range of 1.30 - 1.37. The refractive index sensitivity can reach 2030.5 nm / RIU, and the temperature sensitivity can reach 1.48 nm / °C.

[0046] The above specific embodiments are used to explain and illustrate the present invention, rather than to limit the present invention. Any modifications and changes made within the spirit and protection scope of the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A glass waveguide surface plasmon resonance sensor, characterized in that, Comprising: A glass substrate (1) with a cylindrical waveguide core layer (3), a first groove (4) and a second groove (7), the cylindrical waveguide core layer (3) being arranged parallel to the length direction of the glass substrate (1), and the two grooves (4, 7) being respectively located on the symmetric two sides of the cylindrical waveguide core layer (3) at parallel intervals and respectively provided with nano metal films; the cylindrical waveguide core layer (3) receives an optical signal through a connected external optical fiber, so as to measure the change of the external environment by measuring the change of the optical signal.

2. The glass waveguide surface plasmon resonance sensor according to claim 1, wherein: The described cylindrical waveguide core layer (3) is formed at the top center of the glass substrate (1), and there is a gap between the top surface and the top surface of the glass substrate (1) so as to form a cladding layer (2); the two grooves (4, 7) are rectangular grooves, and the lengths of the cylindrical waveguide core layer (3) and the two grooves (4, 7) are equal to the length of the glass substrate (1).

3. The glass waveguide surface plasmon resonance sensor according to claim 1, characterized in that: A layer of nano gold film (5) is plated on one side surface of the first groove (4) close to the cylindrical waveguide core layer (3), and a polydimethylsiloxane PDMS block (6) is arranged in the groove of the first groove (4) on the side of the nano gold film (5).

4. The glass waveguide surface plasmon resonance sensor according to claim 3, characterized in that: The thickness of the described nano gold film (5) is 30 - 80 nm.

5. The glass waveguide surface plasmon resonance sensor according to claim 1, characterized in that: First, the polydimethylsiloxane PDMS material is added and completely filled in the groove of the first groove (4) on the side of the nano gold film (5), and then the polydimethylsiloxane PDMS block (6) is obtained after curing.

6. The glass waveguide surface plasmon resonance sensor according to claim 1, wherein: A layer of nano silver film (8) is plated on one side surface of the second groove (7) close to the cylindrical waveguide core layer (3), and a layer of nano iron oxide film (9) is plated on the nano silver film (8).

7. The glass waveguide surface plasmon resonance sensor according to claim 6, characterized in that: The thickness of the described nano silver film (8) is 30 - 80 nm, and the thickness of the nano iron oxide film (9) is 20 - 50 nm.

8. The glass waveguide surface plasmon resonance sensor according to claim 1, characterized in that: The refractive index of the circular cross-section of the described cylindrical optical waveguide core layer (3) is in a Gaussian distribution, the refractive index of the cylindrical waveguide core layer (3) is greater than that of other parts of the glass substrate (1), and the refractive index difference between the maximum refractive index of the cylindrical optical waveguide core layer (3) and the refractive index of other parts of the glass substrate (1) is 0.005 - 0.

02.

9. The glass waveguide surface plasmon resonance sensor according to claim 1, characterized in that: The radius of the described cylindrical optical waveguide core layer (3) is 3.0 - 5.0 μm, and the length is 100 - 2500 μm.

10. The glass waveguide surface plasmon resonance sensor according to claim 1, characterized in that: The interval distances between the described cylindrical optical waveguide core layer (3) and the two grooves (4, 7) are both 0.1 - 2 μm; the widths of the two grooves (4, 7) are 10 - 100 μm, the depths are 10 - 100 μm, and the lengths are 100 - 2500 μm.

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