Refractive index measuring device and refractive index measuring method

Abstract

The present application relates to a kind of refractive index measuring device and refractive index measurement method.The refractive index measuring device includes measurement light source, refractive index sensor and signal conversion mechanism, measurement light source is used to emit measurement light;The refractive index sensor is set to the light emitting path of the measurement light source, for placing the sample to be measured to be irradiated by the measurement light, and the measurement light is reflected to form reflected signal;The signal conversion mechanism includes substrate, multiple grating units arranged in the substrate and multiple signal conversion units corresponding to multiple grating units, multiple grating units have the structure parameters corresponding to different resonance wavelengths, and multiple grating units are located at the emission side of the refractive index sensor.The present application is used to solve the problems of high detection cost, long detection time and other problems of current refractive index measuring device.At the same time, a kind of refractive index measurement method is also provided.

Description

Technical Field

[0001] This invention relates to the field of micro-nano optical sensing technology, and in particular to a refractive index measuring device and a refractive index measuring method. Background Technology

[0002] Refractive index sensors have numerous applications in the biological and chemical fields and have been extensively studied in recent years; for example, solution concentration and pH value can be measured by changes in refractive index. Surface plasmon polaritons are light waves that propagate along the interface between a medium and a metal, a characteristic that has led to their widespread research in many application areas such as nanophotonics, biosensing, and imaging.

[0003] When a light source shines on the sensing element, plasmons highly concentrated on the metal surface are excited. Surface plasmon resonance sensors are widely used due to their high sensitivity, label-free operation, and rapid response, for example, in the detection of proteins, DNA, and drugs. When the analyte comes into contact with the sensor, the effective refractive index of the sensor changes, thus shifting the resonant wavelength. Surface plasmon resonances are highly sensitive to changes in the refractive index near the sensor surface. These refractive index changes can be determined by measuring changes in the properties of the light coupled to the sensor surface, such as variations in the position, intensity, or phase of the resonant wavelength.

[0004] However, most current refractive index measurement devices require connection to a spectrometer to detect spectral signals, resulting in high detection costs and long detection times. Summary of the Invention

[0005] Therefore, it is necessary to provide a refractive index measuring device and method to address the aforementioned technical problems, thereby solving the issues of high detection cost and long detection time of current refractive index measuring devices.

[0006] A refractive index measuring device for measuring the refractive index of a sample, the refractive index measuring device comprising:

[0007] A measurement light source, used to emit measurement light;

[0008] A refractive index sensor, positioned in the light emission path of the measurement light source, is used to place the sample to be irradiated by the measurement light and to reflect the measurement light to form a reflected signal; and

[0009] The signal conversion mechanism includes a substrate, a plurality of grating units arranged in an array on the substrate, and a plurality of signal conversion units corresponding to and connected to the plurality of grating units. The plurality of grating units have structural parameters corresponding to different resonant wavelengths. The plurality of grating units are located on the emitting side of the refractive index sensor and are used to receive reflected signals from the refractive index sensor and convert them into multiple spectral signals. The signal conversion units are used to convert the multiple spectral signals into multiple electrical signals so as to determine the refractive index of the sample under test by the intensity trend of the multiple electrical signals.

[0010] The refractive index measuring device disclosed in this invention includes a refractive index sensor positioned in the light emission path of a measuring light source. The sample to be measured is placed thereon and illuminated by the measuring light, reflecting the light to form a reflected signal. The reflected signal is converted into a quantifiable spectral signal by a grating unit of a signal conversion mechanism, and then converted into an electrical signal by a signal conversion unit of the same mechanism. The refractive index of the sample to be measured is calculated using multiple electrical signals.

[0011] With this setup, since the refractive indices of the test samples correspond to different resonant wavelengths, and each grating unit has different structural parameters for corresponding to different resonant wavelengths, when the measuring light from the measuring light source illuminates the test sample located on the refractive index sensor, it passes through the refractive index sensor to form a reflected signal. The grating unit of the signal conversion mechanism reflects spectral signals of different intensities, and the signal conversion unit of the signal conversion mechanism converts the spectral signals into electrical signals of different intensities.

[0012] In this way, the intensity of the spectral response can be determined by measuring the intensity of the electrical signal, and then the refractive index of the sample to be tested can be obtained based on the different refractive indices corresponding to different spectral response intensities.

[0013] In one embodiment, the signal conversion mechanism further includes a plurality of waveguides, each of which extends from the grating unit to the signal conversion unit for transmitting the reflected signal from the grating unit to the signal conversion unit.

[0014] In this configuration, each waveguide extends from the grating unit to the signal conversion unit, which transmits the reflected signal to the signal conversion unit and converts the reflected signal into an electrical signal of different intensities, thereby measuring the refractive index of the sample under test.

[0015] In one embodiment, the refractive index measuring device further includes a measuring element connected to the signal conversion mechanism for measuring the intensity variation trend of multiple electrical signals.

[0016] This setup allows for clear measurement of the intensity variation trends of multiple electrical signals, thereby enabling the measurement of the refractive index of the sample under test.

[0017] In one embodiment, the refractive index sensor includes a substrate layer, a dielectric layer, a metal layer disposed between the substrate layer and the dielectric layer, and a metal micro / nano structure disposed on the dielectric layer.

[0018] With this configuration, the dielectric layer is placed on top of the metal layer, and the metal micro / nano structure is fixed on top of the dielectric layer. When the measurement light from the measurement light source shines on the sample to be measured located on the refractive index sensor, the measurement light passes through the metal micro / nano structure, the dielectric layer, and the metal layer. The resonant mode of the refractive index sensor is excited, which has the characteristics of local electromagnetic field energy, and therefore has a strong sensing capability.

[0019] In one embodiment, the thickness of the dielectric layer is 400 nm to 600 nm, and the thickness of the metal layer is 10 nm to 50 nm.

[0020] With this configuration, as the dielectric layer thickness increases continuously within the range of 400nm to 600nm, a significant redshift occurs at the resonance position, and the intensity of the resonance position changes markedly. When the dielectric layer thickness is 600nm, the resonance valley almost disappears, resulting in the highest reflectivity. When the dielectric layer thickness is 450nm, the reflectivity is the lowest. Since a lower reflectivity indicates a stronger absorption capacity of the structure, leading to a better resonance effect and more accurate measurement results, in this embodiment, the dielectric layer is preferably 450nm.

[0021] As the thickness of the metal layer increases, the resonance position remains almost unchanged, and when the metal layer thickness is greater than or equal to 20 nm, the resonance intensity does not change significantly. This indicates that when the metal layer thickness is in the range of 20 nm to 50 nm, the resonance position and resonance intensity are not sensitive to changes in the metal layer thickness. Therefore, in this embodiment, the dielectric layer is preferably 20 nm to 50 nm.

[0022] In one embodiment, the metal micro / nano structure is arranged in a U-shape.

[0023] With this setup, the sample to be tested is placed on the upper surface of the metal micro / nano structure with a U-shaped structure, resulting in good resonance and accurate measurement results.

[0024] The present invention also provides a method for measuring refractive index, comprising the following steps:

[0025] Step S1: Emit measurement light to illuminate the sample to be tested placed on the refractive index sensor;

[0026] Step S2: The measurement light is reflected by the refractive index sensor to form a reflected signal;

[0027] Step S3: The reflected signal is received by multiple grating units arranged in an array through the signal conversion mechanism and converted into multiple spectral signals; and the multiple spectral signals are converted into multiple electrical signals by multiple signal conversion units of the signal conversion mechanism.

[0028] The refractive index measurement method disclosed in this invention involves placing a sample to be tested using a refractive index sensor, generating a reflected signal that is then reflected to a signal conversion mechanism. The grating unit of the signal conversion mechanism converts this reflected signal into quantifiable spectral signals of varying intensities, and the signal conversion unit of the signal conversion mechanism converts these spectral signals into electrical signals of varying intensities, thereby measuring the refractive index of the sample.

[0029] Since different refractive indices of the test sample correspond to different resonant wavelengths, and each grating element has different structural parameters corresponding to different resonant wavelengths, when the measuring light from the measuring light source illuminates the test sample located on the refractive index sensor, the refractive index sensor generates a reflected signal. This signal is then reflected by the grating unit of the signal conversion mechanism, which converts the spectral signal into an electrical signal of different intensities. Thus, the intensity of the spectral response can be determined by measuring the intensity of the electrical signal, and then, based on the different refractive indices corresponding to different spectral response intensities, the refractive index of the test sample can be further obtained.

[0030] In one embodiment, in step S2, measurement light is provided to the refractive index sensor by measuring the light source.

[0031] With this setup, the measurement light source provides measurement light that illuminates the refractive index sensor, resulting in good measurement performance.

[0032] In one embodiment, in step S3, the signal conversion unit is a photodetector.

[0033] This configuration yields good conversion results for multiple signals of this spectrum.

[0034] In one embodiment, in step S3, multiple spectral signals are transmitted to a signal conversion unit through multiple waveguides, and the refractive index of the sample under test is determined by comparing the strength trends of the multiple electrical signals.

[0035] With this setup, the waveguide is used to transmit the reflected signal to the photodetector, which then converts the reflected signal into electrical signals of different intensities, thereby measuring the refractive index of the sample under test. This method offers good measurement results at a low cost. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of a refractive index measuring device according to an embodiment of the present invention;

[0038] Figure 2 This is a three-dimensional structural schematic diagram of a refractive index sensor according to an embodiment of the present invention;

[0039] Figure 3 This is a three-dimensional structural schematic diagram of a signal conversion mechanism according to an embodiment of the present invention;

[0040] Figure 4 The resonant wavelength variation curve is shown for a dielectric layer thickness ranging from 400 nm to 600 nm according to an embodiment of the present invention.

[0041] Figure 5 The resonant wavelength variation curve of a metal layer thickness ranging from 10 nm to 50 nm is shown in an embodiment of the present invention.

[0042] Figure 6 This is a curve of the resonant wavelength as a function of refractive index in an environment with a refractive index range of 1.3 to 1.5, according to an embodiment of the present invention.

[0043] Figure 7 The image shows a sensing sensitivity function obtained by fitting data in an environment with a refractive index range of 1.3 to 1.5, according to an embodiment of the present invention.

[0044] Explanation of icon numbers:

[0045] 1. Measurement light source; 2. Refractive index sensor; 21. Substrate layer; 22. Dielectric layer; 23. Metal layer; 24. Metal micro / nano structure; 3. Signal conversion mechanism; 31. Substrate; 32. Grating unit; 33. Signal conversion unit; 34. Waveguide; 4. Measurement component. Detailed Implementation

[0046] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0051] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0052] Refractive index sensors have numerous applications in the biological and chemical fields and have been extensively studied in recent years. For example, solution concentration and pH value can be measured by changes in refractive index. However, most current refractive index measurement devices require connection to a spectrometer to detect spectral signals, resulting in high detection costs and long detection times.

[0053] Please see Figures 1 to 7 One embodiment of the present invention provides a refractive index measuring device and a refractive index measuring method to solve the problems of high detection cost and long detection time of current refractive index measuring devices.

[0054] Combination Figures 1 to 3 As shown, the present invention provides a refractive index measuring device for measuring the refractive index of a sample to be tested. The refractive index measuring device includes a measuring light source 1, a refractive index sensor 2, and a signal conversion mechanism 3. The measuring light source 1 is used to emit measuring light.

[0055] The refractive index sensor 2 is positioned in the light emission path of the measurement light source 1, and is used to place the sample to be tested so that it is irradiated by the measurement light and reflects the measurement light to form a reflected signal. The signal conversion mechanism 3 includes a substrate 31, a plurality of grating units 32 arranged in an array on the substrate 31, and a plurality of signal conversion units 33 connected to the plurality of grating units 32. The plurality of grating units 32 have structural parameters corresponding to different resonant wavelengths. The plurality of grating units 32 are located on the emission side of the refractive index sensor 2 and are used to receive the reflected signals from the refractive index sensor 2 respectively and convert them into multiple spectral signals. The signal conversion unit 33 is used to convert the multiple spectral signals into multiple electrical signals so as to determine the refractive index of the sample to be tested by the strength trend of the multiple electrical signals.

[0056] It should be noted that, in this embodiment, the incident angle of the measuring light emitted by the measuring light source 1 is preferably 8°.

[0057] The refractive index measuring device disclosed in this invention includes a refractive index sensor 2 positioned in the light emission path of a measuring light source 1. This sensor is used to place the sample to be measured so that it is irradiated by the measuring light, and reflects the light to form a reflected signal. The reflected signal is converted into multiple quantifiable spectral signals by the grating unit 32 of the signal conversion mechanism 3, and then converted into multiple electrical signals by the signal conversion unit 33 of the signal conversion mechanism 3. Finally, the intensity of the electrical signals is measured using a measuring element 4 to characterize the refractive index of the sample, significantly improving measurement efficiency and reasonably controlling measurement costs. In some embodiments, the refractive index measuring device further includes a measuring element 4 connected to the signal conversion mechanism 3, used to measure the intensity variation trend of multiple electrical signals. In this embodiment, the measuring element 4 is a computer or an ammeter, which can clearly measure the intensity variation trend of multiple electrical signals, thereby measuring the refractive index of the sample. Optionally, any device capable of measuring the intensity variation trend of the multiple electrical signals converted by the signal conversion unit 33 is acceptable.

[0058] In this embodiment, an ammeter is used to measure the changing trends of different electrical signal intensities, and the spectral signal variation law is further calculated. Thus, the refractive index of the sample under test can be obtained.

[0059] It should be noted that the structural parameters of the grating unit 32 in this embodiment are specifically parameters such as duty cycle and height, which are used to correspond to different resonant wavelengths.

[0060] With this setup, since the refractive indices of the test samples with different refractive indices correspond to different resonant wavelengths, and each grating unit 32 has different structural parameters corresponding to different resonant wavelengths, it can be deduced that the more grating units 32 there are, the more accurate the fitted curve will be (please refer to [reference needed]). Figure 6 ).

[0061] When the measuring light from the measuring light source 1 illuminates the sample to be measured located on the refractive index sensor 2, it forms a reflected signal through the refractive index sensor 2. The grating unit 32 of the signal conversion mechanism 3 reflects the spectral signals of different intensities, and the signal conversion unit 33 of the signal conversion mechanism 3 converts the spectral signals into electrical signals of different intensities.

[0062] In this way, the response intensity of the spectral signal can be determined by measuring the intensity curves of multiple electrical signals. Then, based on the different refractive indices corresponding to different spectral signal response intensities, the refractive index of the sample under test can be obtained. Furthermore, by fitting the curves of electrical signals with different intensities to… Figure 6 By comparing the curves, the accurate refractive index of the sample under test can be obtained.

[0063] Preferably, the measuring light source 1 is a broadband laser light source. This is because different refractive indices of the test sample correspond to different resonance wavelengths, and the resonance positions of solutions with different refractive indices can be observed through the broadband laser light source.

[0064] Furthermore, no spectrometer needs to be connected during the measurement process, and the refractive index sensor 2 can be replaced. The detection method is convenient, fast, and effective, and the measurement cost can be reasonably controlled and reduced.

[0065] In this embodiment, the substrate 31 is preferably, but not limited to, a silicon photonics chip.

[0066] Specifically, the signal conversion mechanism 3 also includes a plurality of waveguides 34, each waveguide 34 extending from the grating unit 32 to the signal conversion unit 33, for transmitting the reflected signal from the grating unit 32 to the signal conversion unit 33.

[0067] In this configuration, each waveguide 34 extends from the grating unit 32 to the signal conversion unit 33, which transmits the reflected signal to the signal conversion unit 33 and converts the reflected signal into an electrical signal of different intensities, thereby measuring the refractive index of the sample to be tested.

[0068] In this embodiment, the signal conversion unit 33 is a photodetector. The photodetector is used to convert the reflected signal into electrical signals of different intensities, and then measure the refractive index of the sample to be tested.

[0069] In some embodiments, the refractive index sensor 2 includes a substrate layer 21, a dielectric layer 22, a metal layer 23 disposed between the substrate layer 21 and the dielectric layer 22, and a metal micro / nano structure 24 disposed on the dielectric layer 22.

[0070] With this configuration, the dielectric layer 22 is placed on top of the metal layer 23, and the metal micro / nano structure 24 is fixed on top of the dielectric layer 22. When the measurement light from the measurement light source 1 shines on the sample to be measured located on the refractive index sensor 2, the measurement light passes through the metal micro / nano structure 24, the dielectric layer 22, and the metal layer 23, and the resonant mode of the refractive index sensor 2 is excited, which has the characteristics of local electromagnetic field energy, and therefore has a strong sensing capability.

[0071] Furthermore, in some embodiments, both the metal layer 23 and the dielectric layer 22 are cuboid structures.

[0072] In this embodiment, the metal micro / nano structure 24 is arranged in a U-shape. With this arrangement, the sample to be tested is placed on the upper surface of the U-shaped metal micro / nano structure 24, resulting in good resonance and accurate measurement results.

[0073] In some embodiments, the metal micro / nano structure 24 can also adopt an L-shaped structure, which also has excellent resonance effect.

[0074] Specifically, in this embodiment, both the metal micro / nano structure 24 and the metal layer 23 are preferably, but not limited to, the noble metal gold (Au), the dielectric layer 22 has a refractive index of 1.45, and the incident measurement light is along the x-axis (please refer to the specific details). Figure 2 Polarization, relative to the z-axis (please refer to the following for details) Figure 2 When incident at a certain angle, the surface plasmon resonance mode of the refractive index sensor 2 structure is excited.

[0075] Furthermore, in this embodiment, the thickness of the metal micro / nano structure 24 is preferably 30 nm.

[0076] Please see Figure 4 and Figure 5 In some embodiments, the thickness of the dielectric layer 22 is 400 nm to 600 nm, and the thickness of the metal layer 23 is 10 nm to 50 nm.

[0077] With this configuration, as the thickness of the dielectric layer 22 increases continuously within the range of 400nm to 600nm, a significant redshift occurs at the resonance position, and the intensity of the resonance position changes noticeably. When the thickness of the dielectric layer 22 is 600nm, the resonance valley almost disappears, resulting in the highest reflectivity; when the thickness of the dielectric layer 22 is 450nm, the reflectivity is the lowest. Since a lower reflectivity indicates a stronger absorption capacity of the structure, the resonance effect is better, leading to more accurate measurement results. Therefore, in this embodiment, the thickness of the dielectric layer 22 is preferably 450nm.

[0078] As the thickness of the metal layer 23 increases, the resonant position remains almost unchanged, and when the thickness of the metal layer 23 is greater than or equal to 20 nm, the resonant intensity does not change significantly. This indicates that when the thickness of the metal layer 23 is in the range of 20 nm to 50 nm, the resonant position and resonant intensity are not sensitive to changes in the thickness of the metal layer 23. Therefore, in this embodiment, the thickness of the dielectric layer 22 is preferably 20 nm to 50 nm.

[0079] Please refer to the following for details. Figure 6 and Figure 7 When the refractive index of the environment is in the range of 1.3 to 1.5, as the refractive index of the environment gradually increases, the resonant position of the refractive index sensor 2 exhibits a redshift phenomenon (the redshift phenomenon refers to the resonant position moving towards the longer wavelength direction). By observing the relationship between the change in refractive index and the resonant intensity, the sensitivity of the refractive index sensor 2 can be determined.

[0080] Furthermore, when the ambient refractive index is in the range of 1.3 to 1.5, the reflectivity at the resonance position remains low, which indicates that the refractive index sensor 2 has good performance and high measurement accuracy.

[0081] The linear relationship between refractive index sensitivity and resonant wavelength (λ) and refractive index (n) can be expressed as: sensitivity = (λ - 825) / n. From Figure 7 It can be seen that when the refractive index of the environment varies in the range of 1.3 to 1.5, the refractive index sensitivity is 688.6 nm / RIU, and the sensitivity remains unchanged and is well maintained.

[0082] The present invention also provides a method for measuring refractive index, comprising the following steps:

[0083] Step S1: Emit measurement light to illuminate the sample to be tested placed on the refractive index sensor 2;

[0084] Step S2: The measuring light is reflected by the refractive index sensor 2 to form a reflected signal;

[0085] Step S3: The reflected signal is received by the array of multiple grating units 32 of the signal conversion mechanism 3 and converted into multiple spectral signals; and the multiple spectral signals are converted into electrical signals by the multiple signal conversion units 33 of the signal conversion mechanism 3.

[0086] Among them, multiple grating units 32 have structural parameters corresponding to different resonant wavelengths.

[0087] The refractive index measurement method disclosed in this invention involves placing a sample to be tested on a refractive index sensor 2, generating a reflected signal that is reflected to a signal conversion mechanism 3. The grating unit 32 of the signal conversion mechanism 3 converts this reflected signal into quantifiable spectral signals of different intensities, and the signal conversion unit 33 of the signal conversion mechanism 3 converts these spectral signals into electrical signals of different intensities, thereby measuring the refractive index of the sample to be tested.

[0088] Since the refractive indices of the test samples with different refractive indices correspond to different resonance wavelengths, and each grating unit 32 has different structural parameters for corresponding to different resonance wavelengths.

[0089] When the measuring light from the measuring light source 1 illuminates the sample to be tested located on the refractive index sensor 2, a reflected signal is generated by the refractive index sensor 2. This reflected signal is then transmitted through the grating unit 32 of the signal conversion mechanism 3, reflecting spectral signals of different intensities. The signal conversion unit 33 of the signal conversion mechanism 3 then converts this spectral signal into electrical signals of different intensities. Thus, the intensity of the spectral response can be determined by measuring the intensity of the electrical signal. Based on the different refractive indices corresponding to different spectral response intensities, the refractive index of the sample to be tested can be further obtained.

[0090] Specifically, in step S2, measurement light is provided to the refractive index sensor 2 by the measurement light source 1. This configuration ensures that the measurement light source 1 provides measurement light to the refractive index sensor 2, resulting in good measurement performance.

[0091] Furthermore, in step S3, the signal conversion unit is a photodetector. This configuration provides good conversion performance for multiple spectral signals.

[0092] Furthermore, in step S3, multiple spectral signals are transmitted to the signal conversion unit 33 through multiple waveguides 34, and the refractive index of the sample under test is determined by comparing the strength trends of the multiple electrical signals.

[0093] With this configuration, waveguide 34 is used to transmit the reflected signal to the photodetector, and the photodetector converts the reflected signal into electrical signals of different intensities, thereby measuring the refractive index of the sample under test. This method offers good measurement results and low cost.

[0094] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A refractive index measuring device for measuring the refractive index of a sample, characterized in that, The refractive index measuring device comprises: a measurement light source for emitting measurement light; a refractive index sensor comprising a substrate layer, a medium layer, a metal layer arranged between the substrate layer and the medium layer, and a metal micro-nano structure arranged on the medium layer, the refractive index sensor being arranged in the light emitting path of the measurement light source, for placing the sample to be measured so as to be penetrated by the measurement light through the metal micro-nano structure, the medium layer and the metal layer, the resonance mode of the refractive index sensor being excited, and the measurement light being reflected to form a reflected signal; and a signal conversion mechanism comprising a substrate, a plurality of grating units arranged in an array on the substrate, and a plurality of signal conversion units corresponding to the plurality of grating units, the plurality of grating units having structural parameters corresponding to different resonance wavelengths, the plurality of grating units being located on the emission side of the refractive index sensor for respectively receiving the reflected signal from the refractive index sensor to convert into a plurality of spectral signals, and the signal conversion units being used for converting the plurality of spectral signals into a plurality of electrical signals to determine the refractive index of the sample to be measured by the strength trend of the plurality of electrical signals.

2. The refractive index measuring apparatus according to claim 1, characterized by The signal conversion mechanism further comprises a plurality of waveguides, each of which extends from the grating unit to the signal conversion unit, for transmitting the reflected signal from the grating unit to the signal conversion unit.

3. The refractive index measuring apparatus according to claim 1, characterized by The refractive index measuring device further comprises a measurement unit connected with the signal conversion mechanism for measuring the intensity change trend of the plurality of electrical signals.

4. The refractive index measuring apparatus according to any one of claims 1 to 3, characterized by The thickness of the medium layer is 400-600 nm, and the thickness of the metal layer is 10-50 nm.

5. The refractive index measuring apparatus according to any one of claims 1 to 3, characterized by The metal micro-nano structure is arranged in a U-shaped structure.

6. A method of measuring refractive index, characterized by, The method comprises the following steps: Step S1: emitting measurement light to irradiate the sample to be measured placed on the refractive index sensor, wherein the refractive index sensor comprises a substrate layer, a medium layer, a metal layer arranged between the substrate layer and the medium layer, and a metal micro-nano structure arranged on the medium layer; Step S2: the measurement light penetrates through the metal micro-nano structure, the medium layer and the metal layer, the resonance mode of the refractive index sensor is excited, and the measurement light is reflected through the refractive index sensor to form a reflected signal; Step S3: receiving the reflected signal through the plurality of grating units arranged in an array in the signal conversion mechanism to convert into a plurality of spectral signals, and converting the plurality of spectral signals into a plurality of electrical signals through the plurality of signal conversion units in the signal conversion mechanism; wherein the plurality of grating units have structural parameters corresponding to different resonance wavelengths.

7. The refractive index measurement method according to claim 6, wherein In step S2, the measurement light source is used to provide the measurement light irradiated to the refractive index sensor.

8. The measurement method according to claim 6, characterized by, In step S3, the signal conversion unit is a photodetector.

9. The refractive index measurement method according to any one of claims 6 to 8, characterized by, In step S3, the plurality of spectral signals are transmitted to the signal conversion unit through the plurality of waveguides, and the refractive index of the sample to be measured is determined by comparing the strength trend of the plurality of electrical signals.

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