Method and device for measuring refractive index of material based on optical waveguide

Abstract

The invention discloses a material refractive index measuring method and device based on an optical waveguide. The material refractive index measuring device comprises a light source, the optical waveguide, a first right-angle triangular prism and a rotating mechanism, the material refractive index measurement method comprises the following steps: arranging an optical waveguide and a measurement object layer on a right-angle surface of a first right-angle triangular prism; controlling the light source to output a measurement light beam, wherein the measurement light beam enters the optical waveguide or the measurement object at a preset incidence angle; the rotating mechanism is controlled to drive the first right-angle triangular prism, the optical waveguide and the measurement object to rotate synchronously so as to change the incident angle of the measurement light beam incident to the optical waveguide or the measurement object until the light beam is just refracted into the measurement object from the optical waveguide from total reflection transmission in the optical waveguide; and determining the refractive index of the measured object according to the refraction law. According to the scheme, measurement of the refractive index of the light-transmitting material with the refractive index smaller than that of the optical waveguide is achieved, the device is simple in structure and wide in measurement range, and the requirement for refractive index detection of various light-transmitting materials in industrial production is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material refractive index measurement, and in particular to a material refractive index measurement method and device based on an optical waveguide. BACKGROUND

[0002] In the fields of optical device manufacturing, display technology, etc., the refractive index of a material is a key parameter affecting the optical performance of a product, and the measurement of the refractive index of a material is crucial. Commonly used methods for measuring the refractive index of a material include Abbe refractometer, minimum deviation angle method or interference method, and ellipsometry.

[0003] In the prior art, Abbe refractometer can measure the refractive index of a solid or liquid, but it is greatly affected by temperature and has a small measurement range; the minimum deviation angle method or interference method requires a complex optical system to be built, and the device involved is complex; the ellipsometry can measure the refractive index and thickness of a thin film, but the ellipsometer device is costly and is not conducive to widespread promotion and use. Therefore, there is an urgent need for a material refractive index measurement method with simple device structure and low cost. SUMMARY

[0004] The present application provides a material refractive index measurement method and device based on an optical waveguide, which realizes the measurement of the refractive index of a light-transmitting material with a refractive index less than that of the optical waveguide, has simple device structure and a wide measurement range, is low in cost, and solves the actual demand for the detection of the refractive index of various light-transmitting materials in industrial production.

[0005] In a first aspect, the present application provides a material refractive index measurement method based on an optical waveguide, which is executed by a material refractive index measurement device based on an optical waveguide, the material refractive index measurement device comprising a light source, an optical waveguide, a first right-angle triangular prism, and a rotating mechanism.

[0006] The material refractive index measurement method comprises:

[0007] The optical waveguide and the measurement object are stacked on one right-angle face of the first right-angle triangular prism.

[0008] The light source is controlled to output a measurement light beam, and the measurement light beam is incident on the optical waveguide or the measurement object at a preset incident angle.

[0009] The rotating mechanism is controlled to drive the first right-angle triangular prism, the optical waveguide, and the measurement object to rotate synchronously, so as to change the incident angle of the measurement light beam incident on the optical waveguide or the measurement object, until the light beam is transmitted by total reflection in the optical waveguide and becomes just refracted from the optical waveguide into the measurement object.

[0010] According to the law of refraction, the refractive index of the measurement object is determined.

[0011] Optionally, the optical waveguide includes a transmission grating, and the optical waveguide and the measurement object are stacked on a right-angled face of the first right-angled triangular prism, including:

[0012] The object to be measured is positioned between the optical waveguide and the first right-angled triangular prism;

[0013] The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including:

[0014] The measurement beam is incident on the transmission grating at an incident angle of 0°, and the first-order diffracted light and the negative first-order diffracted light of the transmission grating are totally reflected in the optical waveguide and exit from the edge of the waveguide.

[0015] Optionally, controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object changes the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including:

[0016] The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the measurement object to rotate synchronously, increasing the incident angle of the light incident on the transmission grating. This causes the first-order diffracted light or the negative first-order diffracted light to change from the initial state of total internal reflection transmission in the optical waveguide to being refracted from the optical waveguide into the measurement object, and then exiting through the first right-angled triangular prism. The rotation angle θ1 of the rotating mechanism is recorded.

[0017] Optionally, determining the refractive index of the object being measured according to the law of refraction includes:

[0018] The refractive index of the measured object is calculated using the following formula:

[0019] ;

[0020] Wherein, n0 represents the air refractive index, m represents the diffraction order, λ represents the wavelength of the measurement beam, d1 represents the period of the transmission grating, n represents the refractive index of the object being measured, and θ2 represents the angle of refraction of the diffracted light incident on the object being measured.

[0021] Optionally, the optical waveguide includes a reflective grating, and the material refractive index measuring device further includes a second right-angled triangular prism, wherein the optical waveguide and the object to be measured are stacked on a right-angled face of the first right-angled triangular prism, comprising:

[0022] The object to be measured is positioned on the side of the optical waveguide away from the first right-angled triangular prism, and the second right-angled triangular prism is positioned on the side of the object to be measured away from the optical waveguide.

[0023] The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including:

[0024] The measurement beam is incident on the object being measured at an angle of 0°. After being transmitted through the object, it is incident on the reflective grating. The first-order diffracted light and the negative first-order diffracted light of the reflective grating are totally reflected in the optical waveguide and exit from the edge of the waveguide.

[0025] Optionally, controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object changes the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including:

[0026] The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, the measurement object, and the second right-angled triangular prism to rotate synchronously, increasing the incident angle of the light incident on the measurement object. This causes the first-order diffracted light or the negative first-order diffracted light to change from the initial state of total internal reflection transmission in the optical waveguide to being refracted from the optical waveguide into the measurement object, and then exiting through the second right-angled triangular prism. The rotation angle θ3 of the rotating mechanism is recorded.

[0027] Optionally, determining the refractive index of the object being measured according to the law of refraction includes:

[0028] The refractive index of the measured object is calculated using the following grating formula:

[0029] ;

[0030] Where n0 represents the air refractive index, m represents the diffraction order, λ represents the wavelength of the measurement beam, d2 represents the period of the reflection grating, n represents the refractive index of the object being measured, and θ2 represents the angle of refraction of the diffracted light incident on the object being measured.

[0031] Optionally, the optical waveguide is provided with a third right-angled triangular prism, and the optical waveguide and the measurement object are stacked on a right-angled face of the first right-angled triangular prism, including:

[0032] The object to be measured is placed between the optical waveguide and the first right-angled triangular prism, and a right-angled face of the third right-angled triangular prism is located on the side of the optical waveguide away from the object to be measured.

[0033] The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including:

[0034] The measuring beam is incident on the inclined surface of the third right-angled triangular prism at a first incident angle θ0. After being refracted by the third right-angled triangular prism, it is incident on the optical waveguide, undergoes total internal reflection in the optical waveguide, and exits from the edge of the waveguide.

[0035] Wherein, the first incident angle θ0 is the acute apex angle of the third right-angled triangular prism on the side closest to the object being measured.

[0036] Optionally, controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object changes the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including:

[0037] The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, the measurement object, and the third right-angled triangular prism to rotate synchronously, reducing the incident angle of the light beam incident on the third right-angled triangular prism. This causes the measurement beam to change from its initial state of total internal reflection transmission within the optical waveguide to being refracted from the optical waveguide into the measurement object, and then exiting through the first right-angled triangular prism. The rotation angle θ3 of the rotating mechanism is recorded.

[0038] Optionally, determining the refractive index of the object being measured according to the law of refraction includes:

[0039] The refractive index of the measured object is calculated using the following formula:

[0040] ;

[0041] Wherein, n0 represents the refractive index of air, n1 represents the refractive index of the third right-angled triangular prism, and n represents the refractive index of the object being measured.

[0042] Optionally, the optical waveguide is provided with an inclined reflective surface, and the acute angle between the inclined reflective surface and the surface of the optical waveguide facing away from the measurement object is θ4; the optical waveguide and the measurement object are stacked on a right-angled face of the first right-angled triangular prism, including:

[0043] The object to be measured is positioned between the optical waveguide and the first right-angled triangular prism;

[0044] The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including:

[0045] The measurement beam is incident at a 0° angle onto the surface of the optical waveguide near the first right-angled triangular prism, and is reflected by the tilted reflective surface back to the surface of the optical waveguide near the first right-angled triangular prism. It undergoes total internal reflection within the optical waveguide and exits from the edge of the waveguide.

[0046] Optionally, controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object changes the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including:

[0047] The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the measurement object to rotate synchronously, increasing the incident angle of the light beam into the optical waveguide. This causes the measurement beam to change from its initial state of total internal reflection transmission within the optical waveguide to being refracted into the measurement object from the optical waveguide, and then exiting through the first right-angled triangular prism. The rotation angle θ5 of the rotating mechanism is recorded.

[0048] Optionally, determining the refractive index of the object being measured according to the law of refraction includes:

[0049] When the measurement beam is reflected by the inclined reflective surface to the surface of the optical waveguide on the side away from the first right-angled triangular prism, the refractive index of the measured object is calculated according to the following formula:

[0050] ;

[0051] When the measurement beam is reflected by the inclined reflective surface to the surface of the optical waveguide near the first right-angled triangular prism, the refractive index of the measured object is calculated according to the following formula:

[0052] ;

[0053] Wherein, n0 represents the air refractive index, n2 represents the refractive index of the optical waveguide, and n represents the refractive index of the object being measured.

[0054] Optionally, the object being measured can be a gas, liquid, or solid.

[0055] Optionally, the object being measured is a solid, and a refractive index matching liquid is provided between the optical waveguide and the object being measured, or between the optical waveguide and the first right-angled triangular prism, or between the object being measured and the first right-angled triangular prism.

[0056] Optionally, the refractive index of the refractive index matching liquid satisfies: the refractive index of the first right-angled triangular prism ±0.05 < the refractive index of the refractive index matching liquid < the refractive index of the optical waveguide.

[0057] Optionally, the thickness of the object being measured is in the range of 1 μm to 1 mm.

[0058] Secondly, the present invention also provides a material refractive index measuring device based on an optical waveguide for performing the material refractive index measuring method described above. The material refractive index measuring device includes a light source, an optical waveguide, a first right-angled triangular prism, and a rotating mechanism. The optical waveguide and the object to be measured are stacked on a right-angled surface of the first right-angled triangular prism. The rotating mechanism drives the first right-angled triangular prism, the optical waveguide, and the object to be measured to rotate synchronously.

[0059] Optionally, the material refractive index measurement device based on the optical waveguide further includes a polarizer and a half-wave plate disposed between the light source and the first right-angled triangular prism.

[0060] The technical solution of this invention controls the output of a measurement beam from a light source. The measurement beam is incident on an optical waveguide or the object being measured at a preset incident angle. A rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, thereby changing the incident angle of the measurement beam on the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the object being measured from the optical waveguide. According to the law of refraction, the refractive index of the object being measured is determined, realizing the measurement of the refractive index of light-transmitting materials with a refractive index less than that of the optical waveguide. The device has a simple structure, a wide measurement range, and low cost, solving the practical needs of detecting the refractive index of various light-transmitting materials in industrial production. Attached Figure Description

[0061] Figure 1 This is a schematic flowchart of a material refractive index measurement method based on optical waveguides provided in an embodiment of the present invention;

[0062] Figure 2 This is a schematic diagram of a material refractive index measurement device based on an optical waveguide provided in an embodiment of the present invention;

[0063] Figure 3 This is a schematic flowchart of another material refractive index measurement method based on optical waveguide provided by an embodiment of the present invention;

[0064] Figure 4 This is a schematic diagram of the light incident mode of a material refractive index measurement method based on optical waveguides provided in an embodiment of the present invention;

[0065] Figure 5 This is a schematic diagram of the light incident mode of another material refractive index measurement method based on optical waveguide provided in an embodiment of the present invention;

[0066] Figure 6This is a schematic flowchart of another method for measuring the refractive index of materials based on optical waveguides provided in an embodiment of the present invention;

[0067] Figure 7 This is a schematic diagram of the light incident mode of another material refractive index measurement method based on optical waveguide provided in an embodiment of the present invention;

[0068] Figure 8 This is a schematic flowchart of another method for measuring the refractive index of materials based on optical waveguides provided in an embodiment of the present invention;

[0069] Figure 9 This is a schematic diagram of the light incident mode of another material refractive index measurement method based on optical waveguide provided in an embodiment of the present invention;

[0070] Figure 10 This is a schematic flowchart of another method for measuring the refractive index of materials based on optical waveguides provided in an embodiment of the present invention;

[0071] Figure 11 This is a schematic diagram of the light incident mode of another material refractive index measurement method based on optical waveguide provided in an embodiment of the present invention;

[0072] Figure 12 This is a schematic diagram of the measurement beam provided in an embodiment of the present invention being reflected by an inclined reflecting surface to the surface of the optical waveguide on the side away from the first right-angled triangular prism;

[0073] Figure 13 This is a schematic diagram of the measurement beam provided in an embodiment of the present invention being reflected by an inclined reflecting surface to the surface of the optical waveguide near the first right-angled triangular prism;

[0074] Figure 14 This is a schematic diagram of the contact position when the object being measured is a gas, provided by an embodiment of the present invention;

[0075] Figure 15 This is a schematic diagram of the contact position when the measurement object is a gas, as provided in another embodiment of the present invention;

[0076] Figure 16 This is a schematic diagram of the contact position when the measurement object is a solid, provided by an embodiment of the present invention;

[0077] Figure 17 This is a schematic diagram of another material refractive index measurement device based on optical waveguide provided in an embodiment of the present invention. Detailed Implementation

[0078] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0079] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0080] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0081] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0082] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0083] Figure 1 This is a schematic flowchart of a material refractive index measurement method based on optical waveguides provided by an embodiment of the present invention. Figure 2 This is a schematic diagram of a material refractive index measurement device based on an optical waveguide, provided in an embodiment of the present invention. The material refractive index measurement method based on an optical waveguide can be executed by this device. Figure 2As shown, the material refractive index measuring device includes a light source 10, an optical waveguide 20, a first right-angled triangular prism 30, and a rotating mechanism 40. The light source 10 can be a laser. The laser emitted by the laser is incident on the optical waveguide 20. The optical waveguide 20 and the object to be measured 50 are stacked on a right-angled face of the first right-angled triangular prism 30. The size of the first right-angled triangular prism 30 can be 300mm × 300mm × 300mm. The first right-angled triangular prism 30 is fixed to the rotating mechanism 40. Initially, one right-angled face of the first right-angled triangular prism 30 is perpendicular to the laser propagation direction. The rotating mechanism 40 can drive the first right-angled triangular prism 30, the optical waveguide 20, and the object to be measured 50 to rotate synchronously. Initially, the laser is incident perpendicularly on the optical waveguide 20. By controlling the rotation of the rotating mechanism 40, the incident angle of the incident light and its propagation direction within the optical waveguide 20 and the first right-angled triangular prism 30 are changed, thereby enabling the calculation of the refractive index of the object to be measured 50.

[0084] like Figure 1 As shown, the material refractive index measurement method based on optical waveguides in this embodiment includes:

[0085] S110. The optical waveguide and the object to be measured are stacked on a right-angled face of the first right-angled triangular prism.

[0086] Specifically, an optical waveguide is a structure that guides the directional propagation of a measurement beam within it; the measurement object refers to a light-transmitting material whose refractive index needs to be measured, such as a gas, liquid, or solid. By stacking the optical waveguide and the measurement object on a right-angled face of a first right-angled triangular prism, the measurement beam can be stably propagated into the optical waveguide or transmitted through the optical waveguide to the measurement object, which is beneficial for subsequent measurements of the incident angle, refraction angle, and calculation of the refractive index.

[0087] S120: Control the light source to output a measurement beam, and the measurement beam is incident on the optical waveguide or the object being measured at a preset incident angle.

[0088] Specifically, the measurement beam is incident on the optical waveguide or the object being measured at a preset incident angle, which can be 0° or other angles. For example... Figure 1 In the embodiment shown, the measurement beam is incident perpendicularly (0° incident angle) onto the optical waveguide, and some of the light will be totally reflected within the optical waveguide. In other embodiments, other incident angles can also be designed according to actual conditions.

[0089] S130, control the rotation mechanism to drive the first right-angled triangular prism, optical waveguide and the object to be measured to rotate synchronously, so as to change the incident angle of the measurement beam to the optical waveguide or the object to be measured, until the beam changes from total internal reflection transmission in the optical waveguide to just refracted into the object to be measured.

[0090] Specifically, the control rotation mechanism drives the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, changing the propagation path of the light. As the rotation mechanism rotates, the incident angle of the measurement beam onto the optical waveguide or the object being measured gradually increases until the measurement beam just barely avoids total internal reflection within the optical waveguide and instead enters the object being measured.

[0091] S140. Determine the refractive index of the object being measured according to the law of refraction.

[0092] Specifically, since different objects have different refractive indices, the critical angle at which the measuring beam undergoes total internal reflection on the surface of the object also varies. When the beam changes from total internal reflection transmission within the optical waveguide to refraction into the object, the rotation angle of the rotating mechanism is recorded, and the refractive index of the object can be determined according to the law of refraction.

[0093] This embodiment controls the output of a measurement beam from a light source. The measurement beam is incident on the optical waveguide or the object being measured at a preset incident angle. The rotating mechanism drives the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, thereby changing the incident angle of the measurement beam on the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the object being measured from the optical waveguide. According to the law of refraction, the refractive index of the object being measured is determined, realizing the measurement of the refractive index of light-transmitting materials with a refractive index less than that of the optical waveguide. The device has a simple structure, a wide measurement range, and low cost, solving the practical needs of detecting the refractive index of various light-transmitting materials in industrial production.

[0094] Figure 3 This is a schematic flowchart of another material refractive index measurement method based on optical waveguides provided by an embodiment of the present invention. Based on the above embodiments, this embodiment provides a detailed description of the position of the measurement object and the incident angle of the measurement beam. The optical waveguide includes a transmission grating, such as... Figure 3 As shown, the method for measuring the refractive index of this material includes:

[0095] S210. Position the object to be measured between the optical waveguide and the first right-angled triangular prism.

[0096] Specifically, the object to be measured 50 is positioned between the optical waveguide 20 and the first right-angled triangular prism 30. This can be achieved by attaching one side of the object to the optical waveguide 20 and the other side of the object to the first right-angled triangular prism 30. The propagation path of the measurement beam can be incident on the optical waveguide 20, undergoing total internal reflection within the waveguide 20 before exiting at the edge; or the measurement beam can first be incident on the optical waveguide 20, refracted through the waveguide 20 to the object to be measured, and then exiting through the first right-angled triangular prism 30. The following embodiments use attachment as an example and are not intended to limit the scope of the invention. By positioning the object to be measured between the optical waveguide and the first right-angled triangular prism, it is possible to effectively observe whether total internal reflection or refraction occurs at the interface between the optical waveguide and the object to be measured, which is beneficial for calculating the refractive index.

[0097] S220: Control the light source to output the measurement beam. The measurement beam is incident on the transmission grating at an incident angle of 0°. The first-order diffracted light and the negative first-order diffracted light of the transmission grating are totally reflected in the optical waveguide and exit from the edge of the waveguide.

[0098] Specifically, the measurement beam is incident on the transmission grating at a 0° incident angle. In this case, the measurement beam will not experience any additional deviation due to the shift in the incident angle. Figure 4 This is a schematic diagram of the light incident mode in a material refractive index measurement method based on optical waveguides provided in an embodiment of the present invention. (Refer to...) Figure 4 The transmission grating divides the incident light into 0th order transmitted light, first order diffracted light, and negative first order diffracted light. The 0th order transmitted light is directly transmitted through the optical waveguide and the object being measured, and is incident on the first right-angled triangular prism. The first order diffracted light and the negative first order diffracted light are totally reflected in the optical waveguide and exit from the edge of the waveguide.

[0099] S230: The control rotation mechanism drives the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, so as to change the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission in the optical waveguide to just refracting into the object being measured from the optical waveguide.

[0100] In an optional embodiment, Figure 5 This is a schematic diagram of the light incident mode of another material refractive index measurement method based on optical waveguides provided in an embodiment of the present invention. (Refer to...) Figure 5 , Figure 5A schematic diagram of the optical path after the rotating mechanism rotates is shown. The rotating mechanism drives the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, thereby changing the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the object being measured from the optical waveguide. This includes: controlling the rotating mechanism to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, increasing the incident angle onto the transmission grating, so that the first-order diffracted light or the negative first-order diffracted light changes from the initial state of total internal reflection transmission within the optical waveguide to being refracted into the object being measured from the optical waveguide, and then exiting through the first right-angled triangular prism, and recording the rotation angle θ1 of the rotating mechanism at this time.

[0101] Specifically, Figure 5 Taking the modulation of negative first-order diffracted light as an example, by increasing the incident angle of the light incident on the transmission grating, the angle of the diffracted light at the interface between the optical waveguide and the object being measured is changed: the larger the incident angle of the light incident on the transmission grating, the smaller the incident angle of the diffracted light incident on the interface between the optical waveguide and the object being measured. When the incident angle decreases until the total internal reflection condition is no longer met, the diffracted light will be refracted, refracted from the optical waveguide into the object being measured, and then exit through the first right-angled triangular prism. At this time, the diffracted light at the edge of the optical waveguide disappears, and the diffracted light exits through the first right-angled triangular prism, which is the critical state from total internal reflection to refraction. The rotation angle θ1 of the rotating mechanism at this time is recorded for subsequent calculation of the refractive index of the object being measured.

[0102] S240. Determine the refractive index of the object being measured according to the law of refraction.

[0103] In an optional embodiment, determining the refractive index of the object being measured, according to the law of refraction, includes: calculating the refractive index of the object being measured according to the following formula:

[0104] ;

[0105] Where n0 represents the air refractive index, m represents the diffraction order, λ represents the wavelength of the measurement beam, d1 represents the period of the transmission grating, n represents the refractive index of the object being measured, and θ2 represents the angle of refraction of the diffracted light incident on the object being measured.

[0106] Specifically, based on the grating formula, the refractive index of the object being measured can be calculated. Since the thickness of the object is extremely small (less than 1 mm), the angle of refraction θ2 of the diffracted light incident on the object can be considered approximately -90°. For example, when the wavelength of the measurement beam λ = 532 nm, the period of the transmission grating d1 = 305 nm, the angle of refraction θ2 of the negative first-order diffracted light incident on the object is -90°, the air refractive index n0 = 1, and the diffraction order m = -1, the refractive index of the object being measured is calculated as follows:

[0107] .

[0108] In this embodiment, the object to be measured is placed between the optical waveguide and the first right-angled triangular prism. First, the light source is controlled to output a measurement beam, which is incident on the transmission grating at a 0° incident angle. Then, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the object to be measured to rotate synchronously, increasing the incident angle on the transmission grating. This causes the first-order diffracted light or the negative first-order diffracted light to change from the initial state of total internal reflection propagation in the optical waveguide to refraction into the object to be measured from the optical waveguide. By measuring the rotation angle of the rotating mechanism and combining it with the grating formula, the refractive index of the object to be measured can be calculated, thus realizing a fast and accurate measurement of the material's refractive index.

[0109] Figure 6 This is a flowchart illustrating another method for measuring the refractive index of materials based on optical waveguides provided in this embodiment of the invention. This embodiment is similar in principle to the aforementioned embodiments, but employs a different structure. The optical waveguide includes a reflective grating, and the material refractive index measuring device further includes a second right-angled triangular prism, such as... Figure 6 As shown, the method for measuring the refractive index of this material includes:

[0110] S310. The object to be measured is placed on the side of the optical waveguide away from the first right-angled triangular prism, and the second right-angled triangular prism is placed on the side of the object to be measured away from the optical waveguide.

[0111] Specifically, Figure 7 This is a schematic diagram of the light incident mode of another material refractive index measurement method based on optical waveguides provided in an embodiment of the present invention. (Refer to...) Figure 7 The material refractive index measuring device also includes a second right-angled triangular prism 60. The object to be measured 50 is positioned on the side of the optical waveguide 20 away from the first right-angled triangular prism 30, i.e., one side of the optical waveguide 20 is attached to the object to be measured 50, and the other side of the optical waveguide 20 is attached to the first right-angled triangular prism 30. The propagation path of the measurement beam can be: the measurement beam is incident on the object to be measured 50, refracted by the object to be measured 50 to the optical waveguide 20, and then totally internally reflected within the optical waveguide 20 before exiting at the edge; or the measurement beam is first incident on the object to be measured 50, refracted by the object to be measured 50 to the optical waveguide 20, refracted back by the optical waveguide 20 to the object to be measured 50, and then exiting through the second right-angled triangular prism 60. By using a second right-angled triangular prism 60 with a higher refractive index, such as glass with a refractive index of 1.71, 1.85, or 1.96, the refractive index range of the measured material is wider, which allows for effective observation of whether total internal reflection or refraction occurs at the interface between the optical waveguide and the object to be measured, thus facilitating the calculation of the refractive index.

[0112] S320: Control the light source to output a measurement beam. The measurement beam is incident on the object being measured at an incident angle of 0°. After being transmitted through the object, it is incident on the reflection grating. The first-order diffracted light and the negative first-order diffracted light of the reflection grating are totally reflected in the optical waveguide and exit from the edge of the waveguide.

[0113] Specifically, the measurement beam is incident on the object at an angle of 0°. After being transmitted through the object, it is incident on the reflection grating. The reflection grating divides the incident light into 0th order transmitted light, first order diffracted light, and negative first order diffracted light. The 0th order transmitted light passes through the reflection grating and is incident on the first right-angled triangular prism. The first order diffracted light and the negative first order diffracted light are totally reflected in the optical waveguide and exit from the edge of the waveguide.

[0114] S330, the control rotation mechanism drives the first right-angled triangular prism, the optical waveguide and the object being measured to rotate synchronously, so as to change the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission in the optical waveguide to just refracted into the object being measured from the optical waveguide.

[0115] In an optional embodiment, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, thereby changing the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the object being measured from the optical waveguide. This includes: controlling the rotating mechanism to drive the first right-angled triangular prism, the optical waveguide, the object being measured, and the second right-angled triangular prism to rotate synchronously, increasing the incident angle onto the object being measured, so that the first-order diffracted light or the negative first-order diffracted light changes from the initial state of total internal reflection transmission within the optical waveguide to being refracted into the object being measured from the optical waveguide, and then exiting through the second right-angled triangular prism, and recording the rotation angle θ3 of the rotating mechanism.

[0116] Specifically, by increasing the incident angle of the light incident on the reflection grating, the angle of the diffracted light at the interface between the optical waveguide and the object being measured is changed: the larger the incident angle of the light incident on the reflection grating, the smaller the incident angle of the diffracted light at the interface between the optical waveguide and the object being measured. When the incident angle decreases until the total internal reflection condition is no longer met, the diffracted light will be refracted, refracted from the optical waveguide into the object being measured, and then exit through the second right-angled triangular prism. At this point, the diffracted light at the edge of the optical waveguide disappears, and the diffracted light exits through the second right-angled triangular prism, which is the critical state from total internal reflection to refraction. The rotation angle θ3 of the rotating mechanism at this point is recorded for subsequent calculation of the refractive index of the object being measured.

[0117] S340. Determine the refractive index of the object being measured according to the law of refraction.

[0118] In an optional embodiment, determining the refractive index of the object being measured according to the law of refraction includes: calculating the refractive index of the object being measured according to the following grating formula:

[0119] ;

[0120] Where n0 represents the refractive index of air, m represents the diffraction order, λ represents the wavelength of the measurement beam, d2 represents the period of the reflection grating, n represents the refractive index of the object being measured, and θ2 represents the angle of refraction of the diffracted light incident on the object. The refractive index of the object can be calculated using the grating formula.

[0121] In this embodiment, the object to be measured is positioned on the side of the optical waveguide away from the first right-angled triangular prism, and the second right-angled triangular prism is positioned on the side of the object to be measured away from the optical waveguide. First, the light source is controlled to output a measurement beam, which is incident on the object at a 0° angle of incidence. After being transmitted through the object, the beam is incident on the reflection grating. Then, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, the object to be measured, and the second right-angled triangular prism to rotate synchronously, increasing the angle of incidence on the object. This causes the first-order diffracted light or the negative first-order diffracted light to change from its initial state of total internal reflection transmission within the optical waveguide to being refracted from the optical waveguide into the object to be emitted through the second right-angled triangular prism. By measuring the rotation angle of the rotating mechanism and combining it with the grating formula, the refractive index of the object to be measured can be calculated. By selecting a second right-angled triangular prism with a higher refractive index and a matching liquid with a higher refractive index, a wider range of material refractive index measurements can be achieved.

[0122] Figure 8 This is a flowchart illustrating another method for measuring the refractive index of materials based on optical waveguides, provided by an embodiment of the present invention. The principle of this embodiment is similar to the aforementioned embodiments, except that the optical waveguide does not have a grating; instead, a different method of beam incidence is used, and a third right-angled triangular prism is provided on one side of the optical waveguide, such as... Figure 8 As shown, the method for measuring the refractive index of this material includes:

[0123] S410. The object to be measured is placed between the optical waveguide and the first right-angled triangular prism, and one right-angled face of the third right-angled triangular prism is placed on the side of the optical waveguide away from the object to be measured.

[0124] Specifically, Figure 9 This is a schematic diagram of the light incident mode for another method of measuring the refractive index of materials based on optical waveguides provided in this embodiment of the invention. (Refer to...) Figure 9 The measurement object 50 is positioned between the optical waveguide 20 and the first right-angled triangular prism 30, with one side of the measurement object 50 attached to the optical waveguide 20 and the other side attached to the first right-angled triangular prism 30. A right-angled face of the third right-angled triangular prism 70 is positioned on the side of the optical waveguide 20 away from the measurement object. The third right-angled triangular prism 70 is a triangular prism with a known refractive index and a slope angle θ0, for example, the slope angle θ0 could be 45°. The propagation path of the measurement beam ( Figure 9(Not shown) The measurement beam can be incident on the third right-angled triangular prism 70, refracted by the third right-angled triangular prism 70 to the optical waveguide 20, and then transmitted through total internal reflection within the optical waveguide 20 to exit at the edge; or the measurement beam can be incident on the third right-angled triangular prism 70, refracted by the third right-angled triangular prism 70 to the optical waveguide 20, refracted by the optical waveguide 20 to the measurement object 50, and then exited through the first right-angled triangular prism 30. By setting the third right-angled triangular prism 70, it is possible to effectively observe whether total internal reflection or refraction occurs at the interface between the optical waveguide and the measurement object, which is beneficial for calculating the refractive index.

[0125] S420: Control the light source to output a measurement beam. The measurement beam is incident on the inclined surface of the third right-angled triangular prism at the first incident angle θ0. After being refracted by the third right-angled triangular prism, it is incident on the optical waveguide, undergoes total internal reflection in the optical waveguide, and exits from the edge of the waveguide.

[0126] Wherein, the first incident angle θ0 is the acute apex angle of the third right-angled triangular prism on the side closest to the object being measured. The measurement beam is incident on the inclined surface of the third right-angled triangular prism at the first incident angle θ0. After being refracted by the third right-angled triangular prism, the measurement beam is incident on the optical waveguide, undergoes total internal reflection within the optical waveguide, and exits from the edge of the waveguide.

[0127] S430: The control rotation mechanism drives the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, so as to change the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission in the optical waveguide to just refracting into the object being measured from the optical waveguide.

[0128] In an optional embodiment, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, thereby changing the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the measurement beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the object being measured from the optical waveguide. This includes: controlling the rotating mechanism to drive the first right-angled triangular prism, the optical waveguide, the object being measured, and the third right-angled triangular prism to rotate synchronously, reducing the incident angle onto the third right-angled triangular prism, so that the measurement beam changes from the initial state of total internal reflection transmission within the optical waveguide to being refracted into the object being measured from the optical waveguide, and then exiting through the first right-angled triangular prism, and recording the rotation angle θ3 of the rotating mechanism.

[0129] Specifically, by controlling the rotating mechanism to drive the first right-angled triangular prism, the optical waveguide, the object being measured, and the third right-angled triangular prism to rotate synchronously, the incident angle of the beam onto the third right-angled triangular prism is reduced. This, in turn, changes the angle of the measurement beam at the interface between the optical waveguide and the object being measured. The smaller the incident angle of the measurement beam onto the interface, the more it decreases until the total internal reflection condition is no longer met. At this point, the measurement beam will refract, entering the object being measured through the optical waveguide and then exiting through the first right-angled triangular prism. At this point, the measurement beam does not undergo total internal reflection within the optical waveguide; that is, it is in the critical state of changing from total internal reflection to refraction. The rotation angle θ3 of the rotating mechanism at this moment is recorded for subsequent calculation of the refractive index of the object being measured.

[0130] S440. Determine the refractive index of the object being measured according to the law of refraction.

[0131] In an optional embodiment, determining the refractive index of the object being measured, according to the law of refraction, includes: calculating the refractive index of the object being measured according to the following formula:

[0132] ;

[0133] Where n0 represents the refractive index of air, n1 represents the refractive index of the third right-angled triangular prism, and n represents the refractive index of the object being measured.

[0134] In this embodiment, the object to be measured is placed between the optical waveguide and the first right-angled triangular prism. One right-angled face of the third right-angled triangular prism is located on the side of the optical waveguide away from the object to be measured. First, the light source is controlled to output a measurement beam. The measurement beam is incident on the inclined face of the third right-angled triangular prism at a first incident angle θ0. After being refracted by the third right-angled triangular prism, it is incident on the optical waveguide. It undergoes total internal reflection in the optical waveguide and exits from the edge of the waveguide. Then, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, the object to be measured, and the third right-angled triangular prism to rotate synchronously. This reduces the incident angle of the beam to the third right-angled triangular prism, so that the measurement beam changes from the initial state of total internal reflection transmission in the optical waveguide to being refracted from the optical waveguide into the object to be measured, and then exits through the first right-angled triangular prism. By measuring the rotation angle of the rotating mechanism and combining it with the law of refraction, the refractive index of the object to be measured can be calculated.

[0135] Figure 10 This is a flowchart illustrating another method for measuring the refractive index of materials based on optical waveguides, provided by an embodiment of the present invention. The principle of this embodiment is similar to the previous embodiment, but it provides another method for the measurement beam to be incident. The optical waveguide is provided with an inclined reflecting surface, and the acute angle between the inclined reflecting surface and the surface of the optical waveguide on the side facing away from the measurement object is θ4. Figure 10 As shown, the method for measuring the refractive index of this material includes:

[0136] S510. Position the object to be measured between the optical waveguide and the first right-angled triangular prism.

[0137] Specifically, Figure 11 This is a schematic diagram of the light incident mode for another method of measuring the refractive index of materials based on optical waveguides provided in this embodiment of the invention. (Refer to...) Figure 11 The object to be measured, 50, is positioned between the optical waveguide 20 and the first right-angled triangular prism 30. Specifically, one side of the object to be measured is attached to the optical waveguide 20, and the other side is attached to the first right-angled triangular prism 30. The optical waveguide 20 has an inclined reflective surface, and the acute angle between the inclined reflective surface and the surface of the optical waveguide 20 facing away from the object to be measured is θ4, which can be 30°. The propagation path of the measurement beam can be either: the measurement beam is incident on the optical waveguide 20, undergoes total internal reflection within the optical waveguide 20, and exits at the edge; or the measurement beam is first incident on the optical waveguide 20, refracted by the optical waveguide 20 to the object to be measured, and then exits through the first right-angled triangular prism 30. By using an optical waveguide with an inclined reflective surface, it is possible to effectively observe whether total internal reflection or refraction occurs at the interface between the optical waveguide and the object to be measured, which is beneficial for calculating the refractive index.

[0138] S520: Control the light source to output the measurement beam. The measurement beam is incident at a 0° angle to the surface of the optical waveguide near the first right-angled triangular prism. After being reflected by the tilted reflector, it is reflected back to the surface of the optical waveguide near the first right-angled triangular prism. It undergoes total internal reflection within the optical waveguide and exits from the edge of the waveguide.

[0139] Specifically, the measurement beam is incident at a 0° angle onto the surface of the optical waveguide near the first right-angled triangular prism. After being reflected by the tilted reflector, it is reflected back to the surface of the optical waveguide near the first right-angled triangular prism, undergoes total internal reflection within the optical waveguide, and exits from the edge of the waveguide.

[0140] S530, the control rotation mechanism drives the first right-angled triangular prism, the optical waveguide and the object being measured to rotate synchronously, so as to change the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission in the optical waveguide to just refracted into the object being measured from the optical waveguide.

[0141] In an optional embodiment, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, thereby changing the incident angle of the measurement beam onto the optical waveguide or the object being measured, until the beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the object being measured from the optical waveguide. This includes: controlling the rotating mechanism to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, increasing the incident angle onto the optical waveguide, so that the measurement beam changes from the initial state of total internal reflection transmission within the optical waveguide to being refracted into the object being measured from the optical waveguide, and then exiting through the first right-angled triangular prism, and recording the rotation angle θ5 of the rotating mechanism.

[0142] Specifically, by controlling the rotating mechanism to drive the first right-angled triangular prism, the optical waveguide, and the object being measured to rotate synchronously, the incident angle of the measurement beam onto the optical waveguide is increased. This, in turn, changes the angle of the measurement beam at the interface between the optical waveguide and the object being measured. The smaller the incident angle of the measurement beam onto the interface, the more the measurement beam will refract when the total internal reflection condition is no longer met. The beam will then refract from the optical waveguide into the object being measured and exit through the first right-angled triangular prism. At this point, the measurement beam does not undergo total internal reflection within the optical waveguide; that is, it is in the critical state of changing from total internal reflection to refraction. The rotation angle θ5 of the rotating mechanism at this point is recorded for subsequent calculation of the refractive index of the object being measured.

[0143] S540. Determine the refractive index of the object being measured according to the law of refraction.

[0144] In an optional embodiment, determining the refractive index of the object being measured according to the law of refraction includes: when the measurement beam is reflected by the tilted reflecting surface to the surface of the optical waveguide opposite to the first right-angled triangular prism, Figure 12 This is a schematic diagram of the measurement beam provided in an embodiment of the present invention being reflected by an inclined reflecting surface to the surface of the optical waveguide on the side away from the first right-angled triangular prism. (Refer to...) Figure 12 In this embodiment, the refractive index of the object being measured is calculated according to the following formula:

[0145] ;

[0146] When the measurement beam is reflected by the tilted reflector onto the surface of the optical waveguide near the first right-angled triangular prism... Figure 13 This is a schematic diagram of the measurement beam reflected by the inclined reflecting surface to the surface of the optical waveguide near the first right-angled triangular prism, provided in an embodiment of the present invention. (Refer to...) Figure 13 In this embodiment, the refractive index of the object being measured is calculated according to the following formula:

[0147] ;

[0148] Where n0 represents the air refractive index, n2 represents the refractive index of the optical waveguide, and n represents the refractive index of the object being measured.

[0149] In this embodiment, the object to be measured is placed between the optical waveguide and the first right-angled triangular prism. First, the light source is controlled to output a measurement beam. The measurement beam is incident at a 0° angle onto the surface of the optical waveguide near the first right-angled triangular prism. After being reflected by the tilted reflective surface, it is reflected back to the surface of the optical waveguide near the first right-angled triangular prism. It undergoes total internal reflection within the optical waveguide and exits from the edge of the waveguide. Then, the rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the object to be measured to rotate synchronously, increasing the angle of incidence on the optical waveguide. This changes the initial state of the measurement beam being transmitted through total internal reflection within the optical waveguide to being refracted into the object from the optical waveguide and then exiting through the first right-angled triangular prism. By measuring the rotation angle of the rotating mechanism and combining it with the law of refraction, the refractive index of the object to be measured can be calculated.

[0150] Optionally, the object being measured can be a gas, liquid, or solid.

[0151] in, Figure 14 This is a schematic diagram of the contact position when the object of measurement is a gas, provided by an embodiment of the present invention. Figure 15 This is a schematic diagram of the contact position when the measurement object is a gas, as provided in another embodiment of the present invention. (Refer to...) Figure 14 and Figure 15 When the object to be measured 50 is a gas, a sealing process is required to fill the gas between the optical waveguide 20 and the first right-angled triangular prism 30. For example, a ring of adhesive 80 can be sealed around the laser emitting surface of the optical waveguide 20. The adhesive 80 is of uniform thickness and airtight. The gas to be measured can be filled within this ring of adhesive 80, and then a thin film 90 is used to seal it. Subsequently, a refractive index matching liquid is filled between the thin film 90 and the first right-angled triangular prism 30, and the refractive index of the gas is measured using the material refractive index measurement method provided in this embodiment of the invention. When the object to be measured 50 is a liquid, the liquid can directly fill the gap between the optical waveguide 20 and the first right-angled triangular prism 30, so they can be directly bonded together, with sealing applied to the edges.

[0152] Optional, Figure 16 This is a schematic diagram of the bonding position when the measurement object is a solid, provided by an embodiment of the present invention. (Refer to...) Figure 16 The object being measured 50 is a solid, and a refractive index matching liquid 100 is provided between the optical waveguide 20 and the object being measured 50, or between the optical waveguide 20 and the first right-angled triangular prism 30, or between the object being measured 50 and the first right-angled triangular prism 30.

[0153] When the object being measured 50 is a solid, since there may be tiny gaps on the surface of the solid, it is necessary to fill the refractive index matching liquid 100 between the optical waveguide 20, the object being measured 50, and the first right-angled triangular prism 30 to make the optical waveguide 20, the object being measured 50, and the first right-angled triangular prism 30 fit together completely, which is beneficial to improving the accuracy of the refractive index measurement results of solid materials.

[0154] Optionally, the refractive index of the refractive index matching liquid 100 satisfies: the refractive index of the first right-angled triangular prism ±0.05 < the refractive index of the refractive index matching liquid < the refractive index of the optical waveguide.

[0155] Specifically, the refractive index of the first right-angled triangular prism 30 must be less than that of the refractive index matching liquid 100, or their refractive indices should be close to each other, so that the refractive index difference at their interface is small enough. The lower the reflectivity of light at the critical point, the higher the transmittance, ensuring that sufficient intensity of light enters the subsequent optical path, facilitating the observation of changes in the light state. The refractive index of the refractive index matching liquid 100 should be less than that of the optical waveguide 20 to ensure that when the measurement beam enters the optically less dense medium from the optically dense medium and the incident angle is greater than the critical angle, the measurement beam can undergo total internal reflection. In other words, it ensures that the measurement beam can be transmitted radially with total internal reflection inside the optical waveguide, providing a basis for the subsequent measurement of the critical state where the measurement beam changes from total internal reflection transmission within the optical waveguide to just being refracted into the measured object from the optical waveguide.

[0156] Optionally, the thickness of the object being measured 50 can range from 1 μm to 1 mm.

[0157] The thickness of the object being measured, 50, ranges from 1 μm to 1 mm. If the object being measured, 50, is too thin, the propagation path between the measuring beam and the object being measured, 50, will be extremely short, preventing sufficient refraction and affecting measurement accuracy. If the object being measured, 50, is too thick, the refraction angle under critical conditions cannot be considered as 90°, making it impossible to accurately calculate the refractive index of the material.

[0158] Based on the same inventive concept, this invention also provides a material refractive index measurement device based on an optical waveguide, used to perform the material refractive index measurement method of the above embodiments. Continuing to refer to... Figure 2 The material refractive index measuring device includes a light source 10, an optical waveguide 20, a first right-angled triangular prism 30, and a rotating mechanism 40. The optical waveguide 20 and the object being measured 50 are stacked on a right-angled surface of the first right-angled triangular prism 30. The rotating mechanism 40 drives the first right-angled triangular prism 30, the optical waveguide 20, and the object being measured 50 to rotate synchronously.

[0159] The material refractive index measuring device provided in this embodiment can perform the material refractive index measuring method of any embodiment of the present invention and can achieve the effect of the material refractive index measuring method of the above embodiment. The similarities can be referred to the above description, and will not be repeated here.

[0160] Optional, Figure 17 This is a schematic diagram of another material refractive index measurement device based on an optical waveguide provided in an embodiment of the present invention. (Refer to...) Figure 17The material refractive index measurement device based on optical waveguide also includes a polarizer 110 and a half-wave plate 120 disposed between the light source 10 and the first right-angled triangular prism 30.

[0161] The laser emitted by the light source 10 comprises light with different polarization states. Since the optical waveguide 20 has different diffraction efficiencies and total internal reflection conditions for light with different vibration directions, the laser emitted by the light source 10 first passes through the polarizer 110 to form polarized light vibrating in a single direction, such as retaining only p-light or s-light. This ensures that the polarization state of the beam incident on the optical waveguide 20 is unified, avoiding the influence of chaotic polarization states on the refractive index measurement results. The half-wave plate 120 can change the vibration direction of the polarized light, rotating the polarization state of the incident light to an angle more closely matching the grating direction, further enhancing the intensity of the diffracted light and facilitating the observation of changes in the light's state.

[0162] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for measuring the refractive index of materials based on optical waveguides, characterized in that, The measurement is performed by a material refractive index measuring device based on an optical waveguide, which includes a light source, an optical waveguide, a first right-angled triangular prism, and a rotating mechanism. The method for measuring the refractive index of the material includes: The optical waveguide and the object to be measured are stacked on a right-angled face of the first right-angled triangular prism; The light source is controlled to output a measurement beam, which is incident on the optical waveguide or the object being measured at a preset incident angle. The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the measurement object to rotate synchronously, so as to change the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection transmission in the optical waveguide to just refracted into the measurement object from the optical waveguide; Determine the refractive index of the object being measured based on the law of refraction.

2. The method for measuring the refractive index of materials based on optical waveguides according to claim 1, characterized in that, The optical waveguide includes a transmission grating. The optical waveguide and the measurement object are stacked on a right-angled face of the first right-angled triangular prism, comprising: The object to be measured is positioned between the optical waveguide and the first right-angled triangular prism; The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including: The measurement beam is incident on the transmission grating at an incident angle of 0°, and the first-order diffracted light and the negative first-order diffracted light of the transmission grating are totally reflected in the optical waveguide and exit from the edge of the waveguide.

3. The method for measuring the refractive index of materials based on optical waveguides according to claim 2, characterized in that, Controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object, thereby changing the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including: The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the measurement object to rotate synchronously, increasing the incident angle of the light incident on the transmission grating. This causes the first-order diffracted light or the negative first-order diffracted light to change from the initial state of total internal reflection transmission in the optical waveguide to being refracted from the optical waveguide into the measurement object, and then exiting through the first right-angled triangular prism. The rotation angle θ1 of the rotating mechanism is recorded.

4. The method for measuring the refractive index of materials based on optical waveguides according to claim 3, characterized in that, Determining the refractive index of the object being measured, according to the law of refraction, includes: The refractive index of the measured object is calculated using the following formula: ； Wherein, n0 represents the air refractive index, m represents the diffraction order, λ represents the wavelength of the measurement beam, d1 represents the period of the transmission grating, n represents the refractive index of the object being measured, and θ2 represents the angle of refraction of the diffracted light incident on the object being measured.

5. The method for measuring the refractive index of materials based on optical waveguides according to claim 1, characterized in that, The optical waveguide includes a reflective grating, and the material refractive index measuring device further includes a second right-angled triangular prism. The optical waveguide and the object to be measured are stacked on a right-angled face of the first right-angled triangular prism, including: The object to be measured is positioned on the side of the optical waveguide away from the first right-angled triangular prism, and the second right-angled triangular prism is positioned on the side of the object to be measured away from the optical waveguide. The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including: The measurement beam is incident on the object being measured at an angle of 0°. After being transmitted through the object, it is incident on the reflective grating. The first-order diffracted light and the negative first-order diffracted light of the reflective grating are totally reflected in the optical waveguide and exit from the edge of the waveguide.

6. The method for measuring the refractive index of materials based on optical waveguides according to claim 5, characterized in that, Controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object, thereby changing the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including: The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, the measurement object, and the second right-angled triangular prism to rotate synchronously, increasing the incident angle of the light incident on the measurement object. This causes the first-order diffracted light or the negative first-order diffracted light to change from the initial state of total internal reflection transmission in the optical waveguide to being refracted from the optical waveguide into the measurement object, and then exiting through the second right-angled triangular prism. The rotation angle θ3 of the rotating mechanism is recorded.

7. The method for measuring the refractive index of materials based on optical waveguides according to claim 6, characterized in that, Determining the refractive index of the object being measured, according to the law of refraction, includes: The refractive index of the measured object is calculated using the following grating formula: ； Where n0 represents the air refractive index, m represents the diffraction order, λ represents the wavelength of the measurement beam, d2 represents the period of the reflection grating, n represents the refractive index of the object being measured, and θ2 represents the angle of refraction of the diffracted light incident on the object being measured.

8. The method for measuring the refractive index of materials based on optical waveguides according to claim 1, characterized in that, The optical waveguide is provided with a third right-angled triangular prism, and the optical waveguide and the measurement object are stacked on a right-angled face of the first right-angled triangular prism, including: The object to be measured is placed between the optical waveguide and the first right-angled triangular prism, and a right-angled face of the third right-angled triangular prism is located on the side of the optical waveguide away from the object to be measured. The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including: The measuring beam is incident on the inclined surface of the third right-angled triangular prism at a first incident angle θ0. After being refracted by the third right-angled triangular prism, it is incident on the optical waveguide, undergoes total internal reflection in the optical waveguide, and exits from the edge of the waveguide. Wherein, the first incident angle θ0 is the acute apex angle of the third right-angled triangular prism on the side closest to the object being measured.

9. The method for measuring the refractive index of materials based on optical waveguides according to claim 8, characterized in that, Controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object, thereby changing the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including: The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, the measurement object, and the third right-angled triangular prism to rotate synchronously, reducing the incident angle of the light beam incident on the third right-angled triangular prism. This causes the measurement beam to change from its initial state of total internal reflection transmission within the optical waveguide to being refracted from the optical waveguide into the measurement object, and then exiting through the first right-angled triangular prism. The rotation angle θ3 of the rotating mechanism is recorded.

10. The method for measuring the refractive index of materials based on optical waveguides according to claim 9, characterized in that, Determining the refractive index of the object being measured, according to the law of refraction, includes: The refractive index of the measured object is calculated using the following formula: ； Wherein, n0 represents the refractive index of air, n1 represents the refractive index of the third right-angled triangular prism, and n represents the refractive index of the object being measured.

11. The method for measuring the refractive index of materials based on optical waveguides according to claim 1, characterized in that, The optical waveguide is provided with an inclined reflective surface, and the acute angle between the inclined reflective surface and the surface of the optical waveguide facing away from the measurement object is θ4; the optical waveguide and the measurement object are stacked on a right-angled face of the first right-angled triangular prism, including: The object to be measured is positioned between the optical waveguide and the first right-angled triangular prism; The measurement beam is incident on the optical waveguide or the measurement object at a preset incident angle, including: The measurement beam is incident at a 0° angle onto the surface of the optical waveguide near the first right-angled triangular prism, and is reflected by the tilted reflective surface back to the surface of the optical waveguide near the first right-angled triangular prism. It undergoes total internal reflection within the optical waveguide and exits from the edge of the waveguide.

12. The method for measuring the refractive index of materials based on optical waveguides according to claim 11, characterized in that, Controlling the rotating mechanism to synchronously rotate the first right-angled triangular prism, the optical waveguide, and the measurement object, thereby changing the incident angle of the measurement beam onto the optical waveguide or the measurement object, until the beam changes from total internal reflection within the optical waveguide to just refracted into the measurement object from the optical waveguide, including: The rotating mechanism is controlled to drive the first right-angled triangular prism, the optical waveguide, and the measurement object to rotate synchronously, increasing the incident angle of the light beam into the optical waveguide. This causes the measurement beam to change from its initial state of total internal reflection transmission within the optical waveguide to being refracted into the measurement object from the optical waveguide, and then exiting through the first right-angled triangular prism. The rotation angle θ5 of the rotating mechanism is recorded.

13. The method for measuring the refractive index of materials based on optical waveguides according to claim 12, characterized in that, Determining the refractive index of the object being measured, according to the law of refraction, includes: When the measurement beam is reflected by the inclined reflective surface to the surface of the optical waveguide on the side away from the first right-angled triangular prism, the refractive index of the measured object is calculated according to the following formula: ； When the measurement beam is reflected by the inclined reflective surface to the surface of the optical waveguide near the first right-angled triangular prism, the refractive index of the measured object is calculated according to the following formula: ； Wherein, n0 represents the air refractive index, n2 represents the refractive index of the optical waveguide, and n represents the refractive index of the object being measured.

14. The method for measuring the refractive index of materials based on optical waveguides according to claim 1, characterized in that, The object being measured is a gas, liquid, or solid.

15. The method for measuring the refractive index of materials based on optical waveguides according to claim 14, characterized in that, The object being measured is a solid, and a refractive index matching liquid is provided between the optical waveguide and the object being measured, or between the optical waveguide and the first right-angled triangular prism, or between the object being measured and the first right-angled triangular prism.

16. The method for measuring the refractive index of materials based on optical waveguides according to claim 15, characterized in that, The refractive index of the refractive index matching liquid satisfies the following condition: the refractive index of the first right-angled triangular prism ±0.05 < the refractive index of the refractive index matching liquid < the refractive index of the optical waveguide.

17. The material refractive index measuring device based on optical waveguide according to claim 1, characterized in that, The thickness range of the measured object is 1μm to 1mm.

18. A material refractive index measuring device based on optical waveguide, characterized in that, The material refractive index measurement device is used to perform the material refractive index measurement method according to any one of claims 1 to 17. The material refractive index measurement device includes a light source, an optical waveguide, a first right-angled triangular prism, and a rotation mechanism. The optical waveguide and the object to be measured are stacked on a right-angled surface of the first right-angled triangular prism. The rotation mechanism drives the first right-angled triangular prism, the optical waveguide, and the object to be measured to rotate synchronously.

19. The material refractive index measuring device based on optical waveguide according to claim 18, characterized in that, It also includes a polarizer and a half-wave plate disposed between the light source and the first right-angled triangular prism.

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