A method for detecting optical properties of single-layer thin films based on transmission Goos-Hanchen shift and spectroscopy

Abstract

A method for detecting the optical properties of a single-layer film based on the combination of the transmitted Goos-Hänchen shift and spectroscopy, characterized in that it includes: S1: measuring the spot position information of the transmitted TM polarized wave of the single-layer film; S2: processing the data to obtain the incident wavelength-transmitted Goos-Hänchen shift relationship curve; S3: measuring the spectral information of the single-layer film; S4: judging the type of the single-layer film: when the film type is a reflective film, enter S5, when the film type is a transmissive film, enter S6, and when the film type is a beam splitter film, enter S7; S5: when it is judged that the single-layer film is a reflective film, establish a reflective film objective function and calculate the reflective film parameter vector for the entire wavelength band; S6: when it is judged that the single-layer film is a transmissive film, establish a transmissive film objective function and calculate the transmissive film parameter vector for the entire wavelength band; S7: when it is judged that the single-layer film is a beam splitter film, establish a beam splitter film objective function and calculate the beam splitter film parameter vector for the entire wavelength band. Effect: The measurement efficiency and accuracy of the optical properties of the single-layer film are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of material analysis and measurement, and particularly to a method for detecting the optical properties of a single-layer thin film based on the combination of transmitted Goos-Hänchen shift and spectroscopy. Background Art

[0002] An optical thin film is a thin film material with specific optical properties, usually composed of multiple materials with different refractive indices arranged alternately. Optical thin films can usually be divided into reflection films, transmission films, beam splitting films, etc. At the same time, the optical constants of the thin film play a decisive role in its optical and electromagnetic properties, and the application scenarios of different types of optical thin films are also different. Therefore, how to accurately detect the type of nano-scale optical thin film and its corresponding optical constants has become a crucial technology.

[0003] Disadvantages of the prior art: Currently, most of the prior art uses ellipsometry or photometry to obtain the optical properties of thin films. However, ellipsometry has the problem of film thickness periodicity, which will cause the thickness of the thin film to have multiple solutions, thus affecting the measurement of the optical constants of the thin film. Photometry is easily affected by the environment, resulting in inaccurate calculation results. And for different functional thin films, both photometry and ellipsometry have certain drawbacks. Summary of the Invention

[0004] A method for detecting the optical properties of a single-layer thin film based on the combination of transmitted Goos-Hänchen shift and spectroscopy provided by the present invention improves the measurement efficiency and accuracy of the optical properties of the single-layer thin film.

[0005] To achieve the above object, a method for detecting the optical properties of a single-layer thin film based on the combination of transmitted Goos-Hänchen shift and spectroscopy provided by the present invention is characterized in that it includes the following steps:

[0006] Step S1: Measuring the spot position information of the transmitted TM polarized wave of the single-layer thin film: Measuring the spot position information of the transmitted TM polarized wave of the single-layer thin film by using a transmitted Goos-Hänchen shift measuring device;

[0007] Step S2: Processing data to obtain the incident wavelength - transmitted Goos-Hänchen shift relationship curve: According to the spot position information, obtaining the incident wavelength - transmitted Goos-Hänchen shift relationship curve of the single-layer thin film, and further obtaining the transmitted Goos-Hänchen shift under TM polarization;

[0008] Step S3: Measuring the spectral information of the single-layer thin film: Measuring the reflection spectral data and transmission spectral data of the single-layer thin film under TM polarization and TE polarization at a continuous wavelength λ by using a spectral measuring device, and keeping the incident angle and the incident point unchanged during the measurement process;

[0009] Step S4: Determine the type of the single-layer film: Based on the measured reflection spectral data and transmission spectral data, determine the film type of the single-layer film;

[0010] When the average reflectivity within the incident wavelength is greater than or equal to 0.9, the film type of the single-layer film is a reflective film, and proceed to Step S5;

[0011] When the average transmittance within the incident wavelength is greater than or equal to 0.9, the film type of the single-layer film is a transmissive film, and proceed to Step S6;

[0012] When both the average transmittance and the average reflectivity within the incident wavelength are 0.5 ± 0.05, the film type of the single-layer film is a beam splitter film, and proceed to Step S7;

[0013] Step S5: When it is determined that the single-layer film is a reflective film, normalize the transmission Goos-Hänchen shift and the reflection spectral data of the TM polarized wave to obtain a reflectivity and transmission Goos-Hänchen shift data set of the same order of magnitude, and establish a reflective film objective function;

[0014] Initialize the search range of the solution space {n, k, d}, use fitting calculation, judge the accuracy of the solution according to the magnitude of the reflective film objective function, obtain the refractive index n and extinction coefficient k of the single-layer film when the reflective film objective function is minimized, and further obtain the reflective film parameter vector a1;

[0015] Step S6: When it is determined that the single-layer film is a transmissive film, normalize the transmission Goos-Hänchen shift and the transmission spectral data of the TM polarized wave to obtain a transmittance and transmission Goos-Hänchen shift data set of the same order of magnitude, and establish a transmissive film objective function;

[0016] Initialize the search range of the solution space {n, k, d}, use fitting calculation, judge the accuracy of the solution according to the magnitude of the transmissive film objective function, obtain the refractive index n and extinction coefficient k of the single-layer film when the transmissive film objective function is minimized, and further obtain the transmissive film parameter vector a2;

[0017] Step S7: When it is determined that the single-layer film is a beam splitter film, normalize the transmission Goos-Hänchen shift and the reflection spectral data of the TM polarized wave and TE polarized wave to obtain a reflectivity and transmission Goos-Hänchen shift data set of the same order of magnitude, and establish a beam splitter film objective function;

[0018] Initialize the search range of the solution space {n, k, d}, use fitting calculation, judge the accuracy of the solution according to the magnitude of the beam splitter film objective function, obtain the refractive index n and extinction coefficient k of the single-layer film when the beam splitter film objective function is minimized, and further obtain the beam splitter film parameter vector a3.

[0019] Through the above design, the type of the thin film is initially judged by collecting spectral information, and then the transmission Goos-Hänchen shift information of the single-layer thin film is collected. Combining the corresponding spectral information, the optical constants of the single-layer film of the thin film sample under the continuous spectrum can be calculated, effectively solving the problem of quickly solving the parameters of the single-layer thin film at one time.

[0020] Preferably: in the step S1, when measuring by using the transmission Goos-Hänchen shift measuring device, a three-phase thin film structure of substrate-thin film layer-medium layer is used as the detection structure; the single-layer thin film is the thin film layer deposited on the substrate.

[0021] Preferably: in the step S2, the transmission Goos-Hänchen shift under the TM polarized wave is calculated by the following formula:

[0022]

[0023] φ t = arg(t) (6)

[0024]

[0025] For the TM polarized wave, in the formula:

[0026]

[0027] where p represents the substrate, m represents the thin film layer, s represents the medium layer, q represents the combination of the substrate and the thin film layer, j represents the combination of the thin film layer and the medium layer, r represents the reflection coefficient, t represents the transmission coefficient, D t represents the transmission Goos-Hänchen shift, k x represents the incident light wave vector, θ represents the incident angle, δ represents the phase difference, n represents the refractive index, r pm represents the reflection coefficient under the pm combination, t ms represents the transmission coefficient under the ms combination, t pm represents the transmission coefficient under the pm combination, i is the imaginary part, φ represents the phase, φ t represents the transmission phase, k0 represents the incident light wave vector, λ represents the incident wavelength, and d represents the thin film thickness.

[0028] Preferably: in the step S5, the expression of the reflection film objective function is as follows:

[0029]

[0030] where F1 represents the reflection film objective function, N exp represents the total number of incident wavelength quantities; represents the transmission Goos-Hänchen shift under the TM polarized wave obtained by the inversion calculation; represents the transmittance Goos-Hänchen shift value of the i-th reference point under the TM polarization wave extracted from the experimentally measured transmittance Goos-Hänchen shift curve; represents the reflectance of the reflective film under the TM polarization wave obtained by inversion calculation; represents the reflectance of the reflective film at the i-th reference point under the TM polarization wave extracted from the experimentally measured reflectance curve; a1 represents the parameter vector of the reflective film, a = (n, k), where n is the refractive index and k is the extinction coefficient, the subscript cal represents the value obtained by inversion calculation, the subscript exp represents the value measured experimentally, and the superscript TM represents the transverse magnetic wave.

[0031] Preferably: in Equation (1), the reflectance of the reflective film is calculated as follows:

[0032]

[0033] represents the reflection coefficient of the reflective film under the TM polarization wave.

[0034] Preferably: in the step S6, the expression of the objective function of the transmissive film is as follows:

[0035]

[0036] where F2 represents the objective function of the transmissive film, N exp represents the total number of incident wavelength;

[0037] represents the transmittance Goos-Hänchen shift under the TM polarization wave obtained by inversion calculation; represents the transmittance Goos-Hänchen shift value of the i-th reference point under the TM polarization wave extracted from the experimentally measured transmittance Goos-Hänchen shift curve; represents the transmittance of the transmissive film under the TM polarization wave obtained by inversion calculation; represents the transmittance of the transmissive film at the i-th reference point under the TM polarization wave extracted from the experimentally measured transmittance curve, and a2 represents the parameter vector of the transmissive film.

[0038] Preferably: in Equation (2), the transmittance of the transmissive film is calculated as follows:

[0039]

[0040] Preferably: in the step S7, the expression of the objective function of the beam splitter film is as follows:

[0041]

[0042] where, where F3 represents the objective function of the beam splitter film, Nexp represents the total number of incident wavelengths; represents the transmission Goos-Hänchen shift under TM polarization waves obtained by inversion calculation; represents the transmission Goos-Hänchen shift value of the i-th reference point under TM polarization waves extracted from the experimentally measured transmission Goos-Hänchen shift curve; R 3_cal (i, a3) represents the reflectivity of the beam-splitting film obtained by inversion calculation; R 3_exp (i) represents the reflectivity of the beam-splitting film at the i-th reference point extracted from the experimentally measured reflectivity curve, and a3 represents the parameter vector of the beam-splitting film.

[0043] Preferably: in Equation (3), the calculation expression of the reflectivity R3 of the beam-splitting film is as follows:

[0044]

[0045] wherein, represents the reflection coefficient of the beam-splitting film under TM polarization waves, represents the reflection coefficient of the beam-splitting film under TE polarization waves;

[0046] The reflection coefficient of TE polarization waves The expression is as follows:

[0047]

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] (1) By using continuous wavelengths for measurement and selecting the joint characterization mode of transmission Goos-Hänchen shift and spectrum, the problem that the prior art solves the thin film characteristic parameters by photometric method or ellipsometry is solved, providing a new idea for realizing the calculation of thin film optical constants at multiple wavelengths;

[0050] (2) Improve the measurement method from two aspects of the transmission Goos-Hänchen shift measurement operation and algorithm calculation, and improve the measurement efficiency and accuracy at the same time;

[0051] (3) The present invention can provide effective theoretical guidance and reference for solving the optical constants of multi-layer thin films in the future, and has the characteristics of good optimization effect and strong applicability. Description of the Drawings

[0052] Figure 1 is the flow schematic diagram of the present invention;

[0053] Figure 2 is the schematic diagram of the prism-type three-phase thin film structure in Embodiment 1;

[0054] Figure 3 is the comparison diagram of the wavelength-reflectivity curve obtained by the reflection film in Embodiment 1 and the calculated curve;

[0055] Figure 4 It is a comparison diagram of the incident wavelength-transmission Goos-Hänchen shift curve obtained for the reflective film in Example 1 and the curve obtained by calculation;

[0056] Figure 5 It is an optical constant diagram of the multi-wavelength reflective film obtained in Example 1;

[0057] Figure 6 It is a comparison diagram of the wavelength-reflectivity curve obtained for the transmissive film in Example 2 and the curve obtained by calculation;

[0058] Figure 7 It is a comparison diagram of the incident wavelength-transmission Goos-Hänchen shift curve obtained for the transmissive film in Example 2 and the curve obtained by calculation;

[0059] Figure 8 Optical constant diagram of the multi-wavelength transmissive film obtained in Example 2 of the present invention;

[0060] Figure 9 It is a comparison diagram of the wavelength-reflectivity curve obtained for the beam-splitting film in Example 3 and the curve obtained by calculation;

[0061] Figure 10 It is a comparison diagram of the incident wavelength-transmission Goos-Hänchen shift curve obtained for the beam-splitting film in Example 3 and the curve obtained by calculation;

[0062] Figure 11 It is an optical constant diagram of the multi-wavelength beam-splitting film obtained in Example 3. Detailed implementation mode

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and specific examples. The following examples or drawings are used to illustrate the present invention, but do not limit the scope of the present invention.

[0064] Example 1:

[0065] As Figure 1 shown: Step S1: Measuring the spot position information of the transmitted TM polarized wave of the single-layer thin film: Using a transmitted Goos-Hänchen shift measuring device to measure the spot position information of the transmitted TM polarized wave of the single-layer thin film;

[0066] Step S2: Data processing to obtain the incident wavelength-transmission Goos-Hänchen shift relationship curve: According to the spot position information, obtain the incident wavelength-transmission Goos-Hänchen shift relationship curve of the single-layer thin film, and further obtain the transmitted Goos-Hänchen shift under TM polarization;

[0067] Step S3: Measuring the spectral information of the single-layer film: Using a spectral measurement device to measure the reflection spectral data and transmission spectral data of the TM polarized wave and TE polarized wave of the single-layer film at continuous wavelengths λ, and keeping the incident angle and incident point unchanged during the measurement process;

[0068] Step S4: Judging the type of the single-layer film: Judging the film type of the single-layer film according to the measured reflection spectral data and transmission spectral data;

[0069] When the average reflectivity within the incident wavelength is greater than or equal to 0.9, the film type of the single-layer film is a reflective film, and enter Step S5;

[0070] When the average transmittance within the incident wavelength is greater than or equal to 0.9, the film type of the single-layer film is a transmissive film, and enter Step S6;

[0071] When the average transmittance and average reflectivity within the incident wavelength are both 0.5 ± 0.05, the film type of the single-layer film is a beam splitter film, and enter Step S7;

[0072] Step S5: When it is judged that the single-layer film is a reflective film, normalize the transmission Goos-Hänchen shift and the reflection spectral data of the TM polarized wave to obtain a reflectivity and transmission Goos-Hänchen shift data set of the same order of magnitude, and establish a reflective film objective function;

[0073] Initialize the search range of the solution space {n, k, d}, adopt fitting calculation, judge the accuracy of the solution according to the size of the reflective film objective function, obtain the refractive index n and extinction coefficient k of the single-layer film when the reflective film objective function is the smallest, and further obtain the reflective film parameter vector a1;

[0074] Step S6: When it is judged that the single-layer film is a transmissive film, normalize the transmission Goos-Hänchen shift and the transmission spectral data of the TM polarized wave to obtain a transmittance and transmission Goos-Hänchen shift data set of the same order of magnitude, and establish a transmissive film objective function;

[0075] Initialize the search range of the solution space {n, k, d}, adopt fitting calculation, judge the accuracy of the solution according to the size of the transmissive film objective function, obtain the refractive index n and extinction coefficient k of the single-layer film when the transmissive film objective function is the smallest, and further obtain the transmissive film parameter vector a2;

[0076] Step S7: When it is judged that the single-layer film is a beam splitter film, normalize the transmission Goos-Hänchen shift and the reflection spectral data of the TM polarized wave and TE polarized wave to obtain a reflectivity and transmission Goos-Hänchen shift data set of the same order of magnitude, and establish a beam splitter film objective function;

[0077] Initialize the search range of the solution space {n, k, d}, and use fitting calculation. Determine the accuracy of the solution based on the magnitude of the beam splitting film objective function, and obtain the refractive index n and extinction coefficient k of the single-layer film when the beam splitting film objective function is minimized, thereby obtaining the beam splitting film parameter vector a3.

[0078] According to the judgment of the film type in step S4, after normalizing the transmitted Goos-Hänchen shift data obtained in step S2 and the spectral data in step S3, substitute them into the corresponding objective functions in steps S5 to S7, and initialize the search range of the solution space {n, k, d}. Use fitting calculation, and determine the accuracy of the solution based on the magnitude of the objective function, and obtain the refractive index n and extinction coefficient k of the single-layer film sample when the objective function is minimized.

[0079] In step S1, when measuring using the transmitted Goos-Hänchen shift measurement device, use the substrate-film layer-dielectric layer as the three-phase film structure for detection, as Figure 2 shown; the single-layer film is the film layer deposited on the substrate.

[0080] In step S2, the transmitted Goos-Hänchen shift under the TM polarization wave is calculated by the following formula:

[0081]

[0082] φ t = arg(t) (6)

[0083]

[0084] For the TM polarization wave, in the formula:

[0085]

[0086] where p represents the substrate, m represents the film layer, s represents the dielectric layer, q represents the combination of the substrate and the film layer, j represents the combination of the film layer and the dielectric layer, r represents the reflection coefficient, t represents the transmission coefficient, D t represents the transmitted Goos-Hänchen shift, k x represents the incident light wave vector, θ represents the incident angle, δ represents the phase difference, n represents the refractive index, r pm represents the reflection coefficient under the pm combination, t ms represents the transmission coefficient under the ms combination, t pm represents the transmission coefficient under the pm combination, i is the imaginary part, φ represents the phase, φ t represents the transmission phase, k0 represents the incident light wave vector, λ represents the incident wavelength, and d represents the film thickness.

[0087] In the step S5, the expression of the objective function of the reflective film is as follows:

[0088]

[0089] where F1 represents the objective function of the reflective film, and N exp represents the total number of incident wavelengths; represents the transmitted Goos-Hänchen shift under TM polarization wave obtained by inversion calculation; represents the transmitted Goos-Hänchen shift value of the i-th reference point under TM polarization wave extracted from the experimentally measured transmitted Goos-Hänchen shift curve; represents the reflectivity of the reflective film under TM polarization wave obtained by inversion calculation; represents the reflectivity of the reflective film of the i-th reference point under TM polarization wave extracted from the experimentally measured reflectivity curve; a1 represents the parameter vector of the reflective film, a = (n, k), where n is the refractive index and k is the extinction coefficient. The subscript cal represents the value obtained by inversion calculation, the subscript exp represents the value measured experimentally, and the superscript TM represents the transverse magnetic wave.

[0090] In Equation (1), the data can be directly obtained from the relationship curve of the incident angle - transmitted Goos-Hänchen shift.

[0091] In Equation (1), the calculation expression of the reflectivity of the reflective film is as follows:

[0092]

[0093] represents the reflection coefficient of the reflective film under TM polarization wave.

[0094] In the step S6, the expression of the objective function of the transmissive film is as follows:

[0095]

[0096] where F2 represents the objective function of the transmissive film, and N exp represents the total number of incident wavelengths;

[0097] represents the transmitted Goos-Hänchen shift under TM polarization wave obtained by inversion calculation; represents the transmitted Goos-Hänchen shift value of the i-th reference point under TM polarization wave extracted from the experimentally measured transmitted Goos-Hänchen shift curve; represents the transmittance of the transmissive film under TM polarization wave obtained by inversion calculation; represents the transmittance of the transmissive film of the i-th reference point under TM polarization wave extracted from the experimentally measured transmittance curve, and a2 represents the parameter vector of the transmissive film.

[0098] In formula (2), the transmittance of the transmission film is calculated as follows:

[0099]

[0100] In the step S7, the expression of the beam splitting film objective function is as follows:

[0101]

[0102] where, F3 represents the beam splitting film objective function, N exp represents the total number of incident wavelengths; represents the transmitted Goos-Hänchen shift under TM polarization waves obtained by inversion calculation; represents the transmitted Goos-Hänchen shift value of the i-th reference point under TM polarization waves extracted from the experimentally measured transmitted Goos-Hänchen shift curve; R 3_cal (i, a3) represents the reflectivity of the beam splitting film obtained by inversion calculation; R 3_exp (i) represents the reflectivity of the beam splitting film at the i-th reference point extracted from the experimentally measured reflectivity curve, and a3 represents the beam splitting film parameter vector.

[0103] In formula (3), the calculation expression of the beam splitting film reflectivity R3 is as follows:

[0104]

[0105] where, represents the beam splitting film reflection coefficient under TM polarization waves, represents the beam splitting film reflection coefficient under TE polarization waves;

[0106] The reflection coefficient of the TE polarization wave is expressed as follows:

[0107]

[0108] This embodiment adopts a three-phase structure of a single-layer thin film as shown in Figure 2 . The three-phase thin film structure is a substrate-thin film layer-dielectric layer structure. Among them, the substrate selects the prism material as BK7 glass, and its refractive index n p = 1.5151; the dielectric selects air, and its refractive index n a = 1. When the dielectric layer is other substances, the corresponding dielectric refractive index value can be used.

[0109] In this embodiment, the incident light is selected as [400, 700]. The solution space {n, k} is initialized, the solution domain of n is [0, 1], and the solution domain of k is [0, 5]. It is determined through step S4 that the thin film is a reflective film, so the transmitted Goos-Hänchen shift and the reflection spectrum data are substituted into step S5, and the characteristic parameters of the thin film are obtained based on the minimum value of the objective function. From Figure 3 and Figure 4 it can be seen that the curve of the fitted transmitted Goos-Hänchen shift and the reflectivity curve almost have a very good fitting effect with the curves obtained experimentally, indicating that the characteristic parameters of the thin film obtained by this method are reliable and effective. Figure 5 are the optical constants of the thin film calculated by the present invention.

[0110] Embodiment 2:

[0111] Embodiment 2 is based on Embodiment 1, and the difference lies in that: in Embodiment 2, the incident light selected is [400, 800]. The solution space {n, k} is initialized, the solution domain of n is [0, 3], and the solution domain of k is [0, 2]. It is determined through step S4 that the thin film is a transmissive film, so the transmitted Goos-Hänchen shift and the transmission spectrum data are substituted into step S6, and the characteristic parameters of the thin film are obtained based on the minimum value of the objective function. From Figure 6 and Figure 7 it can be seen that the curve of the fitted transmitted Goos-Hänchen shift and the reflectivity curve almost have a very good fitting effect with the curves obtained experimentally, indicating that the characteristic parameters of the thin film obtained by this method are reliable and effective. Figure 8 are the optical constants of the thin film calculated by the present invention.

[0112] Embodiment 3:

[0113] Embodiment 3 is based on Embodiment 1, and the difference lies in that: in Embodiment 3, the incident light selected is [450, 650]. The solution space {n, k} is initialized, the solution domain of n is [0, 2], and the solution domain of k is [0, 1]. It is determined through step S4 that the thin film is a beam splitter film, so the transmitted Goos-Hänchen shift and the reflection spectrum data are substituted into step S7, and the characteristic parameters of the thin film are obtained based on the minimum value of the objective function. From Figure 9 and Figure 10 it can be seen that the curve of the fitted transmitted Goos-Hänchen shift and the reflectivity curve almost have a very good fitting effect with the curves obtained experimentally, indicating that the characteristic parameters of the thin film obtained by this method are reliable and effective. Figure 11 are the optical constants of the thin film calculated by the present invention.

[0114] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for detecting the optical properties of a single-layer thin film based on the combined use of the transmitted Goos-Hänchen shift and spectroscopy, characterized in that: Including the following steps: Step S1: Measuring the spot position information of the transmitted TM polarized wave of the single-layer film: Measuring the spot position information of the transmitted TM polarized wave of the single-layer film by using a transmitted Goos-Hänchen shift measuring device; Step S2: Processing the data to obtain the incident wavelength - transmitted Goos-Hänchen shift relationship curve: According to the spot position information, obtaining the incident wavelength - transmitted Goos-Hänchen shift relationship curve of the single-layer film, and further obtaining the transmitted Goos-Hänchen shift under TM polarization; Step S3: Measuring the spectral information of the single-layer film: Measuring the reflection spectral data and transmission spectral data of the single-layer film for TM polarized wave and TE polarized wave at a continuous wavelength λ by using a spectral measuring device, and keeping the incident angle and incident point unchanged during the measurement process; Step S4: Judging the type of the single-layer film: Judging the film type of the single-layer film according to the measured reflection spectral data and transmission spectral data; When the average reflectivity within the incident wavelength is greater than or equal to 0.9, the film type of the single-layer film is a reflection film, and enter Step S5; When the average transmittance within the incident wavelength is greater than or equal to 0.9, the film type of the single-layer film is a transmission film, and enter Step S6; When both the average transmittance and average reflectivity within the incident wavelength are 0.5 ± 0.05, the film type of the single-layer film is a beam splitter film, and enter Step S7; Step S5: When it is judged that the single-layer film is a reflection film, normalizing the transmitted Goos-Hänchen shift and the reflection spectral data of the TM polarized wave to obtain a reflectivity and transmitted Goos-Hänchen shift data set at the same order of magnitude, and establishing a reflection film objective function; Initializing the search range of the solution space {n, k, d}, using fitting calculation, judging the accuracy of the solution according to the magnitude of the reflection film objective function, obtaining the refractive index n and extinction coefficient k of the single-layer film when the reflection film objective function is the smallest, and further obtaining the reflection film parameter vector a1; Step S6: When it is judged that the single-layer film is a transmission film, normalizing the transmitted Goos-Hänchen shift and the transmission spectral data of the TM polarized wave to obtain a transmittance and transmitted Goos-Hänchen shift data set at the same order of magnitude, and establishing a transmission film objective function; Initializing the search range of the solution space {n, k, d}, using fitting calculation, judging the accuracy of the solution according to the magnitude of the transmission film objective function, obtaining the refractive index n and extinction coefficient k of the single-layer film when the transmission film objective function is the smallest, and further obtaining the transmission film parameter vector a2; Step S7: When it is judged that the single-layer film is a beam splitter film, normalizing the transmitted Goos-Hänchen shift and the reflection spectral data of the TM polarized wave and TE polarized wave to obtain a reflectivity and transmitted Goos-Hänchen shift data set at the same order of magnitude, and establishing a beam splitter film objective function; Initializing the search range of the solution space {n, k, d}, using fitting calculation, judging the accuracy of the solution according to the magnitude of the beam splitter film objective function, obtaining the refractive index n and extinction coefficient k of the single-layer film when the beam splitter film objective function is the smallest, and further obtaining the beam splitter film parameter vector a3; In the step S1, when measuring by using a transmission Goos-Hänchen shift measuring device, a three-phase thin film structure for detection is a substrate-thin film layer-dielectric layer; the single-layer thin film is the thin film layer deposited on the substrate; In the step S2, the transmission Goos-Hänchen shift under the TM polarized wave is calculated by the following formula: φ t = arg(t) (6) For the TM polarized wave, where: Among them, p represents the substrate, m represents the thin film layer, s represents the dielectric layer, q represents the combination of the substrate and the thin film layer, j represents the combination of the thin film layer and the dielectric layer, r represents the reflection coefficient, t represents the transmission coefficient, D t represents the transmitted Goos-Hänchen shift, k x represents the incident light wave vector, θ represents the incident angle, δ represents the phase difference, n represents the refractive index, r pm represents the reflection coefficient under the pm combination, t ms represents the transmission coefficient under the ms combination, t pm represents the transmission coefficient under the pm combination, i is the imaginary part, φ represents the phase, φ t represents the transmission phase, k0 represents the incident light wave vector, λ represents the incident wavelength, d represents the thin film thickness; In the step S5, the expression of the objective function of the reflective film is as follows: Among them, F1 represents the objective function of the reflective film, N exp represents the total number of incident wavelengths; represents the transmitted Goos-Hänchen shift under TM polarization waves obtained by inversion calculation; represents the transmitted Goos-Hänchen shift value of the i-th reference point under TM polarization waves extracted from the experimentally measured transmitted Goos-Hänchen shift curve; represents the reflectivity of the reflective film under TM polarization waves obtained by inversion calculation; represents the reflectivity of the reflective film at the i-th reference point under TM polarization waves extracted from the experimentally measured reflectivity curve; a1 represents the parameter vector of the reflective film, a = (n, k), where n is the refractive index and k is the extinction coefficient. The subscript cal represents the value obtained by inversion calculation, the subscript exp represents the value measured experimentally, and the superscript TM represents the transverse magnetic wave; In formula (1), the reflectivity of the reflective film is calculated as follows: Indicates the reflection coefficient of the reflective film under TM polarized waves; In the step S6, the expression of the objective function of the transmissive film is as follows: Among them, F2 represents the objective function of the transmissive film, and N exp represents the total number of incident wavelengths; Denotes the transmitted Goos-Hänchen shift under TM polarization wave obtained by inversion calculation; Denotes the transmitted Goos-Hänchen shift value of the i-th reference point under TM polarization wave extracted from the experimentally measured transmitted Goos-Hänchen shift curve; Denotes the transmittance of the transmission film under TM polarization wave obtained by inversion calculation; Denotes the transmittance of the transmission film of the i-th reference point under TM polarization wave extracted from the experimentally measured transmittance curve, and a2 denotes the transmission film parameter vector.

2. The method for detecting the optical properties of a single-layer thin film based on the combined use of the transmitted Goos-Hänchen shift and spectroscopy according to claim 1, wherein: In formula (2), the transmittance of the transmission film is calculated as follows:

3. The method for detecting the optical properties of a single-layer thin film based on the combined use of the transmitted Goos-Hänchen shift and spectroscopy according to claim 1, wherein: In the step S7, the expression of the objective function of the beam splitter film is as follows: Among them, F3 represents the objective function of the beam splitting film, N exp represents the total number of incident wavelengths; represents the transmitted Goos-Hänchen shift under the TM polarization wave obtained by inversion calculation; represents the transmitted Goos-Hänchen shift value of the i-th reference point under the TM polarization wave extracted from the experimentally measured transmitted Goos-Hänchen shift curve; R 3_cal (i,a3) represents the reflectivity of the beam splitting film obtained by inversion calculation; R 3_exp (i) represents the reflectivity of the beam splitting film of the i-th reference point extracted from the experimentally measured reflectivity curve, and a3 represents the beam splitting film parameter vector.

4. The method for detecting the optical properties of a single-layer thin film based on the combined use of the transmitted Goos-Hänchen shift and spectroscopy according to claim 3, wherein: In Equation (3), the calculation expression of the reflectivity R3 of the beam splitter film is as follows: Among them, represents the reflection coefficient of the beam splitting film under TM polarized wave, represents the reflection coefficient of the beam splitting film under TE polarized wave; Reflection coefficient of TE polarized wave The expression is as follows:

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