Single-layer film optical property detection method based on combination of transmission Goos-Hanchen shift and spectrum

Abstract

The invention discloses a single-layer film optical property detection method based on combination of transmission Goos-Hanchen shift and spectrum. The method is characterized by comprising the following steps: S1, measuring light spot position information of transmission TM polarized waves of a single-layer film; s2, carrying out data processing to obtain an incident wavelength-transmission Goos-Hanchen shift relation curve; s3, measuring spectral information of the single-layer film; s4, judging the type of a single-layer film: entering S5 when the film type is a reflective film, entering S6 when the film type is a transmission film, and entering S7 when the film type is a beam splitting film; s5, when the single-layer thin film is judged to be a reflecting film, establishing a reflecting film objective function, and calculating to obtain a full-wave-band reflecting film parameter vector; s6, when the single-layer thin film is judged to be a transmission film, establishing a transmission film objective function, and calculating to obtain a full-wave-band transmission film parameter vector; and S7, when judging that the single-layer film is a beam splitting film, establishing a beam splitting film objective function, and calculating to obtain a full-band beam splitting film parameter vector. The effect is that the measurement efficiency and accuracy of the optical characteristics of the single-layer film are improved.

Description

Technical Field

[0001] The invention relates to the technical field of material analysis and measurement, and in particular to a method for detecting optical properties of a single-layer film based on the combination of transmission Goos-Hanchen shift and spectrum. Background Art

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

[0003] Disadvantages of existing technologies: Currently, most existing technologies use ellipsometry or photometry to obtain the optical properties of thin films. However, the ellipsometry method has the problem of film thickness period, which will cause multiple solutions for the thickness of the film, thereby affecting the measurement of the optical constants of the film. The photometry method is easily affected by the environment, resulting in inaccurate calculation results. And for different functional films, both the photometry method and the ellipsometry method have certain disadvantages. Summary of the invention

[0004] The present invention provides a single-layer film optical property detection method based on transmission Goos-Hanchen shift and spectrum combination, which improves the measurement efficiency and accuracy of the optical property of the single-layer film.

[0005] To achieve the above object, the present invention provides a method for detecting optical properties of a single-layer film based on transmission Goos-Hanchen shift and spectroscopy, the key of which is: comprising the following steps:

[0006] Step S1: measuring the light spot position information of the TM polarized wave transmitted by the single-layer film: using a transmission Goos-Hanchen shift measuring device to measure the light spot position information of the TM polarized wave transmitted by the single-layer film;

[0007] Step S2: Data processing to obtain an incident wavelength-transmission Goos-Hanchen shift relationship curve: According to the light spot position information, the incident wavelength-transmission Goos-Hanchen shift relationship curve of the single-layer film is obtained, and then the transmission Goos-Hanchen shift under TM polarization wave is obtained;

[0008] 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 the TE polarized wave of the single-layer film at a continuous wavelength λ, and keeping the incident angle and the incident point unchanged during the measurement process;

[0009] Step S4: determining the type of the single-layer film: determining the film type of the single-layer film according to the measured reflection spectrum data and transmission spectrum data;

[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 the process proceeds 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 the process proceeds to step S6;

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

[0013] Step S5: when the single-layer film is determined to be a reflective film, the transmission Goos-Hanchen shift and the reflective spectrum data of the TM polarized wave are normalized to obtain a data set of reflectivity and transmission Goos-Hanchen shift at the same order of magnitude, and a reflective film target function is established;

[0014] Initialize the search range of the solution space {n, k, d}, use 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 minimum, and then obtain the reflective film parameter vector a1;

[0015] Step S6: when the single-layer film is determined to be a transmissive film, the transmission Goos-Hanchen shift and the transmission spectrum data of the TM polarized wave are normalized to obtain a data set of transmittance and transmission Goos-Hanchen shift at the same order of magnitude, and a transmissive film target function is established;

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

[0017] Step S7: when it is determined that the single-layer film is a beam splitter film, the transmission Goos-Hanchen shift and the reflection spectrum data of the TM polarized wave and the TE polarized wave are normalized to obtain a data set of reflectivity and transmission Goos-Hanchen shift at the same order of magnitude, and establish a beam splitter film target 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 size 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 minimum, and then obtain the beam splitter film parameter vector a3.

[0019] Through the above design, the film type is first determined by collecting spectral information, and then the transmission Goos-Hanchen shift information of the single-layer film is collected. Combined with the corresponding spectral information, the optical constants of the single-layer film of the thin film sample under the continuous spectrum can be solved, which effectively solves the problem of quickly solving the single-layer film parameters.

[0020] Preferably, in step S1, when a transmission Goos-Hanchen shift measuring device is used for measurement, a three-phase thin film structure of substrate-thin film layer-dielectric layer is used for detection; and the single-layer thin film is a thin film layer plated on the substrate.

[0021] Preferably, in step S2, the transmission Goos-Hanchen shift under the TM polarization wave Calculated by the following formula:

[0022]

[0023] φ t =arg(t) (6)

[0024]

[0025] For TM polarized waves,

[0026]

[0027] Where 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, and D t is the transmitted Goos-Hanchen 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.

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

[0029]

[0030] Among them, F1 represents the reflective film objective function, N exp Represents the total number of incident wavelengths; represents the transmitted Goos-Hanchen shift of TM polarization wave obtained by inversion calculation; represents the transmitted Gous-Hanchen shift value of the i-th reference point under TM polarization wave extracted from the experimentally measured transmitted Gous-Hanchen shift curve; represents the reflectivity of the reflection film under TM polarization wave obtained by inversion calculation; represents the reflectivity of the reflection film at the i-th reference point under the TM polarization wave extracted from the experimentally measured reflectivity curve; a1 represents the reflection film parameter vector, a=(n,k), where n is the refractive index, k is the extinction coefficient, the subscript cal represents that obtained by inversion calculation, the subscript exp represents that obtained from the experiment, and the superscript TM represents the transverse magnetic wave.

[0031] As a preferred embodiment: In formula (1), the reflectivity of the reflective film is The calculation expression is as follows:

[0032]

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

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

[0035]

[0036] Where F2 represents the transmission film objective function, N exp Represents the total number of incident wavelengths;

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

[0038] As a preferred embodiment: In formula (2), the transmittance of the transmissive film is The calculation expression is as follows:

[0039]

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

[0041]

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

[0043] As a preferred embodiment, in formula (3), the calculation expression of the beam splitting film reflectivity R3 is as follows:

[0044]

[0045] in, represents the beam splitter film reflection coefficient under TM polarization, represents the reflection coefficient of the beam splitter film under TE polarization wave;

[0046] Reflection coefficient of TE polarized wave The expression is as follows:

[0047]

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The continuous wavelength measurement is adopted, and the transmission Goos-Hanchen shift and spectral joint characterization mode is selected, which solves the problem that the existing technology uses photometry or ellipsometry to solve the characteristic parameters of the film, and provides a new idea for solving the optical constants of the film under multiple wavelengths;

[0050] (2) Improve the measurement method from two aspects: the transmission Goos-Hanchen shift measurement operation and algorithm calculation, and improve the measurement efficiency and accuracy;

[0051] (3) The present invention can provide effective theoretical guidance and reference for solving the optical constants of multilayer films in the future, and has the characteristics of good optimization effect and strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the process of the present invention;

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

[0054] Figure 3 is a comparison diagram of the wavelength-reflectivity curve obtained by the reflective film in Example 1 and the curve obtained by the solution;

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

[0056] Figure 5 is a graph of optical constants of the multi-wavelength reflective film obtained in Example 1;

[0057] Figure 6 is a comparison diagram of the wavelength-reflectivity curve obtained by the transmission film in Example 2 and the curve obtained by the solution;

[0058] Figure 7 is a comparison diagram of the incident wavelength-transmission Goos-Hanchen shift curve obtained by the transmission film in Example 2 and the curve obtained by the solution;

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

[0060] Fig. 9 is a comparison diagram of the wavelength-reflectivity curve obtained by the beam splitting film in Example 3 and the curve obtained by the solution;

[0061] Fig.10 is a comparison diagram of the incident wavelength-transmission Goos-Hanchen shift curve obtained by the beam splitting film in Example 3 and the curve obtained by the solution;

[0062] Fig.11 Graph showing optical constants of the multi-wavelength beam splitting film obtained in Example 3. DETAILED DESCRIPTION

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

[0064] Embodiment 1:

[0065] like Figure 1 As shown: Step S1: measuring the light spot position information of the TM polarized wave transmitted by the single-layer film: using a transmission Goos-Hanchen shift measuring device to measure the light spot position information of the TM polarized wave transmitted by the single-layer film;

[0066] Step S2: Data processing to obtain an incident wavelength-transmission Goos-Hanchen shift relationship curve: According to the light spot position information, the incident wavelength-transmission Goos-Hanchen shift relationship curve of the single-layer film is obtained, and then the transmission Goos-Hanchen shift under TM polarization wave is obtained;

[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 the TE polarized wave of the single-layer film at a continuous wavelength λ, and keeping the incident angle and the incident point unchanged during the measurement process;

[0068] Step S4: determining the type of the single-layer film: determining the film type of the single-layer film according to the measured reflection spectrum data and transmission spectrum 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 the process proceeds to 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 the process proceeds to step S6;

[0071] When the average transmittance and the average reflectance within the incident wavelength are both 0.5±0.05, the film type of the single-layer film is a beam splitter film, and the process proceeds to step S7;

[0072] Step S5: when the single-layer film is determined to be a reflective film, the transmission Goos-Hanchen shift and the reflective spectrum data of the TM polarized wave are normalized to obtain a data set of reflectivity and transmission Goos-Hanchen shift at the same order of magnitude, and a reflective film target function is established;

[0073] Initialize the search range of the solution space {n, k, d}, use 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 minimum, and then obtain the reflective film parameter vector a1;

[0074] Step S6: when the single-layer film is determined to be a transmissive film, the transmission Goos-Hanchen shift and the transmission spectrum data of the TM polarized wave are normalized to obtain a data set of transmittance and transmission Goos-Hanchen shift at the same order of magnitude, and a transmissive film target function is established;

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

[0076] Step S7: when it is determined that the single-layer film is a beam splitter film, the transmission Goos-Hanchen shift and the reflection spectrum data of the TM polarized wave and the TE polarized wave are normalized to obtain a data set of reflectivity and transmission Goos-Hanchen shift at the same order of magnitude, and establish a beam splitter film target function;

[0077] Initialize the search range of the solution space {n, k, d}, use fitting calculation, judge the accuracy of the solution according to the size 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 minimum, and then obtain the beam splitter film parameter vector a3.

[0078] According to the determination of the film type in step S4, the transmission Goos-Hanchen shift data obtained in step S2 and the spectral data in step S3 are substituted into the corresponding objective functions of steps S5 to S7 after normalization, and the search range of the solution space {n, k, d} is initialized. The accuracy of the solution is determined according to the size of the objective function by fitting calculation, and the refractive index n and extinction coefficient k of the single-layer film sample are obtained when the objective function is minimum.

[0079] In step S1, when the transmission Goos-Hanchen shift measuring device is used for measurement, a three-phase thin film structure of substrate-thin film layer-medium layer is used for detection, such as Figure 2 As shown; the single-layer film is a thin film layer coated on a substrate.

[0080] In step S2, the transmission Goos-Hanchen shift under the TM polarization wave Calculated by the following formula:

[0081]

[0082] φ t =arg(t) (6)

[0083]

[0084] For TM polarized waves,

[0085]

[0086] Where 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, and D t is the transmitted Goos-Hanchen 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 step S5, the expression of the reflective film objective function is as follows:

[0088]

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

[0090] In formula (1), the data It can be directly obtained from the incident angle-transmission Goos-Hanchen shift relationship curve.

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

[0092]

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

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

[0095]

[0096] Where F2 represents the transmission film objective function, N exp Represents the total number of incident wavelengths;

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

[0098] In formula (2), the transmittance of the transmissive film is The calculation expression is as follows:

[0099]

[0100] In step S7, the beam splitter objective function is expressed as follows:

[0101]

[0102] Among them, F3 represents the beam splitter objective function, N exp Represents the total number of incident wavelengths; represents the transmitted Goos-Hanchen shift of TM polarization wave obtained by inversion calculation; represents the transmission Gous-Hanchen shift value of the ith reference point under TM polarization wave extracted from the experimentally measured transmission Gous-Hanchen shift curve; R 3_cal (i,a3) represents the reflectivity of the beam splitter film obtained by inversion calculation; R 3_exp (i) represents the reflectivity of the beamsplitter film at the i-th reference point extracted from the experimentally measured reflectivity curve, and a3 represents the beamsplitter film parameter vector.

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

[0104]

[0105] in, represents the beam splitter film reflection coefficient under TM polarization, represents the reflection coefficient of the beam splitter film under TE polarization wave;

[0106] Reflection coefficient of TE polarized wave The expression is as follows:

[0107]

[0108] This embodiment adopts Figure 2 The three-phase structure of the single-layer film shown in the figure is a structure of substrate-film layer-medium layer. The substrate is made of BK7 glass, whose refractive index n p =1.5151; the medium is air, and its refractive index n a = 1. When the medium layer is made of other materials, the corresponding medium refractive index value can be used.

[0109] In this embodiment, the incident light is selected as [400,700]. Initialize the solution space {n, k}, the solution domain of n is [0,1], and the solution domain of k is [0,5]. In step S4, it is determined that the film is a reflective film, so the transmission Goos-Hanchen shift and reflection spectrum data are substituted into step S5, and the characteristic parameters of the film are obtained according to the minimum value of the objective function. Figure 3 and Figure 4 It can be seen that the fitted transmission Goos-Hanchen shift and reflectivity curves are almost well matched with the experimental curves, indicating that the film characteristic parameters obtained by this method are reliable and effective. Figure 5 These are the optical constants of the film calculated by the present invention.

[0110] Embodiment 2:

[0111] Example 2 is based on Example 1, and the difference is that the incident light selected in Example 2 is [400,800]. Initialize the solution space {n, k}, the solution domain of n is [0,3], and the solution domain of k is [0,2]. In step S4, it is determined that the film is a transmissive film, so the transmission Goos-Hanchen shift and transmission spectrum data are substituted into step S6, and the characteristic parameters of the film are obtained according to the minimum value of the objective function. From Figure 6 and Figure 7 It can be seen that the fitted transmission Goos-Hanchen shift and reflectivity curves are almost well matched with the experimental curves, indicating that the film characteristic parameters obtained by this method are reliable and effective. Figure 8 These are the optical constants of the film calculated by the present invention.

[0112] Embodiment 3:

[0113] Example 3 is based on Example 1, and the difference is that the incident light selected in Example 3 is [450,650]. Initialize the solution space {n, k}, the solution domain of n is [0,2], and the solution domain of k is [0,1]. In step S4, it is determined that the film is a beam splitter film, so the transmission Goos-Hanchen shift and reflection spectrum data are substituted into step S7, and the characteristic parameters of the film are obtained according to the minimum value of the objective function. From Fig. 9 and Fig.10 It can be seen that the fitted transmission Goos-Hanchen shift and reflectivity curves are almost well matched with the experimental curves, indicating that the film characteristic parameters obtained by this method are reliable and effective. Fig.11 These are the optical constants of the film calculated by the present invention.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for detecting optical properties of a single-layer thin film based on the combination of transmission Goos-Hanchen shift and spectroscopy, characterized in that: The following steps are involved: Step S1: measuring the light spot position information of the TM polarized wave transmitted by the single-layer film: using a transmission Goos-Hanchen shift measuring device to measure the light spot position information of the TM polarized wave transmitted by the single-layer film; Step S2: Data processing to obtain an incident wavelength-transmission Goos-Hanchen shift relationship curve: According to the light spot position information, the incident wavelength-transmission Goos-Hanchen shift relationship curve of the single-layer film is obtained, and then the transmission Goos-Hanchen shift under TM polarization wave is obtained; 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 the TE polarized wave of the single-layer film at a continuous wavelength λ, and keeping the incident angle and the incident point unchanged during the measurement process; Step S4: determining the type of the single-layer film: determining the film type of the single-layer film according to the measured reflection spectrum data and transmission spectrum 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 reflective film, and the process proceeds to 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 transmissive film, and the process proceeds to step S6; When the average transmittance and the average reflectance within the incident wavelength are both 0.5±0.05, the film type of the single-layer film is a beam splitter film, and the process proceeds to step S7; Step S5: when the single-layer film is determined to be a reflective film, the transmission Goos-Hanchen shift and the reflective spectrum data of the TM polarized wave are normalized to obtain a data set of reflectivity and transmission Goos-Hanchen shift at the same order of magnitude, and a reflective film target function is established; Initialize the search range of the solution space {n, k, d}, use 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 minimum, and then obtain the reflective film parameter vector a1; Step S6: when the single-layer film is determined to be a transmissive film, the transmission Goos-Hanchen shift and the transmission spectrum data of the TM polarized wave are normalized to obtain a data set of transmittance and transmission Goos-Hanchen shift at the same order of magnitude, and a transmissive film target function is established; Initialize the search range of the solution space {n, k, d}, use fitting calculation, judge the accuracy of the solution according to the size of the transmission film target function, obtain the refractive index n and extinction coefficient k of the single-layer film when the transmission film target function is minimum, and then obtain the transmission film parameter vector a2; Step S7: when it is determined that the single-layer film is a beam splitter film, the transmission Goos-Hanchen shift and the reflection spectrum data of the TM polarized wave and the TE polarized wave are normalized to obtain a data set of reflectivity and transmission Goos-Hanchen shift at the same order of magnitude, and establish a beam splitter film target function; Initialize the search range of the solution space {n, k, d}, use fitting calculation, judge the accuracy of the solution according to the size 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 minimum, and then obtain the beam splitter film parameter vector a3.

2. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 1, characterized in that: In the step S1, when the transmission Goos-Hanchen shift measuring device is used for measurement, the substrate-thin film layer-medium layer is used as a three-phase thin film structure for detection; the single-layer thin film is a thin film layer plated on the substrate.

3. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 2, characterized in that: In step S2, the transmission Goos-Hanchen shift under the TM polarization wave Calculated by the following formula: f t =arg(t) (6) For TM polarized waves, Where 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, and D t is the transmitted Goos-Hanchen 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.

4. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 1, characterized in that: In step S5, the expression of the reflective film objective function is as follows: Among them, F1 represents the reflective film objective function, N exp Represents the total number of incident wavelengths; represents the transmitted Goos-Hanchen shift of TM polarization wave obtained by inversion calculation; represents the transmitted Gous-Hanchen shift value of the i-th reference point under TM polarization wave extracted from the experimentally measured transmitted Gous-Hanchen shift curve; represents the reflectivity of the reflection film under TM polarization wave obtained by inversion calculation; represents the reflectivity of the reflection film at the i-th reference point under the TM polarization wave extracted from the experimentally measured reflectivity curve; a1 represents the reflection film parameter vector, a=(n,k), where n is the refractive index, k is the extinction coefficient, the subscript cal represents that obtained by inversion calculation, the subscript exp represents that obtained from the experiment, and the superscript TM represents the transverse magnetic wave.

5. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 4, characterized in that: In formula (1), the reflectivity of the reflective film is The calculation expression is as follows: It represents the reflection coefficient of the reflecting film under TM polarization wave.

6. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 1, characterized in that: In step S6, the expression of the transmission film objective function is as follows: Where F2 represents the transmission film objective function, N exp Represents the total number of incident wavelengths; represents the transmitted Goos-Hanchen shift of TM polarization wave obtained by inversion calculation; represents the transmitted Gous-Hanchen shift value of the i-th reference point under TM polarization wave extracted from the experimentally measured transmitted Gous-Hanchen shift curve; represents the transmittance of the transmission film under TM polarization wave obtained by inversion calculation; represents the transmittance of the transmission film at the i-th reference point under the TM polarization wave extracted from the experimentally measured transmittance curve, and a2 represents the transmission film parameter vector.

7. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 6, characterized in that: In formula (2), the transmittance of the transmissive film is The calculation expression is as follows:

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

9. The method for detecting optical properties of a single-layer thin film based on transmission Goos-Hanchen shift and spectroscopy according to claim 8, characterized in that: In formula (3), the calculation expression of the beam splitting film reflectivity R3 is as follows: in, represents the beam splitter film reflection coefficient under TM polarization, represents the reflection coefficient of the beam splitter film under TE polarization wave; Reflection coefficient of TE polarized wave The expression is as follows:

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