Anisotropic second harmonic generation detection device

Abstract

This application discloses an anisotropic second harmonic wave detection device, comprising: a first optical polarization shifting component, a semi-reflective prism, a second optical polarization shifting component, a microscope objective, and a detection component. The first optical polarization shifting component converts incident light into first linearly polarized light exiting towards the semi-reflective prism. The second optical polarization shifting component converts the first linearly polarized light into second linearly polarized light exiting towards the side of the microscope objective. The microscope objective focuses the second linearly polarized light onto the surface of the sample and outputs the reflected second harmonic signal to the second optical polarization shifting component. The second optical polarization shifting component further converts the second harmonic signal into S and P polarization split quantities. The semi-reflective prism transmits the first linearly polarized light to the second optical polarization shifting component and reflects the S and P polarization split quantities to the detection component. This application detects the out-of-plane component of the nonlinear polarizability tensor by obliquely incident light into the sample.

Description

Technical Field

[0001] This application relates to the field of laser measurement technology, and in particular to an anisotropic second harmonic detection device. Background Technology

[0002] In related technologies, second harmonic characterization techniques utilize the nonlinear response of a sample to incident light to generate second harmonic signals, thereby obtaining the out-of-plane components of the nonlinear polarizability tensor.

[0003] When measuring the out-of-plane components of the nonlinear polarizability tensor of a small sample, the method of rotating the small sample is prone to the phenomenon that the small sample is removed from the irradiation area of ​​the excitation light during the rotation process. However, when measuring by rotating the polarization direction of the excitation light without rotating the small sample, the excitation light can only be perpendicular to the sample. The resulting spectrum can only resolve the lattice asymmetry in the sample plane and cannot measure the out-of-plane components of the nonlinear polarizability tensor of the small sample. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the related art. To this end, this application proposes an anisotropic second harmonic detection device designed to measure the out-of-plane components of the nonlinear polarizability tensor of a small sample.

[0005] In a first aspect, embodiments of this application provide an anisotropic second harmonic detection device, comprising: a first optical polarization shifting component, a semi-reflective prism, a second optical polarization shifting component, a microscope objective, and a detection component; the first optical polarization shifting component is used to convert incident light into first linearly polarized light emitted toward a first position of the semi-reflective prism; the semi-reflective prism is used to transmit the first linearly polarized light to the second optical polarization shifting component; the second optical polarization shifting component is used to convert the first linearly polarized light into second linearly polarized light emitted toward a second position of the microscope objective, wherein the first optical polarization shifting component... The second position is the side position of the microscope objective; the microscope objective is used to focus the second linearly polarized light onto the surface of the sample, and to emit the second harmonic signal formed by reflecting the second linearly polarized light of the sample to the second optical polarization shifting component; the second optical polarization shifting component is also used to convert the second harmonic signal into an S-polarized beam splitter emitted toward the third position of the semi-reflective prism, and into a P-polarized beam splitter emitted toward the fourth position of the semi-reflective prism; the semi-reflective prism is also used to reflect the S-polarized beam splitter and the P-polarized beam splitter to the detection component.

[0006] According to some embodiments of this application, the first optical polarization shifting component includes a first beam shifter and a first waveplate.

[0007] According to some embodiments of this application, the incident light is circularly polarized light, and the first optical polarization shifting component further includes a first polarizer.

[0008] According to some embodiments of this application, the first polarizer is a rotatable structure.

[0009] According to some embodiments of this application, both the first beam shifter and the first waveplate are rotatable structures.

[0010] According to some embodiments of this application, a third waveplate is provided in the incident direction of the first polarizer, and the third waveplate is used to convert the third linearly polarized light emitted by the laser source into the circularly polarized light.

[0011] According to some embodiments of this application, the polarization direction of the first linearly polarized light is either S-polarization or P-polarization; the second optical polarization shifting component includes a second beam shifter and a second waveplate; the first linearly polarized light is converted by the second beam shifter and the second waveplate into S-polarized or P-polarized light emitted toward the side position of the microscope objective; the second harmonic signal is converted by the second beam shifter and the second waveplate into S-polarized beam splitting emitted toward the third position of the semi-reflective prism and into P-polarized beam splitting emitted toward the fourth position of the semi-reflective prism.

[0012] According to some embodiments of this application, the incident direction of the detection component is provided with a rotatable second polarizer, which is used to allow only the S-polarized beam splitting to be incident on the detection component, or to allow only the P-polarized beam splitting to be incident on the detection component.

[0013] According to some embodiments of this application, the incident direction of the detection component is provided with a filter.

[0014] According to some embodiments of this application, the incident direction of the detection component is provided with a lens.

[0015] According to the technical solution of the embodiments of this application, at least the following beneficial effects are achieved: The embodiments of this application include a first optical polarization shifting component, a semi-reflective prism, a second optical polarization shifting component, a microscope objective, and a detection component; wherein, the first optical polarization shifting component is used to convert incident light into first linearly polarized light emitted toward a first position of the semi-reflective prism; the semi-reflective prism is used to transmit the first linearly polarized light to the second optical polarization shifting component; the second optical polarization shifting component is used to convert the first linearly polarized light into second linearly polarized light emitted toward a second position of the microscope objective. The microscope employs a first or second optical polarization shifter to focus the second linearly polarized light onto the sample surface and to reflect the second linearly polarized light from the sample to form a second harmonic signal, which is then emitted to a second optical polarization shifter. The second optical polarization shifter further converts the second harmonic signal into an S-polarized beam dispersed at a third position towards a semi-reflective prism and a P-polarized beam dispersed at a fourth position towards the semi-reflective prism. The semi-reflective prism also reflects the S-polarized and P-polarized beam dispersed to a detection component. This embodiment of the invention enables the translation of the incident light using either the first or second optical polarization shifter, and, combined with the microscope objective, allows the incident light to be obliquely incident into the sample, thereby obtaining the reflected second harmonic signal and, consequently, the out-of-plane component of the sample's nonlinear polarizability tensor.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0018] Figure 1 This is a schematic diagram of the structure of an anisotropic second harmonic detection device provided in one embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the structure of an anisotropic second harmonic detection device provided in another embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the path and polarization direction of incident light during the rotation of the first optical polarization shifting component provided in one embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the path and polarization direction of incident light during the synchronous rotation of the second optical polarization shifting component provided in one embodiment of this application. Detailed Implementation

[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0023] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0024] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0025] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0026] In related technologies, second harmonic characterization techniques utilize the nonlinear response of a sample to incident light to generate second harmonic signals, thereby obtaining the out-of-plane components of the nonlinear polarizability tensor.

[0027] When measuring the out-of-plane components of the nonlinear polarizability tensor of a small sample, the method of rotating the small sample is prone to the phenomenon that the small sample is removed from the irradiation area of ​​the excitation light during the rotation process. However, when measuring by rotating the polarization direction of the excitation light without rotating the small sample, the excitation light can only be perpendicular to the sample. The resulting spectrum can only resolve the lattice asymmetry in the sample plane and cannot measure the out-of-plane components of the nonlinear polarizability tensor of the small sample.

[0028] Based on the above, this application proposes an anisotropic second harmonic detection device, which aims to measure the out-of-plane components of the nonlinear polarizability tensor of a small sample.

[0029] The various embodiments of the multi-unit water system of this application will be further described below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of an anisotropic second harmonic detection device provided in one embodiment of this application.

[0031] In one embodiment, the anisotropic second harmonic detection device of this application includes, but is not limited to, a first optical polarization shifting component 100, a semi-reflective prism 200, a second optical polarization shifting component 300, a microscope objective 400, and a detection component 500. The first optical polarization shifting component 100 converts incident light into first linearly polarized light emitted toward a first position of the semi-reflective prism 200; the semi-reflective prism 200 transmits the first linearly polarized light to the second optical polarization shifting component 300; and the second optical polarization shifting component 300 converts the first linearly polarized light into second linearly polarized light emitted toward a second position of the microscope objective 400. Polarized light, wherein the second position is the side position of the microscope objective 400; the microscope objective 400 is used to focus the second linearly polarized light onto the surface of the sample 600, and to emit the second harmonic signal formed by reflecting the second linearly polarized light of the sample 600 to the second optical polarization shifting component 300; the second optical polarization shifting component 300 is also used to convert the second harmonic signal into an S-polarized beam dispersed at the third position of the semi-reflective prism 200, and into a P-polarized beam dispersed at the fourth position of the semi-reflective prism 200; the semi-reflective prism 200 is also used to reflect the S-polarized beam dispersed and the P-polarized beam dispersed to the detector component 500.

[0032] It should be noted that, firstly, the incident light is converted into first linearly polarized light by the first optical polarization shifting component 100 and exits towards the first position of the semi-reflective prism 200; secondly, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second optical polarization shifting component 300; thirdly, the first linearly polarized light is converted into second linearly polarized light by the second optical polarization shifting component 300, and the second linearly polarized light exits towards the second position of the microscope objective 400, where the second position is a side position of the microscope objective 400; subsequently, the second linearly polarized light is focused onto the sample 600 by the microscope objective 400. On the surface, after the second linearly polarized light is focused onto the sample 600, it is reflected to form a second harmonic signal. Finally, the second harmonic signal is emitted through the microscope objective 400 to the second optical polarization shifting component 300. In addition, the second harmonic signal is converted into S-polarization and P-polarization by the second optical polarization shifting component 300. The S-polarization is emitted towards the third position of the semi-reflective prism 200, and the P-polarization is emitted towards the fourth position of the semi-reflective prism 200. Furthermore, the S-polarization and P-polarization are reflected by the semi-reflective prism 200 to the detector component 500. Therefore, the embodiments of this application can achieve the translation of the incident light by the first optical polarization shifting component 100 or the second optical polarization shifting component 300, and in combination with the microscope objective 400, the incident light can be obliquely incident on the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600.

[0033] Specifically, the first optical polarization shifting component 100 includes a first beam shifter 110 and a first waveplate 120.

[0034] It should be noted that the first beam shifter 110 is used to direct the incident light toward the fifth position of the first wave plate 120. The first wave plate 120 is used to convert the incident light into first linearly polarized light that is directed toward the first position of the semi-reflective prism 200. The fifth position of the first wave plate 120 and the first position of the semi-reflective prism 200 are on the same horizontal line.

[0035] like Figure 1As shown, the incident light is selected as P-polarized light. First, the P-polarized light passes through the first beam shifter 110 and exits towards the fifth position of the first waveplate 120. Second, the first waveplate 120 converts the P-polarized light into first linearly polarized light that exits towards the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the S-polarization direction. Third, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second optical polarization shifting component 300. Then, the first linearly polarized light passes through the second optical polarization shifting component 300 and is converted into second linearly polarized light, which exits towards the second position of the microscope objective 400, wherein the polarization direction of the second linearly polarized light is the S-polarization direction. The second position is the microscope objective. The objective lens 400 is positioned to the side. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective lens 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. In addition, the second harmonic signal is emitted from the microscope objective lens 400 to the second optical polarization shifting component 300. Furthermore, the second harmonic signal is converted into S-polarized and P-polarized beams by the second optical polarization shifting component 300. The S-polarized beam is emitted towards the third position of the semi-reflective prism 200, and the P-polarized beam is emitted towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beams are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, the embodiments of this application can realize the translation of incident light through the first optical polarization shifting component 100, and combined with the microscope objective 400, can realize the incident light obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600.

[0036] It should be noted that when the incident light is P-polarized light, the P-polarized light will exit towards the fifth position of the first waveplate 120 after passing through the first beam shifter 110. The fifth position is the side position of the first waveplate 120. Since the fifth position of the first waveplate 120 and the first position of the semi-reflective prism 200 are on the same horizontal line, the first position is the side position of the semi-reflective prism 200. The fifth position can be the position 2.7 mm to the side of the first waveplate 120.

[0037] It should be noted that when the incident light is S-polarized light, firstly, the S-polarized light passes through the first beam shifter 110 and exits towards the fifth position of the first waveplate 120; secondly, the first waveplate 120 converts the S-polarized light into first linearly polarized light that exits towards the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the P-polarization direction; thirdly, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second optical polarization shifting component 300; thereafter, the P-polarized light passes through the second optical polarization shifting component 300 and is converted into second linearly polarized light, and the second linearly polarized light exits towards the second position of the microscope objective 400, wherein the polarization direction of the second linearly polarized light is the P-polarization direction, and the second position is... The microscope objective 400 is positioned to the side. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. In addition, the second harmonic signal is emitted from the microscope objective 400 to the second optical polarization shifting component 300. Furthermore, the second harmonic signal is converted into S-polarized and P-polarized beams by the second optical polarization shifting component 300. The S-polarized beam is emitted towards the third position of the semi-reflective prism 200, and the P-polarized beam is emitted towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beams are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, the embodiments of this application can realize the translation of incident light through the second optical polarization shifting component 300, and combined with the microscope objective 400, can realize the incident light obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600.

[0038] It should be noted that when the incident light is S-polarized light, the S-polarized light will be emitted towards the fifth position of the first waveplate 120 after passing through the first beam shifter 110. The fifth position is the middle position of the first waveplate 120. Since the fifth position of the first waveplate 120 and the first position of the semi-reflective prism 200 are on the same horizontal line, the first position is the middle position of the semi-reflective prism 200.

[0039] like Figure 2 As shown, Figure 2 This is a schematic diagram of the structure of an anisotropic second harmonic detection device provided in another embodiment of this application.

[0040] In one embodiment, when the incident light is circularly polarized, the first optical polarization shifting component 100 further includes a first polarizer 130.

[0041] It should be noted that the first polarizer 130 is used to convert circularly polarized light into S-polarized light or P-polarized light that is directed toward the first beam shifter 110.

[0042] It should be noted that the first polarizer 130 is a rotatable structure. By rotating the first polarizer 130, the circularly polarized light can be converted into S-polarized light that is directed toward the first beam shifter 110, or the circularly polarized light can be converted into P-polarized light that is directed toward the first beam shifter 110.

[0043] like Figure 2 As shown, the circularly polarized light is converted into linearly polarized light by the first polarizer 130 and selected as P-polarized light.

[0044] When the incident light is circularly polarized, rotating the first polarizer 130 converts it into P-polarized light directed toward the first beam shifter 110. Then, the P-polarized light exits through the first beam shifter 110 toward the fifth position of the first waveplate 120. Next, the first waveplate 120 converts the P-polarized light into linearly polarized light directed toward the first position of the semi-reflective prism 200, wherein the polarization direction of the linearly polarized light is S-polarization. Then, the linearly polarized light is transmitted through the semi-reflective prism 200 to the second optical polarization shifting assembly 300. From there, the linearly polarized light is converted into second linearly polarized light by the second optical polarization shifting assembly 300, and the second linearly polarized light exits toward the second position of the microscope objective 400, wherein the polarization direction of the second linearly polarized light is S-polarization. The polarization direction is S-polarization, and the second position is the side position of the microscope objective 400. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. In addition, the second harmonic signal is emitted from the microscope objective 400 to the second optical polarization shifting component 300. Furthermore, the second harmonic signal is converted into S-polarized and P-polarized beams by the second optical polarization shifting component 300. The S-polarized beam is emitted towards the third position of the semi-reflective prism 200, and the P-polarized beam is emitted towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beams are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, the embodiments of this application can realize the translation of incident light through the first optical polarization shifting component 100, and combined with the microscope objective 400, can realize the incident light obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600.

[0045] It should be noted that when circularly polarized light is converted into P-polarized light, the P-polarized light will be emitted towards the fifth position of the first waveplate 120 through the first beam shifter 110. The fifth position is the side position of the first waveplate 120. Since the fifth position of the first waveplate 120 and the first position of the semi-reflective prism 200 are on the same horizontal line, the first position is the side position of the semi-reflective prism 200. The fifth position can be the position 2.7 mm to the side of the first waveplate 120.

[0046] In one embodiment, when the incident light is circularly polarized, the circularly polarized light is converted into S-polarized light directed toward the first beam shifter 110 by rotating the first polarizer 130. Then, the S-polarized light exits through the first beam shifter 110 toward the fifth position of the first waveplate 120. Next, the first waveplate 120 converts the S-polarized light into first linearly polarized light exiting toward the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the P-polarization direction. Next, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second optical polarization shifting assembly 300. Thereafter, the P-polarized light is converted into second linearly polarized light by the second optical polarization shifting assembly 300, and the second linearly polarized light exits toward the second position of the microscope objective 400, wherein the second linearly polarized light... The polarization direction of the polarized light is P-polarization, and the second position is the side position of the microscope objective 400. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. In addition, the second harmonic signal is emitted from the microscope objective 400 to the second optical polarization shifting component 300. Furthermore, the second harmonic signal is converted into S-polarized and P-polarized beams by the second optical polarization shifting component 300. The S-polarized beam is emitted towards the third position of the semi-reflective prism 200, and the P-polarized beam is emitted towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beams are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, the embodiments of this application can realize the translation of incident light through the second optical polarization shifting component 300, and combined with the microscope objective 400, can realize the incident light obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600.

[0047] It should be noted that when circularly polarized light is converted into S-polarized light, the S-polarized light will be emitted towards the fifth position of the first waveplate 120 through the first beam shifter 110. The fifth position is the middle position of the first waveplate 120. Since the fifth position of the first waveplate 120 and the first position of the semi-reflective prism 200 are on the same horizontal line, the first position is the middle position of the semi-reflective prism 200.

[0048] It should be noted that both the first beam shifter 110 and the first waveplate 120 mentioned above are rotatable structures.

[0049] like Figure 3 As shown, Figure 3 This is a schematic diagram of the path and polarization direction of incident light during the rotation of the first optical polarization shifting component provided in one embodiment of this application.

[0050] It should be noted that when the incident light is P-polarized light, during the rotation of the first optical polarization shifting component 100, the path of the incident light is a circle with a radius of 2.7 mm, and the polarization direction of the incident light is always tangent to the circle. Therefore, the first optical polarization shifting component 100 can rotate around the center point in space and obtain S-polarized light.

[0051] Specifically, such as Figure 2 As shown, when the incident light is circularly polarized, a third waveplate 700 is provided in the incident direction of the first polarizer 130, wherein the third waveplate 700 is used to convert the third linearly polarized light emitted by the laser source into circularly polarized light.

[0052] It should be noted that the third linearly polarized light is incident on the third waveplate 700 at an angle of 45 degrees away from the fast axis of the third waveplate 700, thereby changing the polarization state of the third linearly polarized light from linearly polarized light to circularly polarized light.

[0053] Specifically, such as Figure 1 and Figure 2 As shown, the second optical polarization shifting assembly 300 includes a second beam shifter 310 and a second waveplate 320.

[0054] It should be noted that after the first linearly polarized light passes through the second beam shifter 310 and the second wave plate 320, the first linearly polarized light will be converted into S-polarized light or P-polarized light emitted toward the side of the microscope objective 400.

[0055] It should be noted that the fast axis of the second waveplate 320 can be set to 0 degrees or 45 degrees relative to the polarization direction of the incident light. When the fast axis of the second waveplate 320 is set to 0 degrees, the polarization direction of the first linearly polarized light remains unchanged after passing through the second waveplate 320. When the fast axis of the second waveplate 320 is set to 45 degrees, the polarization direction of the second linearly polarized light changes after passing through the second waveplate 320. Therefore, by setting the polarization direction of the fast axis of the second waveplate 320 relative to the incident light, oblique incident excitation of P-polarized light and S-polarized light can be achieved in the same anisotropic second harmonic detection device, thereby enabling the detection of the out-of-plane components of the nonlinear polarizability tensor.

[0056] Understandably, when the fast axis of the second waveplate 320 is set to 0 degrees with the polarization direction of the incident light, and the polarization direction of the first linearly polarized light is P-polarized, the first linearly polarized light is transformed by the second beam shifter 310 and the second waveplate 320 into P-polarized light emitted toward the side of the microscope objective 400; when the fast axis of the second waveplate 320 is set to 0 degrees with the polarization direction of the incident light, and the polarization direction of the first linearly polarized light is S-polarized, the first linearly polarized light is transformed by the second beam shifter 310 and the second waveplate 320 into S-polarized light emitted toward the side of the microscope objective 400. When the fast axis of the second waveplate 320 is set at 45 degrees to the polarization direction of the incident light, and the polarization direction of the first linearly polarized light is the P-polarization direction, the first linearly polarized light is transformed into S-polarized light emitted toward the side of the microscope objective 400 by the second beam shifter 310 and the second waveplate 320; when the fast axis of the second waveplate 320 is set at 45 degrees to the polarization direction of the incident light, and the polarization direction of the first linearly polarized light is the S-polarization direction, the first linearly polarized light is transformed into P-polarized light emitted toward the side of the microscope objective 400 by the second beam shifter 310 and the second waveplate 320.

[0057] In one embodiment, when the fast axis of the second waveplate 320 is set at 45 degrees to the polarization direction of the incident light and the incident light is circularly polarized, the circularly polarized light is converted into P-polarized light toward the first beam shifter 110 by rotating the first polarizer 130. Then, the P-polarized light exits through the first beam shifter 110 toward the fifth position of the first waveplate 120. Next, the first waveplate 120 converts the P-polarized light into first linearly polarized light exiting toward the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the S-polarization direction. Then, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second beam shifter 310 and the second waveplate 320. Subsequently, the first linearly polarized light is converted into second linearly polarized light by the second waveplate 320, and the second linearly polarized light exits toward the microscope objective 400. The light exits from the second position, where the polarization direction of the second linearly polarized light is P-polarization, and the second position is the side position of the microscope objective 400. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. Furthermore, the second harmonic signal exits through the microscope objective 400 to the second optical polarization shifting component 300. Moreover, the second harmonic signal is converted into S-polarized and P-polarized beams by the second optical polarization shifting component 300. The S-polarized beam is emitted towards the third position of the semi-reflective prism 200, and the P-polarized beam is emitted towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beams are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, in this embodiment, the incident light can be translated by the first optical polarization shifting component 100, and combined with the microscope objective 400, the incident light can be obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600. In addition, in this embodiment, the polarization direction of the first linearly polarized light can be changed by setting the angle between the fast axis direction of the second waveplate 320 and the polarization direction of the incident light, thereby obtaining the second linearly polarized light. Therefore, in this embodiment, the oblique incident excitation of P-polarized light and S-polarized light in the same anisotropic second harmonic detection device can be used to detect the out-of-plane component of the nonlinear polarizability tensor.

[0058] In one embodiment, when the fast axis of the second waveplate 320 is set to 0 degrees with the polarization direction of the incident light and the incident light is circularly polarized, the circularly polarized light is converted into P-polarized light toward the first beam shifter 110 by rotating the first polarizer 130. Then, the P-polarized light exits through the first beam shifter 110 toward the fifth position of the first waveplate 120. Next, the first waveplate 120 converts the P-polarized light into first linearly polarized light exiting toward the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the S-polarization direction. Then, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second beam shifter 310 and the second waveplate 320. Finally, the first linearly polarized light is converted into second linearly polarized light by the second waveplate 320, and the second linearly polarized light exits toward the microscope objective 400. The light exits from the second position, where the polarization direction of the second linearly polarized light is S-polarization, and the second position is the side position of the microscope objective 400. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. Furthermore, the second harmonic signal exits through the microscope objective 400 to the second optical polarization shifting component 300. Moreover, the second harmonic signal is converted into S-polarized and P-polarized beam splitting by the second optical polarization shifting component 300. The S-polarized beam splitting exits towards the third position of the semi-reflective prism 200, and the P-polarized beam splitting exits towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beam splitting are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, in this embodiment, the incident light can be translated by the first optical polarization shifting component 100, and combined with the microscope objective 400, the incident light can be obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600. In addition, in this embodiment, the polarization direction of the first linearly polarized light can be changed by setting the angle between the fast axis direction of the second waveplate 320 and the polarization direction of the incident light, thereby obtaining the second linearly polarized light. Therefore, in this embodiment, the oblique incident excitation of P-polarized light and S-polarized light in the same anisotropic second harmonic detection device can be used to detect the out-of-plane component of the nonlinear polarizability tensor.

[0059] In one embodiment, when the fast axis of the second waveplate 320 is set at 45 degrees to the polarization direction of the incident light and the incident light is circularly polarized, the circularly polarized light is converted into S-polarized light toward the first beam shifter 110 by rotating the first polarizer 130. Then, the S-polarized light exits through the first beam shifter 110 toward the fifth position of the first waveplate 120. Next, the first waveplate 120 converts the S-polarized light into first linearly polarized light exiting toward the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the P-polarization direction. Then, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second beam shifter 310 and the second waveplate 320. Subsequently, the first linearly polarized light is converted into second linearly polarized light by the second waveplate 320, and the second linearly polarized light exits toward the microscope objective 400. The light exits from the second position, where the polarization direction of the second linearly polarized light is S-polarization, and the second position is the side position of the microscope objective 400. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. Furthermore, the second harmonic signal exits through the microscope objective 400 to the second optical polarization shifting component 300. Moreover, the second harmonic signal is converted into S-polarized and P-polarized beam splitting by the second optical polarization shifting component 300. The S-polarized beam splitting exits towards the third position of the semi-reflective prism 200, and the P-polarized beam splitting exits towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beam splitting are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, this embodiment of the application can achieve translation of the incident light through the second optical polarization shifting component 300, and in combination with the microscope objective 400, the incident light can be obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600; in addition, this embodiment of the application can change the polarization direction of the first linearly polarized light by setting the angle between the fast axis direction of the second waveplate 320 and the polarization direction of the incident light, thereby obtaining the second linearly polarized light. Therefore, this embodiment of the application can detect the out-of-plane component of the nonlinear polarizability tensor by obliquely incident excitation of P-polarized light and S-polarized light in the same anisotropic second harmonic detection device.

[0060] In one embodiment, when the fast axis of the second waveplate 320 is set to 0 degrees with the polarization direction of the incident light and the incident light is circularly polarized, the circularly polarized light is converted into S-polarized light toward the first beam shifter 110 by rotating the first polarizer 130. Then, the S-polarized light exits through the first beam shifter 110 toward the fifth position of the first waveplate 120. Next, the first waveplate 120 converts the P-polarized light into first linearly polarized light exiting toward the first position of the semi-reflective prism 200, wherein the polarization direction of the first linearly polarized light is the P-polarization direction. Then, the first linearly polarized light is transmitted through the semi-reflective prism 200 to the second beam shifter 310 and the second waveplate 320. Subsequently, the first linearly polarized light is converted into second linearly polarized light by the second waveplate 320, and the second linearly polarized light exits toward the microscope objective 400. The light exits from the second position, where the polarization direction of the second linearly polarized light is P-polarization, and the second position is the side position of the microscope objective 400. Finally, the second linearly polarized light is focused onto the surface of the sample 600 by the microscope objective 400. After being focused onto the sample 600, the second linearly polarized light is reflected to form a second harmonic signal. Furthermore, the second harmonic signal exits through the microscope objective 400 to the second optical polarization shifting component 300. Moreover, the second harmonic signal is converted into S-polarized and P-polarized beams by the second optical polarization shifting component 300. The S-polarized beam is emitted towards the third position of the semi-reflective prism 200, and the P-polarized beam is emitted towards the fourth position of the semi-reflective prism 200. In addition, the S-polarized and P-polarized beams are reflected by the semi-reflective prism 200 into the detector component 500. Therefore, this embodiment of the application can achieve translation of the incident light through the second optical polarization shifting component 300, and in combination with the microscope objective 400, the incident light can be obliquely incident into the sample 600, thereby obtaining the reflected second harmonic signal, and then obtaining the out-of-plane component of the linear polarizability tensor of the sample 600; in addition, this embodiment of the application can change the polarization direction of the first linearly polarized light by setting the angle between the fast axis direction of the second waveplate 320 and the polarization direction of the incident light, thereby obtaining the second linearly polarized light. Therefore, this embodiment of the application can detect the out-of-plane component of the nonlinear polarizability tensor by obliquely incident excitation of P-polarized light and S-polarized light in the same anisotropic second harmonic detection device.

[0061] It should be noted that after the second harmonic signal passes through the second beam shifter 310 and the second waveplate 320, it will be transformed into an S-polarized beam splitter emitted toward the third position of the semi-reflective prism 200, and into a P-polarized beam splitter emitted toward the fourth position of the semi-reflective prism 200.

[0062] It should be noted that after the second harmonic signal passes through the second waveplate 320, the second harmonic signal with the P-polarization direction will be converted into the S-polarized beam splitter. Then, after the S-polarized beam splitter passes through the second beam shifter 310, it will exit towards the third position of the semi-reflective prism 200. When the P-polarized beam splitter passes through the second beam shifter, it will move laterally by 2.7 mm, and thus exit towards the fourth position of the semi-reflective prism 200.

[0063] It should be noted that the third position mentioned above refers to the side position of the semi-reflective prism 200, and the fourth position refers to the middle position of the semi-reflective prism.

[0064] It should be noted that the second polarization shifting component 300 is a rotatable structure.

[0065] It should be noted that by synchronously rotating the first polarization shift component 100 and the second polarization shift component 300, the second harmonic signal of the sample can be measured along all directions of the sample.

[0066] like Figure 4 As shown, Figure 4 This is a schematic diagram of the path and polarization direction of incident light during the synchronous rotation of the second optical polarization shifting component provided in one embodiment of this application.

[0067] It should be noted that when the incident light is P-polarized light and the fast axis of the second waveplate 320 is set at 45 degrees to the polarization direction of the incident light, during the rotation of the second optical polarization shifting component 300, the path of the incident light is a circle with a radius of 2.7 mm, and the polarization direction of the incident light is always perpendicular to the circle. Therefore, by using the second optical polarization shifting component 300, it is possible to rotate around the center point in space and obtain P-polarized light.

[0068] Specifically, such as Figure 1 and Figure 2 As shown, the incident direction of the detector component 500 is provided with a rotatable second polarizer 800, wherein the second polarizer 800 is used to allow only S-polarized beam splitting to be incident on the detector component 500, or only P-polarized beam splitting to be incident on the detector component 500.

[0069] It should be noted that rotating the second polarizer 800 can be used to allow the S-polarized beam to be incident on the detector component 500, or rotating the second polarizer 800 can be used to allow the S-polarized beam to be incident on the detector component 500.

[0070] Specifically, a filter 900 is provided in the incident direction of the detection component 500.

[0071] It should be noted that since the reflected second linearly polarized light and the S-polarized and P-polarized spectra can all be collected by the detection component 500, a filter 900 is provided in the incident direction of the detection component 500 to filter out the reflected second linearly polarized light.

[0072] Understandably, after the second linearly polarized light is obliquely incident on the surface of the sample 600, a reflected second harmonic signal is obtained, and the second harmonic signal is reflected to the detector component 500. During the process of the second harmonic signal being reflected to the detector component 500, the reflected second linearly polarized light may be mixed in.

[0073] Specifically, a lens 1000 is provided in the incident direction of the detection component 500.

[0074] It should be noted that the lens 1000 is used to focus the S-polarized beam splitting amount and the P-polarized beam splitting amount into the detector component 500, so that the detector component 500 collects the S-polarized beam splitting amount and the P-polarized beam splitting amount.

[0075] It should be noted that the first wave plate 120 mentioned above can be a half-wave plate or two quarter-wave plates, and this application embodiment does not make specific limitations.

[0076] It should be noted that the second wave plate 320 mentioned above can be a 1 / 2 wave plate or two 1 / 4 wave plates, and this application embodiment does not make specific limitations.

[0077] It should be noted that the third wave plate 700 mentioned above can be a quarter wave plate or two eighth wave plates, and this application does not make specific limitations.

[0078] The above provides a detailed description of the preferred embodiments of this application. However, this application is not limited to the above-described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. An anisotropic second harmonic detection device, characterized in that, include: The system comprises a first optical polarization shifting component, a semi-reflective and semi-transparent prism, a second optical polarization shifting component, a microscope objective, and a detection component. The first optical polarization shifting component includes a first beam shifter and a first waveplate, and the second optical polarization shifting component includes a second beam shifter and a second waveplate. The first optical polarization shifting component is used to convert the incident light into first linearly polarized light that exits toward a first position of the semi-reflective and semi-transparent prism; The semi-reflective prism is used to transmit the first linearly polarized light to the second optical polarization shifting component; The second optical polarization shifting component is used to convert the first linearly polarized light into a second linearly polarized light emitted toward a second position of the microscope objective, wherein the second position is a side position of the microscope objective; The microscope objective is used to focus the second linearly polarized light onto the surface of the sample, and to output the second harmonic signal formed by the reflection of the second linearly polarized light from the sample to the second optical polarization shifting component. The second optical polarization shifting component is also used to convert the second harmonic signal into an S-polarized beam splitter emitted toward the third position of the semi-reflective and semi-transparent prism, and into a P-polarized beam splitter emitted toward the fourth position of the semi-reflective and semi-transparent prism. The semi-reflective prism is also used to reflect the S-polarized beam splitting amount and the P-polarized beam splitting amount to the detection component.

2. The anisotropic second harmonic detection device according to claim 1, characterized in that, The incident light is circularly polarized light, and the first optical polarization shifting component further includes a first polarizer.

3. The anisotropic second harmonic detection device according to claim 2, characterized in that, The first polarizer is a rotatable structure.

4. The anisotropic second harmonic detection device according to claim 1, characterized in that, Both the first beam shifter and the first waveplate are rotatable structures.

5. The anisotropic second harmonic detection device according to claim 2, characterized in that, A third waveplate is provided in the incident direction of the first polarizer, and the third waveplate is used to convert the third linearly polarized light emitted by the laser source into the circularly polarized light.

6. The anisotropic second harmonic detection device according to any one of claims 1-5, characterized in that, The polarization direction of the first linearly polarized light is either the S-polarization direction or the P-polarization direction; The first linearly polarized light is converted into S-polarized light or P-polarized light that exits toward the side of the microscope objective by the second beam shifter and the second waveplate. The second harmonic signal is converted by the second beam shifter and the second waveplate into an S-polarized beam splitter emitted toward the third position of the semi-reflective prism and a P-polarized beam splitter emitted toward the fourth position of the semi-reflective prism.

7. The anisotropic second harmonic detection device according to claim 1, characterized in that, The detection component is provided with a rotatable second polarizer in the incident direction. The second polarizer is used to allow only the S-polarized beam to be incident on the detection component, or only the P-polarized beam to be incident on the detection component.

8. The anisotropic second harmonic detection device according to claim 1, characterized in that, The incident direction of the detection component is equipped with a filter.

9. The anisotropic second harmonic detection device according to claim 1, characterized in that, The detection component is equipped with a lens at the incident direction.

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