Near-field optical coupling structure for AFM

Abstract

The utility model discloses a near field optical coupling structure for AFM, including support module, reflector and OAP unit, the support module includes first mounting plate, second mounting plate and third mounting plate, first mounting plate is located the top of second mounting plate, first mounting plate is equipped with the integrally formed body, first bending part and second bending part, the reflector fixed mounting is in third mounting plate and is located reflector placement area, and OAP includes first reflector and second reflector. Near field optical coupling structure for AFM disclosed in the utility model makes OAP distance needle tip and sample closer, can reduce optical element size, significantly improve numerical aperture, more fully utilize U type / open type space, increase optical axis adjustment degree of freedom, and promote near field coupling module stability, facilitate instrument miniaturization and integration.

Description

Technical Field

[0001] This invention belongs to the field of optical coupling technology, specifically relating to a near-field optical coupling structure for AFM. Background Technology

[0002] In systems that combine atomic force microscopy (AFM) with near-field optics (such as scattering scanning near-field optical microscopy s-SNOM, near-field fluorescence microscopy, etc.), the near-field optical coupling structure is a core component. Its core objective is to efficiently focus light onto the tip region of the AFM probe (nanoscale) and accurately collect near-field optical signals (such as scattered light, fluorescence, Raman, etc.) generated by the tip-sample interaction, while suppressing far-field background interference to the greatest extent.

[0003] To incorporate near-field optical coupling modules, commercial AFM scanners often employ a U-shaped / aperture-shaped structure design. Existing near-field optical coupling solutions based on U-shaped / aperture-shaped AFMs include:

[0004] 1. Coaxial lens near-field coupling method, numerical aperture NA~0.35 (the size of the lens barrel limits the improvement of NA), has dispersion, and cannot be applied to near-field spectral measurements;

[0005] 2. Off-axis parabolic mirror near-field coupling method, numerical aperture NA~0.25 (subsequent optical path requires 1-inch to 2-inch aperture optical elements), no dispersion, applicable to near-field spectral measurement.

[0006] In summary, near-field optical coupling schemes based on off-axis parabolic mirrors (OAPs) can avoid chromatic aberration and have a wider range of applications; however, current near-field schemes are mainly based on large-size OAPs, which face limitations such as low numerical aperture and large optical element size.

[0007] Therefore, further improvements will be made to address the aforementioned issues. Utility Model Content

[0008] The main purpose of this invention is to provide a near-field optical coupling structure for AFM, which is linked by a support module, a reflector and an OAP unit, so that the OAP is closer to the tip and the sample, which can reduce the size of optical components, significantly increase the numerical aperture, make fuller use of the U-shaped / open space, increase the degree of freedom of optical axis adjustment, improve the stability of the near-field coupling module, and facilitate the miniaturization and integration of the instrument.

[0009] To achieve the above objectives, this utility model provides a near-field optical coupling structure for AFM, comprising a support module, a reflector, and an OAP unit, wherein:

[0010] The bracket module includes a first mounting plate, a second mounting plate, and a third mounting plate. The first mounting plate is located above the second mounting plate. The first mounting plate has an integrally formed body, a first bent portion, and a second bent portion. The first bent portion and the second bent portion are located on both sides of the body and face the second mounting plate. The first bent portion and the second bent portion are fixedly connected to the second mounting plate, and a channel is formed between the first bent portion and the second bent portion. The center of the second mounting plate has a reflector placement area. The third mounting plate is located at the bottom of the second mounting plate.

[0011] The reflector is fixedly mounted on the third mounting plate and located in the reflector placement area. The OAP unit includes a first reflector and a second reflector. The first reflector is fixedly mounted on the bottom of the body and the second reflector is fixedly mounted on the inner side of the first bend. The reflector is used to reflect the received light to the first reflector, the first reflector is used to reflect the received light to the second reflector, and the second reflector is located on one side of the first reflector and is used to reflect the received light to the probe holder.

[0012] As a further preferred embodiment of the above technical solution, the third mounting plate is fixedly mounted on the displacement adjustment module.

[0013] As a further preferred technical solution to the above technical solution, the probe holder is mounted on a U-shaped / open-shaped AFM scanning head.

[0014] As a further preferred technical solution to the above technical solution, the AFM scanning head is mounted on the AFM scanning stage.

[0015] As a further preferred embodiment of the above technical solution, the OAP unit is suspended above the sample stage of the AFM scanning stage. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] Figure 2 This is a schematic diagram of the structure of this utility model.

[0018] Figure 3 This is a schematic diagram of the structure of this utility model.

[0019] Figure 4 This is a schematic diagram of the foldable optical path of this utility model.

[0020] The reference numerals in the accompanying drawings include: 10, support module; 11, first mounting plate; 111, body; 112, first bend; 113, second bend; 12, second mounting plate; 121, reflector placement area; 13, third mounting plate; 20, reflector; 30, OAP unit; 31, first reflector; 32, second reflector; 40, displacement adjustment module; 50, AFM scanning head; 51, probe holder; 60, AFM scanning stage. Detailed Implementation

[0021] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0022] This utility model discloses a near-field optical coupling structure for AFM. The specific embodiments of the utility model are further described below with reference to preferred embodiments.

[0023] In the embodiments of this utility model, those skilled in the art will note that the samples and the like involved in this utility model can be considered as prior art.

[0024] Preferred embodiment.

[0025] like Figure 1-4 As shown, this utility model discloses a near-field optical coupling structure for AFM, including a support module 10, a (small) reflector 20, and a (small) OAP (off-axis parabolic mirror) unit 30, wherein:

[0026] The bracket module 10 includes a first mounting plate 11, a second mounting plate 12, and a third mounting plate 13. The first mounting plate 11 is located above the second mounting plate 12. The first mounting plate 11 has an integrally formed body 111, a first bending portion 112, and a second bending portion 113. The first bending portion 112 and the second bending portion 113 are respectively located on both sides of the body 111 and both face the second mounting plate 12. The first bending portion 112 and the second bending portion 113 are respectively fixedly connected to the second mounting plate 12, and a channel (for propagating light) is formed between the first bending portion 112 and the second bending portion 113. The second mounting plate 12 has a reflector placement area 121 at its center. The third mounting plate 13 is located at the bottom of the second mounting plate 12.

[0027] The reflector 20 is fixedly mounted on the third mounting plate 13 and located in the reflector placement area 121. The OAP unit 30 includes a first reflector 31 and a second reflector 32. The first reflector 31 is fixedly mounted on the bottom of the body 111 and the second reflector 32 is fixedly mounted on the inner side of the first bent portion 112. The reflector 20 is used to reflect the received light to the first reflector 31, and the first reflector 31 is used to reflect the received light to the second reflector 32. The second reflector 32 is located on one side of the first reflector 31 and is used to reflect the received light to the probe holder 51 (forming a folded optical path through the reflector 20, the first reflector 31 and the second reflector 32).

[0028] Specifically, the third mounting plate 13 is fixedly mounted on the displacement adjustment module 40 (to realize the three-axis displacement adjustment of the entire near-field optical coupling structure).

[0029] More specifically, the probe holder 51 is mounted on the U-shaped / open-type AFM scanning head 50.

[0030] Furthermore, the AFM scanning head 50 is mounted on the AFM scanning stage 60 (where the sample stage is used to place the sample).

[0031] Furthermore, the OAP unit 30 is suspended above the sample stage of the AFM scanning stage 60, specifically diagonally above it. The optical axis direction after passing through the OAP unit is in the range of 40° to 60° with the vertical direction, preferably 55°.

[0032] Preferably, the first reflector 31 is a right-angle prism reflector, and the second reflector 32 is an off-axis parabolic reflector (OAP).

[0033] The optical element size in the OAP unit is less than or equal to 0.5 inches.

[0034] Regarding this utility model:

[0035] “Small OAP + Suspended Assembly”: The OAP is closer to the tip and the sample, significantly improving the numerical aperture. Experiments show that a numerical aperture ≥0.45 can be achieved.

[0036] "Small reflector + folding optical path": Makes better use of U-shaped / open space and increases the degree of freedom in optical axis adjustment;

[0037] "Compact / integrated structure": Improves the stability of the near-field coupling module and facilitates instrument miniaturization and integration.

[0038] It is worth mentioning that the technical features such as the samples involved in this utility model patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement methods of these technical features can be conventionally selected in the field and should not be regarded as the inventive point of this utility model patent. This utility model patent will not elaborate further.

[0039] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A near-field optical coupling structure for AFM, characterized in that, Includes a support module, a reflector, and an OAP unit, wherein: The bracket module includes a first mounting plate, a second mounting plate, and a third mounting plate. The first mounting plate is located above the second mounting plate. The first mounting plate has an integrally formed body, a first bent portion, and a second bent portion. The first bent portion and the second bent portion are located on both sides of the body and face the second mounting plate. The first bent portion and the second bent portion are fixedly connected to the second mounting plate, and a channel is formed between the first bent portion and the second bent portion. The center of the second mounting plate has a reflector placement area. The third mounting plate is located at the bottom of the second mounting plate. The reflector is fixedly mounted on the third mounting plate and located in the reflector placement area. The OAP unit includes a first reflector and a second reflector. The first reflector is fixedly mounted on the bottom of the body and the second reflector is fixedly mounted on the inner side of the first bend. The reflector is used to reflect the received light to the first reflector, the first reflector is used to reflect the received light to the second reflector, and the second reflector is located on one side of the first reflector and is used to reflect the received light to the probe holder.

2. The near-field optical coupling structure for AFM according to claim 1, characterized in that, The third mounting plate is fixedly installed on the displacement adjustment module.

3. The near-field optical coupling structure for AFM according to claim 1, characterized in that, The probe mount is installed on a U-shaped / open-type AFM scanning head.

4. A near-field optical coupling structure for AFM according to claim 3, characterized in that, The AFM scanner head is mounted on the AFM scanning station.

5. A near-field optical coupling structure for AFM according to claim 4, characterized in that, The OAP unit is suspended above the sample stage of the AFM scanning stage.

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