Quantum microscope and wide field detection system

Abstract

The invention relates to the technical field of solid-state spin sensing, and provides a quantum microscope and a wide-field detection system.The quantum microscope is used for microscopic imaging of a diamond NV color center which is excited to generate photoluminescence and comprises a main light path, a detection area, an objective lens, a laser module, a continuous zoom lens, an optical filter and an industrial camera; the continuous zoom lens and the objective lens are combined to shoot the virtual image, the object distance continuous change measurement requirement under the integrated design requirement is met, the objective lens does not need to be replaced, the accuracy of an observation light path can be guaranteed, meanwhile, continuous zoom can be achieved, the clearness of a detection image is guaranteed, and on the basis of the virtual image imaging mode, the measurement precision is improved. The long object distance imaging requirement required by the continuous zoom lens is met, and the miniaturization design of equipment is ensured.

Description

Technical Field

[0001] The present invention relates to the field of solid-state spin sensing technology, and in particular to a quantum microscope and a wide-field detection system for sensing measurement based on diamond NV color centers. Background Art

[0002] Diamond NV color center refers to a specific defect structure in diamond, which is formed by a vacancy and a nitrogen atom in adjacent positions in the diamond lattice. Here, "NV" is the abbreviation of "Nitrogen-Vacancy", which means nitrogen vacancy color center. The electron spin of NV color center can interact with the environment, so it can be used for high-precision magnetic field and magnetic field detection at the nanoscale.

[0003] Under the existing NV color center wide-field system, for the detection sample, it is necessary to roughly judge the size of the sample to be tested, so as to select the corresponding microscope objective lens. If the field of view of the microscope system is too large or too small, it is not conducive to detection. If the field of view is too large, the display range on the CCD is small, resulting in a waste of CCD detection pixels, thereby reducing the sensitivity; if the field of view is too small, the range of the sample to be tested exceeds the CCD receiving area, and erroneous detection results may occur, which is unacceptable. At this time, only by replacing microscope objective lenses with different magnifications can the detection field of view be adjusted to the appropriate size. However, this method brings two disadvantages. One is that it is troublesome to replace. Each time, the objective lens needs to be unscrewed and reinstalled, which is very unfriendly to the integrated system and difficult to operate. In addition, the optical path may be offset during the replacement process, causing the imaging position to change and reducing the imaging quality; the second is that the microscope objective lens only has a fixed magnification, such as 5X, 10X, 20X, 50X, etc., which cannot meet the flexible and changeable detection requirements. Summary of the invention

[0004] The present invention aims to provide a quantum microscope and a wide-field detection system for sensing measurement based on diamond NV color centers, so as to solve the problems raised in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A quantum microscope for microscopic imaging of diamond NV color centers that are stimulated to produce photofluorescence, comprising: Main optical path; The detection area serves as the placement area for the diamond NV color centers; an objective lens, placed along the main optical path and located at the upper side of the detection area, and when the diamond NV color center is located in the detection area, the objective lens forms a virtual image of the diamond NV color center; A laser module, used for outputting excitation light for exciting the diamond NV color center to generate photoluminescence, and the output excitation light is configured to be connected to the main light path and transmitted toward and through the objective lens; A continuously variable magnification lens configured to image a virtual image formed by the objective lens onto a target surface of the camera; A filter, located at the light incident end of the continuous zoom lens, is used to filter out photofluorescence; Industrial camera, whose camera target surface is located at the image plane of the continuous zoom lens, is used to convert the light signal captured by the continuous zoom lens into detection electrical signal output.

[0006] Furthermore, a dichroic mirror capable of realizing the reflection of the excitation light and the penetration of the photoluminescence is included, which is installed in the main light path and can reflect the excitation light output by the laser module and then merge it into the main light path for transmission.

[0007] Furthermore, the laser module includes a first plano-convex lens and a laser, and the excitation light output by the laser is shaped by the first plano-convex lens and then enters the subsequent transmission light path.

[0008] Furthermore, it comprises a reflector which reflects light transmitted along the main optical path and forms a second optical path which forms a specific angle with the main optical path. The filter, the continuously variable magnification lens and the industrial camera are arranged in sequence from near to far on the second optical path.

[0009] Furthermore, it also includes a loading platform, which can realize loading displacement in three directions of XYZ.

[0010] Furthermore, an illumination module is included for outputting red illumination light with a wide spectrum, and the red illumination light outputted by the illumination module is configured to be connected to the main light path and transmitted toward and pass through the objective lens.

[0011] Furthermore, the lighting module includes a beam splitter and a parallel light source arranged on the main light path. When working, a portion of the red illumination light output by the parallel light source is reflected by the beam splitter and connected to the main light path and transmitted toward and through the objective lens, and a portion of the light transmitted along the main light path can penetrate the beam splitter for transmission.

[0012] Furthermore, the laser module also includes a second plano-convex lens, and the red illumination light output by the parallel light source is shaped by the second plano-convex lens before entering the subsequent transmission light path.

[0013] Furthermore, it also includes a microwave radiator, which is used to receive microwave signals and form a microwave field to radiate to the diamond NV color center.

[0014] In addition, the present invention also proposes a wide-field detection system, comprising: One or more quantum microscopes as described in any of the preceding items; The host is used to process and image the detection electrical signals output by the quantum microscope.

[0015] Furthermore, it also includes: A microwave radiator, arranged on the quantum microscope, for receiving microwave signals and forming a microwave field to radiate to the diamond NV color center; The microwave source is electrically connected to the microwave radiator and is used to output microwave signals to the microwave radiator.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention utilizes a continuously variable magnification lens in combination with an objective lens to shoot a virtual image to achieve the continuous change measurement requirement of the object distance under the integrated design requirement. Since there is no need to replace the objective lens, the accuracy of the observation optical path can be guaranteed. At the same time, continuous magnification can be achieved, ensuring the clarity of the detected image. The mode based on virtual image imaging also avoids the requirement of the continuously variable magnification lens for the long object distance on the optical path, ensuring the miniaturization design of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a structure of a quantum microscope for implementing 1; Figure 2 Another schematic diagram of the structure of the quantum microscope in 1 is provided; Figure 3 A schematic diagram of the structure of a quantum microscope for implementing 2; Figure 4 Schematic diagram of the structure of the quantum microscope for implementing 3 types; Figure 5 A schematic diagram of the structure of the microstrip antenna in implementation 3; Figure 6 Schematic diagram of the structure of the wide-field detection system implemented in 4. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings. Example 1

[0021] As attached Figure 1 As shown, this example proposes a quantum microscope for microscopic imaging of diamond NV color centers 10 that are stimulated to produce photofluorescence, comprising a main optical path 1, a detection area 2, an objective lens 3, a laser module 4, a continuously variable magnification lens 5, a filter 6 and an industrial camera 7.

[0022] In this example, the main optical path 1 is a vertical virtual optical path, which is used as the main transmission channel for optical signals such as excitation light and photofluorescence. It is coaxial with the objective lens 3, and the lower side is covered with the diamond NV color center 10 when working. The upper side can directly pass through the continuous zoom lens 5, or it can be connected to the continuous zoom lens 5 after the optical path is changed through the optical fiber module. In a preferred example, as shown in the attached Figure 2 As shown, a reflector 9 is connected to the upper side of the main optical path 1, which reflects the light transmitted along the main optical path 1 and forms a second optical path 12 that forms a specific angle (preferably a vertical design) with the main optical path 1. The filter 6, the continuous zoom lens 5 and the industrial camera 7 are arranged on the second optical path 12 in sequence from near to far. This structural design can shorten the height of the equipment in the longitudinal direction, which is more conducive to the needs of miniaturized structural design.

[0023] In this example, the detection area 2 is a virtual area, which serves as the placement area of ​​the diamond NV color center 10. Its position is within one focal length of the objective lens 3. When the diamond NV color center 10 is located in the detection area, the objective lens 5 forms a virtual image of the diamond NV color center 10, and the virtual image serves as the observation object of the continuous zoom lens 5.

[0024] In this example, the objective lens 3 is placed along the main optical path 1 and is located on the upper side of the detection area 2. When the diamond NV color center 10 is located in the detection area 2, the objective lens 3 forms a virtual image of the diamond NV color center 10. A feature of the present application is that continuous magnification can be achieved without replacing the objective lens to find a clear observation image, but it should be known that the objective lens 3 can be replaced to obtain different observation starting magnifications, which does not conflict with the former.

[0025] In this example, the laser module 4 is used to output excitation light that excites the diamond NV color center 10 to produce photoluminescence, and the output excitation light is configured to be connected to the main optical path 1 and transmitted toward and through the objective lens 3, such as Figure 1 and Figure 2 In the main optical path 1, a dichroic mirror 8 is installed which can realize the reflection of the excitation light and the penetration of the photofluorescence, and the excitation light output by the laser module 4 can be reflected and then merged into the main optical path 1 for transmission. In addition to the laser 41 (which can emit 532nm laser), the laser module 4 can also preferably be equipped with a first plano-convex lens 42. The excitation light output by the laser 41 is shaped by the first plano-convex lens 42 and then enters the subsequent transmission optical path; Figure 1 The excitation light output by the laser is the third light path 13 , which is connected to the main light path 1 through the dichroic mirror 8 . In a preferred design, the third light path 13 is perpendicular or nearly perpendicular to the main light path 1 .

[0026] In this example, the variable magnification lens 5 is configured to magnify the virtual image of the diamond NV color center 10 formed by the objective lens 3 for a second time, and image it on the camera target surface of the industrial camera 7. As we know, the object distance of the variable magnification lens 5 is relatively large, generally not less than 300 mm, which does not conform to the integrated and miniaturized design of the quantum microscope. Therefore, we use the objective lens 3 to magnify the virtual image of the diamond NV color center 10 for the first time (which is farther away on the same side of the diamond NV color center 10). At this time, the virtual image will be projected on the working object distance area of ​​the variable magnification lens 5. The variable magnification lens 5 uses the virtual image as the observation object for a second magnification and imaging. On the camera target surface of the industrial camera 7, in this design, the diamond NV color center 10 only needs to be in the observation area 2 to satisfy the requirement that its virtual image can be observed by the continuous zoom lens 5, which greatly shortens the height requirement of the equipment; during actual detection, the object to be tested is placed in the detection area, the range to be detected is determined, and the diamond NV color center 10 is placed in the range. By fine-tuning its position until a clear picture is presented in the observation area, observe whether the image occupies an appropriate area of ​​the field of view of the industrial camera 7 lens (about 80% is preferred). By adjusting the magnification of the continuous zoom lens 5, the appropriate imaging effect is achieved. In this process, the position of the object to be tested is synchronously adjusted to maintain a clear image.

[0027] In this example, the filter 6 is located at the light incident end of the continuous zoom lens 5 and is used to filter out photofluorescence. For the diamond NV color center, the photofluorescence it produces is red light near a wavelength of 637nm. The light propagating upward along the main line 1 also contains stray light such as excitation light. The filter 6 can filter out stray light such as excitation light.

[0028] In this example, the industrial camera 7 is connected to the imaging port of the continuous zoom lens 5 so that its camera target surface is located at the image plane position of the continuous zoom lens 5, which is used to convert the light signal captured by the continuous zoom lens 5 into a detection electrical signal output. Conventionally, the industrial camera 7 can be a CCD camera or a CMOS camera; based on small size considerations, the continuous zoom lens 5 we choose should have a smaller image distance, such as 10mm-50mm, which can be met by some FA zoom lenses.

[0029] When the above embodiment is in use, the excitation light generated by the laser 41 is shaped by the first plano-convex lens 42 and then irradiated onto the dichroic mirror 8. After reflection, the excitation light passes downward from the main light path 1 through the objective lens 3 to irradiate the diamond NV color center 10. At this time, the diamond NV color center 10 is placed above the object to be tested (closely placed or with a very small interval). The diamond NV color center 10 senses the magnetic field (or temperature, electric field, etc.) generated by the object to be tested, and generates photoluminescence of corresponding intensity under the irradiation of the excitation light. Since the diamond NV color center 10 is within one focal length of the objective lens 3 (detection area), a virtual image located on the lower side of the diamond NV color center 10 is formed. The photoluminescence passes upward along the main light path 1 through the dichroic mirror 8 and the filter 6 (or as shown in the attached figure). Figure 2 As shown, after being reflected by the reflector 9 and penetrating the filter 6, the continuously variable magnification lens 5 collects and amplifies the virtual image (the virtual image is at its working object distance), and the industrial camera 7 finally realizes the photoelectric signal conversion and transmits its converted signal to the external host.

[0030] For this scheme, it works based on the wide-field detection principle, which requires the diamond NV color center to have a larger detection angle. Therefore, we choose large-sized diamond blocks containing uniform NV color centers.

[0031] In some preferred embodiments, a loading platform (not shown in the figure) is also included, which can realize the displacement of the loading platform in three directions of XYZ (i.e., front and back, left and right, and up and down). The loading platform is located below the objective lens 3, and the top of the loading platform is used to place the object to be tested. When working, the diamond NV color center 10 is placed on the surface of the object to be tested, and the position and height of the object to be tested are adjusted by the loading platform until the observed image is clear and occupies an appropriate proportion of the field of view.

[0032] In the aforementioned embodiments including a carrier platform, the diamond NV color center 10 is directly placed on the object to be measured. When the detection area needs to be replaced, it needs to be manually moved and adjusted, which leads to low measurement efficiency. Therefore, in some preferred designs, the diamond NV color center 10 can be fixed under the objective lens 3 by a connector, which will not block its detection process. The fixed diamond NV color center 10 can be adjusted to be at a very small distance from the surface of the object to be measured to ensure that the object to be measured can be accurately measured in the presence of a gap, while not hindering the carrier platform from moving the object to be measured to switch the detection area; for some special cases, such as the uneven surface of the object to be measured, in order to ensure that the detection lift-off values ​​of the diamond NV color center 10 are basically consistent, a real-time ranging device (such as laser ranging) can also be designed on the connector to adjust the carrier platform according to the displayed lift-off difference feedback to achieve lift-off height compensation. Example 2

[0033] Based on the above embodiments, this example proposes a quantum microscope structure with an illumination structure, as shown in the attached Figure 3 As shown, it also includes an illumination module 14 for outputting red illumination light with a wide spectrum, and the red illumination light outputted by the illumination module 14 is configured to be connected to the main optical path 1 and transmitted toward and pass through the objective lens 3 .

[0034] In the existing diamond NV color center wide-field system, due to the addition of a red filter in front of the industrial camera, the industrial camera can only receive red light waves, resulting in the industrial camera receiving light only when the laser is irradiated on the diamond NV color center and red fluorescence is generated. The rest of the area not covering the diamond NV color center is displayed as a dark field, and the sample status cannot be accurately determined. For the convenience of testing, a modular auxiliary lighting module is added to the existing system.

[0035] As an exemplary design, the lighting module 14 includes a beam splitter 143 and a parallel light source 141 arranged on the main light path 1. When working, a part of the red illumination light output by the parallel light source 141 is reflected by the beam splitter 143 and connected to the main light path 1 and transmitted toward and through the objective lens 3. A part of the light transmitted along the main light path 1 can penetrate the beam splitter 143 for transmission. Preferably, the beam splitter 143 is a beam splitter with high transmittance and low reflection, so as to ensure that enough photoluminescence passes through the beam splitter 143 and propagates upward; the coaxial lighting system can use red wide-band light waves to replace traditional white light, so as to improve lighting efficiency and reduce heat; due to the particularity of the imaging optical path of the system, the optical path distance from the objective lens 3 to the continuous zoom lens 5 can be adjusted at will, so the lighting module 14 can be added here, which can not only make the light beam coaxial with the imaging optical path, but also maximize the integration of the system.

[0036] In some preferred designs, the laser module further includes a second plano-convex lens 142. The red illumination light output by the parallel light source 141 is shaped by the second plano-convex lens 142 before entering the subsequent transmission light path. The shaped illumination light has a larger illumination range.

[0037] During specific work, after placing the object to be tested in the detection area 2, turn on the lighting module 14 and start observing. At this time, the surface state of the object to be tested can be seen in the field of vision. Move the object to be tested until the area to be tested moves to the center of the field of vision. At this time, the diamond NV color center 10 can be placed in the area to be tested for work. Before the detection begins, the lighting module 14 needs to be turned off. Example 3

[0038] Based on the above-mentioned embodiments, this example proposes a quantum microscope structure with microwave radiation function, which works based on the optical detection magnetic resonance method (ODMR) and has higher measurement accuracy. Specifically, as shown in the attached Figure 4 As shown, it also includes a microwave radiator 11, which is used to receive microwave signals (transmitted from the outside) and form a microwave field to radiate to the diamond NV color center 10. In a preferred design, as shown in the attached Figure 5 As shown, the microwave radiator 11 is a microstrip antenna 110 , and there is a light hole 111 on the surface of the microwave radiator 110 . The main light path 1 passes through the light hole 111 to irradiate the diamond NV color center 10 on the lower side.

[0039] This example further improves the quantum microscope in the aforementioned embodiment based on the ODMR technology to improve the measurement effect. The application of ODMR technology in the field of diamond NV color center measurement is a public technology and will not be described in detail here. Example 4

[0040] As attached Figure 6 As shown, this embodiment also provides a wide field detection system, comprising: One or more quantum microscopes 16 as described above (without the microwave radiator); The host 17 is used to process and image the detection electrical signal output by the quantum microscope 16 . The industrial camera 7 is electrically connected to the host 17 .

[0041] In addition, another wide-field detection system based on ODMR technology also includes: A microwave radiator, which is arranged on the quantum microscope 16 and is used to receive microwave signals and form a microwave field to radiate to the diamond NV color center; The microwave source 18 is electrically connected to the microwave radiator and is used to output microwave signals to the microwave radiator. Of course, part of the microwave source 18 needs to be connected to the host 17 for data exchange and control.

[0042] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0043] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A quantum microscope for microscopic imaging of diamond NV color centers that are stimulated to produce photofluorescence, characterized in that: Include: Main optical path; The detection area serves as the placement area for the diamond NV color centers; an objective lens, placed along the main optical path and located at the upper side of the detection area, and when the diamond NV color center is located in the detection area, the objective lens forms a virtual image of the diamond NV color center; A laser module, used for outputting excitation light for exciting the diamond NV color center to generate photoluminescence, and the output excitation light is configured to be connected to the main light path and transmitted toward and through the objective lens; A continuously variable magnification lens configured to image a virtual image formed by the objective lens onto a target surface of the camera; A filter, located at the light incident end of the continuous zoom lens, is used to filter out photofluorescence; Industrial camera, whose camera target surface is located at the image plane of the continuous zoom lens, is used to convert the light signal captured by the continuous zoom lens into detection electrical signal output.

2. A quantum microscope according to claim 1, characterized in that: It includes a dichroic mirror that can realize the reflection of excitation light and the penetration of photofluorescence. It is installed in the main light path and can reflect the excitation light output by the laser module and then merge it into the main light path for transmission.

3. A quantum microscope according to claim 1 or 2, characterized in that: The laser module comprises a first plano-convex lens and a laser. The excitation light output by the laser is shaped by the first plano-convex lens and then enters the subsequent transmission light path.

4. A quantum microscope according to claim 1, characterized in that: It includes a reflector which reflects light transmitted along the main light path and forms a second light path which forms a specific angle with the main light path. The filter, the continuous zoom lens and the industrial camera are arranged on the second light path in sequence from near to far.

5. A quantum microscope according to claim 1, characterized in that: It also includes a loading platform, which can realize loading displacement in three directions of XYZ.

6. A quantum microscope according to claim 1, characterized in that: The invention comprises an illumination module for outputting red illumination light with a wide spectrum, and the red illumination light outputted by the illumination module is configured to be connected to the main optical path and transmitted toward and pass through the objective lens.

7. A quantum microscope according to claim 6, characterized in that: The lighting module includes a beam splitter and a parallel light source arranged on the main light path. When working, a portion of the red lighting light output by the parallel light source is reflected by the beam splitter and connected to the main light path and transmitted toward and through the objective lens, and a portion of the light transmitted along the main light path can penetrate the beam splitter for transmission.

8. A quantum microscope according to claim 6 or 7, characterized in that: The laser module further comprises a second plano-convex lens, and the red illumination light output by the parallel light source is shaped by the second plano-convex lens before entering the subsequent transmission light path.

9. A quantum microscope according to claim 1, characterized in that: The device also comprises a microwave radiator, which is used for receiving microwave signals and forming a microwave field to radiate to the diamond NV color center.

10. A wide field detection system, characterized in that: Include: One or more quantum microscopes as claimed in any one of claims 1 to 8; The host is used to process and image the detection electrical signals output by the quantum microscope.

11. A wide field detection system according to claim 10, characterized in that: Also includes: A microwave radiator, arranged on the quantum microscope, for receiving microwave signals and forming a microwave field to radiate to the diamond NV color center; The microwave source is electrically connected to the microwave radiator and is used to output microwave signals to the microwave radiator.

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