Infinite far field imaging system and quantum wide field imaging device

Abstract

The invention provides an infinite far-field imaging system and a quantum wide-field imaging device, and the system comprises an infinite far-field lens which is used for imaging an object at an infinite position, and enabling the light to be transmitted in the form of parallel light; the imaging lens is used for converging the parallel light onto an imaging plane; the distance between the infinite field lens and the imaging lens is adjustable; the infinite far field lens comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power and a diaphragm which are sequentially arranged from the object side to the image side. And the third lens is glued with the fourth lens. According to the present invention, the working wave band is designed with the working wave band of 630-750 nm, such that the red fluorescence wave band of the diamond NV color center can be well matched so as to avoid the color difference caused by the inability of the wave band to well match so as to improve the imaging quality; when the device is applied to a quantum wide-field imaging device, the placement of a beam splitter and a filter can be met; large-view-field imaging can be realized, and the imaging efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of optical lenses, and particularly to an infinity field imaging system and a quantum wide-field imaging device. Background Art

[0002] In the existing NV color center imaging field, a finished metallographic infinity microscope is generally used for detection. However, the general design wavelength band of the finished imaging system is the FdC wavelength band, which cannot well match the red fluorescence wavelength band of 637 nm and above in the NV color center imaging system. Chromatic aberration will be introduced during precision measurement and high-resolution imaging, reducing the imaging quality.

[0003] Moreover, when the existing infinity microscope is equipped with an FA lens, since other optical devices need to be inserted into the parallel light area in the middle of the imaging system, the aperture of the FA lens acts as the vignetting diaphragm of the entire imaging system under a long optical path, restricting the brightness of off-axis points participating in imaging and making the off-axis area darker. In the field of NV color center wide-field imaging, this will reduce the contrast, amplify the noise, and reduce the detection effect.

[0004] For the existing microscope with a finished magnification, the numerical aperture is small and the field of view is small at a low magnification. As a result, it cannot be applied to a wide-field detection system under large field of view conditions, and due to the limitation of the numerical aperture, the resolution of the imaging system is small. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an infinity field imaging system and a quantum wide-field imaging device, which are used to solve the problems in the prior art that the finished infinity microscope cannot well match the fluorescence wavelength band of the NV color center, reducing the imaging quality, generating vignetting when the FA lens meets the length requirement of the parallel light area, and having a small field of view at a low magnification.

[0006] To achieve the above purpose and other related purposes, the first aspect of the present invention provides an infinity field imaging system, which sequentially includes, along the optical axis direction from the object side to the image side: An infinity field lens for imaging an object at infinity and making light rays propagate in the form of parallel light; An imaging lens for converging parallel light onto an imaging plane; Wherein, the distance between the infinity field lens and the imaging lens is adjustable; the infinity field lens includes a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a negative optical power, a fourth lens with a positive optical power, and a diaphragm, which are sequentially arranged from the object side to the image side; the third lens and the fourth lens are cemented together.

[0007] Further, the imaging lens includes a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power, which are sequentially arranged along the optical axis from the object side to the image side; the seventh lens and the eighth lens are cemented together.

[0008] Further, the adjustable distance between the infinity field lens and the imaging lens is 0 - 350 mm.

[0009] Further, the optical axis lengths of both the infinity field lens and the imaging lens are 80 - 100 mm.

[0010] Further, the focal length f1 of the infinity field lens satisfies: 80 < f1 < 100, and the focal length f2 of the imaging lens satisfies: 60 < f2 < 70.

[0011] Further, the image formed by the system can match a camera with a target surface size of 2 / 3 inch.

[0012] Further, the magnification of the imaging system is 0.7.

[0013] To achieve the above and other related objectives, a second aspect of the present invention provides a quantum wide-field imaging device, including: The infinity field imaging system as described in any item of the first aspect; A diamond containing NV centers, located between the object to be measured and the object side surface of the infinity field lens; An imaging camera, arranged on the image side of the infinity field imaging system; A dichroic filter and a filter, which are sequentially arranged along the optical axis from the object side to the image side between the infinity field lens and the imaging lens; An illumination module, used to generate excitation light and irradiate the excitation light onto the dichroic filter. The excitation light is used to excite the NV centers to generate fluorescence. After being reflected by the dichroic filter, the excitation light is transmitted through the infinity field lens along the direction from the image side to the object side and then irradiates onto the diamond. The fluorescence generated by the diamond is transmitted through the infinity field lens, the dichroic filter, the filter, and the imaging lens in sequence along the direction from the object side to the image side and then transmitted to the imaging camera to be collected and imaged; A microwave module, used to radiate microwaves to the diamond; A control and processing module, connected to the microwave module and the imaging camera, used to control the microwave frequency radiated by the microwave module, read the imaging data output by the imaging camera, and process and analyze the imaging data.

[0014] Further, it further includes a bias magnetic field module, used to apply a bias magnetic field to the diamond.

[0015] Further, it further includes a beam splitter and an illumination light source. The beam splitter is located between the dichroic filter and the filter. The illumination light source is used to irradiate illumination light onto the beam splitter. After being reflected by the beam splitter, the illumination light irradiates the object side after passing through the dichroic filter and the infinity field lens in sequence along the direction from the image side to the object side. The illumination light reflected by the object side irradiates the imaging camera after passing through the infinity field lens, the dichroic filter, the beam splitter, the filter, and the imaging lens in sequence along the direction from the object side to the image side and is collected and imaged therein.

[0016] As described above, an infinity field imaging system and a quantum wide-field imaging device of the present invention have the following beneficial effects: The imaging system includes an infinity field lens that images an object at infinity and an imaging lens that converges parallel light onto an imaging plane. It is designed with a working wavelength range of 630nm - 750nm, which can better match the red fluorescence wavelength range of diamond NV centers above 637nm (mostly within 637 - 800nm), avoiding chromatic aberration introduced by poor wavelength matching, thereby improving the imaging quality. The adjustable distance between the infinity field lens and the imaging lens is 0 - 350mm, which can accommodate some optical devices inserted in the parallel light region required for, for example, wide-field imaging of diamond NV centers. Moreover, the clear aperture of the incident parallel light surface of the imaging lens can be designed according to the range of parallel light to avoid vignetting. It can achieve large-field imaging, can detect a relatively large area at one time, and can be applied to quantum wide-field imaging to improve the detection effect and imaging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Showing an exemplary structural diagram of the infinity field imaging system of the present invention; Figure 2 Showing a schematic diagram of the light ray transmission of the infinity field imaging system of the present invention; Figure 3 Showing spot diagrams of the infinity field imaging system of the present invention under different working wavelength ranges; Figure 4 Showing the MTF curve of the infinity field imaging system of the present invention; Figure 5 Showing the distortion diagram of the infinity field imaging system of the present invention; Figure 6 Showing a first exemplary diagram of the quantum wide-field imaging device of the present invention; Figure 7 Showing a second exemplary diagram of the quantum wide-field imaging device of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0019] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the layout type of the components may also be more complex.

[0020] Embodiment 1: As Figure 1 shown, this embodiment provides an infinite far-field imaging system, which sequentially includes, along the optical axis direction from the object side to the image side: An infinite far-field lens 1, which is used to image an object at infinity and make the light rays propagate in the form of parallel light; An imaging lens 2, which is used to converge the parallel light onto the imaging plane; Among them, the distance between the infinite far-field lens 1 and the imaging lens 2 is adjustable; the infinite far-field lens 1 includes a first lens 11 with a negative focal power, a second lens 12 with a positive focal power, a third lens 13 with a negative focal power, a fourth lens 14 with a positive focal power, and a diaphragm 15, which are sequentially arranged from the object side to the image side; the third lens 13 and the fourth lens 14 are cemented together.

[0021] The infinite far-field imaging system designed in this embodiment is designed with a working wavelength range of 630nm - 750nm, which can better match the red fluorescence wavelength band of diamond NV color centers above 637nm (mostly within 637 - 800nm), avoid chromatic aberration introduced due to poor wavelength matching, and thus improve the imaging quality. Among them, the focal length f1 of the infinite far-field lens satisfies: 80 < f1 < 100, and the focal length f2 of the imaging lens satisfies: 60 < f2 < 70. The focal length of the first lens is 20 < |f 11 | < 30, the focal length of the second lens is 110 < |f 12 | < 130, the focal length of the third lens is 70 < |f 13 | < 85, and the focal length of the fourth lens is 50 < |f 14The optical axis lengths of both the infinity far-field lens and the imaging lens are 80 - 100 mm, and the adjustable distance between the infinity far-field lens and the imaging lens is 0 - 350 mm, which can meet the requirements of some optical devices inserted in the parallel light region for diamond NV center wide-field imaging. When designing the imaging lens, the clear aperture of the incident parallel light surface of the imaging lens can be designed according to the range of the parallel light to avoid vignetting. This method can reduce the probability of not meeting the imaging requirements caused by the size limitation of the finished FA lens. For example, vignetting may occur due to the small size of the FA lens under a long parallel light path.

[0022] Figure 1 Exemplarily, the first lens 11 is a meniscus lens with the surface facing the object side being concave, the second lens 12 is a biconvex lens, the third lens 13 is a meniscus lens with the surface facing the image side being concave, and the fourth lens 14 is a biconvex lens.

[0023] Table 1 gives the parameters of each lens and Table 2 gives the parameters of the surfaces of each lens. The thickness refers to the distance along the optical axis between the specified surface of the lens and the next surface. For the front surface and the cemented surface of the lens, the thickness is the lens thickness, and for the rear surface of the lens, the thickness is the air gap. The transmittance of the lens materials exemplarily given in the table is relatively high in the working wavelength range of 630 nm - 750 nm, above 80%. By selecting different materials and using them in combination, chromatic aberration and spherical aberration can be corrected to optimize the imaging effect.

[0024] Table 1 Parameters of Each Lens in the Infinity Far-Field Lens

[0025] Table 2 Parameters of the Surfaces of Each Lens in the Infinity Far-Field Lens

[0026] It can be seen from Table 2 that the distance between the object to be measured and the object side surface of the infinity far-field lens (i.e., the front surface of the first lens 11) is 8 mm. When used for NV center measurement, a diamond containing NV centers can be placed between the object and the object side surface of the lens to achieve the measurement of physical quantities such as the magnetic field and temperature of the NV centers for the object to be measured. The standard surfaces in the table are spherical surfaces for both the convex and concave surfaces of the lens, and are flat surfaces for the surface with an infinite radius of curvature.

[0027] For the imaging lens 2, in this embodiment, it includes a fifth lens 21 with a positive focal power, a sixth lens 22 with a positive focal power, a seventh lens 23 with a positive focal power, an eighth lens 24 with a negative focal power, a ninth lens 25 with a negative focal power, and a tenth lens 26 with a positive focal power, which are arranged in sequence from the object side to the image side; the seventh lens 23 and the eighth lens 24 are cemented together. Exemplarily, as Figure 1The fifth lens 21 shown is a meniscus lens with a concave surface facing the object side, the sixth lens 22 is a meniscus lens with a concave surface facing the image side, the seventh lens 23 is a plano-convex lens with a convex surface facing the object side, the eighth lens 24 is a plano-concave lens with a concave surface facing the image side, the ninth lens 25 is a biconcave lens, and the tenth lens 26 is a meniscus lens with a concave surface facing the image side. The focal length of the fifth lens is 180<|f 21 |<200, the focal length of the sixth lens is 120<|f 22 |<140, the focal length of the seventh lens is 110<|f 23 |<130, the focal length of the eighth lens is 65<|f 24 |<75, the focal length of the ninth lens is 200<|f 25 |<220, the focal length of the tenth lens is 50<|f 26 |<65. Table 3 gives the parameters of each lens in the imaging lens and Table 4 gives the parameters of the surfaces of each lens.

[0028] Table 3 Parameters of Each Lens in the Imaging Lens

[0029] Table 4 Parameters of the Surfaces of Each Lens in the Imaging Lens

[0030] It can be seen from Table 4 that for the imaging system provided in this embodiment, the imaging size can reach about 11 mm, which can match a camera with a target surface size of 2 / 3 inch, and the numerical aperture is 0.1, and a magnification of 0.7 times can be achieved, and it can be used to detect a range of 10 mm * 10 mm area. In the field of quantum wide-field imaging, it belongs to large-field imaging; and the entire system is designed with a working wavelength range of 630 nm - 750 nm, which can better match the fluorescence wavelength band generated by, for example, diamond NV color centers, reduce aberration, as Figure 3 shown in the spot diagram, at wavelengths of 630 nm, 700 nm, and 750 nm, the spot RMS is basically within the Airy disk range, and Figure 4 as shown in the MTF modulus diagram, it is close to the diffraction limit, Figure 5 and in the distortion diagram of

[0031] it, the distortion is small, showing excellent imaging performance.

[0032] Embodiment 2: As Figure 6 shown, this embodiment provides a quantum wide-field imaging device, including: The infinity-field imaging system in Embodiment 1; A diamond 3 containing NV centers is located between the object to be measured and the object side of the infinity field lens; An imaging camera 4 is arranged on the image side of the infinity field imaging system; A dichroic mirror 5 and a filter 6 are sequentially arranged between the infinity field lens 1 and the imaging lens 2 along the optical axis from the object side to the image side; An illumination module is used to generate excitation light and irradiate the excitation light onto the dichroic mirror 5. This excitation light is used to excite the NV centers in the diamond to generate fluorescence. The excitation light is reflected by the dichroic mirror 5 and then transmitted through the infinity field lens 1 in the direction from the image side to the object side and irradiated onto the diamond 3. The fluorescence generated by the diamond 3 is transmitted through the infinity field lens 1, the dichroic mirror 5, the filter 6, and the imaging lens 2 in sequence in the direction from the object side to the image side and then transmitted to the imaging camera 4 for collection and imaging; A microwave module 8 is used to radiate microwaves to the diamond; A control and processing module 40 is connected to the microwave module 8 and the imaging camera 4, and is used to control the microwave frequency radiated by the microwave module 8, read the imaging data output by the imaging camera 4, and process and analyze the imaging data.

[0033] The quantum wide-field imaging device of this embodiment can reduce aberration and improve imaging quality based on the matching of the working band of the infinity field imaging system and the fluorescence band of the diamond NV centers; there is an adjustable distance of 0 - 350 mm between the infinity field lens 1 and the imaging lens 2, which can meet the placement of the beam splitter and the filter; it can achieve large-field imaging in a 10 mm * 10 mm area, and thus can improve the imaging efficiency.

[0034] The diamond 3 is located between the object to be measured 9 and the object side of the infinity field lens 1, and can be in a sheet structure to form wide-field imaging over a large range. The imaging camera 4 can be a CCD camera or a CMOS camera.

[0035] The illumination module in this embodiment is exemplary as Figure 6 shown and includes an excitation light source 7. The excitation light source 7 can be a light source in the form of a laser or an LED. The illumination module can also include components for processing the light generated by the light source, such as components for filtering, collimating, focusing, polarizing, and adjusting the light quantity. In this embodiment, the excitation light source 7 uses a laser source. The microwave module 8 can be exemplary including a microwave source 81, a microwave switch 82, a microwave amplifier 83, a microwave circulator 84, and a microwave antenna 85 connected in sequence. The microwave generated by the microwave source 81 is radiated to the diamond 3 by the microwave antenna 85 after being transmitted to the microwave antenna 85. The microwave antenna 85 uses a coplanar waveguide antenna, and the sheet diamond is located in the central hole of the coplanar waveguide or below the central hole. For the object 9 to be detected, it is located on the object side of the infinity field imaging system (such as Figure 2 at the object plane in Figure 6As shown, the diamond 3 is located between the object to be measured 9 and the object side of the infinity field lens 1, and is close to the measurement surface of the object to be measured 9, or can be attached to the measurement surface. Physical quantities such as the magnetic field, current, and temperature of the object to be measured 9 are measured through wide-field imaging.

[0036] The control and processing module 40 exemplarily includes a control module for controlling the microwave frequency switching and a processing module for reading and processing the imaging data transmitted by the imaging camera. The control module, for example, transmits a frequency switching pulse to the microwave source 81 to achieve frequency control, such as achieving frequency scanning, which can be exemplarily implemented by a host computer and a pulse board, and the pulse form can be a TTL signal. The processing module obtains the quantum state of the NV center electron spin by analyzing the imaging data, or detects the magnetic field, temperature, etc. by plotting the ODMR spectrum, which can be exemplarily implemented by a host computer.

[0037] It also includes a bias magnetic field module for applying a bias magnetic field to the diamond 3. The bias magnetic field can be used to adjust the resonance peak generated by the NV center, so as to calculate the magnetic field vector using the change amount of the magnetic field in the axial direction of the color center, or to make the weak magnetic detection of the color center work in the linear region, or to adjust the detection frequency band to improve the sensitivity of weak magnetic detection. The bias magnetic field module includes a magnet 10, which can be an electromagnet or a permanent magnet.

[0038] Embodiment 3: On the basis of Embodiment 2, as Figure 7 shown, the quantum wide-field imaging device in this embodiment further includes a beam splitter 20, which is located between the dichroic filter 5 and the filter 6. It also includes an illumination light source 30 for irradiating illumination light to the beam splitter 20. The illumination light is reflected by the beam splitter 20 and then irradiates the object side in sequence through the dichroic filter 5 and the infinity field lens 1 along the direction from the image side to the object side. The illumination light reflected by the object side irradiates the imaging camera 4 through the infinity field lens 1, the dichroic filter 5, the beam splitter 20, the filter 6, and the imaging lens 2 in sequence along the direction from the object side to the image side and is collected and imaged.

[0039] The beam splitter 20 adopts a type with high transmittance and low reflectance to transmit more illumination light for imaging. For example, a beam splitter with a splitting ratio (T:R) of 9:1 is used. The illumination light uses red light or white light, preferably red light, to reduce heat generation under the same brightness. Since the photoluminescence of the diamond NV center is red light (wavelength 637 - 800nm), the filter 6 also filters out the corresponding red light, and the imaging camera can only receive red light. If the illumination on the object side is weak, the object side observed on the image side is not clear enough to judge the state of the object to be measured. In this embodiment, illumination is added in the optical path for supplementary illumination, which can be used to debug the object to be measured before placing the diamond on the object side, observe the state of the object to be measured, and facilitate the adjustment of the position of the object to be measured. After the adjustment is completed, the diamond is placed between the object to be measured and the object side of the infinity field lens 1, and then the illumination light source can be turned off to enter the subsequent detection steps.

[0040] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. An infinity-field imaging system, characterized in that, Along the optical axis direction from the object side to the image side, it sequentially includes: An infinity field lens for imaging an object at infinity, causing light to propagate in the form of parallel light; An imaging lens for converging the parallel light onto the imaging plane; Among them, the distance between the infinity field lens and the imaging lens is adjustable; the infinity field lens includes a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a negative optical power, a fourth lens with a positive optical power, and a diaphragm, which are sequentially arranged from the object side to the image side; the third lens and the fourth lens are cemented together.

2. The infinity field imaging system according to claim 1, wherein: The imaging lens includes a fifth lens with a positive optical power, a sixth lens with a positive optical power, a seventh lens with a positive optical power, an eighth lens with a negative optical power, a ninth lens with a negative optical power, and a tenth lens with a positive optical power, which are sequentially arranged along the optical axis from the object side to the image side; The seventh lens and the eighth lens are cemented together.

3. The infinity-field imaging system according to claim 1, wherein: The adjustable distance between the infinity field lens and the imaging lens is 0 - 350 mm.

4. The infinity-field imaging system according to claim 1, wherein: The optical axis lengths of both the infinity field lens and the imaging lens are 80 - 100 mm.

5. The infinity field imaging system according to claim 1, wherein: The focal length f1 of the infinity field lens satisfies: 80 < f1 < 100, and the focal length f2 of the imaging lens satisfies: 60 < f2 < 70.

6. The infinity-field imaging system according to claim 1, wherein: The image formed by the system can match a camera with a target surface size of 2 / 3 inch.

7. The infinity-field imaging system according to claim 1, characterized in that: The magnification of the imaging system is 0.

7.

8. A quantum wide-field imaging device, characterized in that, The device includes: An infinity field imaging system according to any one of claims 1 - 7; A diamond containing NV color centers, located between the object to be measured and the object side surface of the infinity field lens; An imaging camera, arranged on the image side of the infinity field imaging system; A dichroic filter and a filter, which are sequentially arranged between the infinity field lens and the imaging lens along the optical axis direction from the object side to the image side; An illumination module for generating excitation light and irradiating the excitation light onto the dichroic filter. The excitation light is used to excite the NV color centers to generate fluorescence. After being reflected by the dichroic filter, the excitation light irradiates the diamond along the direction from the image side to the object side through the infinity field lens. The fluorescence generated by the diamond irradiates the imaging camera after being transmitted through the infinity field lens, the dichroic filter, the filter, and the imaging lens in sequence along the direction from the object side to the image side and is collected for imaging; A microwave module for radiating microwaves to the diamond; A control and processing module, connected to the microwave module and the imaging camera, for controlling the microwave frequency radiated by the microwave module, reading the imaging data output by the imaging camera, and processing and analyzing the imaging data.

9. The quantum wide-field imaging device according to claim 8, wherein: It further includes a bias magnetic field module for applying a bias magnetic field to the diamond.

10. The quantum wide-field imaging device according to claim 8 or 9, characterized in that: It further includes a beam splitter and an illumination light source. The beam splitter is located between the dichroic filter and the filter. The illumination light source is used to irradiate illumination light onto the beam splitter. The illumination light irradiates the object side after being reflected by the beam splitter and transmitted through the dichroic filter and the infinity field lens in sequence along the direction from the image side to the object side. The illumination light reflected by the object side irradiates the imaging camera after being transmitted through the infinity field lens, the dichroic filter, the beam splitter, the filter, and the imaging lens in sequence along the direction from the object side to the image side and is collected for imaging.

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