CN116086310A

CN116086310A - High-precision positioning measurement method and device based on KB mirror nano experiment system

Info

Publication number: CN116086310A
Application number: CN202310055359.8A
Authority: CN
Inventors: 于海涵; 汤善治; 何天; 廖瑞颖; 欧自娜; 周亮; 李明
Original assignee: Institute of High Energy Physics of CAS
Current assignee: Institute of High Energy Physics of CAS
Priority date: 2023-01-16
Filing date: 2023-01-16
Publication date: 2023-05-09

Abstract

The invention discloses a high-precision positioning measurement method and device based on a KB mirror nano experiment system. The device comprises two independent cavities and at least one set of stability measuring system, wherein the stability measuring system comprises a laser source, a stability measuring component, a target grating, a reflecting unit and a signal processing unit; wherein, a nano KB mirror is arranged in one cavity, a target grating and a reflecting unit are arranged on the nano KB mirror, a sample table is arranged in the other cavity, and a stability measuring component is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, a stability measuring component is arranged on the nano KB mirror, the other cavity is internally provided with a sample table, and the sample table is provided with a target grating and a reflecting unit; the stability measuring component comprises a light splitting unit, a retroreflection unit and a measuring unit. The invention realizes high-precision direct measurement of the displacement stability between the nano KB mirror and the sample stage through compact optical layout with high stability.

Description

High-precision positioning measurement method and device based on KB mirror nano experiment system

Technical Field

The invention belongs to the technical field of synchronous radiation, and particularly relates to a high-precision positioning measurement method and device based on a KB mirror focusing nano experiment system.

Background

High-energy synchrotron radiation light sources (HEPS) have excellent properties such as lower emission angle, higher brightness and higher energy than third-generation light sources, and can realize higher-requirement experiment requirements, but the high-energy HEPS also has more severe requirements on the stability of a beam line experiment station. The light beam after being split, collimated and focused by the precise optical device on the light beam line enters the experiment station, so that the sample is scanned and the experiment is completed. The nano KB mirror is the last key optical device on a light beam line, is the device with the highest requirement on stability in all optical mechanical devices, can focus light spots to the nano scale, and the stability of the nano KB mirror directly influences the position, the size and the light field distribution of the light spots. For the nano KB mirror experiment system, the stability between the nano KB mirror and the sample table in two cavities also represents the relative stability of the light spot and the sample, and the relative stability of the light spot and the sample directly determines whether the experiment can be normally performed, so that a set of measurement system is required to evaluate the stability of the experiment system so as to compensate and correct the offset subsequently, thereby completing the experiment. In addition, in a stable state, the relative position error between the nano KB mirror and the sample stage is required to be in the nano-scale (generally less than 10 nm), so that strict requirements are also put on the precision and resolution of a measurement system.

The invention mainly aims at an advanced KB mirror-based focusing nano experiment system in a fourth-generation synchrotron radiation light source high-performance beam line station, a schematic diagram of the nano KB mirror experiment system is shown as shown in figure 1, the nano KB mirror experiment system comprises a nano KB mirror and a sample stage, wherein the nano KB mirror arranged in a vacuum cavity of the nano KB mirror consists of two mirrors which are arranged in a V KB and HKB way and a clamping gesture adjusting mechanism thereof, and the two mirrors respectively realize focusing in the vertical direction and the horizontal directionThe vacuum degree of the cavity is higher than 1×10 ^-7 Pa, while the sample chamber is in a low vacuum environment, typically a vacuum of 1X 10 ^-1 Pa～10 ^-4 Pa, the sample on the sample table in the sample cavity needs to realize 360-degree rotation, and the two cavities are divided by the partition board. The nanometer KB mirror and the sample platform are respectively provided with a gesture adjusting mechanism for gesture adjustment, the focal length of the nanometer KB mirror is extremely short, and the distance between the HKB tail end and the sample platform is often only tens of millimeters, so that the requirement on compactness in space is high.

For complex and compact two-cavity environments, direct measurement cannot be achieved using conventional interferometry due to the structural limitations of the separation of the two cavities and the abbe bias principle limitations.

Investigation shows that the positioning measurement methods for the synchronous radiation light source high-resolution experiment system at present mainly comprise two types:

The first kind of third party reference transfer method is to place a laser interferometer on a third party reference except a nano KB mirror and a sample table, obtain displacement stability between the nano KB mirror and the sample table by measuring displacement of the nano KB mirror and the sample table relative to the third party reference respectively and calculating and converting. FIG. 2 is a schematic diagram of a third party reference measurement scheme, wherein FIG. 2 (a) is a schematic diagram of a scheme for realizing displacement stability measurement between an optical element and a sample stage through a third party reference, light beams a and b realize measurement of X-direction displacement of the optical element relative to the sample stage, and light beams c and d realize measurement of Z-direction displacement of the optical element relative to the sample stage; fig. 2 (b) is a schematic diagram of a scheme for measuring displacement stability between the nano KB mirror and the sample stage through a third party reference, wherein beams e and f realize measurement of X-direction displacement of HKB relative to the sample stage, and beams g and h realize measurement of Z-direction displacement of VKB relative to the sample stage.

In the second type of cantilever reference method, a laser interferometer is placed on an extended cantilever of an optical element and a mounting substrate of a posture adjusting mechanism thereof, and the optical element and the interferometer are considered to keep consistent motion based on the cantilever reference method, so that a measuring beam i is normally incident on the surface of a sample stage with high processing precision, and finally, the beam carrying the position information of the sample stage is demodulated, and the scheme is shown in fig. 3. Because the optical element and the laser interferometer keep consistent motion, the information obtained after processing is not only the position information of the sample stage relative to the laser interferometer, but also the position information of the sample stage relative to the optical element, and the positioning measurement between the optical element and the sample stage can be directly realized.

Scheme one disadvantage:

1. in the measurement scheme, a third party reference cannot cross through two different cavities, so that measurement of the meta stability of the nanometer KB mirror and the sample table in the same cavity can be realized, and the measurement method cannot be applied to different cavity environments. The measuring method and the measuring device can realize high-precision measurement of the meta stability of the nanometer KB mirror and the sample table which are respectively positioned in two different cavities.

2. In the measurement scheme, the stability of the third party reference is also required to be evaluated and analyzed in a complex manner so as to meet the measurement requirement of high-precision displacement stability. The laser source on the third party reference has a certain distance relative to the ground, and the error caused by instability of the third party reference can be amplified by the distance, so that the measurement accuracy of the system is reduced. This error is particularly pronounced when measuring the relative displacement of the VKB and sample stage in the Z direction when using a third party reference measurement. The interferometer component and the sample stage keep the same reference, the whole optical layout is compact, the error influence is extremely small, and the precision is higher.

3. In this measurement scheme, the interferometer measuring beam needs to be the same as the movement direction of the part to be measured, i.e. perpendicular to the X-ray beam direction, and if the measurement of multidimensional displacement stability is desired, the number of interferometers needs to be increased and a stereoscopic optical path needs to be designed, as shown in fig. 2, the optical paths need to be arranged in both the vertical direction and the horizontal direction, which increases the cost and the difficulty of structural design. According to the invention, the measuring light path is distributed along the X-ray beam direction only, wherein the interferometer component is arranged on the gantry of the sample stage, the target grating and the plane mirror are arranged on the nano KB mirror base, so that the measurement of two-dimensional relative displacement (the relative displacement of the measuring light path in the same direction and the relative displacement of the measuring light path in the vertical direction) can be realized in a compact space, and the three-dimensional design difficulty of the light path can be reduced.

4. In the measurement scheme, when X displacement stability measurement is carried out, the measuring beam needs to be ensured to be normally incident on the central symmetry axis of the cylindrical sample stage, and the precision of the cylindrical surface is required to be extremely high so as to ensure that the measuring beam can be reflected in an original way and is not lost, thus the requirements on processing precision and assembly precision are very high. According to the invention, the interferometer component and the sample stage are arranged together, and the measuring beam is hit to the target grating and the plane mirror on the KB mirror for measurement, so that the processing and the assembly of a cylindrical sample are not required to be considered.

5. In the scheme, if two light beams measured in the same dimension belong to different laser light sources, the processing of the two light beams is asynchronous, and a large error can be introduced. The invention adopts a single laser source, has good synchronism and avoids errors caused by the asynchronism.

Scheme two has the disadvantage:

1. in the scheme, the cantilever cannot penetrate through two different cavities, is more suitable for high-precision measurement of the relative position between the nano KB mirror and the sample table in the same cavity, cannot directly realize positioning measurement of a high-resolution experiment system in different cavities, and has larger Abbe error caused by Abbe bias when multi-dimensional positioning measurement is carried out. The invention can realize high-precision direct measurement of the relative position between the nano KB mirror and the sample table which are divided into two cavities.

2. In the scheme, the stability design requirement on the extension cantilever erected by the interferometer probe is strict, and the stability is difficult to guarantee under the condition that the cantilever structure is longer. For the nano KB mirror experiment system, the VKB is far away from the sample stage, so that the cantilever of the VKB can be greatly prolonged, and the stability of the VKB needs to be considered seriously. The invention does not need to carry out cantilever structure design, and is not influenced by the instability of the cantilever.

3. In this kind of scheme, even only carry out displacement stability measurement to any one dimension of VKB and HKB, also need two cantilevers, this can make the design of two cavitys become very complicated, and increase the degree of difficulty of assembly, if VKB and HKB all need to realize two-dimensional displacement stability measurement, need four cantilevers altogether, in limited space, structural design and the degree of difficulty of processing assembly are very big. According to the invention, a cantilever structure is not needed, two-dimensional measurement can be realized by adopting the target grating and the plane mirror, the influence of the layout of the optical element on the cavity design is small, and only the design of the optical window arrangement of the two-cavity spacing plate is considered in an important way.

Disclosure of Invention

Aiming at the problems existing in the prior art, the invention aims to provide a high-precision positioning measurement method and a device thereof based on a KB mirror focusing nano experiment system. The invention discloses a nano KB mirror and a sample table which belong to different cavities, and under the precondition of structural limitation such as cavity separation and the like and reduction of Abbe bias and the like, the compact optical layout with high stability is adopted, so that error sources are reduced as much as possible to ensure high-precision requirements, and finally, the direct measurement of three-dimensional displacement stability between the nano KB mirror (including a vertical reflecting mirror VKB and a horizontal reflecting mirror HKB) and the sample table is realized, so that the problem of high-precision monitoring difficulty of the position stability of the nano KB mirror and the sample in two different cavity environments in a nano KB mirror experiment system is solved.

The invention relates to a high-precision relative positioning measurement method for a nanometer Kirkpatric-Baez focusing mirror (referred to as a nanometer KB mirror for short) and a sample/sample table in two independent vacuum cavities in a synchronous radiation light source nanometer focusing experimental system. The invention can realize high-precision measurement of the relative position change of the nano KB mirror and the sample table which are respectively positioned in different cavity environments, the measurement system is arranged in the cavity, the direct measurement of the relative position of the nano KB mirror and the sample table is realized, the error source introduced by indirect measurement is reduced, the measurement precision is improved, the complexity of the measurement system is simplified, and finally the difficult problems of high-precision position monitoring and feedback in different independent cavity environments are solved. The method can realize X, Y, Z three-dimensional positioning measurement between the nano KB mirror and the sample stage.

The invention relates to a high-precision positioning measurement system for a nano KB mirror experiment system in different cavity environments in a fourth-generation synchrotron radiation light source high-performance beam line station, which is a small and compact grating interference three-dimensional displacement measurement device, and the system consists of a laser source, a stability measurement component, an optical window, an integrated grating plane mirror unit and a control and processing unit, and is characterized by comprising the following components:

1. Aiming at the nano KB mirror and the sample platform which are relatively moved in different cavity environments, wherein a laser source and a stability measuring component are arranged at the side of the sample platform, an integrated grating plane mirror unit is arranged at the side of the nano KB mirror, and an optical window is arranged between the nano KB mirror and the sample platform for measuring light beams to pass through;

2. based on the above 1, forming a light path structure and a three-dimensional positioning measurement method in which a single measurement (beam) direction coincides with an X-ray beam flow direction;

3. the high-precision measurement of the two-dimensional relative displacement (relative displacement along the layout direction and relative displacement along the direction perpendicular to the layout direction) is realized through the VKB and the HKB respectively and the sample table, namely, the relative displacement between the VKB and the sample table in the Y, Z direction and the relative displacement between the HKB and the sample table in the X, Y direction are realized, and the X, Y, Z three-dimensional positioning measurement between the nano KB mirror system and the sample table can be realized.

When the existing scheme is used for measuring the characteristic 1, the cavity design and processing difficulty can be greatly increased, and errors caused by a long cantilever structure or reference stability can be introduced; when the existing scheme is used for measuring the characteristic 2, the optical path cannot be distributed along the beam line direction only, and only single-dimension relative displacement (the relative displacement in the same direction as the optical path distribution) measurement can be realized; when the existing scheme is used for measuring the characteristic 3, the measuring system cannot only conduct unidirectional light path layout, and bidirectional light path design is needed, so that complexity of light path layout can be increased, accuracy errors caused by interferometer bias and cantilever structure stability are introduced, namely the existing scheme cannot achieve the

characteristics

1, 2 and 3 at the same time.

The technical scheme of the invention is as follows:

the high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising two independent cavities and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a target grating, a reflection unit and a signal processing unit; a nano KB mirror is arranged in one cavity, the target grating and the reflecting unit are arranged on the nano KB mirror, a sample table is arranged in the other cavity, and the stability measuring assembly is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, the nano KB mirror is provided with the stability measuring component, the other cavity is internally provided with a sample table, and the sample table is provided with the target grating and the reflecting unit; the stability measurement assembly comprises a light splitting unit, a retroreflection unit and a measurement unit;

the laser source is used for providing measuring laser for the stability measuring component;

the light splitting unit is used for splitting the measuring laser into two beams of light and measuring the displacement of the sample stage and the nano KB mirror in two directions respectively;

the first measuring beam is respectively incident to a first measuring unit in a first direction as reference light, and is incident to the target grating through the first measuring unit, the target grating is used for enabling the incident light to be diffracted to generate frequency shift and to be incident to the retroreflection unit, the retroreflection unit enables the incident beam to be incident to the first measuring unit through the target grating as measuring light, the reference light and the measuring light which are incident to the first measuring unit are input to the first signal processing unit after interference, and the first signal processing unit calculates displacement in the first direction according to the received interference signals;

The second measuring beam is respectively incident to a second measuring unit in a second direction and a reflecting unit, the reflecting unit reflects the incident light to the second measuring unit as measuring light, the reference light and the measuring light which are incident to the second measuring unit interfere and then are input to a second signal processing unit, and the second signal processing unit calculates displacement in the second direction according to the received interference signal.

The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising a cavity and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a target grating, a reflection unit and a signal processing unit; a nano KB mirror and a sample table are arranged in the cavity;

the target grating and the reflecting unit are arranged on the nano KB mirror, and the stability measuring component is arranged on the sample table; or the stability measuring component is arranged on the nano KB mirror, and the target grating and the reflecting unit are arranged on the sample stage;

the stability measurement assembly comprises a light splitting unit, a retroreflection unit and a measurement unit;

Further, the device comprises two sets of positioning measurement assemblies which are arranged in the vertical direction, wherein the first set of positioning measurement assemblies are arranged in an X-Y plane and are used for measuring the displacement of the HKB in the nano KB mirror and the sample table in the X, Y direction; the second set of positioning measurement components are arranged in the Y-Z plane and are used for measuring the displacement of the VKB and the sample table in the Y, Z direction in the nano KB mirror.

Further, the measuring laser comprises a first polarized component and a second polarized component which are different in frequency and orthogonal in linear polarization direction; the first measurement unit in the first direction includes a first right angle reflecting prism 301, a first polarization splitting prism 302, a first axicon 303, a first quarter wave plate 401, and a second quarter wave plate 403; the second measuring unit in the second direction includes a second right angle reflecting prism 202, a second pyramid prism 304, a third pyramid prism 306, a second polarization splitting prism 305, and a third quarter wave plate 404;

the beam splitting unit splits the measuring laser into two beams with the same polarization state and light intensity, wherein one beam is marked as a beam A, and the other beam is marked as a beam B; the light beam a is split into P light and S light after passing through the first polarization splitting prism 302;

the P light split by the light beam a is used as first measurement light, the P light is changed into circularly polarized light after passing through the second quarter wave plate 403, the circularly polarized light is normally incident to the target grating 501 and is subjected to +1 diffraction, namely first diffraction, the +1 diffracted light is incident to the retroreflection unit 402 for return at a littrow angle, the second diffraction is performed after the incident light is incident to the target grating 501, the diffracted light is changed into S light after passing through the second quarter wave plate 403, the S light is reflected by the first polarization splitting prism 302 and is incident to the first angular cone prism 303, the emergent light of the first angular cone prism 303 is reflected by the first polarization splitting prism 302 and is then passed through the second quarter wave plate 403, the S light is changed into circularly polarized light and is normally incident to the target grating 501 and is subjected to +1 diffraction, namely third diffraction, the circularly polarized light is incident to the retroreflection unit 402 for return at a littrow angle, the circularly polarized light is changed into P light after passing through the second quarter wave plate 403 after being incident to the target grating 501, and is transmitted through the first polarization splitting prism 302 and is used as one path of measurement light;

The S light split by the light beam a is used as the second measurement light, reflected by the first polarization splitting prism 302 to the first right angle reflecting prism 301, then the outgoing light passes through the first quarter wave plate 401, and is changed into circularly polarized light from the S light to be normally incident to the target grating 501 and is diffracted in-1 order, namely, first diffraction, the-1 order diffracted light is incident to the retroreflection unit 402 at the littrow angle and is returned in the original way, the second diffraction is generated after incidence to the target grating 501, and is changed into P light from circularly polarized light after passing through the first quarter wave plate 401, the P light is reflected by the first right angle reflecting prism 301, then transmitted through the first polarization splitting prism 302 and is incident to the first angular cone prism 303, the outgoing light of the first angular cone prism 303 is transmitted through the first polarization splitting prism 302, then, the light enters the first right-angle reflecting prism 301 and is emitted vertically, the emitted light is converted into circularly polarized light by the first quarter wave plate 401, then is normally incident to the target grating 501 and is diffracted in the-1 order, namely, is diffracted in the third order, enters the retroreflection unit 402 in the Littrow angle and returns in the original way, is diffracted in the fourth order after entering the target grating 501 again, is converted into S light by circularly polarized light by the first quarter wave plate 401, is reflected by the first right-angle reflecting prism 301, and then enters the first polarization beam splitting prism 302 and is reflected, the reflected light is overlapped with the first measuring light transmitted through the first polarization beam splitting prism 302, so that an interference signal is generated and is transmitted to the first signal processing unit COM;

The light beam B vertically exits after entering the second right angle reflecting prism 202, the exiting light enters the second polarization splitting prism 305, and is split into two orthogonally polarized P light and S light at the second polarization splitting prism 305;

the P light split by the light beam B is transmitted through the second polarization splitting prism 305 and then passes through the third quarter wave plate 404, the polarization state of the P light is converted into circularly polarized light and is normally incident to the reflecting unit 502, then the circularly polarized light is converted into S light after being originally reflected to the third quarter wave plate 404 and is incident to the second polarization splitting prism 305, the light beam is reflected to the third pyramid prism 306, the emergent light of the third pyramid prism 306 is reflected by the second polarization splitting prism 305, and the reflected S light is reflected by the third quarter wave plate 404 and the reflecting unit 502 in sequence and is incident to the second right angle reflecting prism 202 through the third quarter wave plate 404 and the second polarization splitting prism 305 to be used as one measuring light;

the S light split by the beam B is reflected to the second pyramid prism 304 by the second polarization splitting prism 305, and the S light emitted by the second pyramid prism 304 is sequentially reflected by the second polarization splitting prism 305 and the second right angle reflecting prism 202, and then is overlapped with the measurement light, so as to generate an interference signal, and is transmitted to the second signal processing unit COM.

Further, the laser source is positioned in the cavity, and an optical fiber is adopted to feed the laser source into the stability measuring assembly, so as to provide measuring laser for the stability measuring assembly; or the laser source is positioned outside the cavity, and the output measuring laser is directly emitted into the cavity through the optical incident window to provide measuring laser for the stability measuring component; the light splitting unit is a non-polarized light splitting prism or a light splitting grating; the target grating is a reflection grating or a transmission grating, and when the target grating is a transmission grating, the retroreflection unit is positioned behind the transmission grating; the reflecting unit is a plane mirror or a grating.

The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising two independent cavities and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a target grating and a signal processing unit; a nano KB mirror is arranged in one cavity, the target grating is arranged on the nano KB mirror, a sample table is arranged in the other cavity, and the stability measuring component is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, the nano KB mirror is provided with the stability measuring component, the other cavity is internally provided with a sample table, and the sample table is provided with the target grating; the stability measurement assembly includes a retroreflective unit, a measurement unit;

the measuring laser is respectively incident to the measuring unit as reference light and the target grating through the measuring unit, the target grating is used for enabling the incident light to be diffracted to generate frequency shift and to be incident to the retroreflection unit, the retroreflection unit enables the incident light beam to be incident to the measuring unit through the target grating as measuring light, the reference light and the measuring light which are incident to the measuring unit are input to the signal processing unit after interference, and the signal processing unit calculates and obtains the displacement of the sample stage and the nano KB mirror according to the received interference signals.

The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising two independent cavities and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a reflection unit and a signal processing unit; wherein a nano KB mirror is arranged in one cavity, the reflecting unit is arranged on the nano KB mirror, a sample table is arranged in the other cavity, and the stability measuring component is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, the nano KB mirror is provided with the stability measuring component, the other cavity is internally provided with a sample table, and the sample table is provided with the reflecting unit; the stability measurement assembly includes a retroreflective unit, a measurement unit;

the measuring laser is respectively incident to the measuring unit as reference light and is incident to the reflecting unit through the measuring unit, the reflecting unit reflects the incident light to the measuring unit as measuring light, the reference light and the measuring light which are incident to the measuring unit are interfered and then input to the signal processing unit, and the signal processing unit calculates and obtains the displacement of the sample stage and the nano KB mirror according to the received interference signal.

Further, two cavities are obtained by arranging a middle partition plate in a cavity made of opaque materials; an optical window is arranged on the middle partition board and is used for passing measuring light beams in the two cavities; or the two cavities are all cavities made of opaque materials, and optical windows are respectively arranged on the opposite surfaces of the two cavities and used for measuring light beams in the two cavities to pass through; or the two cavities are made of transparent materials.

A positioning measurement method based on a multidimensional positioning measurement device comprises the following steps:

1) The laser source is used for making the output measuring laser incident to the light splitting unit, and the light splitting unit is used for splitting the measuring laser into two beams of light;

2) The first measuring beam is incident to a first measuring unit in a first direction as reference light, and simultaneously the first measuring beam is incident to the target grating through the first measuring unit, and the target grating diffracts the incident light to generate frequency shift and is incident to the retroreflection unit;

3) The retroreflection unit makes an incident light beam enter the first measurement unit through the target grating as measurement light;

4) The reference light and the measuring light which are incident to the first measuring unit interfere and then are input into the first signal processing unit, and the first signal processing unit calculates and obtains the displacement of the sample stage and the nano KB mirror in the first direction according to the received interference signals;

5) A second measuring beam is incident on a second measuring unit in a second direction as reference light, while the second measuring beam is incident on the reflecting unit;

6) The reflection unit reflects incident light and makes the incident light incident on the second measurement unit as measurement light;

7) The reference light and the measuring light which are incident to the second measuring unit interfere and then are input into the second signal processing unit, and the second signal processing unit calculates and obtains the displacement of the sample stage and the nano KB mirror in the second direction according to the received interference signals.

A positioning measurement method based on a single-dimension positioning measurement device comprises the following steps:

1) The laser source is used for making the output measuring laser incident to the measuring unit as reference light, and the measuring laser is incident to the target grating through the measuring unit;

2) The target grating diffracts incident light to generate frequency shift and is incident to the retroreflection unit;

3) The retroreflection unit makes an incident light beam incident to the measurement unit through the target grating as measurement light;

4) The reference light and the measuring light which are incident to the measuring unit interfere and then are input into the signal processing unit;

5) And the signal processing unit calculates and obtains the displacement of the sample stage and the nano KB mirror according to the received interference signal.

The invention has the following advantages:

according to the invention, by combining the laser interferometer and the grating measurement, a measuring light path is distributed along the X-ray beam direction, high-precision direct measurement of three-dimensional displacement between the nano KB mirror and the sample table which are respectively in different cavity environments is realized by using compact optical distribution, and meanwhile, the resolution of the system is further improved by subdividing the measuring light path.

Compared with the light path layout parallel to the moving direction in the traditional interferometer measuring method, the light path layout directly measured along the X-ray beam direction avoids complex design and stability measurement of a cavity and a cantilever, reduces the task amount of mechanical design and processing, reduces the processing and assembly precision of a sample stage, simultaneously avoids complex three-dimensional light path design, reduces error sources by adopting a direct measuring method, and ensures the requirement on precision.

Drawings

FIG. 1 is a schematic diagram of a nano KB mirror experiment system showing the relative positions of a nano KB mirror and a sample stage described in the present invention;

FIG. 2 is a schematic diagram of a third party reference transfer method;

(a) Schematic scheme for realizing displacement stability measurement between the optical element and the sample stage through a third party reference;

(b) The scheme is schematically shown for realizing displacement stability measurement between the nano KB mirror and the sample table through a third party reference.

Fig. 3 is a schematic diagram of a cantilever referencing method.

Fig. 4 is a schematic diagram of a nano KB mirror experiment system and a high-precision positioning measurement device in the present invention.

FIG. 5 is a schematic diagram of a HKB stability measurement system apparatus;

(a) A perspective view of the HKB stability measuring system device and (b) a plan view of the HKB stability measuring system device.

Fig. 6 is a schematic diagram of an X-direction stability measurement scheme of HKB, showing a schematic diagram of the apparatus when only HKB X-direction stability measurement is performed.

Fig. 7 is a schematic diagram of secondary diffraction.

Fig. 8 is a schematic diagram of a measurement scheme of HKB stability when the retroreflective unit is external.

Fig. 9 is a schematic view of a retroreflective element alternative;

(a) is a plane mirror, (b) is a plane mirror focusing mirror combination, (c) is a right angle reflecting prism, and (d) is a pyramid prism.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawings, the examples being given for the purpose of illustration only and not for the purpose of limiting the scope of the invention.

Fig. 4 is a schematic diagram of a nano KB mirror experiment system and a high-precision positioning measurement device, wherein a middle partition plate with an optical window for a measurement beam and a beam line to pass through separates a nano KB mirror cavity from a sample cavity, and the positioning measurement device comprises an HKB stability measurement laser source, an HKB stability measurement assembly, a VKB stability measurement laser source, a VKB stability measurement assembly, an HKB measurement integrated grating plane mirror unit, and a VKB measurement integrated grating plane mirror unit. The HKB stability measuring laser source, the HKB stability measuring component, the VKB stability measuring laser source and the VKB stability measuring component are all positioned on a portal frame in a sample cavity, the same standard is kept on the sample table, and the standard is used for measuring an integral grating plane mirror unit (a target grating and a target plane mirror) for HKB measurement and an integral grating plane mirror unit (a target grating and a target plane mirror) for VKB measurement in the cavity of the nano KB mirror, so that the nano KB mirror and the sample stability can be obtained.

Fig. 4 is a schematic diagram of a nano KB mirror experiment system and a high-precision positioning device, which comprises a portal frame 1, a sample stage 2, an hkb stability measuring laser source 3, an hkb stability measuring component 4, an integral grating plane mirror unit for hkb measurement 5, an hkb unit 6, a vkb unit 7, an integral grating plane mirror unit for vkb measurement 8, a vkb stability measuring component 9, and a vkb stability measuring laser source 10.

Because the HKB stability measuring system and the VKB stability measuring system have the same measuring principle and optical path layout, the devices of the two stability measuring systems are the same and only have different installation directions, wherein the HKB stability measuring system is installed in an X-Y plane, and the VKB stability measuring system is installed in a Y-Z plane. The HKB stability measurement system is described in detail. FIG. 5 is a schematic diagram of a HKB stability measurement system. The stability measurement system device main body consists of a laser source, a stability measurement component (comprising a light splitting unit, a retroreflection unit and a measurement unit), an integrated grating plane mirror unit and a signal processing unit COM, wherein the light splitting unit is a non-polarized light splitting prism 201 in the example; the retroreflective elements in the example are reflective gratings 402; the measuring units comprise an X-direction stability measuring unit and a Y-direction stability measuring unit for realizing the HKB, wherein the X-direction stability measuring unit for realizing the HKB in the example comprises a first right-angle reflecting prism 301, a first polarization beam splitter prism 302, a first angular cone prism 303, a first quarter wave plate 401 and a second quarter wave plate 403, and the Y-direction stability measuring unit for realizing the HKB in the example comprises a second right-angle reflecting prism 202, a second angular cone prism 304 and a third angular cone prism 306, a second polarization beam splitter prism 305 and a third quarter wave plate 404; the integrated grating mirror unit in the example consists of a target grating 501 and a target mirror 502. The two cavities are separated by the baffle, and an optical window is arranged on the baffle for the measuring light beam to pass through.

For HKB stability measurement, the X-direction displacement measurement unit includes a first right angle reflecting prism 301, a first polarization splitting prism 302, a first angular cone prism 303, a first quarter wave plate 401, and a second quarter wave plate 403; the Y-direction displacement measuring unit includes a second right angle reflecting prism 202, a second corner cube 304 and a third corner cube 306, a second polarization splitting prism 305, and a third quarter wave plate 404.

The laser source is used for providing a laser beam and a reference signal, the laser beam output by the laser source comprises a first polarized component and a second polarized component which are different in frequency and orthogonal in linear polarization direction, and the frequency of the reference signal corresponds to the frequency difference between the first polarized component and the second polarized component;

the unpolarized beam splitting prism is used for performing beam equal ratio beam splitting;

the right angle reflecting prism is used for changing the light beam path at a right angle of 90 degrees;

the polarization beam splitting prism is used for splitting the light beam into S light and P light with orthogonal polarization states;

the pyramid prism is used for reflecting the incident light in the opposite direction and shifting the incident light;

the quarter wave plate is used for changing the polarization state of a light beam, such as linearly polarized light (S light or P light) perpendicularly entering the wave plate, and when the polarization direction is 45 degrees with the optical axis, the emergent light is circularly polarized light, and after re-entering, the emergent light is changed into linearly polarized light (P light and S light).

The reflection grating is symmetrical in left and right side grating facets, so that the original path of the light beam incident at the Littrow angle can be returned, and the retroreflection is completed;

the integrated grating plane mirror unit processes the target grating and the target plane mirror on the same element through an integrated processing method and consists of the target grating and the target plane mirror, wherein the target grating is used for diffracting incident light to generate frequency shift, and the target plane mirror is used for reflecting the incident light;

the signal processing unit COM is used for collecting and processing the interference light signals to obtain the meta-stability between the nano KB mirror and the sample stage.

The laser source emits dual-frequency laser, and the dual-frequency laser is divided into two beams with identical polarization states and light intensities after passing through the unpolarized beam splitter 201, the transmitted light is taken as a beam A, and the reflected light is taken as a beam B.

X-direction displacement measurement for HKB: the light beam a is split into P light and S light after passing through the first polarization splitting prism 302. The P light split by the light beam a is used as first measurement light, the first measurement light is changed into circularly polarized light from the P light after passing through the second quarter wave plate 403, the circularly polarized light passes through the optical window on the partition plate and then is normally incident to the target grating 501, and +1 diffraction is first diffraction, the +1 diffraction light is incident to the reflection grating 402 at a littrow angle and returns in the original path, the second diffraction is generated after the incident light is incident to the target grating 501, the diffraction light returns through the optical window on the partition plate, then the second quarter wave plate 403 is changed into S light from the circularly polarized light, the S light is reflected by the first polarization splitting prism 302 and then is incident to the first angular cone prism 303, the outgoing light deflected by the first angular cone prism 303 is reflected by the first polarization splitting prism 302 and then is changed into circularly polarized light from the S light after passing through the second quarter wave plate 403, then is normally incident to the target grating 501 through the optical window on the partition plate and then is third diffraction, the +1 diffraction is generated, the +1 diffraction light returns in the original path, the incident light is incident to the reflection grating 402 at a littrow angle and returns in the original path, the first diffraction is generated after passing through the fourth diffraction window on the first polarizing prism 403 and then passes through the second quarter wave plate 302 and then is changed into circularly polarized light as first measurement light after passing through the first quarter wave plate 302; the S light split by the light beam a is also diffracted four times as the second measurement light, reflected to the first right angle reflecting prism 301 by the first polarization splitting prism 302, then the outgoing light passes through the first quarter wave plate 401 and is changed from the S light to the circularly polarized light, the outgoing light passes through the optical window on the partition plate, then normal incidence to the target grating 501 and diffraction of-1 order, namely, first diffraction, occur, the diffraction light of-1 order is incident to the reflecting grating 402 at the littrow angle and returns in the original way, the diffraction light of-1 order is incident to the target grating 501 and is diffracted for the second time and passes through the optical window on the partition plate, then the circularly polarized light is changed to P light after passing through the first quarter wave plate 401, the P light is reflected by the first right angle reflecting prism 301, then passes through the first polarization splitting prism 302 and is incident to the first angular cone prism 303, the outgoing light after the offset is transmitted through the first polarization splitting prism 302, the outgoing light is then incident on the first right angle reflecting prism 301 and is emitted vertically, the outgoing light passes through the first quarter wave plate 401 and is changed into circularly polarized light from P light, then the circularly polarized light passes through the optical window on the partition plate and is incident on the target grating 501 normally, and is diffracted in-1 order, namely, diffracted in third order, the-1 diffracted light is incident on the reflecting grating 402 at a littrow angle and returns in the original way, and is incident on the target grating 501 again, and is diffracted in fourth order and returns through the optical window on the partition plate, then the circularly polarized light is changed into S light after passing through the first quarter wave plate 401, the S light is reflected by the first right angle reflecting prism 301, the S light is incident on the first polarization splitting prism 302 and is reflected, the reflected light is overlapped with the first measuring light transmitted through the first polarization splitting prism 302, an interference signal is generated, the interference signal is transmitted to the signal processing unit COM, the Doppler frequency difference Deltaf between the two can be obtained, and then the X-direction displacement of the HKB relative to the sample table can be obtained by solving. Wherein, the propagation of P light and S light does not have a sequence and occurs simultaneously.

Y-direction displacement measurement for HKB: the light beam B is vertically emitted after being incident on the second right angle reflecting prism 202, the emitted light is incident on the second polarization splitting prism 305, the light beam is split into two P light beams and S light beams with orthogonal polarization at the second polarization splitting prism 305, the P light beam is transmitted through the second polarization splitting prism 305 and then passes through a third quarter wave plate 404, the polarization state of the P light beam is converted into circularly polarized light, the circularly polarized light beam passes through an optical window on a partition plate and normally enters a target plane mirror 502, then the circularly polarized light beam is converted into S light beam after being reflected through the first optical window on the partition plate and passes through the third quarter wave plate 404 again, the light beam is reflected to a third pyramid prism 306 after being incident on the second polarization splitting prism 305, the reflected S light beam is reflected by the second polarization pyramid prism 305, the reflected S light beam is offset from the original P light beam, and then sequentially enters the third quarter wave plate 404 and the target plane mirror 502, and is reflected back to the third quarter wave plate 404, and the polarization state of the light beam is changed as follows: s light, circularly polarized light and P light, wherein the P light is transmitted through the second polarization splitting prism 305 and then is used as one path of measuring light by the second right angle reflecting prism 202; the S light split by the beam B is reflected by the second polarization splitting prism 305 to the second pyramid prism 304, and the outgoing S light shifted by the second pyramid prism 304 is reflected by the second polarization splitting prism 305 and the second right angle reflecting prism 202 in sequence, overlaps with the measurement light, generates an interference signal, and transmits the interference signal to the signal processing unit COM, and after analysis processing, the Y-direction displacement of the HKB can be analyzed. Wherein, the propagation of P light and S light does not exist in sequence, and the propagation occurs simultaneously.

Aiming at the X-direction displacement measurement of HKB, the scheme realizes eight times of subdivision effect through positive and negative diffraction orders and eight times of diffraction of two measurement lights, and further improves the resolution of a measurement system. Wherein the + -1 st order diffracted light normal to the target grating 501 satisfies the following grating equation, where d is the grating constant:

dsinθ＝±λ (1)

when HKB has a slight displacement S in the X direction (set to v), the diffracted light emitted from the target grating 501 will undergo a frequency change, a frequency shift, and the single diffraction shift amount is the same, the first measurement light is subjected to a four-time diffraction shift amount Δf according to the doppler principle ₁ The expression can be as follows:

the combination formula (1) can be obtained:

and the second measuring light has opposite frequency shift direction, the fourth diffraction frequency shift quantity Deltaf of the second measuring light ₂ The expression can be as follows:

according to the heterodyne interference principle, two measuring beams interfere, and the Doppler frequency shift quantity Deltaf of an interference signal relative to a reference signal can be expressed as:

thus, it is possible to obtain:

thus, the X-direction displacement S can be obtained by integrating the above formula:

/>

wherein the integration is

To count the number of pulses in a period, T is the count period.

Similarly, for the measurement of the Y-direction displacement of the HKB, the scheme adopts a quadruple optical subdivision design because the measuring beam is incident perpendicular to the plane mirror, and the measurement resolution is further improved on the basis of the resolution of the interferometer.

In the scheme, the laser source can be fed into the vacuum by adopting the optical fiber, and the optical window can be arranged on the vacuum cavity, so that the laser source outside the vacuum directly penetrates through the optical incident window to enter the cavity, and experimental measurement is satisfied.

The scheme is not only limited to the displacement stability measurement of the nano experiment system in different cavities, but also is applicable to the displacement stability measurement of the nano experiment system in the same cavity.

In this embodiment, the middle partition is not limited to the example, and the optical window may be designed according to the actual space size, and all the measuring beams may pass through a larger optical window or the measuring beams may pass through a plurality of small optical windows according to the need.

The scheme is not only limited to measuring the displacement stability of two parts at the same time, but also can measure the displacement stability of a single part or more parts, and only the units are required to be combined and adjusted at the moment.

The solution is not limited to two-dimensional stability measurement of the same component, but one-dimensional stability measurement can be realized, and the units are simplified at this time, for example, when only the stability of the HKB in the X direction is measured, the unpolarized beam splitter prism 201 and the stability measuring unit in the Y direction can be omitted, and the measurement solution is shown in FIG. 6, namely, the measurement after combination adjustment by using the units is in the protection category.

The scheme is not limited to the double-frequency laser interferometer, and is also applicable to a single-frequency laser interferometer.

The beam splitting unit of this embodiment is not limited to the unpolarized beam splitting prism 201, but may be a beam splitting grating.

The optical element for vertically changing the direction of the optical path in this embodiment is not limited to the right

angle reflecting prisms

202 and 301 described in the example, but a plane mirror may be used to achieve the same purpose.

In the scheme, the compactness and the convenience in installation are considered, the integrated grating plane mirror unit is adopted, the unit can be replaced by two independent gratings and plane mirror elements, wherein the target plane mirror 502 element can be replaced by the grating, the same effect as the target plane mirror 501 can be achieved by utilizing zero-order diffraction of the grating, and the measuring beam returns in the original path.

The scheme is not limited to the layout of examples, the positions of the laser source, the stability measuring component and the integrated grating plane mirror unit can be interchanged, the laser source and the stability measuring component can be placed in the nano KB mirror cavity, and a circumferential grating is arranged on the cylindrical sample stage.

The target grating 501 in this embodiment is not limited to a reflective grating, but may be a transmissive grating, and in this case, the position of the reflective grating 402 in fig. 6 needs to be adjusted to the rear of the transmissive grating (target grating), and the position of the reflective grating 402 is mirror-symmetrical with respect to the transmissive grating (target grating), that is, the retroreflective unit is mirror-arranged with the target grating as an axis.

The present solution is not limited to four-time diffraction, but can only realize secondary diffraction to further simplify the structure, and can realize a two-time optical subdivision design through secondary diffraction, at this time, the first quarter wave plate 401, the third quarter wave plate 403 and the first angular cone prism 303 can be omitted, and at this time, the signal processing unit and the interferometer emission port are integrated in a hole. Fig. 7 is a schematic diagram of secondary diffraction after simplifying the structure.

The scheme is not limited to the target grating + -diffraction orders (namely built-in retroreflective units), and can also be

The diffraction orders (i.e., the retroreflection units are external), and the retroreflection units are reasonably placed on the light paths of the diffraction orders corresponding to the diffraction orders, as shown in fig. 8.

The retroreflective unit in this embodiment is not limited to the reflection grating 402 used in the example, but a plane mirror, a plane mirror focusing mirror combination, a right angle reflecting prism, and a corner cube may be used to accomplish the retroreflection of light beams, and when an alternative optical element is used, the layout of the optical unit is not changed. The retroreflective element replacement optical element solution is shown in fig. 9, which shows only one-sided optical paths (403-402), and the other-sided optical paths (401-402) are only required to symmetrically arrange the illustrated optical paths.

Although specific embodiments of the invention have been disclosed for illustrative purposes, it will be appreciated by those skilled in the art that the invention may be implemented with the help of a variety of examples: various alternatives, variations and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will have the scope indicated by the scope of the appended claims.

Claims

1. The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising two independent cavities and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a target grating, a reflection unit and a signal processing unit; a nano KB mirror is arranged in one cavity, the target grating and the reflecting unit are arranged on the nano KB mirror, a sample table is arranged in the other cavity, and the stability measuring assembly is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, the nano KB mirror is provided with the stability measuring component, the other cavity is internally provided with a sample table, and the sample table is provided with the target grating and the reflecting unit; the stability measurement assembly comprises a light splitting unit, a retroreflection unit and a measurement unit;

2. The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising a cavity and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a target grating, a reflection unit and a signal processing unit; a nano KB mirror and a sample table are arranged in the cavity;

3. The positioning measurement device according to claim 1 or 2, comprising two sets of vertically mounted positioning measurement assemblies, a first set of positioning measurement assemblies being mounted in the X-Y plane for measuring the displacement of HKB in the nano KB mirror and the sample stage in the direction X, Y; the second set of positioning measurement components are arranged in the Y-Z plane and are used for measuring the displacement of the VKB and the sample table in the Y, Z direction in the nano KB mirror.

4. The positioning measurement device according to claim 1 or 2, wherein the measurement laser light includes a first polarization component and a second polarization component which are different in frequency and orthogonal in linear polarization direction; the first measuring unit in the first direction comprises a first right-angle reflecting prism (301), a first polarization splitting prism (302), a first angular cone prism (303), a first quarter wave plate (401) and a second quarter wave plate (403); the second measuring unit in the second direction comprises a second right angle reflecting prism (202), a second pyramid prism (304), a third pyramid prism (306), a second polarization splitting prism (305) and a third quarter wave plate (404);

The beam splitting unit splits the measuring laser into two beams with the same polarization state and light intensity, wherein one beam is marked as a beam A, and the other beam is marked as a beam B; the light beam A is divided into P light and S light after passing through a first polarization beam splitting prism (302);

the P light split by the light beam A is taken as first measuring light, the P light is changed into circularly polarized light and normally enters the target grating (501) after passing through the second quarter wave plate (403) and is subjected to +1 diffraction, namely first diffraction, the +1 diffracted light is incident to the retroreflection unit (402) to return at a Littrow angle, the second diffraction is performed after entering the target grating (501), the diffracted light is changed into S light from circularly polarized light after passing through the second quarter wave plate (403), the S light is reflected by the first polarization splitting prism (302) and then enters the first angular cone prism (303), the emergent light of the first angular cone prism (303) is changed into circularly polarized light and normally enters the target grating (501) and is subjected to +1 diffraction, namely third diffraction, the S light is changed into circularly polarized light and normally enters the retroreflection unit (402) to return at a Littrow angle, the circularly polarized light is changed into P light after passing through the second quarter wave plate (403) and is transmitted by the first polarization splitting prism (302) and is taken as measuring light;

The S light split by the light beam A is used as second measuring light, the second measuring light is reflected to a first right-angle reflecting prism (301) through a first polarization splitting prism (302), then the emergent light passes through the first quarter-wave plate (401), the S light is changed into circularly polarized light and normally enters a target grating (501) and is subjected to-1 diffraction, namely, first diffraction, the-1 diffraction light enters a retroreflection unit (402) at a littrow angle and returns in the original path, the second diffraction after entering the target grating (501) is carried out, the first quarter-wave plate (401) is changed into P light from circularly polarized light, the P light is reflected by the first right-angle reflecting prism (301), then the P light passes through the first polarization splitting prism (302) and enters the first angle reflecting prism (303), the emergent light of the first angle reflecting prism (303) passes through the first polarization splitting prism (302), then enters the first right-angle reflecting prism (301) and vertically exits, the emergent light passes through the first quarter-wave plate (401) and is normally enters the target grating (501) and is subjected to-1 diffraction after being changed into circularly polarized light and returns in the original path, the second diffraction after entering the target grating (501), the P light passes through the first right-angle reflecting prism (401) and returns to the first polarization reflecting prism (301), the reflected light is overlapped with the first measuring light transmitted through the first polarization splitting prism (302), generates an interference signal, and transmits the interference signal to the first signal processing unit COM;

The light beam B vertically exits after entering the second right angle reflecting prism (202), the emergent light enters the second polarization beam splitting prism (305), and the emergent light is split into two orthogonally polarized P light and S light at the second polarization beam splitting prism (305);

the P light split by the light beam B is transmitted through a second polarization splitting prism (305) and then passes through a third quarter wave plate (404), the polarization state of the P light is converted into circularly polarized light and is normally incident to a reflecting unit (502), then the circularly polarized light is converted into S light after being originally reflected to the third quarter wave plate (404) and is incident to the second polarization splitting prism (305), the light beam is reflected to a third pyramid prism (306), the emergent light of the third pyramid prism (306) is reflected by the second polarization splitting prism (305), and the reflected S light is reflected through the third quarter wave plate (404) and the reflecting unit (502) in sequence and is incident to a second right angle reflecting prism (202) as one path of measuring light;

the S light split by the light beam B is reflected to the second pyramid prism (304) through the second polarization beam splitting prism (305), and the S light emitted by the second pyramid prism (304) is overlapped with the measuring light after being reflected by the second polarization beam splitting prism (305) and the second right angle reflecting prism (202) in sequence, so that an interference signal is generated and transmitted to the second signal processing unit COM.

5. The positioning measurement device of claim 1 or 2, wherein the laser source is located within the cavity, and an optical fiber is used to feed the laser source to the stability measurement assembly, providing the stability measurement assembly with a measurement laser; or alternatively

The laser source is positioned outside the cavity, and the output measuring laser is directly emitted into the cavity through the optical incident window to provide measuring laser for the stability measuring component; the light splitting unit is a non-polarized light splitting prism or a light splitting grating; the target grating is a reflection grating or a transmission grating, and when the target grating is a transmission grating, the retroreflection unit is positioned behind the transmission grating; the reflecting unit is a plane mirror or a grating.

6. The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising two independent cavities and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a target grating and a signal processing unit; a nano KB mirror is arranged in one cavity, the target grating is arranged on the nano KB mirror, a sample table is arranged in the other cavity, and the stability measuring component is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, the nano KB mirror is provided with the stability measuring component, the other cavity is internally provided with a sample table, and the sample table is provided with the target grating; the stability measurement assembly includes a retroreflective unit, a measurement unit;

7. The high-precision positioning measurement device based on the KB mirror nano experiment system is characterized by comprising two independent cavities and at least one set of stability measurement system, wherein the stability measurement system comprises a laser source, a stability measurement assembly, a reflection unit and a signal processing unit; wherein a nano KB mirror is arranged in one cavity, the reflecting unit is arranged on the nano KB mirror, a sample table is arranged in the other cavity, and the stability measuring component is arranged on the sample table; or one cavity is internally provided with a nano KB mirror, the nano KB mirror is provided with the stability measuring component, the other cavity is internally provided with a sample table, and the sample table is provided with the reflecting unit; the stability measurement assembly includes a retroreflective unit, a measurement unit;

8. The positioning measurement device according to claim 1, 6 or 7, wherein two of said cavities are obtained by arranging an intermediate partition in a cavity of opaque material; an optical window is arranged on the middle partition board and is used for passing measuring light beams in the two cavities; or the two cavities are all cavities made of opaque materials, and optical windows are respectively arranged on the opposite surfaces of the two cavities and used for measuring light beams in the two cavities to pass through; or the two cavities are made of transparent materials.

9. A positioning measurement method based on the positioning measurement device according to any one of claims 1 to 5, comprising the steps of:

10. A positioning measurement method based on the positioning measurement device of claim 7, comprising the steps of: