Gravity measurement method and measurement device for double-atom interferometer

Abstract

The invention provides a gravity measurement method and device for a double-atom interferometer, and the method comprises the steps: enabling an initial atomic group to freely fall in a gravity field of a vacuum cavity after cooling and initial-state preparation, and dividing the initial atomic group into a first atomic group and a second atomic group through beam splitting laser; after the first atomic group and the second atomic group are interfered by the interference laser of the signal interferometer and the reference interferometer respectively, the first atomic group and the second atomic group act with the detection laser to generate a first interference fringe and a second interference fringe; and calculating the gravitational acceleration based on the differential phases of the signal interferometer and the reference interferometer. According to the invention, the reference interferometer is arranged for synchronous measurement, so that phase components sensitive to the initial velocity of atoms and the external environment in the signal interferometer can be greatly suppressed, high-precision gravity measurement of the path open-loop interferometer is realized, and the method adapts to the condition that the path of the atom interferometer on a dynamic platform cannot be closed.

Description

Technical Field

[0001] The present invention relates to the field of atomic gravimeters, and more specifically, to a gravity measurement method and a measurement device of a diatomic interferometer. Background Art

[0002] Atom interferometry uses lasers or microwaves to manipulate the splitting and convergence of atomic matter wave packets. Atoms passing through different paths experience different physical fields, which enables precise measurement of physical quantities. Usually, the atomic interference path is a closed loop, and it is difficult to achieve stable interference phase and high-precision measurement if the path is open.

[0003] One of the important applications of atom interferometer is to measure gravitational acceleration with high precision. Atoms fall freely in the gravitational field, and the atomic group is divided into two parts by the frequency resonant laser. The two atomic groups act as two paths of the interferometer. The potential energy through the gravitational field is different. Finally, the two paths will merge and interfere under the action of the laser. In the final interference phase, there is a phase contributed by gravitational acceleration. By extracting the phase, accurate measurement of gravitational acceleration can be achieved.

[0004] Gravity measurement is of great significance in resource exploration, earthquake prevention and disaster reduction, geophysical research, and military fields. In recent years, high-precision static atomic gravimeters have gradually moved from prototypes to practical applications and achieved product sales. However, dynamic atomic gravimeters are still in the prototype stage and have low measurement accuracy. This is because on a dynamic platform, the atomic interferometer path cannot be closed due to interference from the platform's attached speed and the complex and changing environment on the atomic interferometer measurement signal, which greatly reduces the measurement accuracy of the atomic gravimeter and limits the use of the atomic gravimeter on a dynamic platform. Summary of the invention

[0005] The present invention aims at the technical problem that the gravitational acceleration cannot be accurately measured on a dynamic platform in the prior art, and provides a gravity measurement method and a measurement device of a diatomic interferometer.

[0006] According to a first aspect of the present invention, a gravity measurement method using a diatomic interferometer is provided, comprising:

[0007] After the initial atomic cluster is cooled and prepared in the initial state, it begins to fall freely in the gravity field of the vacuum cavity, and is divided into a first atomic cluster and a second atomic cluster by the splitting laser.

[0008] The first atomic group is acted upon by three interference lasers of the signal interferometer, and after the interference is completed, it acts upon the detection laser, and collects the first interference fringes generated by the signal interferometer;

[0009] The second atomic group is acted upon by three interference lasers of the reference interferometer, and after the interference is completed, it acts upon the detection laser, and collects the second interference fringes generated by the reference interferometer;

[0010] Data processing and analysis are performed on the first interference fringes and the second interference fringes, and gravitational acceleration is calculated based on the differential phase between the signal interferometer and the reference interferometer.

[0011] Based on the above technical solution, the present invention can also make the following improvements.

[0012] Optionally, the initial atomic group, after completing cooling and initial state preparation, comprises:

[0013] The vacuum degree in the vacuum chamber is maintained below 1×10-8Pa using an ion pump and a getter pump. After the initial atomic group is cooled and trapped in the magneto-optical trap, the temperature of the initial atomic group is further reduced to below 2μK using polarization gradient cooling, Raman sideband cooling or evaporative cooling.

[0014] The initial atomic clusters are prepared in their initial state by microwave state selection and Raman state selection, and are prepared into a single magnetically insensitive state.

[0015] Optionally, the split beam laser and the interference laser are large momentum transfer pulses, and the split beam laser and the interference laser share a common optical fiber.

[0016] Optionally, after the initial atomic cluster is cooled and prepared in the initial state, it starts to fall freely in the gravity field of the vacuum cavity, and the initial atomic cluster is divided into a first atomic cluster and a second atomic cluster by a splitting laser, including:

[0017] After the initial atomic group is cooled and prepared in the initial state, the initial state is in the momentum state. At time 0, it starts to fall freely in the gravitational field from point a; after time t1, a split beam laser is applied at point b to split the initial atomic group into the first atomic group and the second atomic group, where the momentum of the first atomic group does not change and is still in the momentum state. The second atom group gains additional momentum and is in the momentum state On, among them, is Planck's constant, and k is the interfering laser wave vector.

[0018] Optionally, the first atomic group is acted upon by three interference lasers of a signal interferometer, acts upon a detection laser after the interference is completed, and collects first interference fringes generated by the signal interferometer, including:

[0019] After the beam splitting, after a time t2, the first atomic group is split again by the π / 2 pulse of the interference laser of the signal interferometer at point c, and the beam is split into the third atomic group and the fourth atomic group, and the third atomic group and the fourth atomic group each account for half of the number of atoms;

[0020] The third atomic group maintains momentum unchanged, the fourth atomic group gains momentum and jumps to After a time T1, the third atom group flies to point d, and the fourth atom group flies to point e. The π pulse of the interference laser of the signal interferometer acts on the third atom group. The fourth atomic group all jumped to After T1+δT, the third atomic group and the fourth atomic group cross at point f, but their positions do not completely overlap. At this time, the π / 2 pulse of the interference laser of the signal interferometer is applied to complete the interference between the third atomic group and the fourth atomic group.

[0021] After time t3, the third atomic cluster and the fourth atomic cluster fly to the detection area, and after interacting with the lateral detection laser, they emit fluorescent signals, and the first interference fringes are detected.

[0022] Optionally, the second atomic group is acted upon by three interference lasers of a reference interferometer, acts upon a detection laser after the interference is completed, and collects second interference fringes generated by the reference interferometer, including:

[0023] After the second atomic group flies from point b for t4 time, it arrives at point g and is split again by the π / 2 pulse of the interference laser of the reference interferometer into the fifth and sixth atomic groups, each of which accounts for half of the number of atoms; the fifth atomic group maintains the momentum state unchanged, the sixth atomic group gains momentum and jumps to After a time T2, the fifth atom group flies to point h, and the sixth atom group flies to point i. The fifth atom group all jumps to point i under the action of the π pulse of the interferometer laser. All the sixth atomic groups jumped to After T2+δT, the fifth and sixth atomic clusters intersect at point j, but their positions do not completely overlap. At this time, the π / 2 pulse of the interference laser of the reference interferometer completes the interference between the fifth and sixth atomic clusters. After time t5, the fifth and sixth atomic clusters fly to the detection area, and after interacting with the horizontal detection laser, they emit fluorescence signals, and the second interference fringes are detected.

[0024] Optionally, the performing data processing and analysis on the first interference fringes and the second interference fringes, and calculating the gravitational acceleration based on the differential phase between the signal interferometer and the reference interferometer, includes:

[0025] The interference phase expression of the signal interferometer output is:

[0026]

[0027] Where α is the frequency sweep slope when interfering laser compensates for atomic Doppler shift, ω r is the atomic recoil frequency, v 0 is the initial velocity of the initial atomic group when it falls freely at point a, δ 0 is the detuning amount of the initial atomic group resonating with the interfering laser at point a;

[0028] The interference phase expression of the reference interferometer output is:

[0029]

[0030] The interference phase output by the signal interferometer is calculated differentially from the interference phase output by the reference interferometer, and the differential phase of the open-loop diatomic interferometer is obtained as follows:

[0031]

[0032] The time taken by the atomic cluster (2-1) and the atomic cluster (2-2) to fly from point a to the detection area is the same, that is:

[0033] t 1 +t 2 +2T 1 +δT+t 3 =t 1 +t 4 +2T 2 +δT+t 5

[0034] get:

[0035] 2(T 2 -T 1 )+t 4 -t 2 =t 3 -t 5

[0036] The differential phase of the open-loop diatomic interferometer is simplified to:

[0037]

[0038] The differential phase of the open-loop diatomic interferometer is solved to obtain the gravitational acceleration g.

[0039] According to a second aspect of the present invention, there is provided a gravity measuring device of a diatomic interferometer, comprising a vacuum cavity, a signal interferometer, a reference interferometer, a fluorescence collection system and a data acquisition system;

[0040] After the atomic clusters are cooled and prepared in the initial state, they begin to fall freely in the gravity field of the vacuum cavity, and the atomic clusters are divided into a first atomic cluster and a second atomic cluster by the splitting laser.

[0041] The first atomic group is acted upon by the three-interference laser of the signal interferometer, and after the interference is completed, it acts upon the detection laser to emit a first fluorescence signal, which is collected by the fluorescence collection system;

[0042] The second atomic group is acted upon by the three-interference laser of the reference interferometer, and after the interference is completed, it reacts with the detection laser to generate a second fluorescence signal, which is collected by the fluorescence collection system;

[0043] The data acquisition system is used to collect and process the first fluorescence information and the second fluorescence signal collected by the fluorescence collection system to obtain the first interference fringes generated by the signal interferometer and the second interference fringes generated by the reference interferometer respectively; and to perform data processing and analysis on the first interference fringes and the second interference fringes, and calculate the gravitational acceleration based on the differential phase between the signal interferometer and the reference interferometer.

[0044] The present invention provides a gravity measurement method and device for a diatomic interferometer. After the initial atomic group is cooled and prepared in the initial state, it begins to fall freely in the gravity field of the vacuum cavity. The initial atomic group is divided into a first atomic group and a second atomic group by a split beam laser. After the first atomic group and the second atomic group are interfered by the interference lasers of the signal interferometer and the reference interferometer, they interact with the detection laser to generate first interference fringes and second interference fringes. The gravity acceleration is calculated based on the differential phase of the signal interferometer and the reference interferometer. By setting a reference interferometer for synchronous measurement, the present invention can greatly suppress the phase component in the signal interferometer that is sensitive to the initial velocity of atoms and the external environment, realize the high-precision gravity measurement of the path open-loop interferometer, and adapt to the situation where the path of the atomic interferometer on the dynamic platform cannot be closed. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart of a gravity measurement method of a diatomic interferometer provided by the present invention;

[0046] Figure 2 This is the timing schematic diagram of the diatomic interferometer with open-loop path;

[0047] Figure 3 A schematic diagram of a gravity measurement device of a diatomic interferometer provided by the present invention.

[0048] In the accompanying drawings, the names represented by the reference numerals are as follows:

[0049] 1. Vacuum cavity, 2. Initial atomic group, 3. Beam splitting laser, 4. Interference laser, 5. Detection laser, 6. Fluorescence collection system, 7. Data acquisition system. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention can be arbitrarily combined with each other to form a feasible technical solution. This combination is not subject to the constraints of the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0051] Figure 1 A flow chart of a gravity measurement method of a diatomic interferometer provided by the present invention, such as Figure 1 As shown, the method includes:

[0052] Step 1: After the initial atomic cluster is cooled and prepared in the initial state, it begins to fall freely in the gravity field of the vacuum cavity, and the initial atomic cluster is divided into a first atomic cluster and a second atomic cluster by a splitting laser.

[0053] It is understandable that, first, the atomic group completes cooling and initial state preparation in the vacuum cavity 1. Specifically, the vacuum cavity 1 uses ion pumps and getter pumps to maintain the vacuum degree below 1×10-8Pa. After the atomic group completes cooling and trapping in the magneto-optical trap, it is necessary to use polarization gradient cooling, Raman sideband cooling or evaporative cooling to further reduce the temperature of the atomic group to below 2μK. Then the atomic group uses microwave state selection and Raman state selection to prepare the initial state, and the atoms are prepared to a single magnetically insensitive state before they can interact with the subsequent split beam laser and interference laser.

[0054] After the initial atomic cluster is cooled and prepared in its initial state, it falls freely in the gravity field in the vacuum chamber 1 and is divided into two parts, namely, a first atomic cluster and a second atomic cluster, by a split beam laser.

[0055] Step 2: The first atomic group is acted upon three times by the interference laser of the signal interferometer, and then acts upon the detection laser after the interference is completed, and the first interference fringes generated by the signal interferometer are collected.

[0056] Step 3, the second atomic group is acted upon three times by the interference laser of the reference interferometer, and after the interference is completed, it acts upon the detection laser, and collects the second interference fringes generated by the reference interferometer.

[0057] The motion process of the atomic group falling freely in the gravitational field can be found in Figure 2 After the cooling and initial state preparation, the atomic group 2 (initial atomic group) is in the momentum state. At time 0, it starts to fall freely in the gravitational field from point a. After time t1, the splitting laser 3 acts at point b to split the atomic group 2 into atomic group 2-1 and atomic group 2-2. The momentum of atomic group 2-1 does not change and is still in the momentum state On the surface, the atomic group 2-2 has gained additional momentum and is in the momentum state Up, n 1 is a positive integer. is Planck's constant, and k is the interfering laser 4 wave vector.

[0058] After the beam splitting, after a time t2, the atomic cluster 2-1 is split again by the π / 2 pulse of the interference laser 4 at point c, and the beam is split into atomic clusters 2-3 and 2-4, and the two atomic clusters each account for half of the number of atoms. Atomic cluster 2-3 maintains the momentum state unchanged, atomic group 2-4 gains momentum and jumps to Up, n 2 is a positive integer. After time T1, the atomic cluster 2-3 flies to point d, and the atomic cluster 2-4 flies to point e. Then, the π pulse of the interfering laser 4 is applied, and the atomic clusters 2-3 all jump to And all the atoms 2-4 jump to After T1+δ T Afterwards, the atomic clusters 2-3 and 2-4 intersect at point f, but their positions do not completely overlap. At this time, the π / 2 pulse of the interference laser 4 is applied to complete the interference between the atomic clusters 2-3 and 2-4, realizing an open-loop atomic interferometer, which is a signal interferometer. After time t3, it flies to the detection area, and after interacting with the horizontal detection laser 5, it emits a fluorescence signal, detects and obtains interference fringes.

[0059] After flying from point b for t4 time, the atomic cluster 2-2 arrives at point g and is split again by the π / 2 pulse of the interference laser 4 into atomic clusters 2-5 and 2-6, each of which accounts for half of the number of atoms. Atomic cluster 2-5 maintains momentum state unchanged, atomic group 2-6 gains momentum and jumps to After time T2, the atomic cluster 2-5 flies to point h, and the atomic cluster 2-6 flies to point i. Then, the π pulse of the interference laser 4 is applied, and the atomic clusters 2-5 all jump to And all the atoms 2-6 jump to After T2+δ T After that, the atomic clusters 2-5 and 2-6 intersect at point j, but their positions do not completely overlap. At this time, the π / 2 pulse of the interference laser 4 is applied to complete the interference between the atomic clusters 2-5 and 2-6, and realize an open-loop atomic interferometer, which is the reference interferometer. After time t5, it flies to the detection area, and after interacting with the horizontal detection laser 5, it emits a fluorescence signal, detects and obtains interference fringes.

[0060] In a possible embodiment of the present invention, the split beam laser 3 and the interference laser 4 are large momentum transfer pulses, which may be Bragg diffraction pulses, which make the momentum difference between two groups of atoms differ by more than 2 photon momentum, and the internal state of the atomic group remains unchanged, and only the external state changes.

[0061] Step 4, performing data processing and analysis on the first interference fringes and the second interference fringes, and calculating the gravitational acceleration based on the differential phase between the signal interferometer and the reference interferometer.

[0062] For the signal interferometer, the interference phase expression of the interferometer output is:

[0063]

[0064] Where α is the frequency sweep slope when interfering laser 4 compensates for the atomic Doppler frequency shift, ω r is the atomic recoil frequency, v 0 is the initial velocity of the atom group 2 when it falls freely at point a, δ 0 is the detuning amount of the atomic cluster 2 resonating with the interference laser 4 at point a.

[0065] For the reference interferometer, the interferometric phase expression of the interferometer output is:

[0066]

[0067] Then after the interference phase of the two interferometers is differentiated, the differential phase of the open-loop diatomic interferometer is obtained as follows:

[0068]

[0069] Since the time for the atomic cluster 2-1 and the atomic cluster 2-2 to fly from point a to the detection area is the same, that is:

[0070] t 1 +t 2 +2T 1 +δ T +t 3 =t 1 +t 4 +2T 2 +δT +t 5

[0071] So we can get:

[0072] 2(T 2 -T 1 )+t 4 -t 2 =t 3 -t 5

[0073] The differential phase of the open-loop diatomic interferometer can be simplified to:

[0074]

[0075] The phases related to the atomic velocity are differentially eliminated, so a more stable interference phase can be obtained in a dynamic environment without being affected by the initial velocity of the atoms. Except for the g value, all other system parameters and atomic parameters are known in the phase, so the gravitational acceleration can be solved by the above formula, which can achieve accurate measurement of gravitational acceleration.

[0076] See also Figure 3 , a gravity measuring device based on a path-opening diatomic interferometer of the present invention is provided, comprising a vacuum cavity 1, a signal interferometer, a reference interferometer, a fluorescence collection system 6 and a data acquisition system 7.

[0077] After the atomic clusters are cooled and prepared in the initial state, they begin to fall freely in the gravity field of the vacuum chamber 1, and are divided into a first atomic cluster and a second atomic cluster by the beam splitting laser 3;

[0078] The first atomic group is acted upon by the three-interference laser of the signal interferometer, and after the interference is completed, it reacts with the detection laser 5 to emit a first fluorescence signal, which is collected by the fluorescence collection system 6;

[0079] The second atomic group is acted upon by the three-interference laser of the reference interferometer, and after the interference is completed, it reacts with the detection laser 5 to generate a second fluorescence signal, which is collected by the fluorescence collection system 6;

[0080] The data acquisition system 7 is used to collect and process the first fluorescence information and the second fluorescence signal collected by the fluorescence collection system 6 to obtain the first interference fringes generated by the signal interferometer and the second interference fringes generated by the reference interferometer, respectively; and to perform data processing and analysis on the first interference fringes and the second interference fringes, and calculate the gravitational acceleration based on the differential phase between the signal interferometer and the reference interferometer.

[0081] For details, see Figure 3The atomic cluster 2 is in a vacuum chamber 1. A pair of split lasers 3 act on the atomic cluster from above and below, respectively, to divide the atomic cluster 2 into two parts, one for signal detection and the other for reference. A pair of interference lasers 4 and the split laser 3 share the same optical fiber, and act on two atomic clusters through two groups of three laser pulses each, forming an atomic interferometer with two open paths. After the interference is completed, the detection laser 5 acts on the atomic cluster, and the fluorescence signal emitted by the atomic cluster is collected by the fluorescence collection system 6. After the optical signal is converted into an electrical signal, the data is processed and analyzed by the data acquisition system 7 to solve the gravitational acceleration.

[0082] The movement process of the atomic group in the vacuum chamber can be found in the method embodiment, and will not be repeated here.

[0083] The embodiment of the present invention provides a gravity measurement method and a measurement device based on a path-opening diatomic interferometer, which have the following beneficial effects:

[0084] (1) The present invention can solve the problem of interference fringe contrast degradation and inability to measure when measuring on a dynamic platform due to the non-closure of the interference path by constructing a gravity measurement method of a diatomic interferometer.

[0085] (2) The present invention adopts the diatomic interferometer differential measurement, which can significantly suppress the physical effects related to the initial vertical falling velocity and lateral diffusion velocity of the atomic cluster.

[0086] (3) The present invention ensures that the gravity measurement process is highly robust to changes in the external environment such as the electromagnetic field by using the differential measurement and large momentum transfer pulse method.

[0087] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0088] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0089] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A gravity measurement method using a diatomic interferometer, characterized in that: include: After the initial atomic cluster is cooled and prepared in the initial state, it begins to fall freely in the gravity field of the vacuum cavity, and is divided into a first atomic cluster and a second atomic cluster by the splitting laser; The first atomic group is acted upon by three interference lasers of the signal interferometer, and after the interference is completed, it acts upon the detection laser, and collects the first interference fringes generated by the signal interferometer; The second atomic group is acted upon by three interference lasers of the reference interferometer, and after the interference is completed, it acts upon the detection laser, and collects the second interference fringes generated by the reference interferometer; Data processing and analysis are performed on the first interference fringes and the second interference fringes, and gravitational acceleration is calculated based on the differential phase between the signal interferometer and the reference interferometer.

2. The gravity measurement method of the diatomic interferometer according to claim 1, characterized in that: The initial atomic group is cooled and prepared in its initial state, including: The vacuum degree in the vacuum chamber is maintained below 1×10-8Pa using an ion pump and a getter pump. After the initial atomic group is cooled and trapped in the magneto-optical trap, the temperature of the initial atomic group is further reduced to below 2μK using polarization gradient cooling, Raman sideband cooling or evaporative cooling. The initial atomic clusters are prepared in an initial state by using microwave state selection and Raman state selection, and the initial atomic clusters are prepared into a single magnetically insensitive state, thereby completing the cooling and initial state preparation of the initial atomic clusters.

3. The gravity measurement method of the diatomic interferometer according to claim 1, characterized in that: The split beam laser and the interference laser are large momentum transfer pulses, and the split beam laser and the interference laser share a common optical fiber.

4. The gravity measurement method of the diatomic interferometer according to claim 1, characterized in that: After the initial atomic group is cooled and prepared in the initial state, it starts to fall freely in the gravity field of the vacuum cavity, and the initial atomic group is divided into a first atomic group and a second atomic group by a split beam laser, including: After the initial atomic group is cooled and prepared in the initial state, the initial state is in the momentum state. At time 0, it starts to fall freely in the gravitational field from point a; after time t1, a split beam laser is applied at point b to split the initial atomic group into the first atomic group and the second atomic group, where the momentum of the first atomic group does not change and is still in the momentum state. The second atom group gains additional momentum and is in the momentum state On, among them, is Planck's constant, and k is the interfering laser wave vector.

5. The gravity measurement method of the diatomic interferometer according to claim 4, characterized in that: The first atomic group is acted upon by three interference lasers of a signal interferometer, and after the interference is completed, acts upon a detection laser, and collects first interference fringes generated by the signal interferometer, including: After the beam splitting, after a time t2, the first atomic group is split again by the π / 2 pulse of the interference laser of the signal interferometer at point c, and the beam is split into the third atomic group and the fourth atomic group, and the third atomic group and the fourth atomic group each account for half of the number of atoms; The third atomic group maintains momentum unchanged, the fourth atomic group gains momentum and jumps to , n2 is a positive integer; after time T1, the third atom group flies to point d, and the fourth atom group flies to point e. The π pulse of the interference laser of the signal interferometer acts on the third atom group. All the fourth atomic groups jumped to After time T1+δ T After that, the third atomic group and the fourth atomic group intersect at point f, but their positions do not completely overlap. At this moment, the π / 2 pulse of the interference laser of the signal interferometer is applied to complete the interference between the third atomic group and the fourth atomic group. After time t3, the third atomic cluster and the fourth atomic cluster fly to the detection area, and after interacting with the lateral detection laser, they emit fluorescent signals, and the first interference fringes are detected.

6. The gravity measurement method of the diatomic interferometer according to claim 5, characterized in that: The second atomic group is acted upon by three interference lasers of the reference interferometer, and after the interference is completed, acts upon the detection laser, and collects the second interference fringes generated by the reference interferometer, including: After the second atomic group flies from point b for t4 time, it arrives at point g and is split again by the π / 2 pulse of the interference laser of the reference interferometer into the fifth and sixth atomic groups, each of which accounts for half of the number of atoms; the fifth atomic group maintains the momentum state unchanged, the sixth atomic group gains momentum and jumps to In the figure, n1 is a positive integer; after time T2, the fifth atom group flies to point h, and the sixth atom group flies to point i. The π pulse of the interferometric laser of the reference interferometer is used to make all the fifth atom groups jump to All the sixth atomic groups jumped to After T2+δ T Afterwards, the fifth and sixth atomic clusters cross at point j, but their positions do not completely overlap. At this moment, the π / 2 pulse of the interference laser of the reference interferometer is used to complete the interference between the fifth and sixth atomic clusters. After time t5, the fifth and sixth atomic clusters fly to the detection area, and after interacting with the horizontal detection laser, they emit fluorescence signals, and the second interference fringes are detected.

7. The gravity measurement method of the diatomic interferometer according to claim 6, characterized in that: The data processing and analysis of the first interference fringes and the second interference fringes, and calculating the gravitational acceleration based on the differential phase of the signal interferometer and the reference interferometer, includes: The interference phase expression of the signal interferometer output is: Where α is the frequency sweep slope when interfering laser compensates for atomic Doppler shift, ω r is the atomic recoil frequency, v0 is the initial velocity of the initial atomic group when it falls freely at point a, and δ0 is the detuning amount of the initial atomic group resonating with the interfering laser at point a; The interference phase expression of the reference interferometer output is: The interference phase output by the signal interferometer is calculated differentially from the interference phase output by the reference interferometer, and the differential phase of the open-loop diatomic interferometer is obtained as follows: The time it takes for the first atomic group and the second atomic group to fly from point a to the detection area is the same, that is: t1+t2+2T1+δ T +t3=t1+t4+2T2+δ T +t5 get: 2(T2-T1)+t4-t2=t3-t5 The differential phase of the open-loop diatomic interferometer is simplified to: The differential phase of the open-loop diatomic interferometer is solved to obtain the gravitational acceleration g.

8. A gravity measuring device of a diatomic interferometer, characterized in that: It includes a vacuum chamber, a signal interferometer, a reference interferometer, a fluorescence collection system and a data acquisition system; After the initial atomic cluster is cooled and prepared in the initial state, it starts to fall freely in the gravity field of the vacuum cavity, and the atomic cluster is divided into a first atomic cluster and a second atomic cluster by the splitting laser; The first atomic group is acted upon by the three-interference laser of the signal interferometer, and after the interference is completed, it acts upon the detection laser to emit a first fluorescence signal, which is collected by the fluorescence collection system; The second atomic group is acted upon by the three-interference laser of the reference interferometer, and after the interference is completed, it reacts with the detection laser to generate a second fluorescence signal, which is collected by the fluorescence collection system; The data acquisition system is used to collect and process the first fluorescence information and the second fluorescence signal collected by the fluorescence collection system to obtain the first interference fringes generated by the signal interferometer and the second interference fringes generated by the reference interferometer respectively; Furthermore, data processing and analysis are performed on the first interference fringes and the second interference fringes, and gravitational acceleration is calculated based on the differential phase between the signal interferometer and the reference interferometer.

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