Axial vibration continuous measurement and error compensation system of atomic interference gravimeter

Abstract

The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system, which comprises a probe and a collection control subsystem, wherein the collection control subsystem comprises a gravity information processing module and a vibration information processing module; the probe is used to form an interference light path for each measurement period, obtain output measurement light and a fluorescence detection signal, and output the same; the vibration information processing module and the gravity information processing module are connected with the probe; the vibration information processing module is connected with the gravity information processing module; the vibration information processing module is used to obtain a vibration phase shift based on the output measurement light; the gravity information processing module is used to process the fluorescence detection signal, obtain an atomic interference fringe, correct a phase of the atomic interference fringe based on the vibration phase shift, and obtain a gravity acceleration measurement result. The system can realize error compensation, obtain more accurate gravity acceleration, reduce the complexity of the system, and has strong applicability and high measurement precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of atomic interference precision measurement, and particularly relates to an atomic interference gravimeter axial vibration continuous measurement and error compensation system. BACKGROUND

[0002] The atomic interference gravimeter can realize precise measurement of gravity acceleration by laser controlling cold atom groups in the gravity field to interfere. Since the cold atom has the characteristics of short de Broglie wavelength, long free evolution time, large static mass, small velocity distribution, stable internal structure and energy level distribution, and no mechanical friction, high sensitivity, high precision, and no long-term drift of gravity measurement can be realized based on the cold atom. At present, the measurement performance of the atomic interference gravimeter has approached or even exceeded the classical gravimeter, and is developing towards miniaturization and mobility. Commercial products have appeared, and have extremely broad development prospects.

[0003] Vibration noise is one of the main noise sources of the atomic interference gravimeter, and the vibration noise limits the measurement sensitivity of the atomic interference gravimeter, and further limits the application ability of the atomic interference gravimeter in the field and mobile carriers. At present, the method for reducing vibration noise includes the following two ways: the first way is to use an active platform or a passive platform to isolate the influence of vibration on the probe of the atomic interference gravimeter, so as to reduce the vibration noise. The second way is to measure the vibration signal of the mirror of the atomic interference gravimeter, calculate the interference phase shift introduced by the vibration, and realize error compensation on the measurement result, which is equivalent to reducing the vibration noise.

[0004] However, in the case of reducing the vibration noise by using the above-mentioned first way, a complex active platform or passive platform needs to be added, and the use conditions have high restrictions, which does not have applicability. In the case of reducing the vibration noise by using the above-mentioned second way, a vibration sensor rigidly connected with the mirror at the bottom of the atomic interference gravimeter can be used to monitor the vibration acceleration or speed, but the measurement accuracy of the vibration sensor is positively correlated with the volume of the vibration sensor, which not only increases the system complexity, but also needs to strictly align the sensitive axis of the vibration sensor with the gravity measurement direction and the Raman light direction, which has great implementation difficulty. SUMMARY

[0005] The present application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system, which solves the defects of system complexity, low measurement accuracy and lack of applicability in the prior art in the case of reducing vibration noise, and realizes the characteristics of low system complexity, high applicability and high measurement accuracy.

[0006] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system, the system comprises a probe and a collection control subsystem, wherein the collection control subsystem comprises a gravity information processing module and a vibration information processing module;

[0007] The probe is used for receiving input measurement light, processing the input measurement light, forming an interference light path, obtaining output measurement light and fluorescence detection signals and outputting for each measurement period, wherein the input measurement light comprises input vibration measurement light and input Raman light, and the input vibration measurement light and the input Raman light have different wavelengths.

[0008] The vibration information processing module and the gravity information processing module are connected with the probe, and the vibration information processing module is connected with the gravity information processing module, wherein the vibration information processing module is used for obtaining output vibration measurement light based on the output measurement light output by the probe, and obtaining a vibration phase shift based on the output vibration measurement light, and the gravity information processing module is used for processing the fluorescence detection signals output by the probe to obtain atomic interference fringes, and correcting the phase of the atomic interference fringes based on the vibration phase shift to obtain a gravity acceleration measurement result.

[0009] According to the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the application, the probe comprises a dual-wavelength polarizer, a vacuum cavity, a quarter-wave plate, a dual-wavelength mirror and a fluorescence detection module.

[0010] The dual-wavelength polarizer, the vacuum cavity, the quarter-wave plate and the dual-wavelength mirror are sequentially arranged in a direction perpendicular to the surface of the dual-wavelength polarizer.

[0011] The fluorescence detection module is connected with the gravity information processing module and is used for forming the fluorescence detection signals based on the interference light path.

[0012] The upper surface of the vacuum cavity is coated with a dual-wavelength film, and the dual-wavelength film functions as a transmission coating film for Raman light and a half-reflection half-transmission coating film for vibration measurement light.

[0013] Alternatively, the upper surface of the dual-wavelength polarizer is coated with the dual-wavelength film.

[0014] According to the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the application, the probe can further comprise a laser beam expander.

[0015] The laser beam expander is located on the side corresponding to the upper surface of the dual-wavelength polarizer and is connected with the collection control subsystem.

[0016] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0017] The laser generation module is connected with the probe, and is used for generating the input vibration measurement light and the input Raman light acting on the probe.

[0018] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0019] The atomic interference gravimeter measurement laser unit and the vibration measurement laser are connected with the laser coupler.

[0020] The laser coupler is connected with the probe.

[0021] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0022] The laser feedback control unit is connected with the gravity information processing module, the vibration information processing module and the laser generation module, wherein the laser feedback control unit is used for obtaining laser parameters based on the vibration phase shift and the gravity phase and inputting the laser parameters into the laser generation module, and the gravity phase is obtained by the gravity information processing module based on information corresponding to the fluorescence detection signal output by the probe.

[0023] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0024] The filter is connected with the probe.

[0025] The photodetector is connected with the filter and the phase shift calculation unit.

[0026] The phase shift calculation unit is connected with the gravity information processing module and the laser feedback control unit.

[0027] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0028] The laser generation module and the vibration information processing module are connected with the circulator.

[0029] The circulator is connected with the probe through the optical fiber.

[0030] According to the application, an atomic interference gravimeter axial vibration continuous measurement and error compensation system is provided, the ring resonator comprises a first port, a second port and a third port;

[0031] The laser generation module is connected with the first port;

[0032] The second port is connected with the probe through the optical fiber;

[0033] The vibration information processing module is connected with the third port.

[0034] The application further provides an atomic interference gravimeter axial vibration continuous error compensation method, applied to the atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0035] The method comprises:

[0036] For each measurement period, the input measurement light is received by the probe, the input measurement light is processed, the interference light path is formed, the output measurement light and the fluorescence detection signal are obtained and output, wherein the input measurement light comprises input vibration measurement light and input Raman light, the input vibration measurement light and the input Raman light have different wavelengths;

[0037] The output vibration measurement light is obtained based on the output measurement light output by the probe through the vibration information processing module, and the vibration phase shift is obtained based on the output vibration measurement light;

[0038] The fluorescence detection signal output by the probe is processed by the gravity information processing module to obtain the atomic interference fringe, the phase of the atomic interference fringe is corrected based on the vibration phase shift, and the gravity acceleration measurement result is obtained.

[0039] The application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system, which comprises a probe and an acquisition control subsystem, wherein the acquisition control subsystem comprises a gravity information processing module and a vibration information processing module; the probe is used for receiving input measurement light, processing the input measurement light, forming an interference light path, obtaining output measurement light and fluorescence detection signals and outputting the same for each measurement period, wherein the input measurement light comprises input vibration measurement light and input Raman light, the input vibration measurement light and the input Raman light have different wavelengths; the vibration information processing module and the gravity information processing module are connected with the probe; the vibration information processing module is connected with the gravity information processing module, wherein the vibration information processing module is used for obtaining output vibration measurement light based on the output measurement light output by the probe, and obtaining a vibration phase shift based on the output vibration measurement light; the gravity information processing module is used for processing the fluorescence detection signals output by the probe, obtaining atomic interference fringes, correcting the phase of the atomic interference fringes based on the vibration phase shift and outputting a gravity acceleration measurement result.

[0040] The system uses the input vibration measurement light with a wavelength different from that of the input Raman light to perform vibration measurement, avoids the influence of the vibration measurement process on the atomic interference process, can continuously monitor the vibration displacement in the interference process, completes the accurate and continuous measurement of the axial vibration of the atomic interference gravimeter through light path sharing, further obtains the vibration phase shift, realizes error compensation, and obtains more accurate gravity acceleration, compared with the current noise reduction method, without the need to increase the active platform or the passive platform, and without the need to increase the vibration sensor, so that the complexity of the system can be reduced, and the system has the characteristics of strong applicability and high measurement precision. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0042] Figure 1 is one of the structure schematic diagrams of the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the application;

[0043] Figure 2 is the second structure schematic diagram of the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the application;

[0044] Figure 3 is the third structure schematic diagram of the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the application;

[0045] Figure 4 A schematic diagram of an interference optical path provided by the present application is shown in the figure;

[0046] Figure 5 A flowchart of one of the atomic interference gravimeter axial vibration continuous measurement and error compensation methods provided by the present application is shown in the figure.

[0047] Reference signs:

[0048] 101: probe; 102: acquisition control subsystem; 103: gravity information processing module; 104: vibration information processing module; 201: dual-wavelength polarizer; 202: vacuum cavity; 203: quarter-wave plate; 204: dual-wavelength reflector; 205: fluorescence detection module; 301: laser beam expander; 302: laser coupler; 303: atomic interference gravity measurement laser unit; 304: vibration measurement laser; 305: filter; 306: photodetector; 307: phase shift calculation unit; 308: circulator; 309: laser feedback control unit; 310: optical fiber; 401: Raman light path; 402: vibration measurement light path. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0050] In order to reduce the complexity of the system and make the system have the characteristics of strong applicability and high measurement precision, the present application provides an atomic interference gravimeter axial vibration continuous measurement and error compensation system, which will be described below in combination with Figure 1 The atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the present application is described.

[0051] As shown in Figure 1 The present application discloses an atomic interference gravimeter axial vibration continuous measurement and error compensation system, which comprises a probe 101 and an acquisition control subsystem 102. The acquisition control subsystem 102 comprises a gravity information processing module 103 and a vibration information processing module 104.

[0052] The axial vibration continuous measurement and error compensation system of the atomic interference gravimeter can realize atomic interference gravity measurement and vibration continuous measurement. The probe 101 can be referred to as a gravimeter and vibration measurement probe, and is used to realize cold atom group preparation, interference optical path formation, and gravity fringe detection.

[0053] The acquisition control subsystem 102 is connected with the probe 101, and is used to acquire and process the fluorescence detection signal and the output measurement light output by the probe 101. The output vibration measurement light can be obtained based on the output measurement light, and the vibration phase shift can be obtained based on the output vibration measurement light. The atomic interference fringe can be obtained based on the fluorescence detection signal, and the phase of the atomic interference fringe can be corrected based on the vibration phase shift, so as to realize vibration error compensation and obtain the gravity acceleration measurement result.

[0054] The probe 101 can be used to receive the input measurement light, process the input measurement light, form an interference optical path, obtain the output measurement light and the fluorescence detection signal, and output them for each measurement period. The input measurement light includes input vibration measurement light and input Raman light, and the input vibration measurement light and the input Raman light have different wavelengths.

[0055] In each measurement period, that is, in each atomic interference measurement period, the probe 101 can prepare a cold atom group. After the cold atom group is prepared, the input measurement light, that is, the input vibration measurement light and the input Raman light, can be received. Since the wavelength of the input vibration measurement light and the wavelength of the input Raman light can be distinguished from each other, and the wavelength of the input vibration measurement light is far detuned from the atomic transition frequency. Therefore, the optical path of the Raman light and the interference optical path of the vibration measurement light do not affect each other, that is, the vibration measurement process and the atomic interference measurement process do not affect each other.

[0056] In this way, the fluorescence detection signal and the output measurement light can be obtained and input to the acquisition control subsystem 102, that is, the fluorescence detection signal is input to the gravity information processing module 103, and the output measurement light is input to the vibration information processing module 104.

[0057] The vibration information processing module 104 and the gravity information processing module 103 are connected with the probe 101 Figure 1The vibration information processing module 104 is connected with the gravity information processing module 103, and the vibration information processing module 104 can be used to obtain output vibration measurement light based on the output measurement light output by the probe 101, and obtain a vibration phase shift based on the output vibration measurement light. The gravity information processing module 103 can be used to process the fluorescence detection signal output by the probe 101 to obtain an atomic interference fringe, correct the phase of the atomic interference fringe based on the vibration phase shift, realize vibration error compensation, and obtain a gravity acceleration measurement result.

[0058] The vibration information processing module 104 can receive the output measurement light output by the probe 101 in each measurement period, that is, in each atomic interference measurement period. Since the wavelength of the output vibration measurement light can be distinguished from the wavelength of the output Raman light, the output vibration measurement light can be obtained based on the output measurement light, that is, the vibration signal is collected, and then the vibration displacement can be obtained based on the output vibration measurement light.

[0059] The vibration displacement is continuously monitored, the time sequence of the atomic interference is aligned with the time of the vibration measurement signal based on the time sequence of the interaction of the Raman light and the cold atom group, and the vibration signal is integrated with the sensitivity function, so that the atomic interference phase shift caused by the vibration, that is, the vibration phase shift, can be obtained.

[0060] The above-mentioned atomic interference gravimeter axial vibration continuous measurement and error compensation system can use the input vibration measurement light which is distinguished from the input Raman light to measure the vibration, avoid the influence of the vibration measurement process on the atomic interference process, continuously monitor the vibration displacement in the interference process, complete the accurate and continuous measurement of the axial vibration of the gravimeter through the common use of the optical path, and then obtain the vibration phase shift.

[0061] The gravity information processing module 103 can receive the fluorescence detection signal output by the probe 101 to obtain the atomic interference fringe. Then, the phase of the atomic interference fringe is corrected based on the received vibration phase shift, the corrected atomic interference fringe phase is used for calculation, vibration error compensation is realized, and then the single-period gravity acceleration can be obtained, that is, the gravity acceleration measurement result can be obtained.

[0062] Compared with the current noise reduction method, the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the present application does not need additional devices, reduces the complexity of the system, maintains the original typical architecture of the atomic interference gravimeter, is conducive to the miniaturization of the system, and can be transplanted to different scheme atomic interference gravimeter systems based on actual needs, and has strong applicability.

[0063] And, relying on the atomic interference gravimeter to the requirement of light path, that is, relying on the strict alignment of the direction of Raman light and the vertical gravity direction, the positive and negative Raman light (the light path of Raman light) is strictly coincided, the interference light path of vibration measurement light formed by multiplexing the light path is strictly coincided with the light path of Raman light, and the direction is strictly aligned with the vertical gravity direction, so that the axial vibration information of the vertical gravity direction and the Raman light direction can be accurately obtained, with the characteristics of high precision, the precision of vibration phase shift is improved, so that the precision of error compensation can be improved.

[0064] Since the vibration measurement process and the atomic interference measurement process do not affect each other, the atomic interference gravimeter axial vibration continuous measurement and error compensation system provided by the application can continuously monitor the vibration displacement during the interference process, quickly record the change process and details, avoid the phase period ambiguity at different times in the non-continuous measurement scheme, improve the vibration measurement dynamic range, and can adapt to various complex dynamic occasions.

[0065] As an embodiment of the application, as shown in Figure 2 The probe 101 can include a dual-wavelength polarizer 201, a vacuum cavity 202, a quarter-wave plate 203, a dual-wavelength mirror 204, and a fluorescence detection module 205.

[0066] The dual-wavelength polarizer 201, the vacuum cavity 202, the quarter-wave plate 203, and the dual-wavelength mirror 204 are arranged in the direction perpendicular to the surface of the dual-wavelength polarizer 201.

[0067] The fluorescence detection module 205 can be arranged at a position facing a first preset area of the vacuum cavity 202, wherein the first preset area is arranged on a surface adjacent to a surface of the vacuum cavity 202 facing the quarter-wave plate 203, the surface of the vacuum cavity 202 facing the quarter-wave plate 203 can be referred to as a bottom surface, and the first preset area can be arranged on a side surface of the vacuum cavity 202 and close to the position of the quarter-wave plate 203.

[0068] The fluorescence detection module 205 can be connected with a gravity information processing module, and the fluorescence detection module 205 can form a fluorescence detection signal based on the interference light path, and then the fluorescence detection signal can be input to the gravity information processing module.

[0069] In order to form the interference light path of the vibration measurement light, there are two cases:

[0070] The first case: the upper surface of the vacuum cavity 202 can be coated with a dual-wavelength film, wherein the upper surface of the vacuum cavity is the side of the vacuum cavity facing the dual-wavelength polarizer 201. The dual-wavelength film functions as: a transmittance coating film for Raman light, and a half-reflective half-transmissive coating film for vibration measurement light.

[0071] The dual-wavelength film is a thin film with dual-wavelength characteristics, which can process two different wavelengths of light differently. The structure of the dual-wavelength film can be a double-layer film, a single-layer film, or a multi-layer film, all of which are reasonable and can be set according to actual needs.

[0072] To facilitate the explanation of the process of forming the interference light path by the probe 101, the formation process of the light path of the Raman light and the interference light path of the vibration measurement light will be explained separately below. In the first case, that is, when the upper surface of the vacuum cavity 202 is coated with a dual-wavelength film:

[0073] The input Raman light can pass through the dual-wavelength polarizer 201 to achieve polarization purification and obtain linearly polarized light with high polarization. Since the dual-wavelength film is a transmittance coating film for Raman light, it can allow the Raman light after polarization purification to enter the vacuum cavity 202 almost without loss. Therefore, the Raman light after polarization purification can pass through the transmittance film coated on the upper surface of the vacuum cavity 202 to enter the vacuum cavity 202, which is referred to as forward Raman light.

[0074] The forward Raman light can pass through the quarter-wave plate 203 and reach the dual-wavelength mirror 204. The Raman light reflected by the dual-wavelength mirror 204 passes through the quarter-wave plate 203 again. After the linearly polarized Raman light passes through the quarter-wave plate 203 twice, its polarization is rotated by 90° and enters the vacuum cavity 202, which is referred to as reverse Raman light. In this way, the light path of the Raman light can be formed. The forward Raman light, the reverse Raman light, and the prepared cold atom group interact to manipulate the atoms to interfere, thereby realizing atomic interference gravity measurement.

[0075] In this way, the light path of the Raman light, that is, the atomic interference gravity measurement light path, can be formed to facilitate subsequent atomic interference gravity measurement.

[0076] The input vibration measurement light can pass through the dual-wavelength polarizer 201 to achieve polarization purification. Since the dual-wavelength film is a half-reflective half-transmissive coating film for vibration measurement light, the vibration measurement light after polarization purification is divided into two beams on the upper surface of the vacuum cavity 202. One beam is reflected by the dual-wavelength film coated on the upper surface of the vacuum cavity 202, and the reflected vibration measurement light returns to the original path, which can be referred to as reference vibration measurement light.

[0077] Another beam can pass through the dual-wavelength film plated on the upper surface of the vacuum cavity 202 into the vacuum cavity 202, and then pass through the vacuum cavity 202 and the quarter-wave plate 203 to reach the dual-wavelength mirror 204. After being reflected by the dual-wavelength mirror 204, the current vibration measurement light is obtained by passing through the quarter-wave plate 203 and the vacuum cavity 202 in reverse order.

[0078] The current vibration measurement light can be combined with the reference vibration measurement light. Since the vibration measurement light entering the vacuum cavity 202 passes through the quarter-wave plate 203 twice to obtain the current vibration measurement light, the polarization state changes from linearly polarized light to elliptically polarized light, and the reference vibration measurement light is linearly polarized light. Therefore, in order to meet the polarization requirements of interference measurement, the combined vibration measurement light passes through the dual-wavelength polarizer 201, which can achieve polarization assimilation, that is, filtering the current vibration measurement light to obtain linearly polarized light consistent with the reference vibration measurement light. In this way, an interference light path of the vibration measurement light can be formed to obtain the vibration phase shift subsequently.

[0079] The second case: the upper surface of the dual-wavelength polarizer 201 can be plated with a dual-wavelength film. The upper surface of the dual-wavelength polarizer 201 is the surface that is consistent with the direction of the upper surface of the vacuum cavity 202.

[0080] In the second case, that is, when the upper surface of the dual-wavelength polarizer 201 is plated with a dual-wavelength film:

[0081] Since the dual-wavelength film is a transmittance film for Raman light, the input Raman light can pass through the transmittance film plated on the upper surface of the dual-wavelength polarizer 201. The input Raman light passes through the dual-wavelength polarizer 201 to achieve polarization purification, and the purified Raman light enters the vacuum cavity 202, which is referred to as forward Raman light.

[0082] The forward Raman light can pass through the quarter-wave plate 203 to reach the dual-wavelength mirror 204. The Raman light reflected by the dual-wavelength mirror 204 passes through the quarter-wave plate 203 again and enters the vacuum cavity 202, which is referred to as reverse Raman light. In this way, a light path of the Raman light can be formed. The forward Raman light, the reverse Raman light, and the prepared cold atom group interact to control the atoms to realize interference, and then realize atomic interference gravity measurement.

[0083] Since the dual-wavelength film is a half-reflective and half-transmissive film for vibration measurement light, the input vibration measurement light is divided into two beams on the upper surface of the dual-wavelength polarizer 201. One beam is reflected by the dual-wavelength film plated on the upper surface of the dual-wavelength polarizer 201, and the reflected vibration measurement light returns to the original path, which can be referred to as untreated vibration measurement light.

[0084] Another beam can pass through the double-wavelength film plated on the upper surface of the double-wavelength polarizer 201 and achieve polarization purification, and the vibration measurement light after polarization purification can pass through the vacuum cavity 202 and the quarter-wave plate 203 in sequence to reach the double-wavelength mirror 204. After being reflected by the double-wavelength mirror 204, the vibration measurement light passes through the quarter-wave plate 203, the vacuum cavity 202 and the double-wavelength polarizer 201 in reverse sequence to obtain the processed vibration measurement light.

[0085] The processed vibration measurement light can be combined with the unprocessed vibration measurement light. Since the vibration measurement light entering the vacuum cavity 202 passes through the quarter-wave plate 203 twice, the polarization state changes from linearly polarized light to elliptically polarized light. Therefore, in order to meet the interference measurement polarization requirement, the processed vibration measurement light can pass through the double-wavelength polarizer 201 to obtain linearly polarized light, and then the processed vibration measurement light can be combined with the unprocessed vibration measurement light. In this way, the interference light path of the vibration measurement light can be formed to facilitate subsequent obtaining of the vibration phase shift.

[0086] Through the above system, the light path of the Raman light and the interference light path of the vibration measurement light can be formed. Since the vibration measurement process and the atomic interference measurement process do not affect each other, the accuracy of subsequent acquisition of the gravitational acceleration can be improved.

[0087] As an embodiment of the present application, the above probe can further include a laser beam expander.

[0088] The laser beam expander can be located on the side corresponding to the upper surface of the double-wavelength polarizer and connected with the acquisition control subsystem. The laser beam expander can change the diameter size and divergence angle of the input measurement light, so that the interference light path can be formed more accurately subsequently.

[0089] In an embodiment, a double-wavelength film can be plated on the lower surface of the laser beam expander, wherein the lower surface of the laser beam expander is the surface consistent with the direction of the lower surface of the vacuum cavity.

[0090] The input Raman light can pass through the laser beam expander, and the expanded Raman light can pass through the double-wavelength polarizer to achieve polarization purification. The Raman light after polarization purification enters the vacuum cavity and is recorded as forward Raman light.

[0091] The forward Raman light can pass through the quarter-wave plate and reach the double-wavelength mirror. The Raman light reflected by the double-wavelength mirror passes through the quarter-wave plate again and enters the vacuum cavity, and is recorded as reverse Raman light. In this way, the light path of the Raman light can be formed. The forward Raman light, the reverse Raman light and the prepared cold atom group interact, control the atoms to realize interference, and then realize atomic interference gravity measurement.

[0092] The input vibration measurement light is split into two beams at the lower surface of the laser beam expander, one of which is reflected by the dual-wavelength film coated on the lower surface of the laser beam expander, and the reflected vibration measurement light returns along the original path and can be referred to as the comparison vibration measurement light.

[0093] The other beam can pass through the dual-wavelength film coated on the lower surface of the laser beam expander, and the expanded vibration measurement light successively passes through the dual-wavelength polarizer, the vacuum cavity, and the quarter-wave plate to reach the dual-wavelength mirror. After being reflected by the dual-wavelength mirror, the vibration measurement light reversely passes through the quarter-wave plate, the vacuum cavity, the dual-wavelength polarizer, and the laser beam expander to obtain the experimental vibration measurement light. The experimental vibration measurement light is combined with the comparison vibration measurement light to obtain the output vibration measurement light, so that an interference light path of the vibration measurement light is formed to facilitate subsequent vibration phase shift.

[0094] As an embodiment, the lower surface of the vacuum cavity and the quarter-wave plate can be coated with a dual-wavelength antireflection film to enable the Raman light and the vibration measurement light to be completely projected, and the dual-wavelength mirror can be coated with a dual-wavelength antireflection film to enable the Raman light and the vibration measurement light to be completely reflected.

[0095] For the case where the dual-wavelength film is coated at different positions, a dual-wavelength antireflection film can be coated on the upper surface of the vacuum cavity, the upper surface of the dual-wavelength polarizer, or the lower surface of the laser beam expander.

[0096] The fluorescence detection module can be used to collect fluorescence from the cold atom group that has completed atomic interference and fallen to the bottom of the vacuum cavity and convert the fluorescence into an electrical signal (i.e., a fluorescence detection signal). The gravity information processing module can receive the fluorescence detection signal and process it to obtain gravity measurement information, i.e., a gravity phase, and can also obtain a gravity acceleration measurement result.

[0097] As an embodiment of the present application, the acquisition control subsystem can further include a laser generation module.

[0098] The laser generation module can be connected to the probe. In an embodiment, the laser generation module can be connected to the laser beam expander, wherein the laser generation module is configured to generate the input vibration measurement light and the input Raman light acting on the probe.

[0099] In this way, the acquisition control subsystem can provide the probe with functional laser beams (the input Raman light) required in the atomic interference gravity measurement process and vibration measurement laser beams (the input vibration measurement light) through the laser generation module, so that subsequent vibration measurement and error compensation can be implemented to complete high-precision gravity acceleration measurement.

[0100] As an embodiment of the present application, the laser generation module can include an atomic interference gravity measurement laser unit, a vibration measurement laser, and a laser coupler.

[0101] The atomic interference gravity measurement laser unit and the vibration measurement laser can be connected with the laser coupler. The laser coupler can be connected with the probe. The atomic interference gravity measurement laser unit is used to generate various functional lasers required in the atomic interference gravity measurement process, and can specifically include vertical Raman light (input Raman light). Of course, other lasers such as cooling light, back-pumping light, and probe light can also be generated according to actual needs, which are all reasonable and are not specifically limited here.

[0102] The vibration measurement laser is used to generate incident vibration measurement light with stable light intensity and frequency. The laser coupler is used to combine the lasers generated by the atomic interference gravity measurement laser unit and the vibration measurement laser, that is, to combine the input Raman light and the input vibration measurement light to obtain input measurement light.

[0103] The vibration measurement laser can output single-frequency, double-frequency, or continuous-frequency incident vibration measurement light, so as to form a corresponding homodyne or heterodyne laser interferometer. The actual use requirements can be determined, which are all reasonable and are not specifically limited here.

[0104] In this way, the probe can receive the input measurement light provided by the acquisition control subsystem, so as to subsequently realize vibration measurement and error compensation and complete high-precision gravity acceleration measurement.

[0105] As an embodiment of the present application, the above-mentioned acquisition control subsystem can further include a laser feedback control unit.

[0106] The laser feedback control unit can be connected with the gravity information processing module, the vibration information processing module, and the laser generation module. The laser feedback control unit is used to obtain laser parameters based on the gravity phase and the vibration phase shift and input the laser parameters to the laser generation module. The gravity phase is obtained by the gravity information processing module based on the fluorescence probe signal output by the probe.

[0107] For each atomic interference measurement period, the laser feedback control unit can obtain the gravity phase and the vibration phase shift corresponding to the atomic interference measurement period. Then, the laser feedback control unit can obtain laser parameters based on the gravity phase and the vibration phase shift and feed back the laser parameters to the laser generation module, so as to control the laser generation module and realize fringe closed-loop locking and keep the atomic interference gravimeter working at the most sensitive working point.

[0108] In an embodiment, the laser feedback control unit can be connected with the atomic interference gravity measurement laser unit, so as to feed back the obtained laser parameters to the atomic interference gravity measurement laser unit, realize fringe closed-loop locking, and keep the atomic interference gravimeter working at the most sensitive working point.

[0109] Through the system, continuous measurement can be realized, and for each measurement, fringe closed-loop locking can be realized, and the atomic interferometric gravimeter can be kept working at the most sensitive working point.

[0110] As an embodiment of the present application, the vibration information processing module can include a filter, a photodetector, and a phase shift calculation unit.

[0111] The filter can be connected with the probe, the photodetector can be connected with the filter and the phase shift calculation unit, and the phase shift calculation unit can be connected with the gravity information processing module and the laser feedback control unit.

[0112] The filter can filter the output measurement light after receiving the output measurement light, so as to obtain output vibration measurement light, the filter can input the output vibration measurement light to the photodetector, the photodetector can convert the output vibration measurement light into an electrical signal (vibration interference signal), and then the vibration interference signal can be input to the phase shift calculation unit.

[0113] The phase shift calculation unit can obtain the vibration displacement of the atomic interference gravity measurement process based on the vibration interference signal, continuously monitor the vibration displacement, align the time sequence of the atomic interference with the time of the vibration measurement signal based on the time sequence of the Raman light and the cold atom group interaction, and integrate the vibration signal with the sensitivity function, so as to obtain the vibration-induced atomic interference phase shift, that is, the vibration phase shift. After obtaining the vibration phase shift, the vibration phase shift can be input to the gravity information processing module and the laser feedback control unit, so as to obtain the gravity acceleration and realize continuous measurement subsequently.

[0114] In an embodiment, the phase shift calculation unit can be referred to as a vibration signal processing and phase shift calculation unit, and can use various signal processing methods corresponding to the vibration measurement laser, such as signal frequency, period, time, amplitude resolution, etc., to extract the vibration phase from the vibration interference signal, obtain the vibration displacement, and then integrate the vibration displacement with the atomic interferometric gravimeter sensitivity function to obtain the vibration phase shift.

[0115] As an embodiment, the filter can be a band-pass filter. Considering the influence of the control accuracy of the laser polarization, part of the Raman light can be coupled back into the optical fiber and reach the acquisition control subsystem. The center wavelength of the band-pass filter is designed to be the wavelength of the vibration measurement light, and the wavelength of the Raman light is located in the stop band of the band-pass filter, so that the vibration measurement light can pass through, thereby avoiding the influence of the Raman light and other stray light on the vibration measurement result. In this way, the calculation accuracy of the vibration phase shift can be further improved.

[0116] As an embodiment of the present application, the acquisition control subsystem can further include a circulator and an optical fiber.

[0117] The laser generation module, the vibration information processing module and the gravity information processing module are connected with the circulator, and the circulator is connected with the probe through an optical fiber.

[0118] In an embodiment, the circulator can include a first port, a second port and a third port.

[0119] The laser generation module is connected with the first port, the second port is connected with the probe through an optical fiber, and the vibration information processing module is connected with the third port.

[0120] The output measurement light is input into the circulator through the optical fiber and the second port, and then is input into the vibration information processing module through the third port, so as to obtain the vibration phase shift subsequently.

[0121] In order to facilitate the understanding of the atomic interference gravity meter axial vibration continuous measurement and error compensation system provided by the present application, the following will take Figure 3 and Figure 4 as an example to introduce the atomic interference gravity meter axial vibration continuous measurement and error compensation system provided by the present application.

[0122] As shown in Figure 3 , the atomic interference gravity meter axial vibration continuous measurement and error compensation system includes a probe 101 and a collection control subsystem 102, wherein the probe 101 can include a laser beam expander 301, a dual-wavelength polarizer 201, a vacuum cavity 202, a quarter-wave plate 203, a dual-wavelength mirror 204 and a fluorescence detection module 205.

[0123] The collection control subsystem 102 can include: a laser generation module (not labeled in the figure) composed of an atomic interference gravity measurement laser unit 303, a vibration measurement laser 304 and a laser coupler 302, a vibration information processing module (not labeled in the figure) composed of a filter 305, a photodetector 306 and a phase shift calculation unit 307, a gravity information processing module 103, a laser feedback control unit 309 and a circulator 308.

[0124] The probe 101 is connected with the acquisition control subsystem 102 through the optical fiber 310, specifically, the laser beam expander 301 is connected with the circulator 308 through the optical fiber 310. The circulator 308 is connected with the laser coupler 302 and the filter 305. The laser coupler 302 is connected with the atomic interference gravity measurement laser unit 303 and the vibration measurement laser 304. The filter 305 is connected with the photodetector 306, and the photodetector 306 is connected with the phase shift calculation unit 307. The phase shift calculation unit 307 is connected with the gravity information processing module 103 and the laser feedback control unit 309, the gravity information processing module 103 is connected with the fluorescence detection module 205 and the laser feedback control unit 309, and the laser feedback control unit 309 is connected with the atomic interference gravity measurement laser unit 303.

[0125] As shown in Figure 4 Fig. 1, a schematic diagram of the light path 401 (dashed line) of the Raman light and the interference light path 402 (solid line) of the vibration measurement light formed by the probe 101, Figure 4 Only for the convenience of understanding the schematic diagram of the interference light path, in the actual process, the Raman light and the vibration measurement light are one light path.

[0126] Figure 4 In the case that the upper surface of the vacuum cavity 202 is coated with a dual-wavelength film, the Raman light passes through the laser beam expander 301, the dual-wavelength polarizer 201, the vacuum cavity 202, the quarter-wave plate 203 and the dual-wavelength mirror 204, forms a pair of forward and backward propagating lasers, and interacts with the prepared cold atom group (black dots in the figure). In this way, the light path 401 of the Raman light, that is, the atomic interference gravity measurement light path, can be formed, so as to realize subsequent atomic interference gravity measurement.

[0127] The vibration measurement light passes through the laser beam expander 301 and the dual-wavelength polarizer 201, is split into two beams on the upper surface of the vacuum cavity 202, one of which is reflected by the dual-wavelength film coated on the upper surface of the vacuum cavity 202, and the reflected vibration measurement light returns to the original path and can be called reference vibration measurement light.

[0128] The other beam can pass through the dual-wavelength film coated on the upper surface of the vacuum cavity 202 into the vacuum cavity 202, pass through the vacuum cavity 202, the quarter-wave plate 203 in sequence, and reach the dual-wavelength mirror 204. After being reflected by the dual-wavelength mirror 204, the current vibration measurement light is obtained by passing through the quarter-wave plate 203 and the vacuum cavity 202 in reverse order.

[0129] The current vibration measurement light can be combined with the reference vibration measurement light, pass through the dual-wavelength polarizer 201, realize polarization assimilation, and then be reversely coupled into the optical fiber 310 through the laser beam expander 301 and be transmitted to the acquisition control subsystem 102. In this way, the interference light path 402 of the vibration measurement light can be formed, so as to obtain the vibration phase shift subsequently.

[0130] Corresponding to the above-mentioned atomic interference gravimeter axial vibration continuous measurement and error compensation system, the application also provides an atomic interference gravimeter axial vibration continuous error compensation method, which is applied to the above-mentioned atomic interference gravimeter axial vibration continuous measurement and error compensation system.

[0131] The system comprises a probe and an acquisition control subsystem, wherein the acquisition control subsystem comprises a gravity information processing module and a vibration information processing module.

[0132] As shown in Figure 5 The method can comprise:

[0133] S501, for each measurement period, receiving input measurement light through the probe, processing the input measurement light, forming an interference light path, obtaining output measurement light and fluorescence detection signals and outputting.

[0134] The input measurement light comprises input vibration measurement light and input Raman light, and the input vibration measurement light and the input Raman light have different wavelengths.

[0135] S502, obtaining output vibration measurement light based on the output measurement light output by the probe through the vibration information processing module, and obtaining vibration phase shift based on the output vibration measurement light.

[0136] S503, processing the fluorescence detection signals output by the probe through the gravity information processing module to obtain atomic interference fringes, and correcting the phase of the atomic interference fringes based on the vibration phase shift to obtain a gravity acceleration measurement result.

[0137] As an embodiment of the application, the probe can comprise a dual-wavelength polarizer, a vacuum cavity, a quarter-wave plate, a dual-wavelength mirror, and a fluorescence detection module.

[0138] The method comprises that the input measurement light sequentially passes through the dual-wavelength polarizer, the vacuum cavity, the quarter-wave plate, and the dual-wavelength mirror to form an interference light path, obtain output measurement light and output.

[0139] The method comprises collecting fluorescence of a cold atom group that has completed atomic interference and fallen to the bottom of the vacuum cavity by using the fluorescence detection module, converting the fluorescence into a fluorescence detection signal, and outputting the fluorescence detection signal to the gravity information processing module to process and obtain gravity measurement information (gravity phase).

[0140] As an embodiment of the application, the probe can further comprise a laser beam expander,

[0141] The method comprises that the input measurement light can sequentially pass through a laser beam expander, a dual-wavelength polarizer, a vacuum cavity, a quarter-wave plate, and a dual-wavelength mirror to form an interference optical path, and output measurement light is obtained and output.

[0142] As an embodiment of the present application, the acquisition control subsystem can further comprise a laser generation module.

[0143] The method can further comprise generating, by the laser generation module, the input vibration measurement light and the input Raman light acting on the probe.

[0144] As an embodiment of the present application, the laser generation module can comprise an atomic interferometric gravity measurement laser unit, a vibration measurement laser, and a laser coupler.

[0145] The atomic interferometric gravity measurement laser unit generates each functional atomic interferometric gravity laser required in the process of generating atomic gravity interference.

[0146] The vibration measurement laser is used to generate incident vibration measurement light with stable light intensity and frequency.

[0147] The laser coupler combines the input Raman light and the input vibration measurement light to obtain the input measurement light.

[0148] As an embodiment of the present application, the acquisition control subsystem can further comprise a laser feedback control unit.

[0149] The method further comprises obtaining, by the laser feedback control unit, laser parameters based on the gravity phase and the vibration phase shift, and inputting the laser parameters to the laser generation module, wherein the gravity phase is obtained by the gravity information processing module based on information corresponding to the fluorescence detection signal output by the probe.

[0150] As an embodiment of the present application, the vibration information processing module can comprise a filter, a photodetector, and a phase shift calculation unit.

[0151] The method can further comprise filtering, by the filter, the output test light to obtain vibration measurement light, and inputting the vibration measurement light to the photodetector.

[0152] The photodetector converts the output vibration measurement light into an electrical signal, and inputs the electrical signal to the phase shift calculation unit.

[0153] The phase shift calculation unit obtains the vibration displacement of the atomic gravity interference process based on the vibration interference signal, continuously monitors the vibration displacement, aligns the time sequence of the atomic interference with the time of the vibration measurement signal based on the time sequence of the interaction between the Raman light and the cold atom group, integrates the vibration signal with the sensitivity function to obtain the vibration phase shift.

[0154] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A system for continuous measurement and error compensation of axial vibration of an atomic interferometer gravimeter, characterized in that, The system includes: a probe and a data acquisition and control subsystem, wherein the data acquisition and control subsystem includes: a gravity information processing module and a vibration information processing module; The probe is used to receive input measurement light for each measurement cycle, process the input measurement light to form an interference optical path, and obtain and output the output measurement light and fluorescence detection signal. The input measurement light includes input vibration measurement light and input Raman light, and the input vibration measurement light and the input Raman light have different wavelengths. The vibration information processing module and the gravity information processing module are connected to the probe. The vibration information processing module is connected to the gravity information processing module. The vibration information processing module is used to obtain output vibration measurement light based on the output measurement light output by the probe, and to obtain vibration phase shift based on the output vibration measurement light. The gravity information processing module is used to process the fluorescence detection signal output by the probe to obtain atomic interference fringes, and to correct the phase of the atomic interference fringes based on the vibration phase shift to obtain the gravitational acceleration measurement result. The probe includes: a dual-wavelength polarizer, a vacuum cavity, a quarter-wave plate, a dual-wavelength reflector, and a fluorescence detection module; Along a direction perpendicular to the surface of the dual-wavelength polarizer, the vacuum cavity, the quarter-wave plate, and the dual-wavelength reflector are sequentially arranged; The fluorescence detection module is connected to the gravity information processing module and is used to generate the fluorescence detection signal based on the interference optical path; The upper surface of the vacuum cavity is coated with a dual-wavelength film, which functions as an anti-reflection coating for Raman light and a semi-reflective and semi-transparent coating for vibration measurement light. Alternatively, the upper surface of the dual-wavelength polarizer is coated with the dual-wavelength film.

2. The axial vibration continuous measurement and error compensation system of an atomic interferometer gravimeter according to claim 1, characterized in that, The probe also includes: a laser beam expander; The laser beam expander is located on the side corresponding to the upper surface of the dual-wavelength polarizer and is connected to the acquisition and control subsystem.

3. The axial vibration continuous measurement and error compensation system of an atomic interferometer gravimeter according to claim 1, characterized in that, The acquisition and control subsystem also includes: a laser generation module; The laser generating module is connected to the probe, wherein the laser generating module is used to generate the input vibration measurement light and the input Raman light acting on the probe.

4. The axial vibration continuous measurement and error compensation system of an atomic interferometer gravimeter according to claim 3, characterized in that, The laser generation module includes: an atomic interferometry gravity measurement laser unit, a vibration measurement laser, and a laser coupler; Both the atomic interferometric gravity measurement laser unit and the vibration measurement laser are connected to the laser coupler. The laser coupler is connected to the probe.

5. The axial vibration continuous measurement and error compensation system of an atomic interferometer gravimeter according to claim 3, characterized in that, The acquisition and control subsystem also includes: a laser feedback control unit; The laser feedback control unit is connected to the gravity information processing module, the vibration information processing module, and the laser generation module. The laser feedback control unit is used to obtain laser parameters based on the vibration phase shift and the gravity phase and input them to the laser generation module. The gravity phase is obtained by the gravity information processing module based on the information corresponding to the fluorescence detection signal output by the probe.

6. The axial vibration continuous measurement and error compensation system of an atomic interferometer gravimeter according to claim 5, characterized in that, The vibration information processing module includes: a filter, a photodetector, and a phase shift calculation unit; The filter is connected to the probe; The photodetector is connected to the filter and the phase shift calculation unit; The phase shift calculation unit is connected to the gravity information processing module and the laser feedback control unit.

7. A continuous measurement and error compensation system for axial vibration of an atomic interferometer gravimeter according to any one of claims 3-5, characterized in that, The acquisition and control subsystem also includes: a circulator and optical fiber; The laser generating module and the vibration information processing module are connected to the circulator; The circulator is connected to the probe via the optical fiber.

8. The axial vibration continuous measurement and error compensation system of an atomic interferometer gravimeter according to claim 7, characterized in that, The circulator includes a first port, a second port, and a third port; The laser generating module is connected to the first port; The second port is connected to the probe via the optical fiber; The vibration information processing module is connected to the third port.

9. A method for compensating for continuous axial vibration error in an atomic interferometer, characterized in that, Applied to the atomic interferometer axial vibration continuous measurement and error compensation system as described in any one of claims 1-8; The method includes: For each measurement cycle, the probe receives the input measurement light, processes the input measurement light to form an interference optical path, and obtains the output measurement light and fluorescence detection signal, which are then output. The input measurement light includes the input vibration measurement light and the input Raman light, which have different wavelengths. The vibration information processing module obtains the output vibration measurement light based on the output measurement light from the probe, and obtains the vibration phase shift based on the output vibration measurement light. The fluorescence detection signal output by the probe is processed by the gravity information processing module to obtain atomic interference fringes. The phase of the atomic interference fringes is corrected based on the vibration phase shift to obtain the gravitational acceleration measurement result.

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