A gravitational wave detector based on combined pulse atom interferometer

Abstract

The present application provides a gravitational wave detector based on a combined pulse-type atom interferometer, which belongs to the field of atom interferometers for gravitational wave detection. Specifically, a group of lasers with similar frequencies are split into two groups of lasers to respectively manipulate two groups of atoms to achieve interference. When a gravitational wave passes through, it causes a difference in the phase of the laser propagation in two directions. The laser phase difference is recorded when the two atoms interact with the two groups of lasers respectively. The influence of the gravitational wave on the laser propagation phase can be measured by the phase difference between the two atoms and the laser. Since the two groups of atomic groups in the present application are manipulated by the laser generated by the same group of light sources, the differential measurement can effectively suppress the noise of the laser.

Description

Technical Field

[0001] The present application belongs to the field of gravitational wave detection using atom interferometers, and more specifically, relates to a gravitational wave detector based on a combined pulse atom interferometer. Background Art

[0002] Gravitational wave detection is an important research field in modern physics. When using atom interferometers as detectors to detect gravitational waves, the internal and external noise of the atom interferometer, especially the laser frequency and phase noise and the gravitational wave signal intensity, affect the improvement of the atom interferometer's gravitational wave detection sensitivity.

[0003] For example, the frequency noise and phase noise of the laser in an atom interferometer affect the sensitivity of gravitational wave detection. Atom interferometers typically rely on the precise frequency of the laser to manipulate the internal state of atoms or control their motion. When laser frequency noise is present, it can lead to instability in the atomic energy levels, thus affecting the formation of the atomic interference pattern. Laser phase noise can affect the phase relationship of the atomic waves in the atom interferometer, causing the interference fringes to blur and change their position and shape. Furthermore, the gravitational wave signal intensity is very weak, resulting in low detection sensitivity. When detecting gravitational waves with an atom interferometer, it is necessary to suppress the laser frequency and phase noise and amplify the gravitational wave signal to improve the sensitivity of gravitational wave detection.

[0004] Although there are many methods for detecting gravitational waves using atomic interferometry, their principles are all based on the laser phase changes caused by atomic interferometry measuring gravitational waves. Existing methods of detecting gravitational waves using atomic interferometry make it difficult to use dual-frequency lasers emitted by the same light source at the same time to control the two groups of atoms to achieve interference due to the different optical paths between the light source and the two groups of test atoms. This fails to solve the laser phase noise problem and the weak gravitational wave signal problem of the two-photon transition atom interferometer. Summary of the Invention

[0005] In response to the defects of the existing technology, the purpose of this application is to provide a gravitational wave detector combined with a pulsed atom interferometer, aiming to solve the problem that the existing atomic interference detection method of gravitational waves is difficult to control the two groups of atoms to achieve interference using dual-frequency lasers emitted by the same light source at the same time due to the different optical paths between the light source and the two groups of test atoms. It also fails to solve the laser phase noise problem of the two-photon transition atom interferometer and the problem of weak gravitational wave signals.

[0006] To achieve the above objectives, in a first aspect, the present application provides a gravitational wave detector based on a combined pulse-type atom interferometer, comprising: a first reflector, a second reflector, a third reflector, a fourth reflector, a first beam splitter, a second beam splitter, a third beam splitter, a first pulse-type atom interferometer, and a second pulse-type atom interferometer;

[0007] The transmission direction of the two Bragg laser beams incident on the first beam splitter is the x-axis, and the reflection direction is the y-axis; in the y-axis direction, the first beam splitter, the second beam splitter, and the second reflector are sequentially arranged from bottom to top; the third beam splitter and the third reflector are sequentially arranged in front of the first beam splitter in the x-axis direction; the fourth reflector is arranged directly above the third beam splitter in the y-axis direction, and the second pulse-type atom interferometer is arranged directly below it; the first reflector is arranged in front of the second beam splitter in the x-axis direction, and the first pulse-type atom interferometer is arranged directly behind it;

[0008] The same laser source is used to emit a group of Bragg lasers with frequencies that differ by no more than a preset frequency to a first beam splitter; the first beam splitter is used to reflect part of the first Bragg laser and the second Bragg laser to a second beam splitter to form a first laser beam and a second laser beam; wherein the first laser beam is sequentially reflected by the second beam splitter, reflected by the first reflector, and transmitted by the second beam splitter to enter the first pulse-type atom interferometer; the second laser beam is sequentially transmitted by the second beam splitter, reflected by the second reflector, and reflected by the second beam splitter to enter the first pulse-type atom interferometer;

[0009] The first beam splitter is used to transmit the remaining first Bragg laser light and the second Bragg laser light to the third beam splitter to form a third laser beam and a fourth laser beam; the third laser beam is sequentially transmitted through the third beam splitter, reflected by the third reflector, and reflected by the third beam splitter, and enters the second pulse-type atom interferometer; the fourth laser beam is sequentially reflected through the third beam splitter, reflected by the fourth reflector, and transmitted through the third beam splitter, and enters the second pulse-type atom interferometer;

[0010] The first pulse-type atom interferometer and the second pulse-type atom interferometer are respectively provided with the first atomic cluster and the second atomic cluster; gravitational waves are used to change the phases of the first, second, third and fourth laser beams, thereby changing the phases of the first atomic cluster and the second atomic cluster, forming different interference patterns, and the influence of gravitational waves on the laser propagation phase is obtained according to the interference patterns.

[0011] Further preferably, the change in the laser propagation phase under the influence of gravitational waves is:

[0012] Δφ 1,LA -Δφ 2,LA =2(k1+k2)(L1-L2)

[0013] Among them, Δφ 1,LA is the first laser phase difference recorded by the first atomic group, and is also the phase contribution value of a single first laser beam and second laser beam pulse to the state evolution of the first atomic group; Δφ 2,LAis the second laser phase difference recorded by the second atomic cluster, and is also the phase contribution value of a single third laser beam and fourth laser beam pulse to the state evolution of the second atomic cluster; L1 is the distance between the second beam splitter and the first reflector; L2 is the distance between the second beam splitter and the second reflector; k1 is the wave vector of the first Bragg laser; k2 is the wave vector of the second Bragg laser.

[0014] Further preferably, without considering the effect of gravitational waves, L1=L2=L'1=L'2;

[0015] Wherein, L'1 is the distance between the center of the third beam splitter and the third reflector; L'2 is the distance between the center of the third beam splitter and the fourth reflector.

[0016] In a second aspect, the present application provides a gravitational wave detection method based on a combined pulse atom interferometer, comprising the following steps:

[0017] Step S1: using the same laser source to emit a group of Bragg lasers with a frequency difference not exceeding a preset frequency difference, and splitting the beams into a first laser beam, a second laser beam, a third laser beam and a fourth laser beam;

[0018] Step S2: using the first laser beam and the second laser beam to pulse the first atomic cluster to cause interference in the first atomic cluster and record the first laser phase difference;

[0019] At the same time, a third laser beam and a fourth laser beam are used to pulse the second atomic group, causing interference in the second atomic group, and recording the second laser phase difference;

[0020] Step S3: Subtract the first laser phase difference from the second laser phase difference to obtain the laser propagation phase difference containing the gravitational wave signal.

[0021] Further preferably, in step S2, the first laser beam and the second laser beam act on the first atomic cluster with a single pulse, and the third laser beam and the fourth laser beam act on the second atomic cluster with a single pulse, so that the first atomic cluster and the second atomic cluster undergo transition under the action of the single pulse, thereby obtaining a first laser phase difference and a second laser phase difference;

[0022] Alternatively, a time-sequenced laser pulse is set to emit a first laser beam and a second laser beam pulse within a certain time interval to interact with the first atomic cluster, and emit a third laser beam and a fourth laser beam pulse to interact with the second atomic cluster, so that the first atomic cluster and the second atomic cluster undergo transition under the action of each pulse, and the first laser phase difference and the second laser phase difference are obtained after the accumulated phase difference.

[0023] Further preferably, the first laser phase difference under a single pulse is:

[0024]

[0025] The phase difference of the second laser under a single pulse is:

[0026]

[0027] The phase difference of the laser propagation containing the gravitational wave signal is:

[0028] Δφ 1,LA -Δφ 2,LA =2(k1+k2)(L1-L2)

[0029] Among them, Δφ 1,LA is the first laser phase difference recorded by the first atomic group, and is also the phase contribution value of a single first laser beam and second laser beam pulse to the state evolution of the first atomic group; Δφ 2,LA is the second laser phase difference recorded by the second atomic cluster, and is also the phase contribution value of a single third laser beam and fourth laser beam pulse to the state evolution of the second atomic cluster; L1 is the distance between the second beam splitter and the first reflector; L2 is the distance between the second beam splitter and the second reflector; L'1 is the distance between the center of the third beam splitter and the third reflector; L'2 is the distance between the center of the third beam splitter and the fourth reflector; k1 is the wave vector of the first Bragg laser; k2 is the wave vector of the second Bragg laser; ω1 is the frequency of the first Bragg laser; ω2 is the frequency of the second Bragg laser; is the initial phase of the first Bragg laser; is the initial phase of the second Bragg laser.

[0030] Further preferably, the total time of the sequential laser pulses is controlled to be in the order of milliseconds, and the pulse interval is in the order of seconds.

[0031] Further preferably, the momentum p of the first atomic group increases to 0.01 under the action of n pulses of the first laser beam and the second laser beam and the momentum p of the second atomic group increases to 0.01 under the action of n pulses of the third laser beam and the fourth laser beam after absorbing n photons. The phase contribution of the first laser beam and the second laser beam to the state evolution of the first atomic group increases to nΔφ 1,LA The phase contribution of the third and fourth laser beams to the state evolution of the second atomic group increases to nΔφ 2,LA ;in, is the reduced Planck constant.

[0032] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0033] The present application provides a gravitational wave detection method based on a combined pulsed atom interferometer. A group of Bragg lasers with similar frequencies are split into two groups of lasers to respectively manipulate two groups of atoms to achieve interference. When a gravitational wave passes through, it causes a difference in the phase of the laser propagation in the two directions. The laser phase difference can be recorded when the two atoms interact with the two groups of lasers respectively. The phase difference of the laser propagation containing the gravitational wave signal can be measured by the difference between the phase differences of the interaction between the two atoms and the lasers. Since the two groups of atomic groups are manipulated using the lasers generated by the same group of light sources, the differential measurement can effectively suppress the noise of the laser.

[0034] The present application provides a gravitational wave detection method based on a combined pulse atom interferometer, which uses dual-atom differential measurement common mode to suppress laser frequency noise and phase noise. By using combined pulses, atoms and lasers interact multiple times, achieving atomic phase accumulation, enhancing the gravitational wave signal intensity, and thus improving detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the experimental method for detecting gravitational waves using diatomic interferometry provided in an embodiment of the present application.

[0036] Figure 2 is an atomic energy level diagram of the combined pulsed atom interferometer provided in an embodiment of the present application;

[0037] Figure 3 This is a time-space structure diagram of the combined pulsed atomic interferometer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0039] This application provides a gravitational wave detector and method based on a combined pulsed atom interferometer. The basic principle is:

[0040] A group of lasers with similar frequencies are split into two groups of lasers, each of which manipulates two atomic clusters to achieve interference. The phase difference in the interference image includes noise sources and the phase difference introduced by gravitational waves. Noise sources, such as laser frequency noise and phase noise, are present in both interference images. The phase difference introduced by gravitational waves is caused by: gravitational waves cause slight changes in space, affecting the lengths of the two interferometer arms in the x and y directions, and thus affecting the laser phase difference in the x and y directions in the first and second pulse-type atom interferometers.

[0041] The following describes how to obtain the influence of gravitational waves on the phase of laser propagation:

[0042] When an atomic cluster interacts with a laser, an additional laser phase will be obtained relative to free evolution after each atom absorbs a photon transition. The method of accumulating phases by atoms performing n photon transitions can amplify the laser phase signal by n times while ensuring that the number of atoms remains basically unchanged. Two laser beams respectively control two atomic clusters to achieve interference, and the interference image contains atomic phase information, thereby enabling the two atomic clusters to respectively record the two laser phase differences, and subtract the two laser phase differences to obtain the laser propagation phase difference containing the gravitational wave signal.

[0043] First, as Figure 1 As shown, the present application provides a gravitational wave detector based on a combined pulse-type atom interferometer, comprising: a first reflector, a second reflector, a third reflector, a fourth reflector, a first beam splitter, a second beam splitter, a third beam splitter, a first pulse-type atom interferometer A and a second pulse-type atom interferometer B;

[0044] Taking the direction in which two Bragg lasers are incident on the first beam splitter as a reference, a third beam splitter is placed in the transmission direction of the first beam splitter, and a second beam splitter is placed in its reflection direction. Reflectors are set in both the reflection and transmission directions of the second and third beam splitters. The second reflector is placed in the transmission direction of the second beam splitter, and the first reflector is placed in the reflection direction. The third reflector is placed in the transmission direction of the third beam splitter, and a fourth reflector is placed in its reflection direction. A first pulse-type atom interferometer is set in the opposite direction of the reflection direction of the second beam splitter. A second pulse-type atom interferometer is set in the opposite direction of the reflection direction of the third beam splitter.

[0045] The same laser source is used to emit a group of Bragg lasers with similar frequencies to the first beam splitter, namely the first Bragg laser and the second Bragg laser; the first beam splitter is used to reflect the first Bragg laser and the second Bragg laser to the second beam splitter; the first Bragg laser reflected to the second beam splitter is called the first laser beam, and the second Bragg laser reflected to the second beam splitter is called the second laser beam; the second beam splitter reflects the first laser beam to the first reflector, and the first laser beam is reflected by the first reflector and then transmitted through the second beam splitter to the first pulse-type atom interferometer A; the second beam splitter is used to transmit the second laser beam to the second reflector, and is reflected back to the second beam splitter by the second reflector, and then reflected to the first pulse-type atom interferometer A;

[0046] The first beam splitter is used to transmit the first Bragg laser and the second Bragg laser to the third beam splitter; the first Bragg laser transmitted to the third beam splitter is called the third laser beam, and the second Bragg laser transmitted to the third beam splitter is called the fourth laser beam; the third beam splitter is used to transmit the third laser beam to the third reflector, and after being reflected by the third reflector, it is transmitted to the third beam splitter and reflected again to the second pulse-type atom interferometer B; the third beam splitter is used to reflect the fourth laser beam to the fourth reflector, and after being reflected by the fourth reflector, it is transmitted to the second pulse-type atom interferometer B through the third beam splitter;

[0047] The first pulse-type atom interferometer A and the second pulse-type atom interferometer B are respectively provided with the first atomic cluster and the second atomic cluster; the gravitational wave is used to generate changes in the two interference arms of the x-axis and y-axis, thereby changing the phase of the first atomic cluster and the second atomic cluster, forming different interference patterns, and the influence of the gravitational wave on the laser propagation phase is obtained according to the interference patterns; wherein, the phase contribution of a single first laser beam and a second laser beam pulse to the state evolution of the first atomic cluster is Δφ 1,LA , the phase contribution of a single third laser beam and fourth laser beam pulse to the state evolution of the second atomic cluster is Δφ 2,LA ; Among them, the phase difference of the laser propagation containing the gravitational wave signal is:

[0048] Δφ 1,LA -Δφ 2,LA =2k1(L1-L2')+2k2(L1'-L2)≈2(k1+k2)(L1-L2)

[0049] Here are a few definitions: the distance between the second laser beam and the second reflector is L2; ​​the distance between the first laser beam and the second reflector is L1; the distance between the fourth laser beam and the third reflector is L'2; the distance between the third laser beam and the third reflector is L'1.

[0050] In the embodiment of the present application, without considering the effect of gravitational waves, L1≈L2, and L1≈L1′, L2≈L'2; thereby ensuring that the two frequency lasers emitted by the light source at the same time can interact with the atoms almost simultaneously after being reflected by the mirror at the end of the interferometer arm; the passage of gravitational waves will cause space expansion and contraction. When the gravitational waves pass through the first pulse-type atom interferometer and the second pulse-type atom interferometer, L1≈L1′ in the x-direction and L2≈L'2 in the y-direction, but L1≈L2 cannot be guaranteed; resulting in a difference in the laser propagation phase in the two directions.

[0051] First, as Figure 1As shown, the present application provides a gravitational wave detection method based on a combined pulse atom interferometer, which enhances the sensitivity of gravitational wave detection by suppressing laser frequency and phase noise; specifically, the method includes the following steps:

[0052] Step S10: A group of Bragg laser beams with similar frequencies are emitted from the same laser source. After being split by a beam splitter, two groups of laser beams are formed along arm lengths L1, L2 and L'1, L'2. The two groups of laser beams propagate in two perpendicular directions, forming the two arms of the interferometer. For any group of laser beams, the structure is similar to that of LIGO, where one laser beam propagates along the x-direction path L1 (≈ L1′), encounters the reflector at the end of the interferometer arm and is reflected back. The other beam travels back and forth along the y-direction path L2 (≈ L'2).

[0053] It should be noted that the experimental configuration of the embodiment of the present application is set so that the arm lengths in different directions are equal, L1≈L2; thereby ensuring that the two frequency lasers emitted by the light source at the same time can interact with the atoms almost simultaneously after being reflected by the mirror at the end of the interferometer arm;

[0054] Step S20: When the first atomic group and the second atomic group are subjected to a single pulse of the two laser groups, the two atomic groups are manipulated by the two laser groups to achieve interference, and the phase difference of the lasers is recorded;

[0055] In step S20, when the first atomic group and the first group of lasers perform a single pulse action, the first laser phase difference Δφ recorded by the first atomic group is 1,LA The calculation formula is:

[0056]

[0057] When the second atomic group interacts with the second group of lasers in a single pulse, the second laser phase difference Δφ recorded by the second atomic group 2,LA The calculation formula is:

[0058]

[0059] Among them, Δφ 1,LA is the first laser phase difference recorded by the first atomic group, and is also the phase contribution value of a single first laser beam and second laser beam pulse to the state evolution of the first atomic group; Δφ 2,LAis the second laser phase difference recorded by the second atomic cluster, and is also the phase contribution value of a single third laser beam and fourth laser beam pulse to the state evolution of the second atomic cluster; L1 is the distance between the second beam splitter and the first reflector; L2 is the distance between the second beam splitter and the second reflector; L'1 is the distance between the third beam splitter and the third reflector; L'2 is the distance between the third beam splitter and the fourth reflector; k1 is the wave vector of the first Bragg laser; k2 is the wave vector of the second Bragg laser; ω1 is the frequency of the first Bragg laser; ω2 is the frequency of the second Bragg laser; is the initial phase of the first Bragg laser; is the initial phase of the second Bragg laser;

[0060] In this embodiment, the passage of a gravitational wave causes space to expand and contract. When the gravitational wave passes through the detector, it changes the lengths of the four arms in two directions, resulting in a difference in the phase of the laser propagation in the two directions. The atomic cluster and the laser perform a single pulse, and a high-precision detector is used to detect the interference pattern of the two atomic clusters and accurately record the phase information.

[0061] Step S30: Measuring the propagation phase difference of the laser beam containing the gravitational wave signal based on the difference between the first laser phase difference and the second laser phase difference between the two atoms interacting with the laser beam;

[0062] More specifically, in step S30, the phase difference of the laser propagation containing the gravitational wave signal is:

[0063] Δφ 1,LA -Δφ 2,LA =2k1(L1-L2')+2k2(L1'-L2)≈2(k1+k2)(L1-L2)

[0064] Among them, L1, L2 and L'1, L'2 are the arm lengths of two groups of lasers formed after a group of Bragg lasers with similar frequencies are split. The arm length in the x direction is L1≈L1′, and the arm length in the y direction is are the laser wave vectors and initial phases with frequencies of ω1 and ω2 respectively; t is the moment when the laser interacts with the atoms; since the interference paths of the two groups of atomic clusters are independent, their interference patterns can be compared with each other.

[0065] In summary, the gravitational wave detection method based on a combined pulsed atom interferometer provided in this application has the following effects: a group of lasers with similar frequencies (Bragg Lasers) are split into two groups of lasers to manipulate two groups of atoms to achieve interference. When a gravitational wave passes through, it causes a difference in the laser propagation phase in two directions. The laser phase difference can be recorded when the two atoms interact with the two groups of lasers respectively; the influence of gravitational waves on the laser propagation phase can be measured by the difference between the phase differences of the interaction between the two atoms and the laser; since the two groups of atomic groups are manipulated using the laser generated by the same group of light sources, differential measurement can effectively suppress laser noise, such as laser frequency noise and phase noise.

[0066] In the second aspect, the present application provides an atomic phase accumulation method under combined pulses in an atom interferometer to amplify gravitational wave signals and enhance the sensitivity of gravitational wave detection, such as Figure 2 and Figure 3 As shown, the method for amplifying gravitational wave signals specifically includes the following steps:

[0067] Step 1: Prepare a low-temperature atomic cluster in a highly coherent state; design a series of precisely timed laser pulses that interact with the atomic cluster at specific time intervals to manipulate the momentum and phase of the atoms;

[0068] The total time τ of the combined pulses of the constructed atomic interferometer can be controlled in the millisecond order, and the pulse interval T of the embodiment of the present application is in the second order; in such a configuration, the pulse width is much smaller than the atomic interference time (τ<<T);

[0069] Step 2: If Figure 2 and Figure 3 As shown, the atom undergoes transitions under the action of each laser pulse, and each transition accumulates a certain phase;

[0070] In this embodiment, when atoms interact with laser light, after each photon absorption transition, an additional laser phase φ is obtained relative to the free evolution. LA , the momentum of the absorbed photon In the combined pulsed atom interferometer, atoms interact with laser light multiple times in a short period of time, and the initial momentum p increases after absorbing n photons. The phase contribution of the laser to the atomic state evolution increases accordingly to nφ LA ;

[0071] Step 3: Gravitational waves may cause tiny changes in space, thereby affecting the phase of atoms; after a series of laser pulses, the phase differences of the atomic clusters lead to the formation of interference patterns, which can be measured by detectors.

[0072] Further preferably, the embodiment of the present application selects an equivalent Mach-Zehnder interferometer that has been studied in depth, but the atom interferometer of the present application is not limited to a Mach-Zehnder interferometer; in this interferometer, the phase Δφ of the laser LA (t) The relative contribution to the atom interferometer is:

[0073] Δφ AI =n[Δφ LA (t1)-2Δφ LA (t2)+Δφ LA (t3)]

[0074] Among them, t1, t2, and t3 are the moments when the laser interacts with the atom.

[0075] That is, the atomic interferometry method can be used to measure the laser phase difference caused by gravitational waves at different pulse times, and the signal can be amplified by the combined pulse.

[0076] In summary, compared with the prior art, this application has the following advantages:

[0077] This application uses dual-atom differential measurement to suppress the common mode of laser frequency and phase noise. By using combined pulses, atoms and lasers interact multiple times to achieve atomic phase accumulation, enhance the intensity of gravitational wave signals, and thus improve detection sensitivity.

[0078] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0079] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0080] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A gravitational wave detector based on a combined pulse atom interferometer, characterized in that: include: first, second, third and fourth reflecting mirrors, first, second and third beam splitters, a first pulse-type atom interferometer and a second pulse-type atom interferometer; The same laser source is used to emit a group of Bragg lasers with a frequency difference not exceeding a preset frequency difference to the first beam splitter; the first beam splitter is used to reflect part of the first Bragg laser and the second Bragg laser to the second beam splitter to form a first laser beam and a second laser beam; wherein the first laser beam is sequentially reflected by the second beam splitter, reflected by the first reflector, and transmitted by the second beam splitter, and enters the first pulse-type atom interferometer; the second laser beam is sequentially transmitted by the second beam splitter, reflected by the second reflector, and reflected by the second beam splitter, and enters the first pulse-type atom interferometer; The first beam splitter is used to transmit the remaining first Bragg laser light and the second Bragg laser light to the third beam splitter to form a third laser beam and a fourth laser beam; the third laser beam is sequentially transmitted through the third beam splitter, reflected by the third reflector, and reflected by the third beam splitter, and enters the second pulse-type atom interferometer; the fourth laser beam is sequentially reflected through the third beam splitter, reflected by the fourth reflector, and transmitted through the third beam splitter, and enters the second pulse-type atom interferometer; The first pulse-type atom interferometer and the second pulse-type atom interferometer are respectively provided with the first atomic cluster and the second atomic cluster; gravitational waves are used to change the phases of the first, second, third and fourth laser beams, thereby changing the phases of the first atomic cluster and the second atomic cluster, forming different interference patterns, and the influence of gravitational waves on the laser propagation phase is obtained according to the interference patterns.

2. The gravitational wave detector according to claim 1, characterized in that: The phase difference of the laser containing the gravitational wave signal is: Δφ 1,LA -Δφ 2,LA =2(k1+k2)(L1-L2) Among them, Δφ 1,LA is the first laser phase difference recorded by the first atomic group, and is also the phase contribution value of a single first laser beam and second laser beam pulse to the state evolution of the first atomic group; Δφ 2,LA is the second laser phase difference recorded by the second atomic cluster, and is also the phase contribution value of a single third laser beam and fourth laser beam pulse to the state evolution of the second atomic cluster; L1 is the distance between the second beam splitter and the first reflector; L2 is the distance between the second beam splitter and the second reflector; k1 is the wave vector of the first Bragg laser; k2 is the wave vector of the second Bragg laser.

3. The gravitational wave detector according to claim 2, characterized in that: Without considering the effect of gravitational waves, L1=L2=L'1=L'2; Wherein, L'1 is the distance between the center of the third beam splitter and the third reflector; L'2 is the distance between the center of the third beam splitter and the fourth reflector.

4. A gravitational wave detection method based on the gravitational wave detector according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1: using the same laser source to emit a group of Bragg lasers with a frequency difference not exceeding a preset frequency difference, and splitting the beams into a first laser beam, a second laser beam, a third laser beam and a fourth laser beam; Step S2: using the first laser beam and the second laser beam to pulse the first atomic cluster to cause interference in the first atomic cluster and record the first laser phase difference; At the same time, a third laser beam and a fourth laser beam are used to pulse the second atomic group, causing interference in the second atomic group, and recording the second laser phase difference; Step S3: Subtract the first laser phase difference from the second laser phase difference to obtain the laser propagation phase difference containing the gravitational wave signal.

5. The gravitational wave detection method according to claim 4, characterized in that: In step S2, the first laser beam and the second laser beam act on the first atomic cluster with a single pulse, and the third laser beam and the fourth laser beam act on the second atomic cluster with a single pulse, so that the first atomic cluster and the second atomic cluster transition under the action of the single pulse, and obtain a first laser phase difference and a second laser phase difference; Alternatively, a time-sequenced laser pulse is set to emit a first laser beam and a second laser beam pulse within a certain time interval to interact with the first atomic cluster, and emit a third laser beam and a fourth laser beam pulse to interact with the second atomic cluster, so that the first atomic cluster and the second atomic cluster undergo transition under the action of each pulse, and the first laser phase difference and the second laser phase difference are obtained after the accumulated phase difference.

6. The gravitational wave detection method according to claim 5, characterized in that: The first laser phase difference under a single pulse is: The phase difference of the second laser under a single pulse is: The phase difference of the laser propagation containing the gravitational wave signal is: Δφ 1,LA -Δφ 2,LA =2(k1+k2)(L1-L2) Among them, Δφ 1,LA is the first laser phase difference recorded by the first atomic group, and is also the phase contribution value of a single first laser beam and second laser beam pulse to the state evolution of the first atomic group; Δφ 2,LA is the second laser phase difference recorded by the second atomic cluster, and is also the phase contribution value of a single third laser beam and fourth laser beam pulse to the state evolution of the second atomic cluster; L1 is the distance between the second beam splitter and the first reflector; L2 is the distance between the second beam splitter and the second reflector; L'1 is the distance between the center of the third beam splitter and the third reflector; L'2 is the distance between the center of the third beam splitter and the fourth reflector; k1 is the wave vector of the first Bragg laser; k2 is the wave vector of the second Bragg laser; ω1 is the frequency of the first Bragg laser; ω2 is the frequency of the second Bragg laser; is the initial phase of the first Bragg laser; is the initial phase of the second Bragg laser.

7. The gravitational wave detection method according to claim 5, characterized in that: The total time of the set sequential laser pulses is controlled in the millisecond order, and the pulse interval time is in the second order.

8. The gravitational wave detection method according to claim 6, wherein: The momentum p of the first atom group increases to 0.01 under the action of n pulses of the first laser beam and the second laser beam, and the momentum p of the second atom group increases to 0.01 under the action of n pulses of the third laser beam and the fourth laser beam after absorbing n photons. The phase contribution of the first laser beam and the second laser beam to the state evolution of the first atomic group increases to nΔφ 1,LA The phase contribution of the third and fourth laser beams to the state evolution of the second atomic group increases to nΔφ 2,LA ;in, is the reduced Planck constant.

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