A device and method for fast shut-off of cold atom loading

Abstract

The application discloses a device for rapidly shutting off cold atom loading, comprising a laser light source, laser light emitted by the laser light source sequentially passing through an acousto-optic modulator, a collimating lens and a first reflector to serve as forward incident laser light input into a control cavity, the forward incident laser light sequentially passing through a light transmission opening in the center of a first light transmission surface and a light transmission opening in the center of a second light transmission surface on the control cavity and being reflected by a second reflector outside the control cavity. The application also discloses a method for rapidly shutting off cold atom loading, which is used for real-time and accurate control of atom beam loading according to different atom loading requirements. The application can compress the divergence angle to enhance the atom beam flow intensity, improve the atom loading number, and make the near-resonance laser interact with the atom beam flow at a specific angle by slightly adjusting the angles of two reflectors to realize the shutting off of the atom loading. The application can also control the light field intensity and detuning by selecting an external control signal of the acousto-optic modulator to continuously and quantitatively control the atom loading.

Description

Technical Field

[0001] This invention belongs to the field of cold atom physics, specifically relating to a device for rapidly shutting off cold atom loading and a method for rapidly shutting off cold atom loading. It can be used to develop cold atom loading for high-precision optical clocks and can be extended to fields such as quantum computing, quantum storage, and atomic interferometers based on cold atom platforms. Background Technology

[0002] After more than 20 years of rapid development, optical clocks have surpassed the performance of the cesium atomic fountain clock, which is currently used to define the second, propelling the world's time measurement from microwave frequencies to the higher precision of optical frequencies. The core of optical clock research is the cold atom system, typically using strontium or ytterbium atoms with their outermost two electrons as the atomic system. These atomic systems are solids at room temperature and require high-temperature baking to form an atomic beam, followed by laser cooling to create a micro-Kelvin-level cold atom sample. Only then can the clock laser be locked at the energy level corresponding to the clock transition to achieve highly stable optical frequency output.

[0003] In the cold atom preparation stage of an optical clock system, a large number of atoms typically need to be cooled and confined in a magneto-optical trap. During the subsequent clock probing stage, the cold atom loading needs to be rapidly cut off to prevent the continuous influx of low-velocity atoms into the magneto-optical trap from impacting the cold atoms in the optical lattice, which could lead to a decrease in the clock transition detection signal-to-noise ratio and a significant collision frequency shift. Therefore, timely and rapid shut-off of the cold atom loading is crucial for the development of high-precision optical clocks. Currently, commonly used solutions employ vacuum-embedded mechanical switches driven by magnetic coupling. However, the driving speed is limited by the motor speed and magnetic flux response speed, and there are also limitations in lifespan. During the operation of the optical clock system, to maintain system stability and repeatability, while keeping experimental parameters such as the laser frequency, power, and magnetic field used for cold atom preparation constant, this device can rapidly change the path of low-velocity atoms in the atomic beam to control the number of cold atoms in the optical clock system without affecting the clock probing duty cycle. This ensures excellent stability and low uncertainty for the optical clock. Compared to traditional vacuum-embedded mechanical switches, this device offers a faster response speed and virtually unlimited operating life. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by providing a device and a method for rapidly shutting off cold atom loading. This invention achieves quantitative control of a specific velocity group of atoms in a high-temperature atomic beam through optical field modulation, thereby controlling the loading of cold atoms and, in extreme cases, cutting off the loading of cold atoms.

[0005] The above-mentioned objectives of the present invention are achieved through the following technical means: A device for rapidly shutting off cold atom loading includes a laser source. The laser emitted from the laser source passes sequentially through an acousto-optic modulator, a collimating lens, and a first reflector before being input into a control cavity as a forward incident laser. The control cavity is a hollow cube. The forward incident laser passes sequentially through the light-transmitting aperture at the center of the first light-transmitting surface and the light-transmitting aperture at the center of the second light-transmitting surface on the control cavity along the direction of incident into the control cavity, and is reflected by a second reflector outside the control cavity. The first light-transmitting surface and the second light-transmitting surface are two opposite surfaces on the control cavity. The direction from the first light-transmitting surface to the second light-transmitting surface of the control cavity is taken as the positive z-axis direction; among the four surfaces of the control cavity parallel to the z-axis direction, an observation window is set at the center of each of the two opposite sides of one set, and the other two opposite sides are respectively connected to the atomic furnace and one end of the differential tube, and the other end of the differential tube is connected to the vacuum cavity equipped with a magneto-optical trap; the direction from the atomic furnace to the differential tube is taken as the positive x-axis direction; When the laser source is turned off, the atomic beam emitted from the atomic furnace passes through the control cavity and then enters the magneto-optical trap in the vacuum cavity via the differential tube; When it is necessary to compress the atomic beam divergence angle, the angles of the collimating lens, the first reflector, and the second reflector are adjusted so that the normally incident laser and the laser reflected by the second reflector are respectively incident into the control cavity along the positive z-axis and the negative z-axis. When it is necessary to shut down the cold atom loading, the angles of the collimating lens, the first reflector, and the second reflector are adjusted so that the direction of the normally incident laser and the direction of the laser reflected by the second reflector deviate from the z-axis direction according to preset angles. The normally incident laser is in the xz plane, and the laser reflected by the second reflector has an angle with the xz plane.

[0006] As described above, the laser source is connected to the input port of the acousto-optic modulator via an input optical fiber, and an external control voltage signal is input to the SMA interface of the acousto-optic modulator. The output port of the acousto-optic modulator is connected to one end of the output optical fiber, and the other end of the output optical fiber is connected to the optical fiber flange provided at one end of the first sleeve. The other end of the first sleeve is detachably connected to the first lens frame. The first lens frame is also detachably connected to the second sleeve, and a collimating lens is provided inside the second sleeve. The first reflector is installed inside the second frame. The second frame is a hollow right-angled triangular prism, comprising two rectangular right-angled side plates, one rectangular oblique side plate, and two right-angled triangular side plates. The center of each of the two right-angled side plates has a light-transmitting opening. The first frame is connected to one right-angled side plate of the second frame via multiple first connecting rods. The first reflector is mounted on the oblique side plate of the second frame. The other right-angled side plate of the second frame is connected to the first sub-adapter via multiple second connecting rods. The center of the first sub-adapter has a light-transmitting port. The second sub-adapter is mounted on the side of the control cavity opposite to the first sub-adapter. The center of the second sub-adapter has a light-transmitting port. The second sub-adapter is connected to the third frame via multiple third connecting rods. The second reflector is installed inside the third frame.

[0007] As described above, both the first sleeve and the second sleeve are cylindrical structures, and each has an external thread at one end and an internal thread at the other end. The fiber optic flange is located inside the internal thread of the first sleeve, and a corresponding clamp is provided between the side wall of the fiber optic flange and the internal thread of the first sleeve. The collimating lens is located inside the internal thread of the second sleeve, and a clamp is provided between the side wall of the collimating lens and the internal thread of the second sleeve.

[0008] As described above, both the first and third eyeglass frames include a movable plate and a fixed plate, both of which are thick metal plates; the movable plate and the fixed plate are connected by a spring; and both the movable plate and the fixed plate are provided with a central opening. For the first frame, the center opening of the movable plate is provided with an internal thread, and the internal thread is divided into two sections: one section of the internal thread matches the external thread of the first sleeve, and the end of the first sleeve with the external thread passes through the center opening of the fixed plate of the first frame and connects to the center opening of the movable plate of the first frame; the other section of the internal thread of the movable plate of the first frame is installed with the end of the second sleeve with the external thread. For the third mirror frame, the center opening of the movable plate is provided with an internal thread, and the second reflector is fixed in the internal thread by a metal retaining ring.

[0009] As described above, the movable plate and fixed plate in the first frame, as well as the movable plate and fixed plate in the third frame, are provided with evenly distributed coaxial through holes along the circumference of the plate surface, and set screws are provided on the side wall of the fixed plate at the positions corresponding to the through holes. Evenly distributed through holes are provided circumferentially near the edges of the two right-angled side plates of the second frame. One end of the first connecting rod is inserted into a through hole in a right-angled side plate of the second frame and fixed by corresponding set screws on the two right-angled triangular side plates of the second frame; the other end of the first connecting rod passes through a through hole in the movable plate of the first frame and is inserted into a coaxial through hole in the fixed plate of the first frame and fixed by set screws on the side of the fixed plate of the first frame. One end of the second connecting rod has an external thread, and the other end has no thread; a positioning threaded hole is provided on the outer periphery of the light-transmitting port in the center of the first sub-adapter; the threaded end of the second connecting rod is fixed in the positioning threaded hole of the first sub-adapter; the unthreaded end of the second connecting rod is inserted into the corresponding through hole of another right-angled side plate of the second frame, and is fixed by the set screw corresponding to the through hole on the right-angled triangular side plate. One end of the third connecting rod has an external thread, while the other end is unthreaded. A positioning threaded hole is provided on the outer periphery of the light-transmitting port in the center of the second sub-adapter. The threaded end of the third connecting rod is fixed in the positioning threaded hole of the first sub-adapter. The unthreaded end of the third connecting rod passes through the through hole of the movable plate of the third frame and is inserted into the coaxial through hole of the fixed plate of the third frame, and is fixed by the set screw on the side of the fixed plate of the third frame.

[0010] Multiple threaded adjustment holes are provided on the fixing plate of the first frame and the fixing plate of the third frame. The tail of the first adjustment screw passes through the threaded adjustment hole of the fixing plate of the first frame and abuts against the movable plate of the first frame through the corresponding piezoelectric ceramic. The tail of the third adjustment screw passes through the threaded adjustment hole of the fixing plate of the third frame and abuts against the movable plate of the third frame through the corresponding piezoelectric ceramic. The side of the rectangular sloping side plate facing the inside of the second mirror frame is connected to the back of the first mirror via multiple springs. Multiple second adjusting screws are provided on the sloping side plate of the second mirror frame. The tail of the second adjusting screw passes through the adjusting threaded hole on the sloping side plate of the second mirror frame from the outside to the inside, and then abuts against the back of the first mirror via a corresponding piezoelectric ceramic.

[0011] A method for rapidly shutting down cold atom loading, utilizing the apparatus for rapidly shutting down cold atom loading as described above, includes the following steps: Step 1: Construct a device for rapidly shutting down cold atom loading; Step 2: By adjusting the control signal intensity of the piezoelectric ceramics on the first, second, and third mirror frames, the deflection angles of the collimating lens, the first mirror, and the second mirror are scanned, and the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is measured accordingly. The control signal strength of each piezoelectric ceramic was determined to achieve the highest transmission efficiency of the atomic beam, and this signal was used as the control signal parameter for compressing the atomic beam. The intensity of the control signal for each piezoelectric ceramic when atomic loading needs to be turned off is determined and used as the control signal parameter for turning off the atomic beam. The strength of the external control voltage signal of the acousto-optic modulator was determined when quantitatively controlling the transmission efficiency of the atomic beam, and used as the adjustment signal parameter for the atomic loading rate. Step 3: Based on the control signal parameters for compressing the atomic beam, the control signal parameters for turning off the atomic beam, and the adjustment signal parameters for the atomic loading rate obtained in Step 2, the corresponding piezoelectric ceramics are controlled, thereby controlling the transmission efficiency of the atomic beam accordingly.

[0012] The control signal parameters for compressing the atomic beam as described above in step 2 are obtained through the following steps: Multiple rounds of pre-experiments were conducted. In each round, the piezoelectric ceramics corresponding to the first adjustment screw, the second adjustment screw, and the third adjustment screw were adjusted to obtain different combinations of deflection angles of the collimating lens, the first mirror, and the second mirror. In each round of pre-experiments, the laser emitted after passing through the collimating lens was still reflected by the first mirror, passed through the control cavity, and was reflected back to the control cavity by the second mirror. Simultaneously detect the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time; When the number of atoms entering the magneto-optical trap region of the vacuum cavity reaches its maximum per unit time, the control signal intensity of the corresponding piezoelectric ceramic is recorded as the control signal parameter for compressing the atomic beam.

[0013] The control signal parameters for shutting off the atomic beam in step 2, as described above, are obtained through the following steps: Multiple rounds of preliminary experiments were conducted. In each round, the piezoelectric ceramics corresponding to the first adjusting screw and the second adjusting screw were adjusted to deflect the direction of the laser emitted from the first reflecting mirror along the xz plane. Adjust the piezoelectric ceramic corresponding to the third adjusting screw to deflect the reflected laser emitted from the second reflector at a preset angle to the xz plane; Simultaneously detect the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time; When the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is 0, the control signal intensity of the corresponding piezoelectric ceramic is used as the control signal parameter for turning off the atomic beam.

[0014] The adjustment signal parameters for the atom loading rate described above in step 2 are obtained through the following steps: After obtaining the control signal parameters for shutting off the atomic beam, the intensity of the control signal for each piezoelectric ceramic was kept constant, and multiple rounds of pre-experiments were conducted. In each round of pre-experiments, the intensity of the laser emitted by the acousto-optic modulator was adjusted by setting the intensity of the external control voltage signal corresponding to different acousto-optic modulators. The number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is detected, and the intensity of the external control voltage signal of the corresponding acousto-optic modulator is used as the adjustment signal parameter of the atom loading rate.

[0015] Compared with the prior art, the present invention has the following advantages: The laser emitted from the fiber optic acousto-optic modulator resonates nearly with the strong atomic transition lines. With the adjustment of the first mirror, the optical path is shifted by an angle α along the axis. The second mirror can further shift the optical path by an angle β along the axis. After these two deflections, the direction of the light emitted from the acousto-optic modulator incident on the control cavity will be shifted by an angle of (α+2β). The atomic beams generated by different atomic furnaces at isothermal conditions have slightly different collimation and divergence. When the light field resonating near the strong atomic transitions is not orthogonal to the atomic beam direction, it will alter the motion direction of atoms in a specific velocity group. Ultimately, the beam from the differential tube cannot achieve magneto-optical trap loading because it does not meet the trapping conditions for the subsequent magneto-optical trap. This cold atom loading mode, which involves switching off the optical field, is related to the power, frequency detuning, and incident angle of the controlled optical field in this device. It has a fast response speed and is almost unrestricted by its operating life. A cold atom platform with a controllable number of atoms is more conducive to reducing the density frequency shift caused by atomic collisions, which is of concern to optical clocks. It can also be extended to controllable quantum computing based on neutral atom arrays. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the device structure of the present invention; Figure 2 This is a schematic diagram of the application structure of the device of the present invention; Among them, 1-acoustic-optic modulator, 2-first sleeve, 201-fiber optic flange, 3-second sleeve, 4-first lens frame, 401-first connecting rod, 402-first adjusting screw, 5-second lens frame, 501-second connecting rod, 502-second adjusting screw, 6-third lens frame, 601-third connecting rod, 602-third adjusting screw, 7-adapter, 701-first sub-adapter, 702-second sub-adapter, 8-control cavity, 9-atomic furnace, 10-differential tube, 11-atomic cluster in magneto-optical trap, 12-decelerating light. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments described herein are only for illustration and explanation of the present invention and do not limit the present invention.

[0018] This invention employs a laser beam that resonates near the strong atomic transitions onto a stable atomic beam. By controlling the laser parameters, low-velocity atoms within the atomic beam are controlled, ultimately enabling control over the loading of cold atoms into the magneto-optical trap. This device avoids the adverse effects of continuous low-velocity atoms colliding with cold atoms in the optical lattice when cold atom loading is not required, and also helps reduce the collision frequency shift of the optical clock.

[0019] Example 1 A device for rapidly shutting off cold atom loading, such as Figures 1-2 It includes an acousto-optic modulator 1, a collimating lens, a first reflecting mirror, a control cavity 8, a second reflecting mirror, a differential tube 10, a nuclear reactor 9, and intermediate support and connecting components (including a first sleeve 2, a second sleeve 3, a first lens frame 4, a second lens frame 5, a third lens frame 6, and an adapter 7), with the specific structure as follows: The laser emitted from the laser source is modulated by the acousto-optic modulator 1, and then sequentially passes through a collimating lens and a first reflecting mirror before being input into the control cavity 8 as a forward-incident laser. The control cavity 8 is a hollow cube. The forward-incident laser passes sequentially through the light-transmitting aperture at the center of the first light-transmitting surface and the light-transmitting aperture at the center of the second light-transmitting surface on the control cavity 8 along the direction of incident on the control cavity 8, and is reflected by the second reflecting mirror outside the control cavity 8. The first light-transmitting surface and the second light-transmitting surface are two opposite surfaces on the control cavity 8. The angle of the second reflecting mirror is adjustable, so the exit angle of the laser reflected by the second reflecting mirror is adjustable. In this embodiment, the laser reflected by the second reflecting mirror is used as the reverse-incident laser of the control cavity 8 and returns to the control cavity 8.

[0020] The direction from the first light-transmitting surface to the second light-transmitting surface of the control cavity 8 is taken as the positive z-axis direction. Among the four surfaces of the control cavity 8 that are parallel to the z-axis direction, an observation window is set at the center of each of the two opposite sides of one set, and the other two opposite sides are respectively connected to the atomic furnace 9 and one end of the differential tube 10. The other end of the differential tube 10 is connected to the vacuum cavity equipped with a magneto-optical trap. The direction of the line connecting the centers of the two observation windows is denoted as the y-axis direction. The direction from the atomic furnace 9 to the differential tube 10 is taken as the positive x-axis direction.

[0021] When the laser source is off, the atomic beam emitted from the atomic furnace 9 passes through the control cavity 8 and enters the magneto-optical trap of the vacuum cavity via the differential tube 10. However, the atomic beam exhibits a divergence angle. When it is necessary to compress the atomic beam divergence angle, the angles of the collimating lens, the first reflector, and the second reflector are adjusted so that the incident laser beam and the laser beam reflected by the second reflector are incident along the positive and negative z-axis directions, respectively, into the control cavity 8. When it is necessary to shut down the cold atom loading (cut off the atomic beam) to prevent cold atoms from entering the subsequent vacuum cavity, the angles of the collimating lens, the first reflector, and the second reflector are adjusted so that the direction of the incident laser beam and the direction of the laser beam reflected by the second reflector deviate from the z-axis direction by preset angles, while the incident laser beam remains in the xz plane, and the laser beam reflected by the second reflector forms an angle with the xz plane. In this embodiment, when it is necessary to cut off the atomic beam, the incident laser beam is in the xz plane and forms an angle of 2° to 7° with the positive z-axis direction. The xz plane is the plane containing the x-axis and z-axis.

[0022] Furthermore, to integrate the above optical paths, the laser source is connected to the input port of the acousto-optic modulator 1 via an input optical fiber. An external control voltage signal is input to the SMA interface of the acousto-optic modulator 1, and the intensity and frequency of the laser output by the acousto-optic modulator 1 are controlled by an external control radio frequency signal. The output port of the acousto-optic modulator 1 is connected to one end of the output optical fiber, and the other end of the output optical fiber is connected to the optical fiber flange 201 provided at one end of the first sleeve 2. The other end of the first sleeve 2 is detachably connected to the first lens frame 4, and the first lens frame 4 is also detachably connected to the second sleeve 3. A collimating lens is provided inside the second sleeve 3. The laser emitted from the laser source is acousto-optic modulated by the acousto-optic modulator 1, passes through the first sleeve 2, and is collimated by the collimating lens inside the second sleeve 3.

[0023] The first reflector is installed inside the second mirror frame 5. The second mirror frame 5 is a reflector frame, which is a hollow right-angled triangular prism shape, including two rectangular right-angled side plates, one rectangular oblique side plate, and two right-angled triangular side plates. Specifically, the center of the two right-angled side plates is provided with light-transmitting openings. The first mirror frame 4 is connected to one right-angled side plate of the second mirror frame 5 through multiple first connecting rods 401. The first reflector is installed on the oblique side plate of the second mirror frame 5. The other right-angled side plate of the second mirror frame 5 is connected to the first sub-transfer member 701 in the adapter 7 through multiple second connecting rods 501. The center of the first sub-transfer member 701 is provided with a light-transmitting opening to allow incident laser light to pass through. The side of the control cavity 8 opposite to the first sub-transfer member 701 is provided with a second sub-transfer member 702. The center of the second sub-transfer member 702 is provided with a light-transmitting opening to allow incident laser light and reflected laser light to pass through. The second sub-transfer member 702 is connected to the third mirror frame 6 through multiple third connecting rods 601. The third mirror frame 6 is provided with a second reflector.

[0024] The acousto-optic modulator 1 is an optical fiber type acousto-optic modulator with two optical fiber ports (serving as input and output ports respectively) and an SMA interface. An external control voltage signal is applied to the piezoelectric transducer inside the acousto-optic modulator 1 through the SMA interface to excite the characteristic of sound wave controlling laser propagation, thereby controlling the frequency and intensity of the laser output by the acousto-optic modulator 1.

[0025] Both the first sleeve 2 and the second sleeve 3 are cylindrical structures, each with an external thread at one end and an internal thread at the other. The fiber optic flange 201 is located within the internal thread of the first sleeve 2. Two corresponding clamps are provided between the side wall of the fiber optic flange 201 and the internal thread of the first sleeve 2, thereby fixing the fiber optic flange 201 within the first sleeve 2. The collimating lens is located within the internal thread of the second sleeve 3. Two clamps are provided between the side wall of the collimating lens and the internal thread of the second sleeve 3, thereby fixing the collimating lens within the second sleeve 3.

[0026] Both the first frame 4 and the third frame 6 include two thick metal plates (serving as a movable plate and a fixed plate, respectively), which are connected by a spring. Both the movable plate and the fixed plate have a central opening. The central opening of the fixed plate of the first frame 4 is used for light transmission, and the central opening of the movable plate has an internal thread for installing corresponding components. For the first frame 4, the central opening of the movable plate is provided with an internal thread, and the internal thread is divided into two sections: one section of the internal thread matches the external thread of the first sleeve 2, and the threaded end of the first sleeve 2 passes through the central opening of the fixed plate of the first frame 4 and connects to the central opening of the movable plate of the first frame 4; the other section of the internal thread of the movable plate of the first frame 4 matches the external thread of the second sleeve 3, and is used to install the threaded end of the second sleeve 3. By installing both the first sleeve 2 and the second sleeve 3 in the movable plate of the first frame 4, the relative positions of the first sleeve 2 and the second sleeve 3 are fixed.

[0027] For the third mirror frame 6, the second reflector is fixed in the internal thread of the movable plate by a metal retaining ring.

[0028] The movable plate and fixed plate in the first frame 4, as well as the movable plate and fixed plate in the third frame 6, are all provided with evenly distributed coaxial through holes along the circumference of the plate surface (the through holes in the first frame 4 are used to insert the first connecting rod 401, and the through holes in the third frame 6 are used to insert the corresponding third connecting rod 601). Set screws are provided on the side wall of the fixed plate at the positions corresponding to the through holes to fix the corresponding connecting rods.

[0029] Multiple threaded adjustment holes are provided on the fixing plates of both the first frame 4 and the third frame 6. The tail of the adjusting screw passes through the corresponding threaded adjustment hole and abuts against the corresponding movable plate through the corresponding piezoelectric ceramic (i.e., the tail of the first adjusting screw 402 passes through the threaded adjustment hole of the fixing plate of the first frame 4 and abuts against the movable plate of the first frame 4 through the corresponding piezoelectric ceramic; the tail of the third adjusting screw 602 passes through the threaded adjustment hole of the fixing plate of the third frame 6 and abuts against the movable plate of the third frame 6 through the corresponding piezoelectric ceramic). Piezoelectric ceramics are placed between the tail of each adjusting screw and the corresponding position of the movable plate to precisely control the tilt angle of the movable plate relative to the fixing plate in real time, thereby controlling the angle of the collimating lens or the second reflecting mirror.

[0030] The second mirror frame 5 is a hollow right-angled triangular prism shape, including two rectangular right-angled side plates (the two right-angled side plates are at 90° between them), a rectangular oblique side plate, and two right-angled triangular side plates. Light-transmitting openings are provided at the center of the two right-angled side plates. At the edge of the two right-angled side plates, evenly distributed through holes are provided around the circumference for inserting corresponding connecting rods (the first connecting rod 401 is inserted into one right-angled side plate, and the second connecting rod 501 is inserted into the other right-angled side plate). Threaded holes are provided on the two right-angled triangular side plates, and the connecting rods inserted into the corresponding through holes are fixed by set screws passing through the corresponding threaded holes. The side of the rectangular oblique side plate facing the inside of the second mirror frame 5 is connected to the back of the first reflector by multiple springs. The reflecting surface of the first reflector faces the inside of the second mirror frame 5, so that the collimated laser can pass through one right-angled side plate and be reflected by the first reflector, then pass through the other right-angled side plate and be emitted into the control cavity 8. In this embodiment, the diameter of the collimated laser is larger than the diameter of the atomic beam ejected from the atomic furnace 9, so that the laser reflected from the first mirror and the atoms in the control cavity 8 can interact fully.

[0031] Furthermore, to adjust the angle of the first reflector, multiple second adjusting screws 502 are provided on the inclined side plate of the second mirror frame 5. The tail of the second adjusting screw 502 passes through the adjusting threaded hole on the inclined side plate of the second mirror frame 5 from the outside to the inside, and then abuts against the back of the first reflector through the corresponding piezoelectric ceramic. By adjusting the depth of the tail of the second adjusting screw 502 into the corresponding adjusting threaded hole or adjusting the extension and retraction of the corresponding piezoelectric ceramic, the first reflector is pushed to deflect.

[0032] For the first frame 4 and the third frame 6, the positions of the corresponding fixed plates are fixed. The angle of the corresponding movable plates can be adjusted by manually tightening the corresponding adjusting screws or by extending and retracting the piezoelectric ceramic, thereby adjusting the angle of the optical components installed in the corresponding movable plates. For the second frame 5, the position of the inclined side plate is fixed. The angle of the first reflector can be adjusted by manually tightening the corresponding second adjusting screw 502 or by extending and retracting the corresponding piezoelectric ceramic. However, the piezoelectric ceramic has a faster response speed and more precise adjustment.

[0033] In this embodiment, the piezoelectric ceramics installed in the first frame 4 and the third frame 6 can cause the axis of the corresponding movable plate to deflect by an angle α (ranging from -5° to 5°) relative to the axis of the fixed plate; the piezoelectric ceramics installed in the second frame 5 can cause the central axis of the first reflector to deflect by an angle β (ranging from -4° to 4°) relative to the central axis of the inclined side plate. Through the control of the first frame 4 and the second frame 5, the direction of the light path incident on the control cavity 8 can be shifted by (α+2β).

[0034] Each surface of the control cavity 8 is provided with a CF flange knife edge and screw holes for fixing the flange. On two opposite surfaces of the six surfaces of the control cavity 8, a differential tube 10 and a nuclear furnace 9 are respectively installed through flanges that match the CF flange knife edges of the control cavity 8. The CF flange knife edges on the other four surfaces are equipped with corresponding optical windows. The two optical windows distributed along the z-axis serve as the first and second light-transmitting surfaces of the control cavity 8, respectively, and the two optical windows distributed along the y-axis both serve as observation windows. The four corners of each surface of the control cavity 8 have positioning threaded holes. On the two surfaces perpendicular to the z-axis (i.e., the first and second light-transmitting surfaces), the first sub-adapter 701 and the second sub-adapter 702 are respectively installed through the positioning threaded holes.

[0035] The atomic furnace 9 is a vacuum-heated atomic furnace with an integrated flange. It has four external leads: two for power supply and heating, and the other two for monitoring the temperature inside the furnace. Under constant temperature, it generates a stable atomic beam with low divergence. The furnace 9 can be fixed to the control cavity 8 using screws. After the two power supply and heating leads of the atomic furnace 9 are connected to a power source, the furnace 9 will generate a constant atomic beam that passes through the differential tube 10 and enters the magneto-optical trap region of the vacuum cavity at the experimental end, thereby achieving cold atom loading of the optical clock.

[0036] The differential tube 10 includes a hollow pipe with flanges including CF flange blades at both ends. There are through holes around the blades. The differential tube 10 can be fixed to the control cavity 8 with screws. The hollow pipe can confine the atomic beam and also perform vacuum differential between the vacuum degree at the end of the atomic furnace 9 and the experimental end on the left side of the atomic furnace 9.

[0037] The adapter 7 includes a first sub-adapter 701 and a second sub-adapter 702. The first sub-adapter 701 is fixed to the first light-transmitting surface of the control cavity 8 by screws at the four corners of the same surface of the first sub-adapter 701. The second sub-adapter 702 is fixed to the second light-transmitting surface of the control cavity 8 by screws at the four corners of the same surface of the second sub-adapter 702. Both the first sub-adapter 701 and the second sub-adapter 702 are metal blocks with a cubic outer contour. The projected contours of the first sub-adapter 701 and the second sub-adapter 702 along the z-axis are square, thus perfectly matching the first and second light-transmitting surfaces of the control cavity 8. Both the first sub-adapter 701 and the second sub-adapter 702 are provided with light-transmitting openings that penetrate along the z-axis, and the light-transmitting openings are located on the central axis of symmetry of the corresponding sub-adapter. Grooves are provided on the side of the first sub-interchange member 701 that contacts the first light-transmitting surface and on the side of the second sub-interchange member 702 that contacts the second light-transmitting surface, for matching the corresponding optical windows. The diameter of the groove is greater than the outer diameter of the corresponding optical window, and the depth of the groove is greater than the height of the corresponding optical window protruding from the surface of the corresponding control cavity 8.

[0038] The specific connection method of the connecting rods (including the first connecting rod 401, the second connecting rod 501, and the third connecting rod 601) is as follows: The first connecting rod 401 is used to connect the first frame 4 and the second frame 5; the second connecting rod 501 is used to connect the second frame 5 and the first sub-adapter 701; and the third connecting rod 601 is used to connect the third frame 6 and the second sub-adapter 702. Both ends of the first connecting rod 401 are unthreaded; one end of the first connecting rod 401 is inserted into a through hole provided around a right-angled side plate of the second frame 5, and is fixed by corresponding set screws on the two right-angled triangular side plates of the second frame 5; the other end of the first connecting rod 401 passes through the through hole of the movable plate of the first frame 4 and is inserted into the coaxial through hole of the fixed plate of the first frame 4, and is fixed by set screws on the side of the fixed plate of the first frame 4. One end of the second connecting rod 501 is externally threaded, and the other end is unthreaded; a positioning threaded hole is provided on the outer periphery of the light-transmitting opening in the center of the first sub-adapter 701, and the externally threaded end of the second connecting rod 501 is fixed in the positioning threaded hole of the first sub-adapter 701; the unthreaded end of the second connecting rod 501 is inserted into the corresponding through hole of another right-angled side plate of the second frame 5, and is fixed by a set screw on the right-angled triangular side plate corresponding to the through hole; One end of the third connecting rod 601 has an external thread, while the other end is unthreaded. A positioning threaded hole is provided on the outer periphery of the light-transmitting port in the center of the second sub-adapter 702. The threaded end of the third connecting rod 601 is fixed in the positioning threaded hole of the first sub-adapter 701. The unthreaded end of the third connecting rod 601 passes through the through hole of the movable plate of the third frame 6 and is inserted into the coaxial through hole of the fixed plate of the third frame 6, and is fixed by the set screw on the side of the fixed plate of the third frame 6.

[0039] The dimensions of the through holes on the fixing plates of the first connecting rod 401 and the third connecting rod 601 are matched with the dimensions of the corresponding connecting rods, thereby stabilizing the position of the fixing plates. The inner diameters of the through holes on the movable plates of the first connecting rod 401 and the third connecting rod 601 are both larger than the inner diameters of the through holes on the corresponding fixing plates (i.e., larger than the diameter of the corresponding connecting rods).

[0040] The length of the first connecting rod 401 is longer than the length of the second sleeve 3, so that a gap is reserved between the first lens frame 4 and the second lens frame 5, thereby ensuring that the second sleeve 3 can be removed from between the first connecting rods 401 at any time; so as to adjust the relative position of the fiber optic flange (201) in the first sleeve 2 and the collimating lens in the second sleeve 3, change the focal length of the collimating lens, and thus adapt to the spot size of different collimated beams.

[0041] Example 2 A method for rapidly shutting down cold atom loading, utilizing the apparatus for rapidly shutting down cold atom loading described in Example 1, includes the following steps: Step 1: Construct the device for rapidly shutting off cold atom loading as described in Example 1; Turn on the atomic furnace 9 so that the atomic beam output from the atomic furnace 9 flows into the differential tube 10 after passing through the control cavity 8; Turn on the laser source. The frequency of the laser emitted by the laser source is at the strong atomic transition frequency. Turn on the external control voltage signal of the acousto-optic modulator 1 and adjust the frequency of the external control voltage signal so that the frequency detuning of the laser emitted by the acousto-optic modulator 1 is -17 MHz and the output optical power is 14 mW. Adjust the relative distance between the collimating lens inside the second sleeve 3 and the fiber optic flange 201 so that the collimating lens emits collimated laser light; adjust the first adjusting screw 402 or the piezoelectric ceramic corresponding to the first adjusting screw 402 until the laser light emitted from the collimating lens is incident on the center of the corresponding right-angle side plate on the second frame 5. Adjust the second adjusting screw 502 so that the laser reflected by the first reflector is incident into the control cavity 8; Adjust the third adjusting screw 602 so that the laser reflected by the second reflector is incident on the control cavity 8.

[0042] The above steps bring the device for rapidly shutting down cold atom loading to its initial state.

[0043] Step 2: Preliminary experiment. By adjusting the control signal intensity of the piezoelectric ceramics on the first mirror frame 4, the second mirror frame 5, and the third mirror frame 6, the deflection angles of the collimating lens, the first mirror, and the second mirror are scanned, and the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is measured accordingly. The control signal strength of each piezoelectric ceramic was determined to achieve the highest transmission efficiency of the atomic beam, and this signal was used as the control signal parameter for compressing the atomic beam. The intensity of the control signal for each piezoelectric ceramic when atomic loading needs to be turned off is determined and used as the control signal parameter for turning off the atomic beam. The intensity of the external control voltage signal for the acousto-optic modulator 1 is determined to quantitatively control the transmission efficiency of the atomic beam, and is used as an adjustment signal parameter for the atomic loading rate. The specific process is as follows: Obtain the control signal parameters for the compressed atomic beam: Multiple rounds of pre-experiments were conducted. In each round of pre-experiments, the piezoelectric ceramics corresponding to the first adjusting screw 402, the second adjusting screw 502, and the third adjusting screw 602 were adjusted to obtain different combinations of deflection angles of the collimating lens, the first reflecting mirror, and the second reflecting mirror. In each round of pre-experiments, the laser emitted after passing through the collimating lens was still reflected by the first reflecting mirror, passed through the control cavity 8, and was reflected back to the control cavity 8 by the second reflecting mirror. Simultaneously detect the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time (i.e., the transmission efficiency of the atomic beam). When the transmission efficiency of the atomic beam reaches its maximum, the control signal strength of the corresponding piezoelectric ceramic is recorded as the control signal parameter for compressing the atomic beam.

[0044] In this embodiment, the method for detecting the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time in each round of pre-experiment is as follows: In the initial stage of loading atoms into the magneto-optical trap, a probe light is irradiated into the magneto-optical trap to excite atomic fluorescence. The fluorescence signal is collected by a photomultiplier tube (PMT). When the initial increase in the intensity of the electrical signal output by the PMT is the maximum, it indicates that the most atoms have entered the magneto-optical trap region per unit time. At this time, the transmission efficiency of the corresponding atomic beam is the highest (corresponding to the optimal combination of atomic beam diameter and divergence angle).

[0045] Obtain the control signal parameters for shutting off the atomic beam: Multiple rounds of preliminary experiments were conducted. In each round, the piezoelectric ceramics corresponding to the first adjusting screw 402 and the second adjusting screw 502 were adjusted to deflect the direction of the laser emitted from the first reflector along the xz plane (a plane where the atomic beam emission direction is located). Adjust the piezoelectric ceramic corresponding to the third adjusting screw 602 to deflect the reflected laser emitted from the second reflector at a preset angle to the xz plane (in this embodiment, it is chosen to be perpendicular to the xz plane); Simultaneously detect the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time (i.e., the transmission efficiency of the atomic beam). When the transmission efficiency of the atomic beam is 0, the control signal strength of the corresponding piezoelectric ceramic is used as the control signal parameter to turn off the atomic beam.

[0046] In this embodiment, in the initial stage of loading atoms into the magneto-optical trap, a photomultiplier tube (PMT) collects fluorescence signals. When the intensity of the electrical signal output by the PMT remains unchanged, it indicates that the atomic beam in the magneto-optical trap remains unchanged, and the number of atoms entering the magneto-optical trap region per unit time is 0.

[0047] Obtain the adjustment signal parameters for the atomic loading rate: Furthermore, after obtaining the control signal parameters for shutting off the atomic beam, the control signal strength of each piezoelectric ceramic is kept constant, and multiple rounds of pre-experiments are conducted. In each round of pre-experiments, the intensity of the external control voltage signal corresponding to different acousto-optic modulators 1 is set to adjust the intensity of the laser emitted by the acousto-optic modulator 1, thereby adjusting the force of the laser emitted by the first reflector on the atomic beam in the control cavity 8. The number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is detected (i.e., the transmission efficiency of the atomic beam); and the intensity of the external control voltage signal of the acousto-optic modulator 1 corresponding to different atomic beam transmission efficiencies is used as the adjustment signal parameter of the atomic loading rate, which can be used to quantitatively control the atomic loading rate during subsequent experiments.

[0048] After each preliminary experiment, the atoms in the magneto-optical trap are removed.

[0049] In the process of obtaining the control signal parameters for compressing the atomic beam and obtaining the control signal parameters for shutting off the atomic beam, the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time can also be confirmed by detecting the fluorescence absorption.

[0050] Furthermore, extending to general cases, the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time can be detected by changing the laser frequency detuning, or the angle of the collimating lens or the angle of the first reflecting mirror, thereby obtaining the corresponding adjustment signal parameters of the atom loading rate and realizing the continuous and adjustable loading of cold atoms by the subsequent magneto-optical trap.

[0051] Step 3: Conduct the formal experiment, and based on the control signal parameters for compressing the atomic beam, the control signal parameters for turning off the atomic beam, and the adjustment signal parameters for the atomic loading rate obtained in Step 2, control the corresponding piezoelectric ceramics, thereby controlling the transmission efficiency of the atomic beam accordingly.

[0052] When the maximum number of atoms need to enter the magneto-optical trap: Based on the control signal parameters of the compressed atomic beam obtained in step 2, the corresponding piezoelectric ceramic is controlled so that the deflection angles of the collimating lens, the first reflector, and the second reflector can sequentially collimate the detuned -17 MHz laser modulated by the acousto-optic modulator 1 through the collimating lens, reflect it along the z-axis through the control cavity 8, and then reflect it back to the control cavity 8 along the z-axis by the second reflector. Under the action of the relative lasers along the positive and negative z-axis in the control cavity 8, when the atomic beam generated by the atomic furnace 9 passes through the center of the control cavity 8, the divergence angle of the atomic beam is narrowed. The atomic beam passing through the differential tube 10 contains the most atoms. Under the same deceleration light 12 (deceleration light 12 irradiates the magneto-optical trap) and the action of the magneto-optical trap, the number of atoms in the atomic cluster 11 in the magneto-optical trap increases, which can ultimately improve the signal-to-noise ratio of the optical clock.

[0053] When a quantitative loading of atoms is required: By deflecting the incident light at a certain angle and controlling the intensity of the incident light by changing the acousto-optic modulator, the deflection angle of the atomic beam coming out of the atomic furnace is changed, thereby controlling the quantitative amount of atoms entering the system per unit time and achieving quantitative loading of atoms.

[0054] When it is necessary to shut down the atomic beam: After the cold atom loading into the magneto-optical trap is completed, a voltage is applied to the corresponding piezoelectric ceramic according to the control signal parameters for shutting off the atomic beam obtained in step 2. The laser emitted from the first reflector then completely deflects the atomic beam ejected from the atomic furnace 9 away from the hollow channel in the middle of the differential tube 10, shutting off the loading of cold atoms in the magneto-optical trap behind the differential tube 10. Alternatively, by applying a voltage to the corresponding piezoelectric ceramic using the control signal parameters for shutting off the atomic beam, the paths of the low- and medium-speed atoms in the atomic beam are deflected away from the hollow channel in the middle of the differential tube 10. Combined with the decelerating light 12 irradiating the magneto-optical trap, even the higher-speed atoms that do not meet the trapping conditions cannot be loaded into the magneto-optical trap.

[0055] When it is necessary to restore atomic beam loading: The external control voltage signal of the acousto-optic modulator 1 was removed, so that the output light power of the acousto-optic modulator 1 was 0. The atomic beam ejected from the atomic furnace 9 passed through the differential tube 10 normally, and the normal loading of cold atoms into the subsequent magneto-optical trap was restored.

[0056] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All modifications made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

Claims

1. A device for rapidly shutting off cold atom loading, characterized in that, The system includes a laser source. The laser emitted from the laser source passes through an acousto-optic modulator (1), a collimating lens, and a first reflecting mirror in sequence before being input into the control cavity (8) as a forward incident laser. The control cavity (8) is a hollow cube. The forward incident laser passes through the light-transmitting port at the center of the first light-transmitting surface and the light-transmitting port at the center of the second light-transmitting surface on the control cavity (8) in sequence along the direction of incident to the control cavity (8), and is reflected by the second reflecting mirror outside the control cavity (8). The first light-transmitting surface and the second light-transmitting surface are two opposite surfaces on the control cavity (8). The direction from the first light-transmitting surface to the second light-transmitting surface of the control cavity (8) is taken as the positive z-axis direction; among the four surfaces of the control cavity (8) parallel to the z-axis direction, an observation window is set at the center of each of the two opposite sides of one set, and the other two opposite sides are respectively connected to the atomic furnace (9) and one end of the differential tube (10), and the other end of the differential tube (10) is connected to the vacuum cavity equipped with a magneto-optical trap; the direction from the atomic furnace (9) to the differential tube (10) is taken as the positive x-axis direction; When the laser source is turned off, the atomic beam emitted from the atomic furnace (9) passes through the control cavity (8) and then enters the magneto-optical trap of the vacuum cavity via the differential tube (10); When it is necessary to compress the atomic beam divergence angle, the angles of the collimating lens, the first reflector, and the second reflector are adjusted so that the incident laser and the laser reflected by the second reflector are incident into the control cavity (8) along the positive z-axis and the negative z-axis, respectively. When it is necessary to shut down the cold atom loading, the angles of the collimating lens, the first reflector, and the second reflector are adjusted so that the direction of the normally incident laser and the direction of the laser reflected by the second reflector deviate from the z-axis direction according to preset angles. The normally incident laser is in the xz plane, and the laser reflected by the second reflector has an angle with the xz plane.

2. The device for rapidly shutting down cold atom loading according to claim 1, characterized in that, The laser source is connected to the input port of the acousto-optic modulator (1) via an input optical fiber. An external control voltage signal is input to the SMA interface of the acousto-optic modulator (1). The output port of the acousto-optic modulator (1) is connected to one end of the output optical fiber. The other end of the output optical fiber is connected to the optical fiber flange (201) provided at one end of the first sleeve (2). The other end of the first sleeve (2) is detachably connected to the first lens frame (4). The first lens frame (4) is also detachably connected to the second sleeve (3). A collimating lens is provided inside the second sleeve (3). The first reflector is installed inside the second frame (5); the second frame (5) is a hollow right-angled triangular prism, including two rectangular right-angled side plates, one rectangular oblique side plate, and two right-angled triangular side plates. The center of the two right-angled side plates is respectively provided with light-transmitting openings. The first frame (4) is connected to one right-angled side plate of the second frame (5) through multiple first connecting rods (401). The first reflector is installed on the oblique side plate of the second frame (5). The other right-angled side plate of the second frame (5) is... The side panel is connected to the first sub-adapter (701) by multiple second connecting rods (501); the first sub-adapter (701) has a light-transmitting port in the center, and a second sub-adapter (702) is provided on the side of the control cavity (8) opposite to the first sub-adapter (701). The second sub-adapter (702) has a light-transmitting port in the center, and the second sub-adapter (702) is connected to the third mirror frame (6) by multiple third connecting rods (601); a second reflecting mirror is provided inside the third mirror frame (6).

3. The device for rapidly shutting off cold atom loading according to claim 2, characterized in that, The first sleeve (2) and the second sleeve (3) are both cylindrical structures, and both have external threads at one end and internal threads at the other end. The fiber optic flange (201) is located in the internal thread of the first sleeve (2), and a corresponding clamp is provided between the side wall of the fiber optic flange (201) and the internal thread of the first sleeve (2). The collimating lens is located inside the internal thread of the second sleeve (3), and a clamp is provided between the side wall of the collimating lens and the internal thread of the second sleeve (3).

4. The device for rapidly shutting off cold atom loading according to claim 3, characterized in that, Both the first frame (4) and the third frame (6) include a movable plate and a fixed plate, both of which are thick metal plates; the movable plate and the fixed plate are connected by a spring; both the movable plate and the fixed plate are provided with a central opening; For the first frame (4), the center opening of the movable plate is provided with an internal thread, and the internal thread is divided into two sections: one section of the internal thread matches the external thread of the first sleeve (2), and the end of the first sleeve (2) with the external thread passes through the center opening of the fixed plate of the first frame (4) and connects to the center opening of the movable plate of the first frame (4); the other section of the internal thread of the movable plate of the first frame (4) is installed with the end of the second sleeve (3) with the external thread. For the third mirror frame (6), the center opening of the movable plate is provided with an internal thread, and the second reflector is fixed in the internal thread by a metal retainer.

5. The device for rapidly shutting off cold atom loading according to claim 4, characterized in that, The movable plate and fixed plate in the first frame (4), and the movable plate and fixed plate in the third frame (6) are all provided with uniformly distributed coaxial through holes along the circumference of the plate surface, and the fixed plate is provided with set screws on the side wall corresponding to the through holes. On the two right-angled side plates of the second frame (5), near the edges, there are evenly distributed through holes along the circumference. One end of the first connecting rod (401) is inserted into a through hole in a right-angled side plate of the second frame (5) and fixed by corresponding set screws on the two right-angled triangular side plates of the second frame (5); the other end of the first connecting rod (401) passes through the through hole of the movable plate of the first frame (4) and is inserted into the coaxial through hole of the fixed plate of the first frame (4) and fixed by set screws on the side of the fixed plate of the first frame (4). One end of the second connecting rod (501) is externally threaded, and the other end is unthreaded; a positioning threaded hole is provided on the outer periphery of the light-transmitting port in the center of the first sub-adapter (701), and the externally threaded end of the second connecting rod (501) is fixed in the positioning threaded hole of the first sub-adapter (701); the unthreaded end of the second connecting rod (501) is inserted into the corresponding through hole of another right-angled side plate of the second frame (5), and fixed by the set screw corresponding to the through hole on the right-angled triangle side plate; One end of the third connecting rod (601) is externally threaded, and the other end is unthreaded; a positioning threaded hole is provided on the outer periphery of the light-transmitting port in the center of the second sub-adapter (702); the externally threaded end of the third connecting rod (601) is fixed in the positioning threaded hole of the first sub-adapter (701); the unthreaded end of the third connecting rod (601) passes through the through hole of the movable plate of the third frame (6) and is inserted into the coaxial through hole of the fixed plate of the third frame (6), and is fixed by the set screw on the side of the fixed plate of the third frame (6).

6. The device for rapidly shutting down cold atom loading according to claim 5, characterized in that, Multiple threaded adjustment holes are provided on the fixing plate of the first frame (4) and the fixing plate of the third frame (6). The tail of the first adjusting screw (402) passes through the threaded adjustment hole of the fixing plate of the first frame (4) and abuts against the movable plate of the first frame (4) through the corresponding piezoelectric ceramic. The tail of the third adjusting screw (602) passes through the threaded adjustment hole of the fixing plate of the third frame (6) and abuts against the movable plate of the third frame (6) through the corresponding piezoelectric ceramic. The side of the rectangular inclined plate facing the inside of the second mirror frame (5) is connected to the back of the first mirror by multiple springs. Multiple second adjusting screws (502) are provided on the inclined plate of the second mirror frame (5). The tail of the second adjusting screw (502) passes through the adjusting thread hole on the inclined plate of the second mirror frame (5) from the outside to the inside, and then abuts against the back of the first mirror through the corresponding piezoelectric ceramic.

7. A method for rapidly shutting down cold atom loading, utilizing the apparatus for rapidly shutting down cold atom loading as described in claim 6, characterized in that, Includes the following steps: Step 1: Construct a device for rapidly shutting down cold atom loading; Step 2: By adjusting the control signal intensity of the piezoelectric ceramic on the first mirror frame (4), the control signal intensity of the piezoelectric ceramic on the second mirror frame (5), and the control signal intensity of the piezoelectric ceramic on the third mirror frame (6), the deflection angles of the collimating lens, the first mirror, and the second mirror are scanned, and the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is measured accordingly. The control signal strength of each piezoelectric ceramic was determined to achieve the highest transmission efficiency of the atomic beam, and this signal was used as the control signal parameter for compressing the atomic beam. The intensity of the control signal for each piezoelectric ceramic when atomic loading needs to be turned off is determined and used as the control signal parameter for turning off the atomic beam. The strength of the external control voltage signal of the acousto-optic modulator (1) is determined when quantitative control of the transmission efficiency of the atomic beam is performed, and is used as the adjustment signal parameter of the atomic loading rate. Step 3: Based on the control signal parameters for compressing the atomic beam, the control signal parameters for turning off the atomic beam, and the adjustment signal parameters for the atomic loading rate obtained in Step 2, the corresponding piezoelectric ceramics are controlled, thereby controlling the transmission efficiency of the atomic beam accordingly.

8. The method for rapidly shutting down cold atom loading according to claim 7, characterized in that, The control signal parameters for compressing the atomic beam in step 2 are obtained through the following steps: Multiple rounds of pre-experiments were conducted. In each round of pre-experiments, the piezoelectric ceramics corresponding to the first adjusting screw (402), the second adjusting screw (502), and the third adjusting screw (602) were adjusted to obtain different combinations of deflection angles of collimating lenses, deflection angles of the first reflecting mirror, and deflection angles of the second reflecting mirror. In each round of pre-experiments, the laser emitted through the collimating lens was still reflected by the first reflecting mirror, passed through the control cavity (8), and then reflected back to the control cavity (8) by the second reflecting mirror. Simultaneously detect the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time; When the number of atoms entering the magneto-optical trap region of the vacuum cavity reaches its maximum per unit time, the control signal intensity of the corresponding piezoelectric ceramic is recorded as the control signal parameter for compressing the atomic beam.

9. The method for rapidly shutting down cold atom loading according to claim 7, characterized in that, The control signal parameters for shutting off the atomic beam in step 2 are obtained through the following steps: Multiple rounds of preliminary experiments were conducted. In each round, the piezoelectric ceramics corresponding to the first adjusting screw (402) and the piezoelectric ceramics corresponding to the second adjusting screw (502) were adjusted so that the direction of the laser emitted from the first reflecting mirror was deflected along the xz plane. Adjust the piezoelectric ceramic corresponding to the third adjusting screw (602) to deflect the reflected laser emitted from the second reflector at a preset angle to the xz plane; Simultaneously detect the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time; When the number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is 0, the control signal intensity of the corresponding piezoelectric ceramic is used as the control signal parameter for turning off the atomic beam.

10. The method for rapidly shutting down cold atom loading according to claim 9, characterized in that, The adjustment signal parameter for the atom loading rate mentioned in step 2 is obtained through the following steps: After obtaining the control signal parameters for shutting off the atomic beam, the control signal strength of each piezoelectric ceramic is kept constant, and multiple rounds of pre-experiments are conducted. In each round of pre-experiments, the intensity of the laser emitted by the acousto-optic modulator (1) is adjusted by setting the intensity of the external control voltage signal corresponding to different acousto-optic modulators (1). The number of atoms entering the magneto-optical trap region of the vacuum cavity per unit time is detected, and the intensity of the external control voltage signal of the corresponding acousto-optic modulator (1) is used as the adjustment signal parameter of the atom loading rate.

Images