All-optical cold atom production apparatus and method

Abstract

The application provides a kind of all-optical cold atom preparation device and method, it is related to super low temperature atom technical field.The device includes: optical switch and vacuum cavity;Vacuum cavity is provided with atom furnace, screening device and catcher;Wherein, in the first direction, the first central region of screening device and the second central region of catcher are collinear;In the second direction perpendicular to the first direction, screening device is arranged at the output position of atom furnace;Optical switch is fixedly arranged outside the vacuum cavity;Atom furnace is used to generate initial atom in the second direction, and sends initial atom to screening device;Screening device is used to carry out isotope screening to initial atom, obtains target atom, and sends target atom beam to catcher;Optical switch is used to emit laser beam, laser beam passes through the atom transmission path in the first direction between screening device and catcher, and laser beam is used to control the direction of target atom beam;Catcher is used to capture and cool target atom, and obtain cold atom.

Description

Technical Field

[0001] This application relates to the field of ultra-low temperature atomic technology, and more specifically, to an all-optical cold atom preparation apparatus and method. Background Technology

[0002] In cutting-edge scientific fields such as atomic physics, quantum information, and precision measurement, the efficient preparation of cold atoms is a prerequisite for conducting related experimental research. The current mainstream experimental approach involves generating a hot atomic beam in a high-temperature atomic furnace, which is then collimated and decelerated to form a directionally propagated atomic beam. This beam is then injected into a three-dimensional magneto-optical trap (3D-MOT) to achieve atomic trapping and cooling. To precisely control the experimental process (e.g., stopping loading after atom loading is complete for subsequent quantum state manipulation or measurement) and to avoid prolonged bombardment of expensive ultra-high vacuum components (such as ion pumps) and sensitive detectors by the atomic beam, reliable and rapid control of the atomic beam's on / off state is required.

[0003] Currently, mechanical shutters are commonly used to control the passage of atomic beams. A mechanical shutter, typically driven by a stepper motor or electromagnet, is placed in the transmission path of the atomic beam and installed inside the vacuum system. An external electrical signal is applied to switch the shutter between "open" and "closed" states: in the open state, the atomic beam can pass through without obstruction; in the closed state, the shutter completely blocks the path of the atomic beam through physical obstruction.

[0004] However, the opening and closing process of a mechanical shutter inevitably generates mechanical vibrations. These vibrations are transmitted to the entire vacuum chamber system through the support structure, causing serious interference to experiments requiring extremely high stability (such as atomic interference, optical clocks, and quantum bit manipulation). Furthermore, if the mechanical shutter is installed inside the vacuum system, its moving parts (such as motor bearings and sliding mechanisms) are at risk of single-point failure due to mechanical jamming or motor failure. In the event of a failure, the entire vacuum system often needs to be destroyed for repair or replacement. Restoring the system vacuum requires a lengthy baking and degassing process, which is not only time-consuming but also severely impacts research progress. Due to the inertia and transmission delay of mechanical components, the opening and closing response time is typically on the order of several to hundreds of milliseconds, making it difficult to meet the requirements of rapid experimental sequences requiring microsecond or even nanosecond precision control. The installation of a mechanical shutter also requires additional space and mechanical support structures, increasing the complexity of the vacuum chamber and beam path design and hindering the miniaturization and compact integration of the system.

[0005] Therefore, current structures for controlling the on / off state of atomic beams suffer from problems such as vibration interference, low reliability, slow response speed, and complex structure, resulting in poor performance in controlling the on / off state of atomic beams and failing to meet current needs for cold atom preparation. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide an all-optical cold atom preparation apparatus and method to improve the problem of poor atomic beam interruption effect in the prior art.

[0007] To address the aforementioned problems, in a first aspect, embodiments of this application provide an all-optical cold atom preparation apparatus, the apparatus comprising: an optical switch and a vacuum chamber; The vacuum chamber is equipped with an atomic furnace, a filter, and a trap; wherein, in a first direction, the first central region of the filter and the second central region of the trap are collinear; in a second direction perpendicular to the first direction, the filter is positioned at the output position of the atomic furnace; The optical switch is fixedly mounted outside the vacuum cavity; The atomic furnace is used to generate initial atoms in the second direction and send the initial atoms to the filter; The filter is used to perform isotopic screening on the initial atoms to obtain target atoms, and send the target atom beam to the trapper. The optical switch is used to emit a laser beam that passes through an atomic transport path in the first direction between the filter and the trap, and the laser beam is used to control the direction of the target atomic beam. The trap is used to trap and cool the target atom to obtain a cold atom.

[0008] In the above implementation process, the first central region of the filter and the second central region of the trap are collinear in the first direction. In the second direction perpendicular to the first direction, the filter is set at the output position of the atomic furnace, that is, the atomic beam travels from the output to the trap in an L-shaped path. In order to control the on / off state of the atomic beam, this application provides an optical switch, which is fixed outside the vacuum cavity equipped with various devices. The atomic furnace can generate initial atoms in the second direction to send the initial atoms to the filter in the second direction. The filter can perform isotope screening on the initial atoms to obtain the desired target atoms and send the target atomic beam to the trap in the first direction. The optical switch can send a laser beam, which can pass through the atomic transport path in the first direction between the filter and the trap to adjust the transport direction of the target atomic beam passing through the laser beam, thereby realizing the on / off control of the atomic beam. The trap can capture the target atoms in the target atomic beam that have reached its position to obtain the corresponding cold atoms. An optical switch can be placed outside the vacuum cavity, replacing the mechanical switch inside the vacuum cavity based on the optical principle of resonant laser deflection, to achieve control of the atomic beam flow interruption. The device has a simple structure, does not affect the vacuum cavity, and is free from vibration interference. It has high reliability, fast response speed, and optimizes the atomic beam flow interruption control effect, meeting the current needs of cold atom preparation.

[0009] Optionally, the device further includes: a controller; The controller is connected to the optical switch; The controller is used to send control signals to the optical switch based on control requirements; The optical switch is used to generate the laser beam based on the control signal.

[0010] In the above implementation process, to control the operating state of the optical switch, a controller can also be included in the device. The controller is connected to the optical switch and can send control signals to the optical switch based on actual control requirements. The optical switch can respond to the control signals and generate corresponding laser beams to achieve on / off control of the atomic beam. By controlling the operating state of the optical switch according to actual control requirements, the efficiency and accuracy of the optical switch in controlling the atomic beam's on / off state are effectively improved.

[0011] Optionally, the control signal includes an on signal and an off signal; When the control signal is the off signal, the optical switch is used to generate a first type of laser beam whose laser frequency resonates with the target atom, and the first type of laser beam is used to provide the target atom beam with a motion increment deviating from the first direction; When the control signal is the on signal, the optical switch stops generating the first type of laser beam, or the optical switch is used to generate a second type of laser beam whose laser frequency does not resonate with the target atom.

[0012] In the above implementation process, the control signal can include an on signal that does not interfere with the transmission of the atomic beam, and an off signal that adjusts the transmission direction of the atomic beam. When the control signal is off, the optical switch can generate a first-type laser beam whose laser frequency resonates with the target atoms. This first-type laser beam provides an incremental motion of the target atomic beam away from the ground direction, adjusting the motion direction of the target atomic beam through the resonant laser deflection principle of the first-type laser beam. This prevents the target atomic beam from moving to the trap along its original atomic transmission path, achieving a shutdown effect. When the control signal is on, the optical switch stops generating the first-type laser beam. Alternatively, the optical switch can generate a second-type laser beam whose laser frequency does not resonate with the target atoms. The second-type laser beam does not affect the motion of the target atomic beam, and the target atomic beam moves to the trap along its original atomic transmission path, achieving a conduction effect. The optical switch can operate accordingly based on different types of control signals, achieving efficient on / off control of the atomic beam.

[0013] Optionally, a conduit structure is provided between the filter and the trap, through which the target atomic beam is transmitted to the trap; Under the action of the first type of laser beam, the target atomic beam moves away from the atomic transport path, and the pipe wall of the pipe structure and the inner wall of the vacuum cavity are used to adsorb the deviated target atomic beam.

[0014] In the above implementation process, a conduit structure is provided between the filter and the trap, which allows the target atomic beam to move and propagate normally along the atomic transport path while isolating the filter and the trap. Under the action of the first type of laser beam with the shutdown signal, due to the principle of resonant laser deflection, the target atomic beam will deviate from its original atomic transport path and move. The pipe wall and the inner wall of the vacuum cavity can adsorb the deviated target atomic beam, which can effectively control the matter in the target atomic beam under the shutdown effect, reducing the adverse situation of target atoms floating in the vacuum cavity or moving to other devices.

[0015] Optionally, the optical switch includes: a laser, optical components, and a frequency modulation device; The laser is used to generate the laser beam; The frequency modulation device is used to adjust the laser frequency of the laser beam; The optical device is used to shape the laser beam.

[0016] In the above implementation process, the optical switch may include a laser that generates a laser beam, a frequency modulation device that adjusts the laser frequency of the laser beam, and an optical device that shapes the laser beam to generate a variety of laser beams that meet the requirements and achieve the corresponding atomic beam flow interruption control effect.

[0017] Optionally, the optical switch further includes: a guiding device; The guiding device is disposed between the optical devices; The guiding device is used to adjust the direction of the laser beam.

[0018] In the above implementation process, considering that the direction of the laser beam will also affect the direction of the atomic beam, a guiding device can also be set in the optical switch. The guiding device is set among multiple optical devices and can adjust the direction of the laser beam so that the laser beam can enter at a suitable angle, thereby adjusting the movement direction of the atomic beam and achieving the corresponding atomic beam flow interruption control effect.

[0019] Optionally, the transmission direction of the laser beam within the vacuum cavity intersects with the first direction, and the angle of intersection ranges from 89° to 91°.

[0020] In the above implementation process, in order to achieve a better directional deflection effect during shutdown, the transmission direction of the laser beam in the vacuum cavity intersects with the first direction, and the angle of intersection is between 89° and 91°, that is, maintaining a roughly perpendicular intersection angle. This allows the laser beam with a roughly perpendicular intersection angle to effectively adjust the movement direction of the target atomic beam, reducing the adverse situation where the target atomic beam deflection is too small due to the angle being too small or too large, thus preventing it from moving to the trap and being unable to be shut off. This effectively improves the control effect during shutdown.

[0021] Optionally, the device further includes: a pusher; In the first direction, the pusher is positioned at the end of the filter that is away from the catcher; The pusher is used to send push light in the first direction to the filter, and push the target atoms in the filter to the capture device through the push light.

[0022] In the above implementation process, in order to provide the target atoms with the power to move into the trap, the device can also be equipped with a pusher. The pusher is located at the end of the filter away from the trap in the first direction. The pusher can send push light in the first direction to the filter, so as to push the target atoms in the filter to the trap through the push light, thereby realizing the transmission of the target atom beam.

[0023] Optionally, a window area is provided on the wall of the vacuum cavity, through which the laser beam enters the interior of the vacuum cavity.

[0024] In the above implementation process, the optical switch is located outside the vacuum cavity, which will not adversely affect the operation of the vacuum cavity and facilitates maintenance or replacement. In order for the externally located optical switch to function properly, a window area is provided on the cavity wall of the vacuum cavity, so that the laser beam can enter the interior of the vacuum cavity through the window area to control the target atomic beam accordingly.

[0025] Secondly, embodiments of this application also provide an all-optical cold atom preparation method, wherein the method is applied to the apparatus described in any one of the first aspects above, and the method includes: Initial atoms in a second direction are generated by an atomic furnace and sent to a filter. The initial atoms are isotopically screened by the filter to obtain target atoms, and the target atom beam is sent to the trap. A laser beam is emitted via the optical switch, the laser beam passes through an atomic transport path in a first direction between the filter and the trap, and the laser beam is used to control the direction of the target atomic beam stream; The target atom is captured and cooled by the trap to obtain cold atoms.

[0026] In the above implementation process, the atomic furnace can generate initial atoms in a second direction to send the initial atoms to the filter in the second direction. The filter can perform isotope screening on the initial atoms to obtain the desired target atoms and send the target atomic beam to the trap in a first direction. The optical switch can send a laser beam, which can pass through the atomic transport path in the first direction between the filter and the trap to adjust the transport direction of the target atomic beam passing through the laser beam, thereby realizing the on / off control of the atomic beam. The trap can capture the target atoms in the target atomic beam that have reached its position to obtain the corresponding cold atoms.

[0027] In summary, the embodiments of this application provide an all-optical cold atom preparation apparatus and method, which can set an optical switch outside the vacuum cavity and replace the mechanical switch set inside the vacuum cavity based on the optical principle of resonant laser deflection to achieve control of the atomic beam flow interruption. The device has a simple structure, does not affect the vacuum cavity, does not have vibration interference, has high reliability, fast response speed, optimizes the atomic beam flow interruption control effect, and meets the current cold atom preparation requirements. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of a fully optical cold atom preparation apparatus provided for an embodiment of this application; Figure 2 A schematic diagram of the specific structure of an all-optical cold atom preparation device provided for an embodiment of this application; Figure 3 This is a schematic flowchart of an all-optical cold atom preparation method provided in an embodiment of this application.

[0030] Icons: 110-Optical switch; 120-Vacuum cavity; 131-Atomic furnace; 132-Filter; 133-Trapper; F1-First direction; F2-Second direction; F3-Atomic transport path; F4-Laser beam; A-Initial atom; B-Target atom; 140-Controller; 150-Pipe structure; 121-Window area; 111-Laser; 112-Optical device; 113-Frequency tuning device; 114-Guiding device; 160-Pusher; 161-Pushing light. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0032] Currently, mechanical shutters are commonly used to control the on / off state of atomic beams. A mechanical shutter, typically driven by a stepper motor or electromagnet, is placed in the transmission path of the atomic beam and installed inside the vacuum system. An external electrical signal controls the shutter to switch between "open" and "closed" states: in the open state, the atomic beam passes through unimpeded; in the closed state, the shutter physically blocks the path of the atomic beam. However, the opening and closing process of a mechanical shutter inevitably generates mechanical vibrations. These vibrations are transmitted to the entire vacuum cavity system through the support structure, causing serious interference to experiments requiring extremely high stability (such as atomic interference, optical clocks, and quantum bit manipulation). Furthermore, if the mechanical shutter is installed inside the vacuum system, its moving parts (such as motor bearings and sliding mechanisms) are at risk of single-point failure due to mechanical jamming or motor failure. In the event of a failure, the entire vacuum system often needs to be destroyed for repair or replacement. Restoring the system vacuum requires a lengthy baking and degassing process, which is not only time-consuming but also severely impacts research progress. Due to the inertia and transmission delay of mechanical components, the opening and closing response times are typically on the order of several to hundreds of milliseconds, making it difficult to meet the requirements of rapid experimental sequences that require precise timing control at the microsecond or even nanosecond level. The installation of mechanical shutters also requires additional space and mechanical support structures, increasing the complexity of the vacuum chamber and beam path design and hindering the miniaturization and compact integration of the system. Therefore, current structures for controlling the on / off state of atomic beams suffer from problems such as vibration interference, low reliability, slow response speed, and complex structure, resulting in poor performance in atomic beam on / off control and failing to meet current cold atom preparation requirements.

[0033] To address the aforementioned issues, this application provides an all-optical cold atom preparation apparatus and method. An optical switch is installed outside the vacuum cavity, replacing the mechanical switch inside the vacuum cavity based on the optical principle of resonant laser deflection. This achieves control over the atomic beam flow interruption. The device has a simple structure, does not affect the vacuum cavity, and is free from vibration interference. It boasts high reliability, fast response speed, and optimizes the atomic beam flow interruption control effect, meeting current cold atom preparation requirements.

[0034] Please see Figure 1 , Figure 1 This is a schematic diagram of a fully optical cold atom preparation device provided in an embodiment of this application. The device may include: an optical switch 110 and a vacuum cavity 120. The vacuum chamber 120 contains an atomic furnace 131, a filter 132, and a trap 133. In the first direction F1, the first central region of the filter 132 and the second central region of the trap 133 are collinear. In the second direction F2, perpendicular to the first direction F1, the filter 132 is positioned at the output position of the atomic furnace 131. The first central region of the filter 132 and the second central region of the trap 133 are collinear in the first direction F1. In the second direction F2, perpendicular to the first direction F1, the filter 132 is positioned at the output position of the atomic furnace 131, meaning the atomic beam travels in an L-shaped path from output to trapping.

[0035] Optionally, the first direction F1 and the second direction F2 can be determined based on the actual situation. Taking the vacuum cavity 120 as a horizontally placed example, the first direction F1 can be a horizontal direction, and the second direction F2 is a vertical direction perpendicular to the horizontal plane. Taking the vacuum cavity 120 as a vertically placed example, the first direction F1 can be a vertical direction, and the second direction F2 is a horizontal direction perpendicular to the vertical plane.

[0036] It should be noted that the optical switch 110 is fixedly installed outside the vacuum chamber 120. The operation of the optical switch 110 will not generate mechanical vibration. Furthermore, since the optical switch 110 is installed outside the vacuum chamber 120, there is no need to reserve additional space or set up additional mechanical support structures inside the vacuum chamber 120 for installation. This reduces the complexity of the internal structure of the vacuum chamber 120 and is conducive to the miniaturization and compact integration of the vacuum chamber 120 system. Even if the optical switch 110 fails, it can be repaired or replaced independently without damaging the vacuum system. The optical switch 110 is controlled based on optical principles, and the response time for opening and closing is in the microsecond or even sub-microsecond range, which can meet the high-precision timing control requirements of rapid experimental sequences.

[0037] The atomic furnace 131 is used to generate initial atoms A in the second direction F2 and send the initial atoms A to the filter 132. The filter 132 is used to perform isotope screening on the initial atoms A to obtain target atoms B and send the target atom beam to the trapper 133. The optical switch 110 is used to emit a laser beam F4. The laser beam F4 passes through the atom transport path F3 in the first direction F1 between the filter 132 and the trapper 133. The laser beam F4 is used to control the direction of the target atom beam. The trapper 133 is used to trap and cool the target atoms B to obtain cold atoms. The atomic furnace 131 can generate initial atoms A in the second direction F2, and send the initial atoms A to the filter 132 in the second direction F2. The filter 132 can perform isotope screening on the initial atoms A to obtain the desired target atoms B, and send the target atomic beam to the trapper 133 in the first direction F1. The optical switch 110 can send a laser beam F4, which can pass through the atomic transport path F3 in the first direction F1 between the filter 132 and the trapper 133 to adjust the transport direction of the target atomic beam passing through the laser beam F4, thereby realizing the on / off control of the atomic beam. The trapper 133 can capture the target atoms B in the target atomic beam that have reached its position, and obtain the corresponding cold atoms.

[0038] For example, the laser beam F4 can be a continuous laser, and the target atom B used in this device is typically a neutral atom.

[0039] Optionally, the optical switch 110 may include devices such as a light source capable of emitting a laser beam F4. It can utilize the momentum exchange (optical pressure) between the resonant laser and atoms to change the direction of the atomic beam, thereby achieving the "on" and "off" of the atomic beam. By placing the optical switch 110 outside the vacuum cavity 120, the problems of mechanical vibration interference, low reliability of the vacuum system, and slow response speed caused by existing mechanical shutters can be solved. This application enables a non-mechanical contact, vibration-free, high-speed, and highly reliable atomic beam interruption control method without altering or damaging the existing vacuum cavity 120 system.

[0040] Optionally, the initial atoms A generated in the atomic furnace 131 can be various types of thermal atomic beams or atomic vapors, capable of heating and vaporizing solid or liquid target materials to form a directional atomic beam. For example, the atomic furnace 131 can heat solid metals (such as rubidium, cesium, sodium, etc.) to high temperatures (typically 200–500°C), causing them to sublimate or evaporate and form gaseous atoms. These atoms are then collimated through small holes (or capillary arrays) at the furnace opening, generating a thermal atomic beam with good collimation (velocity distribution of approximately several hundred m / s). The density and velocity distribution of the atomic beam can be controlled by adjusting the furnace temperature and nozzle size of the atomic furnace 131 to reduce the adverse effects of excessively rapid saturation.

[0041] For example, the type of initial atom A is determined based on the target material within the atomic furnace 131. The appropriate target material can be selected to prepare the corresponding type of cold atoms according to actual needs. The initial atom A produced by the atomic furnace 131 can include alkali metal atoms (e.g., rubidium, cesium, sodium, potassium, etc.), alkaline earth metal atoms (e.g., strontium, ytterbium, calcium, etc.) or other special atoms (e.g., helium, neodymium, erbium, etc.). The prepared cold atoms can be applied in various fields such as atomic clocks, quantum simulation, and precision measurement. The furnace body material of the atomic furnace 131 can use high-temperature resistant and corrosion-resistant materials, such as stainless steel and titanium alloys. Furthermore, considering the susceptibility of alkali metals to reaction with oxygen / water, high vacuum or inert gas protection can be used. Heating methods such as resistance heating, induction heating, or electron bombardment can be used for furnace heating. The nozzle of the atomic furnace 131 can be designed as a multi-hole nozzle or a long capillary to improve the collimation of the initial atom A. Additionally, the nozzle temperature can be set slightly higher than the furnace body temperature to reduce the adverse effects of atomic condensation and blockage.

[0042] Optionally, the initial atoms A emitted by the atomic furnace 131 may include various types of atoms. The atoms can be cooled and trapped in a two-dimensional plane based on the special magnetic field and laser configuration of the filter 132, while allowing non-target atoms B to escape or be guided in directions other than the first direction F1, thereby achieving the screening of atomic velocity, position or energy state to obtain target atoms B.

[0043] For example, the filter 132 may include a two-dimensional magneto-optical trap, i.e., a 2D-MOT, which may be a permanent magnet and two opposing and orthogonal laser beams F4 to form a two-dimensional optical adhesive. The laser beams F4 can interact with the initial atom A to produce Doppler cooling and magneto-optical trap effects, confining the screened target atom B in a two-dimensional plane, so as to screen and capture the initial atom A generated by the atomic furnace 131 in two dimensions and confine the target atom B to the first central region, thereby achieving an atomic deceleration effect.

[0044] For example, the trapper 133 may include a three-dimensional magneto-optical trap, which may be an anti-Helmholtz coil and three opposing and orthogonal laser beams F4 to cover all spatial directions. The magnetic field of the second central region of the three-dimensional magneto-optical trap is 0. The three-dimensional magneto-optical trap has magnetic field gradients in multiple directions. The laser beams F4 cooperate with the magnetic field gradients to achieve Doppler cooling and magneto-optical trapping in three-dimensional space. It can trap and cool the target atom B in three dimensions to obtain the desired cold atom.

[0045] Optionally, please refer to Figure 2 , Figure 2This application provides a schematic diagram of a fully optical cold atom preparation apparatus. The apparatus may further include a controller 140. The controller 140 is connected to an optical switch 110. The controller 140 sends control signals to the optical switch 110 based on control requirements, and the optical switch 110 generates a laser beam F4 based on the control signals. To control the operating state of the optical switch 110, the apparatus may also include a controller 140 connected to the optical switch 110. The controller 140 can send control signals to the optical switch 110 based on actual control requirements. The optical switch 110 responds to the control signals and generates a corresponding laser beam F4 to achieve on / off control of the atomic beam. By controlling the operating state of the optical switch 110 based on actual control requirements using the controller 140, the efficiency and accuracy of the optical switch 110 in controlling the atomic beam flow are effectively improved.

[0046] Optionally, the controller 140 can be configured as an electronic device with logic computing capabilities, such as a server, personal computer (PC), tablet computer, smartphone, or personal digital assistant (PDA), capable of acquiring user input information and parsing it to determine the user's control requirements when preparing cold atoms. The control requirements may include: when the atomic beam needs to be turned on and when the atomic beam needs to be turned off as required.

[0047] It should be noted that the control signals include on signals and off signals. That is, the control signals can include on signals that do not interfere with the transmission of the atomic beam, and off signals that adjust the transmission direction of the atomic beam. The on signal is determined based on the conduction period specified in the control requirements, and the off signal is determined based on the off period specified in the control requirements.

[0048] Optionally, when the control signal is off, the optical switch 110 generates a first type of laser beam whose laser frequency resonates with that of the target atom B. This first type of laser beam provides a motion increment to the target atomic beam, deviating from the first direction F1. When the control signal is off, the optical switch 110 generates a first type of laser beam whose laser frequency resonates with that of the target atom B. This first type of laser beam provides a motion increment to the target atomic beam, deviating from the first direction. In other words, the resonant laser deflection principle of the first type of laser beam adjusts the motion direction of the target atomic beam, preventing it from moving along its original atomic transport path F3 to the trapper 133, thus achieving a shutdown effect.

[0049] It should be noted that the first type of laser beam is based on a clever application of the principle of optical pressure. The resonant photon carries momentum p = h / λ (where h is Planck's constant and λ is the laser wavelength). After the target atom B absorbs the photon, its momentum state changes. The deflection field formed by the first type of laser beam acts on one side of the target atomic beam, giving it momentum perpendicular to the atomic transport path F3. By designing the propagation direction and intensity of the first type of laser beam, the trajectory of the target atom B is altered, thereby achieving control over the on / off state of the atomic beam.

[0050] Optionally, when the control signal is on, the optical switch 110 stops generating the first type of laser beam, or the optical switch 110 generates a second type of laser beam whose laser frequency does not resonate with the target atom B. When the control signal is on, the optical switch 110 stops generating the first type of laser beam, or the optical switch 110 can generate a second type of laser beam whose laser frequency does not resonate with the target atom B. The second type of laser beam does not affect the movement of the target atomic beam, and the target atomic beam moves to the trapper 133 along its original atomic transport path F3, achieving a conduction effect.

[0051] It should be noted that the specific frequencies of the first and second type laser beams are determined based on the type of target atom B, in order to achieve different effects of resonance and non-resonance. To further reduce the cost of preparing cold atoms, it is preferable that the optical switch 110 stops generating the first type laser beam when the on signal is activated, i.e., the optical switch 110 is paused.

[0052] Optionally, the optical switch 110 provided in this application is not limited to cold atom preparation devices, but can also be widely used in any device that needs to control the on / off state of a neutral particle beam (including a molecular beam).

[0053] Alternatively, please continue reading Figure 2 A conduit structure 150 is also provided between the filter 132 and the trap 133, through which the target atomic beam is transmitted to the trap 133. This allows the target atomic beam to move and transmit normally along the atomic transport path F3 while isolating the filter 132 and the trap 133.

[0054] It should be noted that, under the action of the first type of laser beam, the target atomic beam deviates from the atomic transport path F3 and moves. The tube wall of the pipe structure 150 and the inner wall of the vacuum cavity 120 are used to adsorb the deviated target atomic beam. Under the action of the first type of laser beam with the shutdown signal, due to the principle of resonant laser deflection, the target atomic beam will deviate from the original atomic transport path F3 and move. The tube wall of the pipe structure 150 and the inner wall of the vacuum cavity 120 can adsorb the deviated target atomic beam, which can effectively control the matter in the target atomic beam under the shutdown effect, reducing the adverse situation of target atom B floating in the vacuum cavity 120 or moving to other devices.

[0055] Optionally, the device can be cleaned periodically. Since the attached atoms are small in size, a longer periodic cleaning cycle can be set to clean the substances attached to the inner wall of the vacuum chamber 120 and the pipe wall of the pipe structure 150.

[0056] Alternatively, please continue reading Figure 2 The optical switch 110 may include a laser 111, an optical device 112, and a frequency modulation device 113.

[0057] Among them, laser 111 is used to generate laser beam F4, frequency modulation device 113 is used to adjust the laser frequency of laser beam F4, and optical device 112 is used to shape laser beam F4 to generate a variety of laser beams F4 that meet the requirements, thereby achieving the corresponding atomic beam flow interruption control effect.

[0058] For example, laser 111 can be any light source device capable of outputting the desired resonant wavelength, such as a diode laser or fiber laser. For instance, laser 111 can be a continuous-wave laser capable of outputting a wavelength resonating with a specific electronic transition energy level of the target atom B, or a device capable of generating pulsed light. Optical device 112 can include various types of optical lenses capable of shaping the laser beam F4 output by laser 111 to better match the operating region of the radio frequency device or the target atomic beam. Frequency modulation device 113 can be a device capable of modulating the laser frequency, such as an acousto-optic modulator (AOM) or an acousto-optic deflector, which can control the on / off state of the atomic beam based on frequency adjustment.

[0059] Alternatively, the intensity of the laser beam F4 can be controlled by directly controlling the current of the laser 111, or the frequency modulation device 113 can be manually controlled to achieve the on / off control function. However, in terms of timeliness, the on / off control function based on the frequency modulation function of the frequency modulation device 113 is faster, and the appropriate control method can be selected based on actual needs.

[0060] Optionally, considering that the direction of the laser beam F4 also affects the direction of the atomic beam, the optical switch 110 may further include a guiding device 114, which is disposed among the optical devices 112 and is used to adjust the direction of the laser beam F4. The guiding device 114, disposed among multiple optical devices 112, can adjust the direction of the laser beam F4 so that it can enter at a suitable angle, thereby adjusting the direction of the atomic beam and achieving the corresponding atomic beam flow interruption control effect.

[0061] Optionally, the guide device 114 can also effectively reduce the space volume required by the optical switch 110, and can set the optical path of the laser beam F4 in the optical switch 110 and the position of the guide device 114 according to the actual installation space.

[0062] For example, the guiding device 114 can be a device such as a reflector that can adjust the direction of the laser beam F4.

[0063] It should be noted that, in order to achieve a better directional deflection effect during shutdown, the transmission direction of the laser beam F4 in the vacuum cavity 120 intersects with the first direction F1, and the angle of intersection is in the range of 81° to 91°. For example, the intersection angle can be set to 90°, that is, to maintain a roughly perpendicular intersection angle, so as to effectively adjust the movement direction of the target atomic beam by using the laser beam F4 with a roughly perpendicular intersection angle. This reduces the adverse situation where the target atomic beam deflection is too small due to the angle being too small or too large, thus preventing it from moving to the trap 133 and failing to shut down, and effectively improves the control effect during shutdown.

[0064] Optionally, under the off signal, i.e., when it is necessary to prevent target atom B from entering trap 133, the laser 111 in optical switch 110 is turned on to modulate AOM, guiding the first type of laser beam to the interaction region of the atomic transport path F3 of target atom B. The propagation direction of the first type of laser beam is approximately perpendicular to the propagation direction of the atomic beam. Due to the resonance between the laser frequency of the first type of laser beam and the target atom B, the moving target atom B will absorb photons and obtain an atomic transport path F3 perpendicular to the first direction F1, i.e., the momentum increment of the second direction F2. After multiple "absorption-spontaneous emission" cycles, the target atom B accumulates a sufficiently large velocity in the second direction F2, and its trajectory is significantly deflected. The deflected target atom B cannot enter trap 133 along the original atomic transport path F3, but instead collides with the inner wall of vacuum cavity 120 or the tube wall of pipe structure 150 and is adsorbed, thereby achieving effective blocking of the target atomic beam. When the activation signal is activated, i.e., when the target atom B needs to enter the trap 133, the AOM is turned off or the frequency of the laser 111 is adjusted to be far from the atomic resonance frequency, thus generating a second type of laser beam. At this time, there is no resonant light field in the interaction region of the atomic transport path F3 of the target atom B, and the target atom beam propagates along the original atomic transport path F3 without interference, successfully entering the trap 133.

[0065] For example, with 171 Taking Yb as an example, the spot size of the first type of laser beam after shaping is 10. 5mm 2 The beam power is 3mW (0.1 times the saturation intensity), and after being modulated by the frequency modulation device 113, the laser frequency is synchronized with the target atom B. 1 S0- 1 At P1 resonance, after the first type of laser beam interacts with the target atom B, the deviation of the target atom B in the second direction F2 is on the order of centimeters or more. The diameter of the pipe structure 150 can be set within 4 mm to prevent the target atom B from entering the trap 133 through the pipe structure 150.

[0066] Alternatively, please continue reading Figure 2 To provide the propulsion for the target atom B to move into the trap 133, the device may further include a pusher 160. In the first direction F1, the pusher 160 is positioned at the end of the filter 132 furthest from the trap 133. The pusher 160 is used to send a pushing light 161 in the first direction F1 to the filter 132, thereby pushing the target atom B in the filter 132 into the trap 133 via the pushing light 161. The pusher 160 is capable of sending a pushing light 161 in the first direction F1 to the filter 132 to push the target atom B in the filter 132 into the trap 133 via the pushing light 161, thus achieving the transmission of the target atom beam.

[0067] For example, pusher 160 can be configured as a device of various types capable of transmitting push light 161, such as tuned semiconductor laser 111, etc.

[0068] It should be noted that a window region 121 is provided on the cavity wall of the vacuum cavity 120, through which the laser beam F4 enters the interior of the vacuum cavity 120. The optical switch 110 is located outside the vacuum cavity 120, so it will not adversely affect the operation of the vacuum cavity 120 and is convenient for maintenance or replacement. In order for the externally located optical switch 110 to function properly, a window region 121 is provided on the cavity wall of the vacuum cavity 120, so that the laser beam F4 can enter the interior of the vacuum cavity 120 through the window region 121 to control the target atomic beam accordingly.

[0069] Optionally, the window region 121 can be positioned between the filter 132 and the trap 133 so that the laser beam F4 enters the vacuum cavity 120 at a roughly vertical angle.

[0070] For example, window region 121 can be configured as an optical lens with an anti-reflective coating to reduce the loss caused by the laser beam F4 passing through window region 121.

[0071] For example, the initial atomic beam, ejected from the atomic furnace, is filtered and captured by a filter. Parameters such as the frequency, intensity, and magnetic field gradient of the capture device can be adjusted to achieve the desired isotope target atom. The target atom is then propelled into the capture device by a pusher beam. An optical switch is positioned between the filter and the capture device. The laser beam emitted from the optical switch is expanded by optical components and then frequency-modulated by a frequency-modulating device. Under normal operating conditions, +1 or -1 level modulated light is taken, reflected by a guide device, and shaped into a stripe-shaped spot by optical components. After the laser beam direction is adjusted by the guide device, it enters the vacuum cavity through a window area and interacts with the target atomic beam on the atomic transport path. This causes the target atom to deviate from its initial direction and strike the inner wall of the vacuum cavity or the wall of the pipe structure, preventing it from moving into the capture device. The optical switch's operation is controlled by a controller, allowing for on / off control based on actual control requirements.

[0072] Please see Figure 3 , Figure 3 This is a schematic flowchart of an all-optical cold atom preparation method provided in an embodiment of this application. The method is applied to the apparatus described in any of the above embodiments and includes steps S210-S240.

[0073] In step S210, initial atoms in the second direction are generated by an atomic furnace and sent to a filter.

[0074] Step S220: The initial atoms are screened for isotopes using a filter to obtain target atoms, and the target atom beam is sent to the trapper.

[0075] In step S230, a laser beam is emitted through an optical switch. The laser beam passes through the atom transport path in a first direction between the filter and the trap. The laser beam is used to control the direction of the target atom beam.

[0076] Step S240: The target atom is captured and cooled by a trap to obtain cold atoms.

[0077] exist Figure 3 In the illustrated embodiment, the atomic furnace can generate initial atoms in a second direction to send the initial atoms to a filter in the second direction. The filter can perform isotopic sieving on the initial atoms to obtain the desired target atoms and send the target atomic beam to a trap in a first direction. An optical switch can send a laser beam that passes through the atomic transport path in the first direction between the filter and the trap to adjust the transport direction of the target atomic beam passing through the laser beam, thereby realizing the on / off control of the atomic beam. The trap can capture the target atoms in the target atomic beam that have reached its position to obtain the corresponding cold atoms.

[0078] Since the principle of the method in this embodiment is similar to that of the aforementioned device embodiment, the implementation of the method in this embodiment can refer to the description in the aforementioned device embodiment, and repeated details will not be repeated.

[0079] In summary, this application provides an all-optical cold atom preparation apparatus and method. The control process of the optical switch is completed solely through the interaction between light and atoms, fundamentally eliminating the interference of mechanical vibration on the precision experimental system. The optical switch is located outside the vacuum cavity, avoiding the introduction of vulnerable mechanical components within the vacuum cavity. Even if the optical switch is damaged, repair or replacement can be performed outside the vacuum cavity without disrupting its structure, greatly improving system reliability and maintainability, and reducing maintenance costs and downtime. The opening / closing speed of the optical switch (achieved via an acousto-optic modulator or acousto-optic deflector) is extremely fast, reaching microseconds or even nanoseconds, enabling seamless integration of atomic beam on / off control into rapid experimental sequences requiring complex timing. The optical switch eliminates the need for a mechanical shutter and its drive and control systems, simplifying the design and structure of the vacuum cavity and saving space.

[0080] In the several embodiments provided in this application, it should be understood that the disclosed device can also be implemented in other ways. The device embodiments described above are merely illustrative; for example, the block diagrams in the accompanying drawings illustrate the possible architecture, functions, and operations of the device according to various embodiments of this application. In this regard, each block in the block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram, and combinations of block diagrams, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0081] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0082] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0083] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0084] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0085] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A fully optical cold atom preparation device, characterized in that, The device includes: an optical switch and a vacuum chamber; The vacuum chamber is equipped with an atomic furnace, a filter, and a trap; wherein, in a first direction, the first central region of the filter and the second central region of the trap are collinear; in a second direction perpendicular to the first direction, the filter is positioned at the output position of the atomic furnace; The optical switch is fixedly mounted outside the vacuum cavity; The atomic furnace is used to generate initial atoms in the second direction and send the initial atoms to the filter; The filter is used to perform isotopic screening on the initial atoms to obtain target atoms, and send the target atom beam to the trapper. The optical switch is used to emit a laser beam that passes through an atomic transport path in the first direction between the filter and the trap, and the laser beam is used to control the direction of the target atomic beam. The trap is used to trap and cool the target atom to obtain a cold atom.

2. The apparatus according to claim 1, characterized in that, The device further includes: a controller; The controller is connected to the optical switch; The controller is used to send control signals to the optical switch based on control requirements; The optical switch is used to generate the laser beam based on the control signal.

3. The apparatus according to claim 2, characterized in that, in, The control signals include an on signal and an off signal; When the control signal is the off signal, the optical switch is used to generate a first type of laser beam whose laser frequency resonates with the target atom, and the first type of laser beam is used to provide the target atom beam with a motion increment deviating from the first direction; When the control signal is the on signal, the optical switch stops generating the first type of laser beam, or the optical switch is used to generate a second type of laser beam whose laser frequency does not resonate with the target atom.

4. The apparatus according to claim 3, characterized in that, in, A pipe structure is provided between the filter and the trap, and the target atomic beam is transmitted to the trap through the pipe structure; Under the action of the first type of laser beam, the target atomic beam moves away from the atomic transport path, and the pipe wall of the pipe structure and the inner wall of the vacuum cavity are used to adsorb the deviated target atomic beam.

5. The apparatus according to any one of claims 1-4, characterized in that, The optical switch includes: a laser, optical components, and a frequency modulation device; The laser is used to generate the laser beam; The frequency modulation device is used to adjust the laser frequency of the laser beam; The optical device is used to shape the laser beam.

6. The apparatus according to claim 5, characterized in that, The optical switch further includes: a guiding device; The guiding device is disposed between the optical devices; The guiding device is used to adjust the direction of the laser beam.

7. The apparatus according to any one of claims 1-4, characterized in that, in, The transmission direction of the laser beam within the vacuum cavity intersects with the first direction, and the angle of intersection ranges from 89° to 91°.

8. The apparatus according to any one of claims 1-4, characterized in that, The device further includes: a pusher; In the first direction, the pusher is positioned at the end of the filter that is away from the catcher; The pusher is used to send push light in the first direction to the filter, and push the target atoms in the filter to the capture device through the push light.

9. The apparatus according to any one of claims 1-4, characterized in that, in, The vacuum cavity has a window area on its wall, through which the laser beam enters the interior of the vacuum cavity.

10. A fully optical method for preparing cold atoms, characterized in that, The method is applied to the apparatus according to any one of claims 1-9, the method comprising: Initial atoms in a second direction are generated by an atomic furnace and sent to a filter. The initial atoms are isotopically screened by the filter to obtain target atoms, and the target atom beam is sent to the trap. A laser beam is emitted via the optical switch, the laser beam passes through an atomic transport path in a first direction between the filter and the trap, and the laser beam is used to control the direction of the target atomic beam stream; The target atom is captured and cooled by the trap to obtain cold atoms.

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