A clock laser control device

Abstract

This application discloses a clock laser control device. In this device, a clock laser source is connected to the first port of a laser beam splitting module; the second port of the laser beam splitting module is connected to the first port of a quantum state interrogation and control module; the third port of the laser beam splitting module is connected to the first port of a phase elimination module; and the second port of the phase elimination module is connected to the second port of the quantum state interrogation and control module. The laser beam splitting module splits an initial beam into a first initial beam and a second initial beam; the phase elimination module performs phase locking on the second initial beam to generate a reference beam; the quantum state interrogation and control module generates a modulated beam based on the first initial beam and the reference beam; the propagation direction of the modulated beam is time-controlled to obtain an alternately output first target beam and a second target beam; the first target beam is attenuated to obtain a third target beam; and the third target beam and the second target beam are controlled to be output from the third port of the quantum state interrogation and control module.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to a clock laser control device. Background Technology

[0002] An optical clock uses the frequency of photons generated by the transition of electron energy levels as a time reference, and defines time by the transition of electrons between different energy levels inside an atom.

[0003] In optical clock systems, Rabi interrogation and Ramsey interrogation are two mainstream measurement methods. Rabi interrogation has the advantages of strong robustness and accurate locking of the resonant frequency, but it is prone to introducing Dick effect noise, resulting in lower system stability. Ramsey interrogation has the advantage of reducing Dick effect noise, but it has the disadvantage of strict requirements for initial frequency alignment accuracy and the tendency for measurement errors to increase due to excessive frequency deviation in the initial stage of resonant frequency locking.

[0004] Therefore, how to integrate the technological advantages of the two inquiry methods and improve the performance of the optical clock system is of great value and significance for the application of portable optical clocks and space optical clocks. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a clock laser control device that is compatible with both Rabi and Ramsey interrogation methods, thereby improving the performance of the optical clock system.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] This application discloses a clock laser control device, which includes: a clock laser source, a laser beam splitting module, a quantum state probing and control module, and a phase elimination module;

[0008] The clock laser source is connected to the first port of the laser beam splitter module; the second port of the laser beam splitter module is connected to the first port of the quantum state interrogation and control module; the third port of the laser beam splitter module is connected to the first port of the phase elimination module; and the second port of the phase elimination module is connected to the second port of the quantum state interrogation and control module.

[0009] The laser beam splitting module is used to split the initial beam output by the clock laser source into a first initial beam and a second initial beam.

[0010] The phase cancellation module is used to perform phase locking on the received second initial beam to generate a reference beam;

[0011] The quantum state interrogation and control module is used to generate a modulated beam based on the first initial beam and the reference beam; to perform time-series control on the propagation direction of the modulated beam to obtain an alternately output first target beam and second target beam; to attenuate the light intensity of the first target beam to obtain a third target beam; and to control both the third target beam and the second target beam to be output from the third port of the quantum state interrogation and control module; the third target beam is used as a Rabi interrogation light source, and the second target beam is used as a Ramsey interrogation light source.

[0012] Compared with existing technologies, this application discloses a clock laser control device that is compatible with both Rabi and Ramsey probing. When Rabi and Ramsey probing are periodically applied to atomic clusters, the resonant frequency can be precisely locked using Rabi probing, while Ramsey probing effectively reduces Dick effect noise. This fully leverages the technical advantages of both probing methods, significantly improving the stability and measurement accuracy of the optical clock system. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of a clock laser control device provided in an embodiment of this application;

[0015] Figure 2 This is a schematic diagram of the structure of a beam splitting and combining unit provided in an embodiment of this application;

[0016] Figure 3 This is a schematic diagram of a phase elimination module provided in an embodiment of this application. Detailed Implementation

[0017] An optical clock system refers to a complex experimental apparatus and technological system that uses laser technology to achieve ultra-high precision time measurement based on the optical frequency band energy level transitions of atoms or ions. Interrogation refers to the experimental operation of capturing the frequency of atomic energy level transitions by exciting atomic transitions with a laser and measuring the corresponding laser frequency. In optical clock systems, Rabi interrogation and Ramsey interrogation are two mainstream measurement methods.

[0018] Rabi probing is a probing method that involves preparing atoms at specific energy levels, irradiating them with π pulses, and detecting the probability of an atom transitioning when the pulse frequency approaches the frequency of the atom's energy level transition.

[0019] The Rabi probing scheme is simple, and high-excitation-rate transitions only occur when the laser frequency resonates with the atomic transitions. This allows the optical clock system to accurately find the resonant transition frequency, making the closed-loop feedback loop of the optical clock more robust. However, in the Rabi probing method, the sensitivity function of atomic transitions to clock laser noise is limited, increasing the Dick effect noise of the optical clock system and limiting the system stability of the atomic optical clock. In other words, Rabi probing has the advantages of strong robustness and accurate frequency locking, but also the disadvantages of easily introducing Dick effect noise and lower system stability.

[0020] Ramsey probing involves preparing atoms at specific energy levels, irradiating them with a first π / 2 pulse to put them into a quantum superposition state, allowing the quantum state to evolve freely for a period of time, with the phase evolution of the ground and excited states being related to the frequency detuning of the light pulse; then irradiating the atom with a second π / 2 pulse; and finally detecting the probability of the atom undergoing a transition.

[0021] The sensitivity function of Ramsey interrogation approximates a rectangular function, which has the advantage of reducing Dick effect noise. When two atomic systems perform alternating Ramsey interrogations, a dead-time-free optical clock is formed, which can almost completely suppress Dick effect noise and significantly improve the stability of the optical clock system. However, Ramsey interrogation requires the first and second π / 2 pulses to be phase-matched. When the optical pulse is turned off during the free evolution phase of the atom, there is a 50% probability that the second π / 2 pulse will produce a π phase jump, causing Ramsey interrogation to fail. Ramsey interrogation also has the disadvantages of requiring strict initial frequency alignment accuracy and being prone to increased measurement error due to excessive frequency deviation in the early stage of resonant frequency locking. In other words, Ramsey interrogation has the advantage of reducing Dick effect noise, but suffers from the disadvantages of phase jump leading to interrogation failure and requiring strict initial frequency alignment accuracy, which is prone to increased measurement error due to excessive frequency deviation in the early stage of resonant frequency locking.

[0022] Furthermore, for narrow-linewidth atomic spectral lines with a linewidth of 1 Hz, the required π pulse time in Rabi probing is 500 ms; while in Ramsey probing, the free evolution time is typically set to 500 ms, and the π pulse time is controlled between 5 and 50 ms. This means that the light intensity of Ramsey probing is approximately 100 to 10,000 times that of Rabi probing. This results in the incompatibility of Ramsey probing and Rabi probing modes within the same optical scheme.

[0023] Solving the phase transition of the Ramsey interrogation pulse in optical clock systems, the incompatibility of Ramsey interrogation with Rabi interrogation optics, and at least some of the problems in meeting the miniaturization requirements of optical clock systems have become some of the urgent problems to be solved in the field of portable and space optical clock technology.

[0024] To address at least some of the aforementioned problems, this application discloses a clock laser control device, comprising a clock laser source, a laser beam splitting module, a quantum state interrogation and control module, and a phase elimination module. The laser beam splitting module splits the initial beam output from the clock laser source into a first initial beam and a second initial beam; the phase elimination module performs phase locking on the received second initial beam to generate a reference beam; the quantum state interrogation and control module generates a modulated beam based on the first initial beam and the reference beam; it then performs time-series control on the propagation direction of the modulated beam to obtain an alternately output first target beam and a second target beam; it attenuates the intensity of the first target beam to obtain a third target beam; and it controls both the third target beam and the second target beam to be output from the third port of the quantum state interrogation and control module; the third target beam is used as a Rabi interrogation light source, and the second target beam is used as a Ramsey interrogation light source.

[0025] This application discloses a clock laser control device compatible with both Rabi and Ramsey probing methods. When Rabi and Ramsey probing are periodically applied to atomic clusters, the resonant frequency can be precisely locked using Rabi probing, while Ramsey probing effectively reduces Dick effect noise. This fully leverages the technical advantages of both probing methods, significantly improving the stability and measurement accuracy of the optical clock system.

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0027] Figure 1 This is a schematic diagram of a clock laser control device provided in an embodiment of this application. (Combined with...) Figure 1 As shown, the clock laser control device 100 disclosed in this application includes: a clock laser source 1, a laser beam splitting module 2, a quantum state probing and control module 3, and a phase elimination module 4.

[0028] Among them, the clock laser source 1 is connected to the first port 21 of the laser beam splitter module 2; the second port 22 of the laser beam splitter module 2 is connected to the first port 3011 of the quantum state query and control module 3; the third port 23 of the laser beam splitter module 2 is connected to the first port 41 of the phase elimination module 4; and the second port 42 of the phase elimination module 4 is connected to the second port 3062 of the quantum state query and control module 3.

[0029] Laser beam splitting module 2 is used to split the initial beam output by clock laser source 1 into a first initial beam and a second initial beam;

[0030] Phase cancellation module 4 is used to phase lock the received second initial beam and generate a reference beam;

[0031] The quantum state interrogation and control module 3 is used to generate a modulated beam based on a first initial beam and a reference beam; to perform time-series control on the propagation direction of the modulated beam to obtain an alternately output first target beam and second target beam; to attenuate the light intensity of the first target beam to obtain a third target beam; and to control both the third target beam and the second target beam to be output from the fifth port 3035 of the quantum state interrogation and control module 3; the third target beam is used as the light source for Rabi interrogation, and the second target beam is used as the light source for Ramsey interrogation.

[0032] Combination Figure 1 As shown, the quantum state probing and control module 2 includes: a frequency shift modulation unit 301, a beam switching unit 302, a beam splitting and combining unit 303, an optical power detector 304, a PID servo control unit 305, a beat frequency detector 306, and a frequency division phase-locked servo control unit 307.

[0033] Specifically, the first port 3011 of the frequency shift modulation unit 301 is the first port of the quantum state probing and control module 3; the second port 3012 of the frequency shift modulation unit 301 is connected to the first port 3021 of the beam switching unit 302; the second port 3022 of the beam switching unit 302 is connected to the first port 3031 of the beam splitting and combining unit 303; and the third port 3023 of the beam switching unit 302 is connected to the second port 3032 of the beam splitting and combining unit 303.

[0034] The third port 3033 of the beam splitting and combining unit 303 is connected to the first port 3041 of the optical power detector 304; the second port 3042 of the optical power detector 304 is connected to the first port 3051 of the PID servo control unit 305; and the second port 3052 of the PID servo control unit 305 is connected to the third port 3013 of the frequency shift modulation unit 301.

[0035] The fourth port 3034 of the beam splitting combination unit 303 is connected to the first port 3061 of the beat frequency detector 306; the second port 3062 of the beat frequency detector 306 is the second port of the quantum state interrogation and control module 3; the third port 3063 of the beat frequency detector 306 is connected to the first port 3071 of the frequency division phase-locked servo control unit 307; the second port 3072 of the frequency division phase-locked servo control unit 307 is connected to the fourth port 3014 of the frequency shift modulation unit 301.

[0036] The specific uses of each unit in the quantum state probing and control module 3 are as follows:

[0037] The frequency shift modulation unit 301 is used to modulate the first initial beam according to the first control signal output by the PID servo control unit 305 and the second control signal output by the frequency division phase-locked servo control unit 307 to generate a modulated beam.

[0038] The beam switching unit 302 is used to time-control the propagation direction of the modulated beam, so that the modulated beam can be periodically switched between the two optical paths to obtain the alternating output of the first target beam and the second target beam.

[0039] The beam splitting and combining unit 303 is used to attenuate the light intensity of the first target beam to obtain the third target beam; and to control both the third target beam and the second target beam to be output from the third port 3035 of the quantum state probing and control module 3.

[0040] Optical power detector 304 is used to detect the second target beam or the third target beam to obtain the first detection signal;

[0041] The PID servo control module 305 is used to generate a first control signal based on the first detection signal;

[0042] Beat frequency detector 306 is used to detect a second target beam or a third target beam to obtain a second detection signal; to detect a reference beam to obtain a third detection signal; and to obtain a beat frequency signal based on the second detection signal and the third detection signal.

[0043] The frequency division phase-locked servo control unit 307 is used to generate a second control signal based on the beat frequency signal.

[0044] The process of using the clock laser control device 100 is as follows:

[0045] A1, start the clock laser source 1 to output the initial beam.

[0046] A2, after the initial beam enters the laser beam splitting module 2 through the first port 21, it is split into a first initial beam and a second initial beam inside the laser beam splitting module 2; the first initial beam is transmitted from the second port 22 of the laser beam splitting module 2 to the first port 3011 of the frequency shift modulation unit 301; the second initial beam is transmitted from the third port 23 of the laser beam splitting module 2 to the first port 41 of the phase elimination module 4; after the phase elimination module 4 performs phase locking on the received second initial beam, it outputs a reference beam from the second port 42 of the phase elimination module 4.

[0047] The laser beam splitter module 2 consists of a waveplate and a polarizing beam splitter; the first port 21 of the laser beam splitter module 2 corresponds to the spatial optical path, the second port 22 of the laser beam splitter module 2 corresponds to the spatial optical path or fiber optic interface, and the third port 23 of the laser beam splitter module 2 corresponds to the spatial optical path.

[0048] A3, upon receiving the first initial beam, the first control signal output by the PID servo control unit 305 (the first control signal is used to modulate the power of the first initial signal), and the second control signal output by the frequency division phase-locked servo control unit 307 (the second control signal is used to modulate the frequency of the first initial signal), the frequency shift modulation unit 301 modulates the first initial beam to generate a modulated beam. The modulated beam is output from the second port 3012 of the frequency shift modulation unit 301.

[0049] The frequency shift modulation unit 301 includes an acousto-optic modulator and a radio frequency driver. The first initial light beam input into the frequency shift modulation unit 301 is modulated by the acousto-optic modulator, i.e., the first-order diffracted light, and outputs from the second port 3012 of the frequency shift modulation unit 301. The second port 3012 of the frequency shift modulation unit 301 corresponds to a spatial optical path or fiber optic interface. The radio frequency power output by the radio frequency driver is controlled by a first control signal input to the third port 3013 of the frequency shift modulation unit 301. The radio frequency frequency output by the radio frequency driver is controlled by a second control signal input to the fourth port 3014 of the frequency shift modulation unit 301.

[0050] A4, after the modulated beam output by the frequency modulation unit 301 enters the beam switching unit 302, the beam switching unit 302 performs timing control on the propagation direction of the modulated beam, so that the modulated beam periodically switches between the two optical paths to obtain the alternating output of the first target beam and the second target beam; wherein, the first target beam is output from the second port 3022 of the beam switching unit 303; the second target beam is output from the third port 3023 of the beam switching unit 303; essentially, the first target beam and the second target beam both originate from the same modulated beam; they are two branches obtained by the same modulated beam mirror after being propagated through different transmission paths; the core parameters of the first target beam and the second target beam, such as laser power and laser frequency, are exactly the same.

[0051] The beam switching unit 302 can be a free-space dual mechanical gate optical switch, a fiber optic microelectromechanical optical switch, or a dual acousto-optic modulator optical switch.

[0052] It is understandable that the beam switching unit 302 does not output the first target beam and the second target beam simultaneously, but outputs the first target beam and the second target beam in an alternating manner.

[0053] A5, the first target beam output from the second port 3022 of the beam switching unit 303 enters the interior of the beam splitting and combining unit 303 through the first port 3031 of the beam splitting and combining unit 303; the second target beam output from the third port 3023 of the beam switching unit 303 enters the interior of the beam splitting and combining unit 303 through the second port 3032 of the beam splitting and combining unit 303; the beam splitting and combining unit 303 attenuates the intensity of the first target beam to obtain the third target beam; the beam splitting and combining unit 303 controls the third target beam or the second target beam to be output outward from the third port 3033, the fourth port 3034 and the fifth port 3034 of the beam splitting and combining unit 303; wherein, the fifth port of the beam splitting and combining unit 303 is the third port of the quantum state interrogation and control module 3.

[0054] In this application, controlling the third target beam and the second target beam to be output from the third port of the quantum state interrogation and control module 3 and acting on the target detection material (such as atomic clusters) has the advantage that after the first initial beam output from the clock laser source 1 enters the quantum control module 3, only a light-transmitting aperture facing the target detection material needs to be opened on the quantum control module 3 to realize interrogation, thereby reducing the complexity of the mechanical structure of the quantum control module 3.

[0055] It should be noted that in the subsequent embodiments of this application Figure 3 The specific structure of the beam splitting and combining unit 303 will be described in detail.

[0056] A6, the beam output from the third port 3033 of the beam splitting and combining unit 303 is transmitted to the first port 3041 of the optical power detector 304. After detecting the beam, the optical power detector 304 converts the detected light intensity into a first electrical signal, which is transmitted outward from the second port 3042 of the optical power detector 304. At the same time, the beam output from the fourth port 3034 of the beam splitting and combining unit 303 is transmitted to the first port 3061 of the beat frequency detector 306. The beat frequency detector 306 processes the beam output from the beam splitting and combining unit 303 and the reference beam output from the phase matching module 4 to obtain the beat frequency signal.

[0057] The optical power detector 304 includes a photodiode, which uses the photoelectric effect to convert the laser power signal into a corresponding first electrical signal with a bandwidth greater than 100kHz.

[0058] A7, the first electrical signal output from the second port 3042 of the optical power detector 304 enters the PID servo control unit 305 through the first port 3051 of the PID servo control unit 305. The PID servo control unit 305 performs a PID algorithm on the first electrical signal to generate a first control signal. The first control signal is transmitted outward from the second port 3052 of the PID servo control unit 305 and enters the frequency shift modulation unit 301 through the third port 3013 of the frequency shift modulation unit 301. The PID servo control unit 305 can be a digital PID board or an analog PID board with a bandwidth greater than 100kHz to achieve laser power stabilization.

[0059] Simultaneously, the beat frequency signal is output from the third port 3063 of the beat frequency detector 306 to the first port 3071 of the frequency division phase-locked servo control unit 307. The frequency division phase-locked servo control unit 307 performs servo calculation on the beat frequency signal to generate a second control signal. The second control signal is transmitted outward from the second port 3072 of the frequency division phase-locked servo control unit 307 and enters the frequency shift modulation unit 301 through the fourth port 3014 of the frequency shift modulation unit 301.

[0060] The frequency division phase-locked servo control unit 307 consists of a phase-locked board with frequency division function, used to divide the beat frequency signal and then phase-lock it with a reference signal. Specifically, the phase-locked board in the frequency division phase-locked servo control unit 307 is used to divide the beat frequency signal by a positive even number.

[0061] In this application, the reference beam is represented as cos(ω0t), where ω0 is the frequency of the reference beam and t is time; the clock laser injected into the atomic group for probing is represented as cos[(ω0+ωt)]. d )t+θ(t)], where ω0 is the frequency of the reference beam, ω d Let θ(t) be the frequency shift frequency, and θ(t) be the phase noise of the link. The beat frequency signal between the clock laser injected into the atomic cluster for interrogation and the reference beam is represented as the clock laser interrogating the atomic cluster. The beat frequency signal is divided N times (N is a positive even number) by the phase-locked loop board in the frequency division phase-locked servo control unit 307 to obtain the N-division signal, which is represented as cos{[ω] d The radio frequency reference signal is expressed as cos(ωt)[t+θ(t)] / N}; ref t), where ω ref Given the frequency of the RF reference signal, after using a phase-locked loop (PLL) board to lock the N-division signal to the RF reference signal, we obtain [ω]. d t+θ(t)] / N=ωref t+mπ, where m is an integer.

[0062] From the formula [ω d t+θ(t)] / N=ω ref From t+mπ, we know that when N is a positive odd number, and m jumps between odd and even numbers, the clock laser will exhibit a π-phase jump problem; since N is a positive even number, the clock laser is cos(ω0t+Nω ref The phase is stable, eliminating the π phase jump problem. This application uses a phase-locked loop (PLL) board in the frequency division phase-locked servo control unit 307 to perform positive even-number frequency division on the beat frequency signal, thus solving the problem of probe failure caused by phase jumps during Ramsey probing.

[0063] Upon receiving the first initial beam, the first control signal output by the PID servo control unit 305, and the second control signal output by the frequency division phase-locked servo control unit 307, the frequency shift modulation unit 301 can control the power and frequency of the first initial beam according to the contents recorded in A3-A7, to obtain a third target beam used as a light source for Rabi interrogation and a second target beam used as a light source for Ramsey interrogation; and cause the third target beam and the second target beam to alternately act on the target interrogation substance, such as atomic groups.

[0064] As can be seen from the description of the structure of the clock laser control device 100 and the description of its usage, the clock laser control device disclosed in this application is compatible with both Rabi and Ramsey probing methods; it solves the problem of phase transition of Ramsey probing pulses in existing optical clock systems and the problem that Ramsey probing is incompatible with Rabi probing optical schemes. At the same time, the clock laser control device 100 meets the miniaturization requirements of optical clock systems.

[0065] Figure 2 This is a schematic diagram of a beam-splitting unit provided in an embodiment of this application. Below, in conjunction with… Figure 2 Regarding this application Figure 1 The structure of the mid-splitter combination unit 303 is described in detail.

[0066] Combination Figure 2 As shown, incident on Figure 2 The propagation path of the first target beam in the beam splitting unit 303 is indicated by a green arrow, and the propagation path of the second target beam is indicated by a red arrow; the beam splitting unit 303 includes: a first branch optical path, a second branch optical path, a third branch optical path, and a fourth branch optical path.

[0067] The first branch optical path includes a first polarizing beam splitter, a first non-polarizing beam splitter, an attenuator, a first reflecting mirror, and a second non-polarizing beam splitter; the second branch optical path includes a first polarizing beam splitter, a first non-polarizing beam splitter, a second reflecting mirror, and a third non-polarizing beam splitter; the third branch optical path includes a second polarizing beam splitter and a second non-polarizing beam splitter; and the fourth branch optical path includes a second polarizing beam splitter, a second non-polarizing beam splitter, and a third non-polarizing beam splitter.

[0068] The first target beam propagates along the first branch beam, passing sequentially through the first polarizing beam splitter, the first unpolarizing beam splitter, the attenuator, the first reflecting mirror, and the second unpolarizing beam splitter before acting on the target probing substance. The intensity of the first target beam weakens after passing through the attenuator, becoming the third target beam, which is used as the light source for Rabi probing.

[0069] The first target beam propagates along the second branch optical path, passing sequentially through the first polarizing beam splitter, the first unpolarizing beam splitter, the second reflector, and the third unpolarizing beam splitter, before acting on the optical power detector and the beat frequency detector.

[0070] The second target beam propagates along the third branch optical path, passes sequentially through the second polarizing beam splitter and the second unpolarizing beam splitter, and acts on the target probing substance; the second target beam is used as the light source for Ramsey probing.

[0071] The second target beam propagates along the fourth branch optical path, passing sequentially through the second polarizing beam splitter, the second unpolarizing beam splitter, and the third unpolarizing beam splitter, before acting on the optical power detector and the beat frequency detector.

[0072] Figure 3 This is a schematic diagram of a phase elimination module provided in an embodiment of this application. Below, in conjunction with... Figure 3 As shown, for Figure 1 The structure of the phase elimination module 4 in the middle is described in detail.

[0073] Combination Figure 3 As shown, the phase cancellation module 4 includes a first direction control unit, a second direction control unit, and a phase locking unit;

[0074] The first direction control unit is used to control the propagation direction of the second initial beam, so that the second initial beam is transmitted to the phase locking unit;

[0075] The second direction control unit is used to control the propagation direction of the second initial beam carrying noise, so that the second initial beam carrying noise is transmitted to the phase locking unit.

[0076] A phase-locking unit is used to generate a reference beam based on a radio frequency reference signal, a second initial beam, and a second initial beam carrying noise.

[0077] The first direction control unit includes a half-wave plate, a third polarizing beam splitter, and a polarizer; the second initial beam passes sequentially through the half-wave plate, the third polarizing beam splitter, and the polarizer before being transmitted to the phase-locking unit.

[0078] The second directional control unit includes a half-wave plate, a third polarizing beam splitter, an acousto-optic modulator, a first quarter-wave plate, a semi-transparent mirror, a second quarter-wave plate, a total reflection mirror, and a polarizer. The second initial beam passes sequentially through the half-wave plate, the third polarizing beam splitter, the acousto-optic modulator, and the first quarter-wave plate before being transmitted to the semi-transparent mirror. The transmitted beam through the semi-transparent mirror in the second initial beam is used as a reference beam. The reflected beam in the second initial beam, reflected by the semi-transparent mirror, passes sequentially through the first quarter-wave plate, the acousto-optic modulator, the third polarizing beam splitter, and the second quarter-wave plate before being transmitted to the total reflection mirror. The reflected beam, after being reflected by the total reflection mirror, passes sequentially through the second quarter-wave plate, the third polarizing beam splitter, and the polarizer before being transmitted to the phase-locking unit.

[0079] The phase-locked unit includes an RF reference source (outputting an RF reference signal), a target beat detector, a mixer, a PID board, and an RF driver.

[0080] Combination Figure 3 As shown, the output port of the RF reference source is connected to the first port m1 of the mixer, the output port of the target beat detector is connected to the second port m2 of the mixer, the third port m3 of the mixer is connected to the first port d1 of the PID board, the second port d2 of the PID board is connected to the first port s1 of the RF driver, and the second port s2 of the RF driver is connected to the acousto-optic modulator.

[0081] A target beat frequency detector is used to detect the second initial beam to obtain a first target detection signal; it also detects the second initial beam carrying noise to obtain a second target detection signal; the first and second target detection signals are transmitted to a mixer, which mixes the two signals and extracts the difference frequency error signal reflecting the noise; a PID board calculates the control quantity based on the error signal and outputs an adjustment command; an RF driver adjusts the frequency or amplitude of the high-frequency drive signal according to the adjustment command; an acousto-optic modulator modulates the second initial beam under the action of the drive signal to cancel the noise effect; the modulated beam is detected again to form a closed loop, and finally a stable reference beam is output.

[0082] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the method embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The method embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate. The components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0083] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A clock laser control device, characterized in that, The clock laser control device includes: a clock laser source, a laser beam splitting module, a quantum state probing and control module, and a phase elimination module; The clock laser source is connected to the first port of the laser beam splitter module; the second port of the laser beam splitter module is connected to the first port of the quantum state interrogation and control module; the third port of the laser beam splitter module is connected to the first port of the phase elimination module; and the second port of the phase elimination module is connected to the second port of the quantum state interrogation and control module. The laser beam splitting module is used to split the initial beam output by the clock laser source into a first initial beam and a second initial beam. The phase cancellation module is used to perform phase locking on the received second initial beam to generate a reference beam; The quantum state interrogation and control module is used to generate a modulated beam based on the first initial beam and the reference beam; to perform time-series control on the propagation direction of the modulated beam to obtain an alternately output first target beam and second target beam; to attenuate the light intensity of the first target beam to obtain a third target beam; and to control both the third target beam and the second target beam to be output from the third port of the quantum state interrogation and control module; the third target beam is used as a Rabi interrogation light source, and the second target beam is used as a Ramsey interrogation light source.

2. The clock laser control device according to claim 1, characterized in that, The quantum state probing and control module includes: a frequency shifting modulation unit, a beam switching unit, a beam splitting and combining unit, an optical power detector, a PID servo control unit, a beat frequency detector, and a frequency division phase-locked servo control unit; The first port of the frequency shift modulation unit is the first port of the quantum state probing and control module; the second port of the frequency shift modulation unit is connected to the first port of the beam switching unit; the second port of the beam switching unit is connected to the first port of the beam splitting and combining unit; the third port of the beam switching unit is connected to the second port of the beam splitting and combining unit. The third port of the beam splitting and combining unit is connected to the first port of the optical power detector; the second port of the optical power detector is connected to the first port of the PID servo control unit; and the second port of the PID servo control unit is connected to the third port of the frequency shift modulation unit. The fourth port of the beam splitting unit is connected to the first port of the beat frequency detector; the second port of the beat frequency detector is the second port of the quantum state interrogation and control module; the third port of the beat frequency detector is connected to the first port of the frequency division phase-locked servo control unit; and the second port of the frequency division phase-locked servo control unit is connected to the fourth port of the frequency shift modulation unit.

3. The clock laser control device according to claim 2, characterized in that, Each unit in the quantum state probing and control module is specifically used for: The frequency shift modulation unit is used to modulate the first initial beam according to the first control signal output by the PID servo control unit and the second control signal output by the frequency division phase-locked servo control unit to generate the modulated beam. The beam switching unit is used to time-control the propagation direction of the modulated beam, so that the modulated beam can be periodically switched between the two optical paths to obtain the first target beam and the second target beam that are output alternately. The beam splitting and combining unit is used to attenuate the intensity of the first target beam to obtain the third target beam; and to control both the third target beam and the second target beam to be output from the third port of the quantum state probing and control module. The optical power detector is used to detect the second target beam or the third target beam to obtain a first detection signal; The PID servo control unit is used to generate the first control signal based on the first detection signal; The beat frequency detector is used to detect the second target beam or the third target beam to obtain a second detection signal; to detect the reference beam to obtain a third detection signal; and to obtain a beat frequency signal based on the second detection signal and the third detection signal. The frequency division phase-locked servo control unit is used to generate the second control signal based on the beat frequency signal.

4. The clock laser control device according to claim 2, characterized in that, The beam switching unit is a free-space dual mechanical gate optical switch, a fiber optic microelectromechanical optical switch, or a dual acousto-optic modulator optical switch.

5. The clock laser control device according to claim 2, characterized in that, The beam splitting and combining unit includes: a first branch optical path, a second branch optical path, a third branch optical path, and a fourth branch optical path; The first branch optical path includes a first polarizing beam splitter, a first unpolarizing beam splitter, an attenuator, a first reflector, and a second unpolarizing beam splitter; The second branch optical path includes the first polarizing beam splitter, the first unpolarizing beam splitter, the second reflecting mirror, and the third unpolarizing beam splitter; The third branch optical path includes a second polarizing beam splitter and a second non-polarizing beam splitter; The fourth branch optical path includes the second polarizing beam splitter, the second unpolarizing beam splitter, and the third unpolarizing beam splitter; The first target beam is transmitted along the first branch beam and passes sequentially through the first polarizing beam splitter, the first unpolarizing beam splitter, the attenuator, the first reflector and the second unpolarizing beam splitter to act on the target probing substance. The first target beam propagates along the second branch optical path, and sequentially passes through the first polarizing beam splitter, the first unpolarizing beam splitter, the second mirror and the third unpolarizing beam splitter, and acts on the optical power detector and the beat frequency detector; The second target beam is transmitted along the third branch optical path, and passes sequentially through the second polarizing beam splitter and the second unpolarizing beam splitter to act on the target probing substance; The second target beam is transmitted along the fourth branch optical path, and passes sequentially through the second polarizing beam splitter, the second unpolarizing beam splitter, and the third unpolarizing beam splitter before acting on the optical power detector and the beat frequency detector.

6. The clock laser control device according to claim 3, characterized in that, The phase-locked loop board in the frequency division phase-locked servo control unit is used to divide the beat frequency signal into positive even numbers.

7. The clock laser control device according to claim 1, characterized in that, The phase cancellation module includes: a first direction control unit, a second direction control unit, and a phase locking unit; The first direction control unit is used to control the propagation direction of the second initial beam, so that the second initial beam is transmitted to the phase locking unit; The second direction control unit is used to control the propagation direction of the second initial beam carrying noise, so that the second initial beam carrying noise is transmitted to the phase locking unit; The phase-locking unit is used to generate the reference beam based on the radio frequency reference signal, the second initial beam, and the second initial beam carrying noise.

8. The clock laser control device according to claim 7, characterized in that, The first direction control unit includes a half-wave plate, a third polarizing beam splitter, and a polarizer; The second initial beam passes sequentially through the half-wave plate, the third polarizing beam splitter, and the polarizer before being transmitted to the phase-locking unit.

9. The clock laser control device according to claim 8, characterized in that, The second direction control unit includes: the half-wave plate, the third polarizing beam splitter, an acousto-optic modulator, a first quarter-wave plate, a semi-reflective mirror, a second quarter-wave plate, a total reflection mirror, and the polarizer; The second initial beam passes sequentially through the half-wave plate, the third polarizing beam splitter, the acousto-optic modulator, and the first quarter-wave plate before being transmitted to the half-reflective lens; The transmitted beam through the semi-reflective lens in the second initial beam is used as the reference beam. The reflected beam reflected by the semi-reflective lens in the second initial beam is transmitted to the total reflection mirror after passing through the first quarter-wave plate, the acousto-optic modulator, the third polarizing beam splitter, and the second quarter-wave plate in sequence. After being reflected by the total reflection mirror, the reflected beam is transmitted sequentially through the second quarter-wave plate, the third polarizing beam splitter, and the polarizer to the phase-locking unit.

10. The clock laser control device according to claim 9, characterized in that, The phase-locking unit includes: an RF reference source, a target beat detector, a mixer, a PID board, and an RF driver; The output port of the RF reference source is connected to the first port of the mixer; the output port of the target beat detector is connected to the second port of the mixer; the third port of the mixer is connected to the first port of the PID board; the second port of the PID board is connected to the first port of the RF driver; and the second port of the RF driver is connected to the acousto-optic modulator. The target beat frequency detector is used to detect the second initial beam to obtain a first target detection signal; to detect the second initial beam carrying noise to obtain a second target detection signal; and to transmit the first target detection signal and the second target detection signal to the mixer.

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