An apparatus and method for cold atom laser power stabilization

Abstract

The application relates to a device and method for cold atom laser power stabilization, belonging to the field of cold atoms. The device for cold atom laser power stabilization comprises a laser generating unit, an acousto-optic modulator, an acousto-optic modulator driving module and a power stabilization unit. Laser output by the laser generating unit is modulated by the acousto-optic modulator and then enters the power stabilization unit, the power stabilization unit feeds back to the acousto-optic modulator driver to complete feedback of laser power and realize laser power stabilization. A timing control unit controls the state selection module through instructions to trigger real-time control of the switching of timing states. The power stabilization unit further comprises an arbitrary function generating module, the arbitrary function generating module generates an arbitrary waveform function image as a reference signal, the laser power is locked on the reference signal by the power stabilization unit, and arbitrary function image locking of the laser power is completed. The application has the advantages of high reliability, high stability, short locking time, easy operation and the like.

Description

Technical Field

[0001] This invention belongs to the field of cold atoms and relates to a device and method for stabilizing the power of cold atom lasers. Background Technology

[0002] In the field of cold atoms, fluctuations in optical power can affect measurement accuracy. It plays a crucial role in areas such as cold atom quantum simulation, computation, and precision measurement.

[0003] Current laser power locking techniques used in cold atom measurements typically employ analog or digital circuits. Most techniques utilize slow-loop feedback with locking times generally on the order of milliseconds, failing to achieve μs-level locking during cold atom measurements. Furthermore, laser power ratios can exceed 1:10 within the measurement cycle, making it difficult for traditional single-loop power feedback circuits to lock power under such rapid and varied conditions, and their primary purpose is often to suppress long-term drift. In cold atom measurements, real-time laser state locking, where laser power continuously changes during the measurement process, is a significant challenge and a key research area. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for stabilizing the power of cold atom lasers. This method enables feedback of laser power in the cold atom field to achieve laser power stability and suppresses the effects caused by optical power fluctuations. This invention has advantages such as high reliability, high stability, short lock-up time, and ease of operation.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention discloses a device for stabilizing the power of a cold atom laser, comprising a laser generating unit, an acousto-optic modulator, an acousto-optic modulator driver, and a power stabilization unit. The laser output from the laser generating unit is modulated by the acousto-optic modulator and then enters the power stabilization unit. The power stabilization unit feeds back to the acousto-optic modulator driver to complete the feedback of laser power and achieve laser power stabilization.

[0007] The timing control unit sends instructions to the state selection module via command control, and triggers real-time control of the switching of timing states.

[0008] The power stabilization unit includes a photodiode, an AD acquisition module, a digital filtering module, a timing control unit, a digital PID feedback module, and a DA output module. The photodiode converts the optical signal into an electrical signal, which is then acquired by the AD acquisition module. After passing through the digital filtering module, the signal is controlled by the laser control timing module. The regulated laser then enters the digital PID module, and the DA output module outputs a signal to control the laser power.

[0009] The power stabilization unit also includes an arbitrary function generation module. The arbitrary function generation module generates a function image of arbitrary waveform as a reference signal. The power stabilization unit locks the laser power onto the reference signal, thereby completing the arbitrary function image locking of the laser power and suppressing long-term fluctuations in optical power.

[0010] The timing control unit is used to achieve short-time laser power stabilization and slow-loop PID feedback locking for cold atoms. The laser output from the laser generator unit is modulated by an acousto-optic modulator before entering the timing control module. The output laser passes through a photodiode, is acquired by an AD acquisition module, and fed back to the digital PID feedback module. The DA output module then outputs the DA value to the acousto-optic modulator driver to lock the laser power. After conversion, different timing controls are used to lock the long-pulse laser power. Then, the DA output module is fixed to output a fixed DA value during the short-pulse timing. The DA output is corrected in each cycle to stabilize the short-pulse laser power. In the acousto-optic modulator driver, a mixer is used instead of a voltage-controlled attenuator. The mixer is a passive device, which can solve the problem of slow response of active devices and achieve microsecond-level optical power stabilization.

[0011] This invention discloses a method for stabilizing the power of a cold atom laser, implemented based on the aforementioned apparatus for stabilizing the power of a cold atom laser. The method for stabilizing the power of a cold atom laser is implemented as follows:

[0012] In the laser control timing, the initial state is the first timing state. When a control command is received, the state is reversed to the second timing state. Digital PID feedback is performed in different timing states, and different DA values ​​are output to complete the laser timing reversal.

[0013] In cold atom experiments, laser power is not constant and often needs to be varied by function. This invention adds an arbitrary function generation module on the basis of time-sequence flipping, and completes the scanning of laser power by scanning acousto-optic modulator driver. At this time, the laser power is stabilized by power stabilization unit.

[0014] Beneficial effects:

[0015] 1. This invention discloses a device and method for stabilizing cold atom laser power. It employs a multi-channel AD acquisition and multi-channel DA output working mode to address the need for one or more photodiodes to provide feedback to a multi-channel acousto-optic modulator driver in different operating states within the cold atom measurement field. Depending on the measurement requirements, it can switch between multi-channel AD acquisition with single-channel DA output or single-channel AD acquisition with multiple-channel DA output modes to meet the different laser power requirements at different stages of cold atom measurement.

[0016] 2. In cold atom measurement timing, it is necessary to lock the laser power to different reference values. Using a single set of PID parameters can lead to deterioration of locking noise. This invention discloses a device and method for stabilizing cold atom laser power. It employs a state-flipping function, using corresponding PID parameters in different states to lock the laser power, and locks the laser power as a function graph based on the timing state. This invention can significantly reduce locking noise and improve the stability of the cold atom laser power stabilization device.

[0017] 3. This invention discloses a device and method for stabilizing cold atom laser power. It employs different timing control sequences to lock the power of long-pulse lasers and then fixes the output DA module to maintain a fixed output DA value during short-pulse timing. Each cycle corrects the DA output to achieve short-pulse laser power stabilization. In the acousto-optic modulator driver, a mixer replaces the voltage-controlled attenuator. The mixer, being a passive device, solves problems such as slow response of active devices, achieving microsecond-level optical power stabilization.

[0018] 4. This invention discloses a device and method for stabilizing cold atom laser power. An arbitrary function generation module generates an arbitrary waveform function image as a reference signal. The power stabilization unit locks the laser power onto the reference signal, completing arbitrary function image locking of the laser power and suppressing long-term optical power fluctuations. A photodiode converts the optical signal into an electrical signal, which is then acquired by an AD acquisition module, filtered by a digital filter module, and controlled by a laser control timing module. The regulated laser then enters a digital PID module, where a DA module outputs a signal to control the laser power. This invention provides better stability and higher sampling and calculation accuracy. Attached Figure Description

[0019] Figure 1 This invention provides an example structural block diagram of a device for stabilizing the power of a short-pulse cold atom laser.

[0020] Figure 2 An example structural block diagram of a laser power stabilization device provided by the present invention;

[0021] Figure 3 This invention provides an example structural block diagram of a device for stabilizing the laser power of multiple AD acquisition and multiple DA outputs.

[0022] Figure 4 A structural block diagram illustrating an example of a method for stabilizing short-pulse laser power provided by the present invention;

[0023] Figure 5 A block diagram of the laser power state reversal structure provided by the present invention;

[0024] Figure 6 A block diagram of the power-locked structure for arbitrary function of laser power provided by the present invention;

[0025] In the diagram: 10—Laser generating unit, 20—Acousto-optic modulator, 30—Power stabilization unit, 40—Acousto-optic modulator driver, 31—Photodiode, 32—AD acquisition module, 33—Digital filter, 34—Digital PID feedback control unit, 35—DA output module, 100—Laser power control timing, 101—Command control, 102—State selection module, 103—First timing state, 104—Second timing state, 105—Nth timing state, 200—Arbitrary function generating module. Detailed Implementation

[0026] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.

[0027] Example 1:

[0028] like Figure 1 As shown, this embodiment discloses a method for stabilizing the power of a cold atom laser, comprising a laser generating unit 10, an acousto-optic modulator 20, an acousto-optic modulator driver 40, and a power stabilization unit 30. The laser output from the laser generating unit 10 is modulated by the acousto-optic modulator 20 and then enters the power stabilization unit 30. The power stabilization unit feeds back to the acousto-optic modulator driver 40 to complete the feedback of laser power and achieve laser power stabilization. The power stabilization unit is twice the size of a standard VPX architecture 3U board.

[0029] The laser power control timing module 100 sends instructions to the state selection module 102 through the instruction control 101, thereby triggering the switching of the real-time control timing state.

[0030] The power stabilization unit 30 further includes an arbitrary function generation module 200. The arbitrary function generation module 200 generates an arbitrary waveform function image as a reference signal. The power stabilization unit 30 locks the laser power to the reference signal, completing the arbitrary function image locking of the laser power and suppressing long-term optical power fluctuations. The locking speed is less than 10.

[0031] μs, and the optical power fluctuation over 15 hours is less than 0.8%.

[0032] The power stabilization unit 30 includes a photodiode 31, an AD acquisition module 32, a digital filtering module 33, a laser power control timing module 100, a digital PID feedback module 34, and a DA output module 35. The photodiode 31 converts the optical signal into an electrical signal, which is then acquired by the AD acquisition module 32, filtered by the digital filtering module 33, controlled by the laser control timing module, and the regulated laser power enters the digital PID module 34. The DA output module 35 outputs a signal to complete the laser power control.

[0033] The laser power control timing module 100 is used to achieve short-time laser power stabilization and slow-loop PID feedback locking in cold atom lasers. After light enters the laser power control timing module 100, different timing controls are used to complete long-pulse laser power locking, and then the DA output module is fixed to output a fixed DA value during the short-pulse timing. The DA output is corrected in each cycle to complete short-pulse laser power stabilization. In the acousto-optic modulator driver, a mixer is used instead of a voltage-controlled attenuator. The mixer is a passive device, which can solve the problem of slow response of active devices and can suppress optical power stabilization on the order of 5µs.

[0034] This embodiment discloses a method for stabilizing the power of cold atom lasers, and the implementation method is as follows:

[0035] The laser generating unit produces laser light, which is modulated by an acousto-optic modulator and then enters the laser power control timing module 100. In the laser power control timing module 100, because the optical pulse duration is too short, a longer pulse is added in the subsequent timing sequence, such as the second timing state 104. The optical signal is collected by the photodiode 31, completing the conversion from optical signal to electrical signal. The AD acquisition module 32 acquires the electrical signal and, after passing through the digital PID module 34, calculates and records the DA output value after the laser power has stabilized. In the next cycle, the DA output module 35 outputs the electrical signal recorded in the previous cycle, which is then input to the acousto-optic modulator driver to lock the optical power of the short pulse, thereby suppressing long-term fluctuations in optical power. The initial state of the laser power control timing module 100 is the first timing state 103. When a command control 101 is received, the state is reversed to the second timing state 104. Digital PID feedback 34 is performed in different timing states to output different DA values, completing the laser timing reversal.

[0036] In cold atom experiments, laser power is not constant and often needs to be varied by function. This invention adds an arbitrary function generation module 200 to the time-flipping mechanism. The laser power is scanned by scanning acousto-optic modulator driver, and then stabilized by power stabilization unit.

[0037] In the laser control timing, the initial state is the first timing state. When a control command is received, the state is reversed to the second timing state. Digital PID feedback is performed in different timing states to output different DA values ​​to complete the laser timing reversal.

[0038] The above-described specific details further elaborate on the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is merely a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for stabilizing the power of a cold atom laser, characterized in that, It includes a laser generating unit (10), an acousto-optic modulator (20), an acousto-optic modulator driving module (40), and a power stabilization unit (30); the laser output from the laser generating unit (10) is modulated by the acousto-optic modulator (20) and then enters the power stabilization unit (30). The power stabilization unit feeds back to the acousto-optic modulator driving module (40) to complete the feedback of laser power and realize laser power stabilization. The power stabilization unit (30) includes a photodiode (31), an AD acquisition module (32), a digital filtering module (33), a laser power control timing module (100), a digital PID feedback module (34), and a DA output module (35). The photodiode (31) converts the optical signal into an electrical signal, which is then acquired by the AD acquisition module (32). After passing through the digital filtering module (33), the signal is controlled by the laser control timing module (100). The laser signal after regulation enters the digital PID feedback module (34), and the laser power is controlled by the DA output module (35). The power stabilization unit (30) further includes an arbitrary function generation module (200). The arbitrary function generation module (200) generates a function image of arbitrary waveform as a reference signal. The power stabilization unit (30) locks the laser power on the reference signal, thereby completing the arbitrary function image locking of the laser power and suppressing long-term fluctuations in optical power. The laser power control timing module (100) sends instructions to the state selection module (102) through instruction control (101) to trigger the switching of the real-time control timing state.

2. The device for stabilizing the power of a cold atom laser according to claim 1, characterized in that, The laser power control timing module (100) is used to achieve short-time laser power stabilization and slow-loop PID feedback locking of cold atoms. After the light enters the laser power control timing module (100), different timing control is adopted to complete the long-pulse laser power locking. Then, the DA output module (35) is fixed to fix the output DA value during the short-pulse timing. The DA output is corrected in each cycle to complete the short-pulse laser power stabilization. In the acousto-optic modulator drive module (40), a mixer is used instead of a voltage-controlled attenuator. The mixer is a passive device.

3. A method for stabilizing the power of a cold atom laser, implemented according to the apparatus for stabilizing the power of a cold atom laser as described in claim 1 or 2, characterized in that, The implementation method is as follows: In the timing control unit (100), the initial state is in the first timing state (103). When the command control (101) is received, the state is reversed to the second timing state (104). Digital PID feedback is performed in different timing states to output different DA values ​​to complete the flipping of the laser timing. In cold atom experiments, the laser power undergoes functional changes. Based on the time-reversal, an arbitrary function generation module (200) is added. The laser power is scanned by scanning acousto-optic modulator driver based on the arbitrary function generation module (200), and the laser power is stabilized by power stabilization unit (30).

Images