High-sensitivity miniaturized atom magnetometer control method

Abstract

A high-sensitivity miniaturized atom magnetometer control method is favorable for guaranteeing long-time stable measurement and magnetic field measurement precision of a miniaturized atom magnetometer, and comprises the following steps: step 1, a control module is arranged in an atom magnetometer system, the control module is integrated with a constant-current control module, a current detection module, a temperature acquisition module and a temperature control module, and the constant-current control module, the current detection module, the temperature acquisition module and the temperature control module are connected with the control module; the first VCSEL laser and the second VCSEL laser are respectively connected with the differential amplifier through the upper computer; 2, the upper computer is started to work, PID parameters are set and controlled, the working current is set, and the expected temperature is set; 3, the constant current control module provides stable driving current, the temperature acquisition module acquires the working temperature, and the temperature control module performs closed-loop control on the working temperature by using a PID algorithm; 4, the upper computer scans the temperature parameters and draws images in real time, and scans the current parameters and draws images in real time; and step 5, the upper computer forms current closed-loop control by using a constant-current control module according to the current detected by the current detection module.

Description

Technical Field

[0001] This invention relates to the field of atomic magnetometer technology, and in particular to a control method for a high-sensitivity miniaturized atomic magnetometer. Background Technology

[0002] High-precision weak magnetic field measurements have wide applications in fields such as biomagnetic field detection, geomagnetic exploration, deep space magnetic exploration, and magnetic anomaly detection. Spin-Exchange Relaxation Free Regime (SERF) atomic magnetometers possess extremely high theoretical sensitivity; however, the magnetic field measurement sensitivity of current single-beam SERF atomic magnetometers is nearing its limit, making significant improvements difficult. Therefore, a miniaturized atomic magnetometer control method with high measurement sensitivity is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a control method for a high-sensitivity miniaturized atomic magnetometer. By setting up a control module to perform current closed-loop control and temperature closed-loop control on the first and second VCSEL lasers in the atomic magnetometer system, it is beneficial to ensure the long-term stable measurement and magnetic field measurement accuracy of the miniaturized atomic magnetometer.

[0004] The technical solution of the present invention is as follows:

[0005] A control method for a high-sensitivity miniaturized atomic magnetometer, characterized by comprising the following steps:

[0006] Step 1: Set up a control module in the atomic magnetometer system. The control module integrates a constant current control module, a current detection module, a temperature acquisition module, and a temperature control module. The control module is connected to a first VCSEL laser for providing detection light and a second VCSEL laser for providing pump light. The constant current control module, current detection module, temperature acquisition module, and temperature control module are all connected to the differential amplifier at the end of the detection optical path through a host computer.

[0007] Step 2: The host computer starts working, sets the control PID parameters, sets the operating current, and sets the desired temperature;

[0008] Step 3: The constant current control module provides stable drive current to the first VCSEL laser and the second VCSEL laser respectively according to the set operating current. The current detection module detects the magnitude and stability of the stable drive current. The temperature acquisition module acquires the operating temperature of the first VCSEL laser and the second VCSEL laser respectively. The temperature control module uses a PID algorithm to perform closed-loop control on the operating temperature.

[0009] Step 4: The host computer scans the temperature parameters and draws images in real time as a reference for adjusting the temperature PID parameters of the first VCSEL laser and the second VCSEL laser. The host computer receives the output signal of the differential amplifier, scans the current parameters and draws images in real time as a reference for adjusting the power closed-loop PID parameters of the first VCSEL laser and the second VCSEL laser.

[0010] Step 5: The host computer uses the constant current control module to form a current closed-loop control for the first VCSEL laser and the second VCSEL laser based on the current magnitude detected by the current detection module.

[0011] The constant current control module in step 1 includes a power management chip with internal soft start, thermal shutdown and current limiting; the temperature acquisition module includes an NTC temperature acquisition circuit and a temperature ADC chip; the current detection module includes an inverting amplifier circuit and a current ADC chip; and the temperature control module includes a TEC control chip.

[0012] Step 3, closed-loop control of the operating temperature, includes: the temperature acquisition module converts temperature changes into digital signals through the NTC temperature acquisition circuit and the temperature ADC chip; the temperature control module acquires the digital signals from the temperature ADC chip through the FPGA chip and performs PID calculations; controls the DAC chip to change the output voltage; and controls the TEC control chip to drive the TEC to change the operating temperature of the VCSEL laser.

[0013] Step 5, the current closed-loop control, includes: the constant current control module acquires the digital signal from the current ADC chip in the current detection module through the FPGA chip and performs PID calculation, and controls the DAC chip to change the constant current output by the power management chip, thus forming a current closed-loop control.

[0014] In step 1, the detection optical path of the atomic magnetometer system includes a first VCSEL laser, a first collimating lens, a first polarization beam splitter, a rubidium atom gas cell in the magnetic field modulation coil, a λ / 2 waveplate, and a second polarization beam splitter connected in sequence. The transmission side of the second polarization beam splitter is connected to the first input terminal of the differential amplifier through a first photodetector, and the reflection side of the second polarization beam splitter is connected to the second input terminal of the differential amplifier through a second photodetector. The output terminal of the differential amplifier is connected to a host computer.

[0015] In step 1, the pump optical path of the atomic magnetometer system includes a second VCSEL laser, a second collimating lens, a combined prism, and a rubidium atom gas cell in a magnetic field modulation coil, which are connected in sequence.

[0016] The technical effects of this invention are as follows: The high-sensitivity miniaturized atomic magnetometer control method of this invention can improve the light output quality of VCSEL laser and improve the magnetic field measurement sensitivity of miniaturized atomic magnetometer by realizing closed-loop control of VCSEL laser current and closed-loop control of temperature. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the atomic magnetometer system structure involved in the high-sensitivity miniaturized atomic magnetometer control method of the present invention.

[0018] Figure 2 yes Figure 1 Diagram showing the connection between the laser and the control module.

[0019] Figure 3 yes Figure 1 Schematic diagram of the control module structure.

[0020] Figure 4 This is a flowchart illustrating the control method for the high-sensitivity miniaturized atomic magnetometer of the present invention. Figure 4 The process includes the following steps: Step 1: The host computer starts working, sets the control PID parameters (PID, Proportional-Integral-Derivative), sets the operating current, scans the current parameters to draw a real-time image, sets the desired temperature, obtains the resistance value of the temperature measuring resistor, and scans the temperature parameters to draw a real-time image; Step 2: A power management chip with internal soft-start, thermal shutdown, and current limiting provides a safe and stable constant current to the VCSEL laser (VCSEL, Vertical-Cavity Surface-Emitting Laser); Step 3: The VCSEL laser is connected to an inverting amplifier circuit and an ADC chip to output current sampling signals (ADC, Analog-to-Digital Converter), and connected to an NTC temperature acquisition circuit and an ADC chip to output temperature sampling signals (NTC, Negative Temperature Coefficient); Step 4: The FPGA chip receives the current sampling signals and temperature sampling signals through the ADC chip (FPGA, Field Programmable Gate). The array (Field Programmable Gate Array) performs PID calculations (PID, Proportional-Integral-Derivative) and outputs control signals to the ADC chip; in step 5, the ADC chip outputs signals to the power management chip to change the current supplied to the VCSEL laser, forming a current closed-loop control, and outputs signals to the TEC control chip to control the operation of the TEC (Thermoelectric Cooler), forming a temperature closed-loop control.

[0021] The reference numerals in the attached figures are explained as follows: 1-Control module; 2-First VCSEL laser (VCSEL, Vertical-Cavity Surface-Emitting Laser); 3-Second VCSEL laser; 4-First collimating lens; 5-Second collimating lens; 6-First polarization beam splitter; 7-Combined prism; 8-Magnetic field modulation coil; 9-Rubydium atom gas cell; 10-λ / 2 waveplate; 11-Second polarization beam splitter; 12-First photodetector; 13-Second photodetector; 14-Differential amplifier; 15-Host computer; 16-Constant current control module; 17-Current detection module; 18-Temperature acquisition module; 19-Temperature control module. Detailed Implementation

[0022] The following is in conjunction with the attached diagram ( Figures 1-4 The present invention will be described in conjunction with the examples.

[0023] Figure 1 This is a schematic diagram of the atomic magnetometer system structure involved in the high-sensitivity miniaturized atomic magnetometer control method of the present invention. Figure 2 yes Figure 1 Diagram showing the connection between the laser and the control module. Figure 3 yes Figure 1 Schematic diagram of the control module structure. Figure 4 This is a flowchart illustrating the control method for the high-sensitivity miniaturized atomic magnetometer of the present invention. (Reference) Figures 1 to 4As shown, a high-sensitivity miniaturized atomic magnetometer control method includes the following steps: Step 1, setting up a control module 1 in the atomic magnetometer system. The control module 1 integrates a constant current control module 16, a current detection module 17, a temperature acquisition module 18, and a temperature control module 19. The control module 1 is respectively connected to a first VCSEL laser 2 for providing detection light and a second VCSEL laser 3 for providing pump light (VCSEL, Vertical-Cavity Surface-Emitting). Laser (Vertical Cavity Surface Emitting Laser), the constant current control module 16, current detection module 17, temperature acquisition module 18, and temperature control module 19 are all connected to the differential amplifier 14 at the end of the detection optical path via the host computer 15; Step 2, the host computer 15 starts working, sets the control PID parameters (PID, Proportional-Integral-Derivative), sets the operating current, and sets the desired temperature; Step 3, the constant current control module 16 provides stable drive current to the first VCSEL laser 2 and the second VCSEL laser 3 respectively according to the set operating current, the current detection module 17 detects the magnitude and stability of the stable drive current, the temperature acquisition module 18 acquires the operating temperature of the first VCSEL laser 2 and the second VCSEL laser 3 respectively, and the temperature control module 19 uses the PID algorithm to perform closed-loop control of the operating temperature. Step 4: The host computer 15 scans the temperature parameters and plots images in real time as a reference for temperature PID parameter tuning of the first VCSEL laser 2 and the second VCSEL laser 3. The host computer 15 receives the output signal of the differential amplifier 14, scans the current parameters and plots images in real time as a reference for power closed-loop PID parameter tuning of the first VCSEL laser 2 and the second VCSEL laser 3. Step 5: Based on the current magnitude detected by the current detection module 17, the host computer 15 uses the constant current control module 16 to form current closed-loop control for the first VCSEL laser 2 and the second VCSEL laser 3 respectively.

[0024] The constant current control module 16 in step 1 includes a power management chip with internal soft start, thermal shutdown and current limiting. The temperature acquisition module 18 includes an NTC temperature acquisition circuit and a temperature ADC chip (NTC, Negative Temperature Coefficient). The current detection module 17 includes an inverting amplifier circuit and a current ADC chip (ADC, Analog-to-Digital Converter). The temperature control module 19 includes a TEC control chip (TEC, Thermoelectric cooler).

[0025] The closed-loop control of the operating temperature in step 3 includes: the temperature acquisition module 18 converts temperature changes into digital signals through the NTC temperature acquisition circuit and the temperature ADC chip; the temperature control module 19 acquires the digital signals from the temperature ADC chip through the FPGA chip and performs PID calculations; controls the DAC chip to change the output voltage (DAC, Digital-to-Analog Converter); and controls the TEC control chip to drive the TEC to change the operating temperature of the VCSEL laser.

[0026] Step 5, the current closed-loop control includes: the constant current control module 16 acquires the digital signal from the current ADC chip in the current detection module 17 through the FPGA chip and performs PID calculation, and controls the DAC chip to change the constant current output by the power management chip, thus forming a current closed-loop control.

[0027] In step 1, the detection optical path of the atomic magnetometer system includes a first VCSEL laser 2, a first collimating lens 4, a first polarization beam splitter 6, a rubidium atom gas cell 9 in the magnetic field modulation coil 8, a λ / 2 waveplate 10, and a second polarization beam splitter 11 connected in sequence. The transmission side of the second polarization beam splitter 11 is connected to the first input terminal of the differential amplifier 14 through a first photodetector 12, and the reflection side of the second polarization beam splitter 11 is connected to the second input terminal of the differential amplifier 14 through a second photodetector 13. The output terminal of the differential amplifier 14 is connected to a host computer.

[0028] In step 1, the pump optical path of the atomic magnetometer system includes a second VCSEL laser 3, a second collimating lens 5, a combined prism 7, and a rubidium atom gas cell 9 in a magnetic field modulation coil 8, which are connected in sequence.

[0029] This invention provides a high-sensitivity miniaturized atomic magnetometer and its control method. The high-sensitivity miniaturized atomic magnetometer includes a pump laser, a detection laser, a rubidium atom gas chamber, a magnetic field modulation coil, a differential amplifier, a photodetector, and a control module. The pump laser is used to polarize the rubidium atoms, and the detection laser is used to detect the magnetic field strength in the axial direction of the atomic magnetometer. The rubidium atom gas chamber is filled with rubidium atoms. The magnetic field modulation coil uses non-magnetic electric heating and a three-dimensional magnetic coil, enabling the rubidium atoms to operate in a high-temperature, low-magnetic-field environment, ensuring efficient pumping. The differential amplifier receives the output signal from the photodetector, amplifies it differentially, and transmits it to a host computer. The control module includes a host computer, a current detection module, a constant current control module, a temperature acquisition module, and a temperature control module, and is connected to a VCSEL laser. The current detection module uses an inverting amplifier circuit and an ADC chip to convert the current into a digital signal; the constant current control module uses an FPGA chip to acquire the digital signal from the ADC chip and perform PID calculations to control the DAC chip to change the constant current output by the power management chip; the temperature acquisition module uses an NTC temperature acquisition circuit and an ADC chip to convert temperature changes into digital signals; the temperature control module uses an FPGA chip to acquire the digital signal from the ADC chip and perform PID calculations to control the DAC chip to change the output voltage (DAC, Digital-to-Analog Converter), and controls the TEC control chip to drive the TEC to change the operating temperature of the VCSEL laser (TEC, Thermoelectric cooler); this application ensures long-term stable measurement and magnetic field measurement accuracy of the miniaturized atomic magnetometer.

[0030] A high-sensitivity miniaturized atomic magnetometer and its control method are disclosed. The system comprises: a control module 1, a first VCSEL laser 2, a second VCSEL laser 3, a first collimating lens 4, a second collimating lens 5, a first polarization beam splitter 6, a combined prism 7, a magnetic field modulation coil 8, a rubidium atomic gas cell 9, a λ / 2 waveplate 10, a second polarization beam splitter 11, a first photodetector 12, a second photodetector 13, and a differential amplifier 14. The control module 1 includes a host computer 15, a constant current control module 16, a current detection module 17, a temperature acquisition module 18, and a temperature control module 19. The detection beam is emitted from the first VCSEL laser 2, passes through the first collimating lens 4, the first polarization beam splitter 6, the magnetic field modulation coil 8, the rubidium atom gas cell 9, and the λ / 2 waveplate 10, and enters the second polarization beam splitter 11. The transmitted light enters the first photodetector 12 and is connected to the first input side of the differential amplifier 14. The reflected light enters the second photodetector 13 and is connected to the second input side of the differential amplifier 14. The output signal of the differential amplifier 14 is transmitted to the host computer 15. The pump beam is emitted from the second VCSEL laser 3, passes through the second collimating lens 5, the combined prism 7, and the magnetic field modulation coil 8, and enters the rubidium atom gas cell 9.

[0031] The laser emitted from the first VCSEL laser 2 is collimated by the first collimating lens 4, making the emitted light parallel. This allows it to be incident relatively completely into the rubidium atom gas cell 9. The light emitted from the first collimating lens 4 is then linearly polarized by the first polarization beam splitter 6 and incident on the magnetic field modulation coil 8 and the rubidium atom gas cell 9 as a detection beam. The laser polarization is then purified by the λ / 2 waveplate 10 and the second polarization beam splitter 11, resulting in a laser with better linear polarization. The transmitted light from the second polarization beam splitter 11 enters the first photodetector 12, and the reflected light enters the second photodetector 13. The input side of the differential amplifier 14 is connected to the two photodetectors. After differential operation and amplification, the light is input to the host computer 15, reflecting the change in the polarization direction of the detection light caused by the change in magnetic field strength. The laser emitted from the second VCSEL laser 3 is collimated by the second collimating lens 5, making the emitted light parallel, so that it can be incident into the rubidium atom gas cell 9 relatively completely. The emitted light from the second collimating lens 5 is then processed by the combined prism 7 to generate circularly polarized pump light, which is used to achieve the polarization of rubidium atoms.

[0032] The constant current control module 16 is connected to the first VCSEL laser 2 and the second VCSEL laser 3, providing a stable drive current for the lasers and controlling the output power of the lasers to remain constant; the current detection module 17 is connected to the first VCSEL laser 2 and the second VCSEL laser 3, used to detect the magnitude and stability of the laser drive current; the temperature acquisition module 18 is connected to the first VCSEL laser 2 and the second VCSEL laser 3, used to acquire the operating temperature of the lasers; the temperature control module 19 is connected to the first VCSEL laser 2 and the second VCSEL laser 3, used to perform closed-loop control of the laser operating temperature using a PID algorithm based on the laser operating temperature, so that the laser operating temperature is maintained within the operating temperature range.

[0033] The host computer 15 primarily implements slow start-up and slow shutdown of the DC current of the first VCSEL laser 2 and the second VCSEL laser 3; obtains the resistance value of the temperature measuring resistor for temperature acquisition; sets the temperature control PID parameters, sets the desired temperature, displays the actual temperature, and scans the temperature parameters to draw real-time images as a reference for tuning the temperature PID parameters of the first VCSEL laser 2 and the second VCSEL laser 3; receives the signal from the amplifier 14 and draws the photodetector signal in real-time; scans the current parameters to draw real-time images as a reference for tuning the power closed-loop PID parameters of the first VCSEL laser 2 and the second VCSEL laser 3; performs host computer serial communication and packages and unpacks communication data. It interacts with the user through an interface to complete the operation of each module, ultimately achieving closed-loop control of the first VCSEL laser 2 and the second VCSEL laser 3.

[0034] A highly sensitive miniaturized atomic magnetometer and its control method are disclosed, which can simultaneously achieve closed-loop control of VCSEL laser current and closed-loop control of temperature. By improving the output quality of the VCSEL laser, the magnetic field measurement sensitivity of the miniaturized atomic magnetometer is improved. Figure 1 As shown, the atomic magnetometer system mainly consists of a control module 1, a first VCSEL laser 2, a second VCSEL laser 3, a first collimating lens 4, a second collimating lens 5, a first polarization beam splitter 6, a combined prism 7, a magnetic field modulation coil 8, a rubidium atomic gas cell 9, a λ / 2 waveplate 10, a second polarization beam splitter 11, a first photodetector 12, a second photodetector 13, a differential amplifier 14, and a host computer 15.

[0035] like Figure 1 As shown, under the control of control module 1, the laser emitted from the first VCSEL laser 2 passes through the first collimating lens 4 and the first polarization beam splitter 6 to become a detection laser, which is then incident on the rubidium atom gas cell 9 within the magnetic field modulation coil 8 to detect the magnetic field strength in the axial direction of the atomic magnetometer. The laser emitted from the first VCSEL laser 2 passes through the second collimating lens 5 and the combined prism 7 to become a pump laser, which is also incident on the rubidium atom gas cell 9 within the magnetic field modulation coil 8 to polarize rubidium atoms. After emission, the laser passes through the λ / 2 waveplate 10 and the second polarization beam splitter 11. The transmitted light enters the first photodetector 12 and is converted into an electrical signal, while the reflected light enters the second photodetector 13 and is converted into an electrical signal. The input terminal of the differential amplifier 14 is connected to the first photodetector 12 and the second photodetector 13, performing differential operations and amplifying the signals from the photodetectors before sending them to the host computer 15.

[0036] like Figure 2 The diagram shows the connection between the VCSEL laser and the control module, which consists of a first VCSEL laser 2, a second VCSEL laser 3, a constant current control module 16, a current detection module 17, a temperature acquisition module 18, and a temperature control module 19. The constant current control module 16, current detection module 17, temperature acquisition module 18, and temperature control module 19 are simultaneously connected to the first VCSEL laser 2 and the second VCSEL laser 3, used to detect and control the power supply current and operating temperature of the lasers, ensuring the accuracy and reliability of the emitted laser light, and further ensuring the accuracy and sensitivity of this high-sensitivity miniaturized atomic magnetometer.

[0037] like Figure 3As shown, the control module includes a differential amplifier 14, a host computer 15, a constant current control module 16, a current detection module 17, a temperature acquisition module 18, and a temperature control module 19. The host computer 15 receives signals from the differential amplifier 14, the current detection module 17, and the temperature acquisition module 18, plots real-time images of the photodetector signal, the VCSEL laser input current, and the VCSEL laser operating temperature, sends signals to the constant current control module 16 to achieve slow current start-up and slow current shutdown, and sends signals to the temperature control module 19 to set the temperature control PID parameters and the desired operating temperature, thereby achieving closed-loop control of the first VCSEL laser 2 and the second VCSEL laser 3.

[0038] like Figure 4 The control module's workflow is shown below. First, the host computer 15 interacts with the user via an interface, allowing them to set control PID parameters, set the operating current, scan current parameters to generate real-time graphs, set the desired temperature, obtain the resistance value of the temperature-sensing resistor, scan temperature parameters to generate real-time graphs, and initiate control operation. Upon receiving the start signal, the power management chip outputs a constant current to supply the VCSEL laser to begin operation. The VCSEL laser connects to an inverting amplifier circuit, converting the current signal into a voltage signal, which is then sent to the ADC chip for conversion into a digital signal, completing current signal acquisition. The VCSEL laser connects to an NTC temperature acquisition circuit, converting temperature changes into a voltage signal, which is then sent to the ADC chip for conversion into a digital signal, completing temperature acquisition. The FPGA chip receives the output signal from the ADC chip, performs PID calculations, and outputs a control signal to the ADC chip. The ADC chip outputs a signal to the power management chip to change the current supplied to the VCSEL laser, forming a current closed-loop control. It also outputs a signal to the TEC control chip to control the TEC's operation, forming a temperature closed-loop control.

[0039] The pump laser emitted from the second VCSEL laser 3 is used to polarize rubidium atoms, and the detection laser emitted from the first VCSEL laser 2 is used to detect the magnetic field strength in the axial direction of the atomic magnetometer. The rubidium atom gas chamber 9 is filled with rubidium atoms and buffer gas. The rubidium atoms are the working atoms and are in a spin-free exchange relaxation state during operation. The buffer gas is an inert gas used to reduce spin collisions between atoms. The magnetic field modulation coil 8 uses a non-magnetic electric heating, three-dimensional magnetic coil, so that the rubidium atoms work in a high-temperature, low-magnetic-field environment to ensure their efficient pumping. The input side of the differential amplifier 14 is connected to the output signals of the first photodetector 12 and the second photodetector 13, and after differential operation and amplification, it is input to the host computer 15. The constant current control module 16 is used to provide a stable driving current for the first VCSEL laser 2 and the second VCSEL laser 3, and the current detection module 17 is used to detect the magnitude of the current flowing into the laser, and as feedback to realize the closed-loop control of the laser current. The temperature acquisition module 18 is used to detect the operating temperature of the laser. The temperature control module 19 uses a proportional-integral-derivative (PID) algorithm to perform closed-loop control and regulation of the laser's operating temperature, ensuring that the laser's operating temperature remains within the operating temperature range. The host computer 15 receives signals from the differential amplifier 14 and plots the photodetector signal in real time; it receives signals from the current detection module 17 and scans the current parameters to plot images in real time; it receives signals from the temperature acquisition module 18, displays the actual operating temperature of the laser, and scans the temperature parameters to plot images in real time; it sends signals to the constant current control module 16 to achieve slow start and slow shutdown of the DC current; and it sends signals to the temperature control module 19 to set the temperature control PID parameters and the desired operating temperature. The interface allows for user interaction, enabling operation of each module and ultimately achieving closed-loop control of the first VCSEL laser 2 and the second VCSEL laser 3.

[0040] The emitted laser from the first VCSEL laser 2 passes sequentially through the first collimating lens 4 and the first polarization beam splitter 6 before entering the magnetic field modulation coil 8 and the rubidium atom gas chamber 9.

[0041] The emitted laser from the first VCSEL laser 2 is collimated into parallel light by the first collimating lens 4, and then becomes linearly polarized light by the first polarization beam splitter 6. This light is then used as a detection beam and incident on the magnetic field modulation coil 8 and the rubidium atom gas cell 9 to detect the change in the polarization direction of the detection light caused by the change in the magnetic field strength.

[0042] The combined prism 7 consists of a polarizing beam splitter and a λ / 4 waveplate.

[0043] The laser emitted from the second VCSEL laser 3 passes sequentially through the second collimating lens 5 and the combined prism 7 before entering the magnetic field modulation coil 8 and the rubidium atom gas chamber 9.

[0044] The laser emitted from the second VCSEL laser 3 is collimated into parallel light by the second collimating lens 5, and then generated into circularly polarized pump light by the combined prism 7, which is used to achieve the polarization of alkali metal atoms.

[0045] The first photodetector 12 is used to detect the transmitted light from the second polarization beam splitter 11 and convert it into an electrical signal.

[0046] The second photodetector 13 is used to detect the reflected light from the second polarization beam splitter 11 and convert it into an electrical signal.

[0047] The input terminal of the differential amplifier 14 is connected to the first photodetector 12 and the second photodetector 13. The signal from the photodetector is amplified after differential operation and sent to the host computer 15.

[0048] The control module 1 includes a host computer 15, a constant current control module 16, a current detection module 17, a temperature acquisition module 18, and a temperature control module 19.

[0049] The constant current control module 16 acquires digital signals from the ADC chip through the FPGA chip and performs PID calculations, controls the DAC chip to change the constant current (DAC) output by the power management chip, and controls its output power to remain constant.

[0050] The current detection module 17 is connected to the first VCSEL laser 2 and the second VCSEL laser 3. It uses an inverting amplifier circuit and an ADC chip to convert the current into a digital signal, which is used to detect the magnitude of the current flowing into the VCSEL laser and to realize the closed-loop control of the laser current as feedback.

[0051] The temperature acquisition module 18 is connected to the first VCSEL laser 2 and the second VCSEL laser 3. It converts temperature changes into digital signals through an NTC temperature acquisition circuit and an ADC chip to acquire the operating temperature of the VCSEL laser.

[0052] The temperature control module 19 is connected to the first VCSEL laser 2 and the second VCSEL laser 3. It acquires digital signals from the ADC chip through the FPGA chip and performs PID calculations, controls the DAC chip to change the output voltage, and controls the TEC control chip to drive the TEC to change the operating temperature of the VCSEL laser. It performs closed-loop control of the operating temperature of the VCSEL laser to keep the operating temperature of the VCSEL laser within the operating temperature range.

[0053] Since the accuracy and reliability of the laser emitted from the first VCSEL laser 2 and the second VCSEL laser 3 directly determine the performance of this high-sensitivity miniaturized atomic magnetometer, it is necessary to maintain the accurate and reliable output power and emission wavelength of the VCSEL lasers. Furthermore, to avoid temperature effects such as temperature drift, it is necessary to ensure that the operating temperature of the VCSEL lasers does not change with external factors or their own heat generation.

[0054] According to the technical solution provided in the embodiments of the present invention, the output power of the VCSEL laser is controlled by the current detection module and the constant current control module, and the temperature acquisition module and the temperature control module are used to monitor and control the temperature of the VCSEL laser, thereby ensuring the accuracy and sensitivity of the high-sensitivity miniaturized atomic magnetometer.

[0055] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, and / or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A control method of a high-sensitivity miniaturized atomic magnetometer, characterized by, The method comprises the following steps: Step 1, setting a control module in an atomic magnetometer system, the control module is integrated with a constant current control module, a current detection module, a temperature acquisition module and a temperature control module, the control module is connected with a first VCSEL laser for providing detection light and a second VCSEL laser for providing pumping light, the constant current control module, the current detection module, the temperature acquisition module and the temperature control module are connected with a differential amplifier at the end of the detection light path through an upper computer; Step 2, the upper computer starts to work, sets the control PID parameters, sets the working current and sets the expected temperature; Step 3, the constant current control module provides stable driving current to the first VCSEL laser and the second VCSEL laser according to the set working current, the current detection module detects the size and stability of the stable driving current, the temperature acquisition module acquires the working temperature of the first VCSEL laser and the second VCSEL laser, and the temperature control module controls the working temperature in a closed loop by using a PID algorithm; Step 4, the upper computer scans the temperature parameters and draws images in real time as a reference for temperature PID parameter setting of the first VCSEL laser and the second VCSEL laser, and receives the output signal of the differential amplifier, scans the current parameters and draws images in real time as a reference for power closed loop PID parameter setting of the first VCSEL laser and the second VCSEL laser; Step 5, the upper computer forms current closed loop control for the first VCSEL laser and the second VCSEL laser by using the constant current control module according to the current size detected by the current detection module.

2. The control method of a high-sensitivity miniaturized atomic magnetometer according to claim 1, characterized in that, The constant current control module in step 1 contains a power management chip with internal soft start, thermal shutdown and current limit, the temperature acquisition module includes an NTC temperature acquisition circuit and a temperature ADC chip, the current detection module includes a reverse amplification circuit and a current ADC chip, and the temperature control module includes a TEC control chip.

3. The control method of a high-sensitivity miniaturized atomic magnetometer according to claim 1, characterized in that, The closed loop control of the working temperature in step 3 includes: the temperature acquisition module converts the temperature change into a digital signal through the NTC temperature acquisition circuit and the temperature ADC chip, the temperature control module acquires the digital signal from the temperature ADC chip through the FPGA chip and performs PID calculation, controls the DAC chip to change the output voltage, and controls the TEC control chip to drive the TEC to change the working temperature of the VCSEL laser.

4. The control method of a high-sensitivity miniaturized atomic magnetometer according to claim 1, characterized by, The current closed loop control in step 5 includes: the constant current control module acquires the digital signal from the current ADC chip in the current detection module through the FPGA chip and performs PID calculation, controls the DAC chip to change the constant current output by the power management chip, and forms the current closed loop control.

5. The control method of a high-sensitivity miniaturized atomic magnetometer according to claim 1, characterized in that, The detection light path of the atomic magnetometer system in step 1 comprises a first VCSEL laser, a first collimating lens, a first polarization beam splitter, a rubidium atom cell in a magnetic field modulation coil, a lambda / 2 wave plate and a second polarization beam splitter connected in sequence, the transmission side of the second polarization beam splitter is connected to the first input end of a differential amplifier through a first photodetector, the reflection side of the second polarization beam splitter is connected to the second input end of the differential amplifier through a second photodetector, and the output end of the differential amplifier is connected to a host computer.

6. The control method of a high-sensitivity miniaturized atomic magnetometer according to claim 1, characterized in that, The pumping light path of the atomic magnetometer system in step 1 comprises a second VCSEL laser, a second collimating lens, a combined prism and a rubidium atom cell in a magnetic field modulation coil connected in sequence.

Images