Laser control system and spectral analysis system

Abstract

Disclosed are a laser control system and a spectral analysis system, comprising: an ARM module and a laser control module, wherein the laser control module comprises a TEC module and a DA module, and the TEC module is communicatively connected to the ARM module; when a laser initiates operation, the ARM module determines whether a detected temperature of a laser housing is within a predefined range, and if so, the TEC module remains inactive; otherwise, the ARM module controls the TEC module to initiate operation until the TEC module reaches a predefined target temperature, after which stable operation is maintained; the DA module is communicatively connected to the ARM module, wherein an LD current feedback circuit is provided within the DA module, the ARM module computes an error between present power and target power according to current data acquired by the LD current feedback circuit, and then drives the DA module to adjust output power of the laser in real time, so that the laser operates stably around the target power. The present invention effectively reduces power loss in lasers.

Description

A laser control system and a spectral analysis system Technical Field

[0001] This invention relates to the field of spectral analysis, and more particularly to a laser control system and a spectral analysis system. Background Technology

[0002] Lasers have been widely used in fields such as spectral analysis, precision machining, and medical imaging. Especially in applications requiring high-precision optical measurement and control, the stability and controllability of lasers are crucial. Currently, most laser control systems on the market rely on hardware circuits for control, characterized by fast response speed and relatively simple physical structure, but they suffer from the following shortcomings:

[0003] Unstable laser output: Traditional lasers exhibit unstable output power during operation, with overcharging issues occurring as the laser is turned on and off. This can subject the laser's semiconductor components to excessive current surges, damaging internal components and affecting the laser's efficiency and stability.

[0004] Poor environmental adaptability: Existing laser systems often rely on passive heat dissipation or simple air cooling systems for temperature control, which cannot cope with extreme environments (such as extreme cold or high temperature), resulting in unstable performance or even failure of the laser under these conditions.

[0005] Insufficient closed-loop control: The feedback control of traditional laser control systems is not perfect, and it is usually unable to adjust the output power and status of the laser in real time. This may lead to unstable laser output, thereby affecting the consistent results of repeatable operation.

[0006] The above shortcomings limit the application of existing technologies in scenarios with high environmental requirements, especially in scenarios requiring high stability and high precision control, such as spectral analysis and precision machining.

[0007] Therefore, it is necessary to provide a control system and spectral analysis system for a dual-soft-controlled laser based on an ARM system to achieve comprehensive control of the laser system, covering dual regulation of temperature and power, thereby reducing the overall power loss of the laser and improving the stability and reliability of the laser. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a laser control system and a spectral analysis system that can effectively reduce the power loss of the laser and improve the stability and reliability of the laser.

[0009] To address the aforementioned technical problems, this invention provides a laser control system, comprising: an ARM module and a laser control module; the laser control module includes a TEC module and a DA module; the TEC module is communicatively connected to the ARM module. When the laser starts working, the ARM module determines whether the detected laser housing temperature is within a preset range. If it is within the preset range, the TEC module does not operate; otherwise, the ARM module controls the TEC module to start working until the TEC module reaches a preset target temperature and maintains stable operation; the DA module is communicatively connected to the ARM module. The DA module is equipped with an LD current feedback circuit. The ARM module calculates the error between the current power and the target power based on the current data collected by the LD current feedback circuit, and then drives the DA module to adjust the laser's output power in real time, so that the laser operates stably near the target power.

[0010] Furthermore, the control method of the TEC module is as follows: when the laser starts working, the ARM module judges the difference between the detected laser housing temperature and the target temperature set by the TEC module. If the difference is within 35°C, the TEC module does not work; otherwise, the target temperature of the TEC is set to 25°C, and the TEC module is controlled to start working, so that the TEC module maintains stable operation after reaching the target temperature. When the laser stops and re-enters the working state, the above steps are repeated.

[0011] Furthermore, the control method of the TEC module is as follows: When the laser starts working, the ARM module determines the detected laser housing temperature. When the ARM module detects that the laser housing temperature is between 0 and 35°C, the TEC module does not work; when the ARM module detects that the laser housing temperature is between -20°C and -10°C, the ARM module controls the TEC module to start working, and the target temperature of the TEC module is set to -10°C, so that the TEC module maintains stable operation after reaching the target temperature; when the ARM module detects that the laser housing temperature is between -10°C and 0°C, the ARM module controls the TEC module to work, and the target temperature of the TEC module is set to 0°C, so that the TEC module maintains stable operation after reaching the target temperature; when the ARM module detects that the laser housing temperature is higher than 35°C, the ARM module controls the TEC module to work, and the target temperature of the TEC module is set to 35°C, so that the TEC module maintains stable operation after reaching the target temperature; when the laser stops and restarts, the above steps are repeated.

[0012] Furthermore, the relationship between the laser's output power and the set voltage adopts an eighth-order calibration method: the ARM module sets the voltage to drive the laser, and sets the voltage starting from 0mV, increasing it by 100mV sequentially up to 2500mV. The voltage value is read through the LD feedback circuit, and the power value after stabilization is recorded. Based on the 26 sets of recorded values, the eighth-order calibration parameters between the output power and the set voltage are calculated. The eighth-order calibration parameters between the set voltage and the output power are read back, and then these two sets of eighth-order calibration data are written into the flash memory of the ARM module. By inputting the target power value, the initial set voltage value to achieve the target power can be calculated based on the eighth-order calibration parameters between the output power and the set voltage.

[0013] Furthermore, the relationship between the laser's output power and the set voltage is calibrated using a lookup table method: the ARM module sets the voltage to drive the laser, increasing the voltage sequentially from 0mV to 2500mV, and the voltage value is read through the LD feedback circuit. The optical power value measured by the optical power meter at this time is recorded, resulting in 26 sets of set voltage values, LD feedback voltage values, and optical power values. These data are stored in the flash memory of the ARM module. Based on the set target power value, the set voltage range can be obtained by looking up the list. At this point, the linear relationship between voltage and power can be approximated within a small voltage range, thereby calculating the initial set voltage value to achieve the target power.

[0014] Furthermore, the ARM module is equipped with a 12-bit DA module and a 12-bit ADC module. The output power of the laser is set through the 12-bit DA module, while the 12-bit ADC module collects the LD feedback current loop in real time. Combined with the PID control algorithm, the ARM module calculates the error between the current power and the target power based on the collected current data, and then drives the DA module to adjust the output power of the laser in real time, so that the laser can operate stably near the target power.

[0015] Furthermore, the ARM employs ADC and DMA loop modes to acquire the temperature feedback value of the TEC module and the voltage feedback value of the LD feedback current loop in real time.

[0016] To address the aforementioned problems, the present invention also provides a spectral analysis system, including a spectrometer and a laser. The laser includes the aforementioned laser control system. The spectrometer includes a spectral acquisition module, which includes a CCD module and an FPGA module. The FPGA module generates a timing drive based on received instructions to perform exposure of the CCD module for a certain integration time. The CCD module feeds back the acquired analog quantity to the FPGA through an A / D conversion circuit. The FPGA transmits the acquired spectral data to the ARM module for data processing.

[0017] Furthermore, the ARM module configures registers with the FPGA module via SPI or MIPI protocol, and the FPGA module transmits the acquired spectral data to the ARM module for data processing via SPI or MIPI protocol.

[0018] Furthermore, the ARM module integrates Boxcar smoothing and stretching algorithms to process the acquired spectral data, and the processed data is transmitted to a PC terminal or handheld device terminal via USB or serial communication.

[0019] Compared with existing technologies, this invention offers the following advantages: The laser control system and spectral analysis system provided by this invention utilize an ARM module for digital signal processing, enabling the system to quickly respond to user commands and system changes, achieving real-time adjustment and control of the laser, thereby improving work efficiency; real-time monitoring and closed-loop adjustment of the laser output power are achieved through an LD feedback loop, ensuring the stability of the laser output, and enabling quantitative management of power and voltage, guaranteeing the accuracy and reliability of the system during long-term operation; bidirectional temperature control of the laser is achieved through a TEC module, enabling precise cooling and heating in extremely cold and high-temperature environments, ensuring stable operation of the laser in extreme environments. The laser control system provided by this invention has real-time monitoring and control parameter adjustment functions, enabling timely detection and handling of abnormal laser conditions, ensuring stable operation and long-term reliability of the laser. The ARM-based dual-soft control system for lasers offers excellent flexibility and scalability, adapting to diverse laser control requirements. The high integration and low power consumption of the ARM module significantly improve the cost-effectiveness of the entire laser control system, saving on electrical components, optimizing board space, and further reducing hardware costs. The software-based laser control system facilitates integration into existing laser equipment, while the modular design also facilitates maintenance and upgrades, offering high portability and saving development time. Therefore, this invention provides a flexible, efficient, and stable dual-soft control system for lasers, widely applicable to demanding applications such as spectral analysis, precision machining, and medical imaging. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the framework of the spectral analysis system in an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of the laser control process in an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of the framework of the spectral analysis system in an embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of the workflow of the spectral analysis system in an embodiment of the present invention;

[0024] Figures 5a and 5b are comparison diagrams showing the power consumption of the laser in the embodiment of the present invention and the power consumption of the existing laser.

[0025] Figure 6a shows the silicon wafer test spectrum at room temperature in an embodiment of the present invention; Figure 6b shows the silicon wafer test spectrum at 46°C in an embodiment of the present invention; Figure 6c shows the silicon wafer test spectrum at 20°C in an embodiment of the present invention; Figure 6d shows the silicon wafer test spectrum at 0°C in an embodiment of the present invention; and Figure 6e shows the silicon wafer test spectrum at -20°C in an embodiment of the present invention.

[0026] Figure 7a shows the wavelength deviation results at room temperature in an embodiment of the present invention; Figure 7b shows the wavelength deviation results at 46℃ in an embodiment of the present invention; Figure 7c shows the wavelength deviation results at 20℃ in an embodiment of the present invention; Figure 7d shows the wavelength deviation results at 0℃ in an embodiment of the present invention; Figure 7e shows the wavelength deviation results at -20℃ in an embodiment of the present invention.

[0027] Figure 8a shows the Raman signal spectra of alcohol and acetone detected after 2 hours of low-temperature storage at 0°C in an embodiment of the present invention. Figure 8b shows the interface display of alcohol on a mobile terminal. Figure 8c shows the interface display of acetone on a mobile terminal.

[0028] Figure 9a shows the Raman signal spectra of alcohol and acetone detected after 2 hours of high-temperature storage at 40°C in an embodiment of the present invention. Figure 9b shows the interface display of acetone on a mobile terminal. Figure 9c shows the interface display of alcohol on a mobile terminal.

[0029] Figure 10a shows the Raman signal spectra of alcohol and acetone detected after 2 hours of high-temperature storage at 45°C in an embodiment of the present invention. Figure 10b shows the interface display of acetone on a mobile terminal. Figure 10c shows the interface display of alcohol on a mobile terminal.

[0030] Figure 11a shows the Raman signal spectra of alcohol and acetone detected after the working temperature was -20℃ for 24 hours and then restored to room temperature for 1 hour in an embodiment of the present invention. Figure 11b shows the interface display of acetone on a mobile terminal. Figure 11c shows the interface display of alcohol on a mobile terminal.

[0031] Figure 12a shows the Raman signal spectra of alcohol and acetone detected after the working temperature was 70°C for 24 hours and then restored to room temperature for 1 hour in an embodiment of the present invention. Figure 12b shows the interface display of alcohol on a mobile terminal, and Figure 12c shows the interface display of acetone on a mobile terminal. Detailed Implementation

[0032] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0033] The purpose of this invention is to provide a control system for a dual-soft-controlled laser based on an ARM system. This control system uses an ARM processor as its control core to achieve comprehensive control of the laser system, encompassing both temperature and power regulation, thereby reducing overall power loss. This invention employs two-way soft-control closed-loop control: one channel controls the laser's TEC module to maintain a constant operating temperature; the other channel controls the laser's DA module to achieve precise output power control.

[0034] Please refer to Figures 1, 2 and 3. The laser control system provided by the present invention includes: an ARM module (Advanced RISC Machines) and a laser control module; the laser control module includes a TEC module (Thermoelectric Cooler) and a DA module (Digital to Analog Converter).

[0035] The TEC module is communicatively connected to the ARM module. When the laser starts working, the ARM module determines whether the laser housing temperature is within a preset range. If it is, the TEC module does not operate; otherwise, the ARM module controls the TEC module to start working until it reaches the preset target temperature and maintains stable operation. The TEC module enables bidirectional temperature control of the laser, allowing for precise cooling and heating in extremely cold and hot environments, ensuring stable operation of the laser in extreme conditions and enhancing its environmental adaptability.

[0036] The DA module is communicatively connected to the ARM module. The DA module contains an LD current feedback circuit (Laser Diode). Based on the current data collected by the LD current feedback circuit, the ARM module calculates the error between the current power and the target power, and then drives the DA module to adjust the laser's output power in real time, ensuring stable operation of the laser near the target power. The LD current feedback loop enables real-time monitoring and closed-loop adjustment of the laser's output power, ensuring its stability and allowing for quantitative management of power and voltage, guaranteeing the system's accuracy and reliability during long-term operation.

[0037] In one embodiment, the control method of the TEC module is as follows: When the laser starts working, the ARM module determines the difference between the detected laser housing temperature and the target temperature set by the TEC module. If the difference is within 35°C, the TEC module does not work; otherwise, the target temperature of the TEC is set to 25°C, and the TEC module is controlled to start working, so that the TEC module maintains stable operation after reaching the target temperature. When the laser stops and restarts, the above steps are repeated. This control method allows for manual input of the TEC target temperature, which can be detected by setting a temperature sensor on the laser housing. The PID control algorithm inside the ARM module can be used to precisely adjust the laser operating temperature to ensure stable operation of the laser under various temperature conditions.

[0038] In another embodiment, the control method of the TEC module is as follows: When the laser starts working, the ARM module determines the detected laser housing temperature. When the ARM module detects that the laser housing temperature is between 0 and 35°C, the TEC module does not work; when the ARM module detects that the laser housing temperature is between -20°C and -10°C, the ARM module controls the TEC module to start working, and the target temperature of the TEC module is set to -10°C, so that the TEC module maintains stable operation after reaching the target temperature; when the ARM module detects that the laser housing temperature is between -10°C and 0°C, the ARM module controls the TEC module to work, and the target temperature of the TEC module is set to 0°C, so that the TEC module maintains stable operation after reaching the target temperature; when the ARM module detects that the laser housing temperature is higher than 35°C, the ARM module controls the TEC module to work, and the target temperature of the TEC module is set to 35°C, so that the TEC module maintains stable operation after reaching the target temperature. This mode can adopt an automatic mode, using one digital signal (TMPGD) and one analog temperature acquisition signal to determine whether the laser TEC is ready. Similarly, the PID control algorithm inside the ARM module can be used to precisely adjust the laser's operating temperature to ensure stable operation under various temperature conditions.

[0039] In one specific embodiment, the laser device supports both manual and automatic modes. When the PID (Proportional, Integral, and Derivative) driver TEC module is powered on by default, the target temperature is set to 25°C in automatic mode. After the device starts, it enters the software control interface (i.e., manual mode), allowing for customized temperature adjustment from 15-35°C via a host computer through a USB interface. This flexible and adjustable design solves the problems of poor laser flexibility and high power consumption in cold or hot environments.

[0040] During laser equipment testing, it was found that changes in ambient temperature significantly impact the preset target temperature of the laser tube. The temperature difference between the preset target temperature and the ambient temperature should not be too large; otherwise, the laser system will struggle to reach the preset target temperature, resulting in a consistently high power consumption. The TEC module's feedback signal TMPGD returns a digital value. In this case, the laser control system receives a logic 0, indicating that the TEC module has not reached its optimal operating state. Turning on the laser at this point will prevent it from operating. Another issue arises when the temperature feedback is at the critical value of the set target temperature, causing the laser to intermittently turn on and off. High and low temperature experiments revealed that when the laser tube operates within the 0-35℃ range, the presence or absence of the TEC module has almost no impact on the Raman signal. Therefore, how to efficiently control the laser and reduce its overall power consumption is the problem this invention aims to solve. The solution is to optimize the temperature control strategy of the laser TEC module. The readiness of the laser TEC module is determined by using one digital signal (TMPGD) and one analog temperature acquisition signal. If the preset laser tube temperature is 25℃, and TMPGD = 1, the laser device is in normal working condition and can operate. Otherwise, it checks whether the difference between the target temperature of the TEC module and the ambient temperature (laser housing temperature) is within ±10℃. If so, the laser device is in normal working condition; otherwise, it waits for the laser device's TEC module to become ready. This invention uses both TMPGD digital and real-time temperature analog feedback to comprehensively evaluate the TEC module's operating status, thereby achieving control of the TEC module. High and low temperature test results show that this TEC control strategy can effectively solve the problem of abnormal equipment operation caused by temperature differences, and the handheld Raman device can operate normally in an environment of 0-45℃, as shown in Figures 8a-12c.

[0041] In one embodiment, the relationship between the laser's output power and the set voltage employs an eighth-order calibration method: the ARM module sets the voltage to drive the laser, increasing the voltage sequentially from 0mV to 2500mV, reading the voltage value through the LD feedback circuit, recording the stabilized power value, and calculating the eighth-order calibration parameters between the output power and the set voltage based on the 26 recorded values. These eighth-order calibration parameters are then read back and written to the ARM module's flash memory via USB / UART; this data is retained even when power is lost. Thus, by inputting a target power value, the user can calculate the initial set voltage value required to achieve that target power based on the eighth-order calibration parameters between the output power and the set voltage.

[0042] In another embodiment, the relationship between the laser's output power and the set voltage is calibrated using a lookup table method: the ARM module sets the voltage to drive the laser, increasing the voltage sequentially from 0mV to 2500mV, and the voltage value is read through the LD feedback circuit. The optical power value measured by the optical power meter at this time is recorded, resulting in 26 sets of set voltage values, LD feedback voltage values, and optical power values. This data is stored in the ARM module's flash memory. Based on the set target power value, the set voltage range can be obtained by looking up the list. Within this small voltage range, a linear relationship between voltage and power can be approximated, allowing the calculation of the initial set voltage value required to reach the target power. This method yields a more accurate optical power value than the eight-order calibration method and reduces the multiplication operations of multi-order calibrations, significantly improving the operating efficiency of the ARM module.

[0043] In one specific embodiment, the ARM module is equipped with a 12-bit DA module and a 12-bit ADC module (Analog-to-Digital Converter Module). The 12-bit DA module sets the output power of the laser, while the 12-bit ADC module collects the LD feedback current loop in real time. Combined with the PID control algorithm, the ARM module calculates the error between the current power and the target power based on the collected current data, and then drives the DA module to adjust the output power of the laser in real time, so that the laser operates stably near the target power.

[0044] The ARM uses ADC and DMA (Direct Memory Access) cyclic mode to obtain the temperature feedback value of the TEC module and the voltage feedback value of the LD feedback current loop in real time.

[0045] Furthermore, the laser also includes a storage module, a power supply module, a fan module, an equipment information monitoring module, and a crystal oscillator module. The storage module consists of an EEPROM (Electrically Erasable Programmable Read-Only Memory) module and an SRAM (Static Random Access Memory) module. The EEPROM module stores spectral coefficients and calibration parameters, as well as other spare storage areas; the SRAM module stores spectral data and performs spectral storage analysis. The power supply module consists of a DC-DC circuit, a filter circuit, and a protection circuit; it supplies power to the ARM module, laser control module, fan module, etc. The equipment information monitoring module consists of RGB (red, green, blue) indicator lights and a PCB (Printed Circuit Board) temperature acquisition module. The RGB indicator light module is used for normal operation and fault indication. The fan module is used for laser heat dissipation; the fan-assisted heat dissipation and the temperature acquisition module provide real-time temperature feedback, further improving the system's environmental adaptability. The crystal oscillator module provides a heartbeat packet, which, after PLL frequency division, generates clock buses of different frequencies to provide clocks for different module peripherals.

[0046] The specific workflow of the control system for the dual soft-controlled laser based on the ARM system provided by this invention is as follows:

[0047] Process 101: The system is powered on and each module starts up: first the power module, then the ARM module, the laser control module and the fan module;

[0048] Procedure 102: System initialization begins. This includes: USB module initialization; AD_TEC temperature acquisition module initialization; AD_power acquisition module initialization; DA_TEC temperature setting output module initialization; DA_power setting output module initialization; timer module initialization; and fan module initialization.

[0049] Procedure 103: After system startup, the ARM module enables PID control by default, controlling the TEC temperature by driving the TEC module, with the target temperature set to 25℃. The system is in a waiting state, waiting for the host computer to send instructions via the USB interface;

[0050] Process 104: Once the ARM module receives an instruction from the PC via the USB module, it immediately receives and parses the instruction. It then performs the corresponding operation based on the user's instructions, such as laser voltage and power calibration parameter setting instructions, power setting instructions, and TEC module on / off control instructions.

[0051] Process 105: When the ARM module receives the power setting command, it starts the PID driver DA module, drives the power output circuit to control the power output module circuit, and adjusts the DA power setting output module to control the laser's output power and frequency in real time according to the voltage value of the LD current feedback circuit sampled by the AD power acquisition module, so as to achieve the effect of accurately outputting the laser power.

[0052] There is a large error between the laser output power and the preset power. In order to improve the accuracy of the output power, this invention solves the problem from two aspects: circuit and drive: (1) An LD current feedback loop is added to the ARM module in the circuit. The system forms a closed-loop regulation through the LD feedback circuit to ensure the stability of the laser output power. (2) The ARM module is used as the controller. The power output of the laser is set through the 12-bit DA module. At the same time, the LD current feedback loop is collected in real time through the 12-bit ADC module. Combined with the PID control algorithm, the ARM calculates the error between the current and the target power based on the collected current data. Then, it drives the DA module to adjust the output power of the laser in real time to ensure that the laser operates stably near the target power. Existing lasers are all driven by a fixed voltage value. This invention introduces a PID closed-loop algorithm to adjust the output of the DA module in real time. This not only effectively reduces the instantaneous overshoot of the laser power output, but also greatly improves the accuracy of the laser power output. The error is controlled within ±1mW.

[0053] This invention employs an ARM+Free RTOS (lightweight real-time operating system kernel) architecture to create temperature control and power output control tasks for the TEC module. Task priorities are rationally allocated, and semaphores and message queue mechanisms are introduced to support interrupts and task priority preemption. The ARM module uses an ADC+DMA loop mode to acquire TEC temperature and voltage feedback values ​​in real time. The introduction of DMA effectively reduces CPU scheduling pressure, saves CPU workload, and improves data exchange efficiency.

[0054] This invention not only improves the stability and reliability of the laser system, but also achieves optimized control of laser performance through the efficient processing power and intelligent control algorithm of the ARM system. As shown in Figures 5a and 5b, the efficient control of the laser control system provided by this invention can reduce the energy consumption of the laser, reduce output coupling loss and heat loss, and meet the requirements of modern industry for environmental protection and energy conservation.

[0055] Please refer to Figures 1, 3, and 4. This embodiment also provides a spectral analysis system, including a spectrometer and a laser. The laser includes the laser control system described above. The spectrometer includes a spectral acquisition module, which includes a CCD module and an FPGA module. The FPGA module generates a timing drive to perform exposure of the CCD module for a certain integration time according to the received instructions. The CCD module feeds back the acquired analog quantity to the FPGA through an A / D conversion circuit. The FPGA transmits the acquired spectral data to the ARM module for data processing.

[0056] Furthermore, the ARM module configures registers with the FPGA module via SPI or MIPI protocol, and the FPGA module transmits the acquired spectral data to the ARM module for data processing via SPI or MIPI protocol. During system operation, the ARM module can control the FPGA reset pin to synchronously control the communication between the ARM and FPGA.

[0057] Furthermore, the ARM module integrates Boxcar smoothing and stretching algorithms to process the acquired spectral data. The processed data is then transmitted to a PC terminal or handheld device terminal via USB, serial port, or Gigabit Ethernet communication for real-time data transmission and remote control with the PC or mobile terminal.

[0058] This invention supports multiple communication protocols, ensuring that the system can interact with PCs or mobile terminals in real time. At the same time, the spectral coefficients and parameters stored in the EEPROM ensure data security in the event of a power outage.

[0059] The silicon wafers were tested using the spectral analysis system provided in this invention at room temperature, -20℃, 0℃, 20℃, and 46℃, and the changes in characteristic peaks were observed. The peak deviation test results at -20℃ to 46℃ are shown in Table 1, and the test spectra are shown in Figures 6a-6e. The Raman peak of the silicon wafer at room temperature was measured at 521 cm⁻¹. -1 The Raman peak of the silicon wafer was measured at 523 cm⁻¹ at -20℃, 0℃, 20℃ and 46℃. -1 The wavelength shifts by 2cm compared to that at room temperature. -1 The spectral peak deviation is small.

[0060] Table 1 Peak deviation (cm) at several different temperatures -1 )

[0061] Wavelength deviation tests were conducted using a mercury argon lamp at room temperature, -20℃, 0℃, 20℃, and 46℃. The wavelength deviation test results at -20℃ to 46℃ are shown in Table 2, and the original test spectra are shown in Figures 7a-7e. Table 2 compares the changes in four standard mercury argon lamp values ​​(811.531nm, 826.452nm, 842.465nm, and 912.297nm) at different temperatures. As shown in Table 2, under the conditions of room temperature, -20℃, 0℃, 20℃, and 46℃, the RSD values ​​of each spectral line at 811.531nm, 826.452nm, 842.465nm, and 912.297nm are relatively small, indicating that the wavelength deviation is not significant under these temperature conditions.

[0062] Table 2. Wavelength deviation of the handheld device's internal core at different temperatures (nm)

[0063] The spectral analysis system provided by this invention can operate normally at different storage temperatures: using a high and low temperature chamber, and referring to national standards, the testing equipment can operate normally at storage temperatures of -20℃, 0℃, 40℃, 45℃, and 70℃.

[0064] Table 3

[0065] The test results at a working temperature of 0℃ are shown in Figures 8a-8c. After 2 hours of low-temperature storage, the spectral analysis system provided by this invention can still detect the Raman signals of alcohol and acetone. Under these conditions, the spectral analysis system provided by this invention can work normally.

[0066] The test results at a working temperature of 40℃ are shown in Figures 9a-9c. After 2 hours of high-temperature storage, the spectral analysis system provided by this invention can still detect the Raman signals of alcohol and acetone. Under these conditions, the spectral analysis system provided by this invention can work normally.

[0067] The test results at a working temperature of 45℃ are shown in Figures 10a-10c. After 2 hours of high-temperature storage, the spectral analysis system provided by this invention can still detect the Raman signals of alcohol and acetone. Under these conditions, the spectral analysis system provided by this invention can work normally.

[0068] The test results of storage at -20℃ for 24 hours are shown in Figures 11a-11c. After 24 hours of low-temperature storage, the system was taken out and allowed to recover at room temperature for 1 hour. Raman signals of alcohol and acetone could be detected. Under these conditions, the spectral analysis system provided by this invention can work normally.

[0069] The test results after storage at 70℃ for 24 hours are shown in Figures 12a-12c. After 24 hours of high-temperature storage, the invention was taken out and allowed to recover at room temperature for 1 hour. The invention can still detect the Raman signals of alcohol and acetone. The invention can still work normally after high-temperature storage.

[0070] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined by the claims.

Claims

1. A control system for a laser, characterized in that, include: An ARM module and a laser control module, wherein the ARM module is equipped with a PID control algorithm; The laser control module includes a TEC module and a DA module; The TEC module is communicatively connected to the ARM module. When the laser starts working, the ARM module determines whether the detected laser housing temperature is within a preset range. If it is within the preset range, the TEC module does not work; otherwise, the ARM module controls the TEC module to start working, using its internal PID control algorithm to precisely adjust the laser's operating temperature until the TEC module reaches the preset target temperature and maintains stable operation. The control method of the TEC module is as follows: when the laser starts working, the ARM module determines the difference between the detected laser housing temperature and the target temperature set by the TEC module. If the difference is within 35°C, the TEC module does not work; otherwise, the target temperature of the TEC is set to 25°C, and the TEC module is controlled to start working, so that the TEC module maintains stable operation after reaching the target temperature. When the laser stops and restarts, the above steps are repeated. The DA module is communicatively connected to the ARM module. The DA module contains an LD current feedback circuit. Based on the current data collected by the LD current feedback circuit and combined with a PID control algorithm, the ARM module calculates the error between the current power and the target power. It then drives the DA module to adjust the laser's output power in real time, ensuring stable operation of the laser near the target power. The relationship between the laser's output power and the set voltage employs an eighth-order calibration method: the ARM module sets a voltage to drive the laser, increasing the voltage sequentially from 0mV to 2500mV, reading the voltage value through the LD feedback circuit, recording the stabilized power value, and calculating the eighth-order calibration parameters between the output power and the set voltage based on the 26 recorded values. These eighth-order calibration parameters are then read back and written into the ARM module. In the flash memory of the module, by inputting the target power value, the initial set voltage value to achieve the target power can be calculated based on the eighth-order calibration parameters between the output power and the set voltage; or, the relationship between the laser's output power and the set voltage can be calibrated using a lookup table method: the ARM module sets the voltage to drive the laser, setting the voltage from 0mV, increasing it by 100mV sequentially up to 2500mV. The set voltage drives the laser, and the voltage value is read through the LD feedback circuit. The optical power value measured by the optical power meter at this time is recorded, thus obtaining 26 sets of set voltage values, LD feedback voltage values, and optical power values. This data is stored in the flash memory of the ARM module. Based on the set target power value, the set voltage range can be obtained by looking up the list. At this point, the linear relationship between voltage and power can be approximated within a small voltage range, thereby calculating the initial set voltage value to achieve the target power.

2. A control system for a laser, characterized in that, include: ARM module and laser control module; the ARM module is equipped with a PID control algorithm; The laser control module includes a TEC module and a DA module; The TEC module is communicatively connected to the ARM module. When the laser starts working, the ARM module determines whether the detected laser housing temperature is within a preset range. If it is within the preset range, the TEC module does not work; otherwise, the ARM module controls the TEC module to start working, using its internal PID control algorithm to precisely adjust the laser operating temperature until the TEC module reaches the preset target temperature and maintains stable operation. The control method of the TEC module is as follows: when the laser starts working, the ARM module determines the detected laser housing temperature. When the ARM module detects that the laser housing temperature is between 0 and 35°C, the TEC module does not work; when the ARM module detects that the laser housing temperature is within... When the laser housing temperature is between -20℃ and -10℃, the ARM module controls the TEC module to start working, and the target temperature of the TEC module is set to -10℃, so that the TEC module maintains stable operation after reaching the target temperature. When the ARM module detects that the laser housing temperature is between -10℃ and 0℃, the ARM module controls the TEC module to start working, and the target temperature of the TEC module is set to 0℃, so that the TEC module maintains stable operation after reaching the target temperature. When the ARM module detects that the laser housing temperature is higher than 35℃, the ARM module controls the TEC module to start working, and the target temperature of the TEC module is set to 35℃, so that the TEC module maintains stable operation after reaching the target temperature. When the laser stops and then restarts, the above steps are repeated. The DA module is communicatively connected to the ARM module. The DA module contains an LD current feedback circuit. Based on the current data collected by the LD current feedback circuit and combined with a PID control algorithm, the ARM module calculates the error between the current power and the target power. It then drives the DA module to adjust the laser's output power in real time, ensuring stable operation of the laser near the target power. The relationship between the laser's output power and the set voltage employs an eighth-order calibration method: the ARM module sets a voltage to drive the laser, increasing the voltage sequentially from 0mV to 2500mV, reading the voltage value through the LD feedback circuit, recording the stabilized power value, and calculating the eighth-order calibration parameters between the output power and the set voltage based on the 26 recorded values. These eighth-order calibration parameters are then read back and written into the ARM module. In the flash memory of the module, by inputting the target power value, the initial set voltage value to achieve the target power can be calculated based on the eighth-order calibration parameters between the output power and the set voltage; or, the relationship between the laser's output power and the set voltage can be calibrated using a lookup table method: the ARM module sets the voltage to drive the laser, setting the voltage from 0mV, increasing it by 100mV sequentially up to 2500mV. The set voltage drives the laser, and the voltage value is read through the LD feedback circuit. The optical power value measured by the optical power meter at this time is recorded, thus obtaining 26 sets of set voltage values, LD feedback voltage values, and optical power values. This data is stored in the flash memory of the ARM module. Based on the set target power value, the set voltage range can be obtained by looking up the list. At this point, the linear relationship between voltage and power can be approximated within a small voltage range, thereby calculating the initial set voltage value to achieve the target power.

3. The control system as described in claim 1 or 2, characterized in that, The ARM module is equipped with a 12-bit DA module and a 12-bit ADC module. The output power of the laser is set through the 12-bit DA module, and the 12-bit ADC module collects the LD feedback current loop in real time. Combined with the PID control algorithm, the ARM module calculates the error between the current power and the target power based on the collected current data, and then drives the DA module to adjust the output power of the laser in real time, so that the laser operates stably near the target power.

4. The control system as described in claim 1 or 2, characterized in that, The ARM uses ADC and DMA loop mode to acquire the temperature feedback value of the TEC module and the voltage feedback value of the LD feedback current loop in real time.

5. A spectral analysis system, characterized in that, The system includes a spectrometer and a laser, wherein the laser includes the laser control system according to any one of claims 1-4, the spectrometer includes a spectral acquisition module, the spectral acquisition module includes a CCD module and an FPGA module, the FPGA module generates a timing drive to the CCD module to perform exposure for a certain integration time according to the received instructions, the CCD module feeds back the acquired analog quantity to the FPGA through an A / D conversion circuit, and the FPGA transmits the acquired spectral data to the ARM module for data processing.

6. The spectral analysis system as described in claim 5, characterized in that, The ARM module configures registers with the FPGA module via SPI or MIPI protocol, and the FPGA module transmits the acquired spectral data to the ARM module for data processing via SPI or MIPI protocol.

7. The spectral analysis system as described in claim 5, characterized in that, The ARM module integrates Boxcar smoothing and stretching algorithms to process the acquired spectral data. The processed data is then transmitted to a PC terminal or handheld device terminal via USB or serial communication.

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