A high power laser electric vector locking method and device

Abstract

The application discloses a high-power laser electric vector locking method and device, and relates to the technical field of lasers.The device comprises a collimator which receives laser generated by a laser through an optical fiber to form incident laser; the incident laser sequentially passes through an executing element module and a beam splitting detection module to obtain a feedback signal and send the feedback signal to a control processing module; the control processing module processes the feedback signal to generate a servo control instruction and send the servo control instruction to the executing element module; and the executing element module executes the servo control instruction to realize real-time closed-loop control of the high-power laser electric vector.The application realizes precise locking of the electric vector of laser with any intensity, and is especially suitable for a high-power and high single-photon energy laser system in which an electrically-controlled optical fiber attenuating device cannot be used, and has the characteristics of high precision, high speed and high sensitivity.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a method and apparatus for high-power laser electric vector locking. Background Technology

[0002] The amplitude (intensity) and direction (polarization) of a laser's electric vector have a significant impact on the interaction between light and matter, and are important parameters of the laser's electric vector. In the field of quantum precision measurement, extremely high stability of the laser's electric vector is required, necessitating precise adjustment to meet the experimental requirements of varying laser power and polarization states. Specifically, in quantum optics and atomic physics experiments, as ambient temperature and vibration conditions change, the laser's electric vector fluctuates over time after transmission through optical fibers, meaning the laser cannot couple into the experimental setup with stable power and polarization. Furthermore, the laser's own power fluctuations and polarization state changes are major sources of error in precision measurements. To avoid affecting the interaction between light and atoms and to ensure the accuracy of quantum precision measurements, the long-term stability of the laser's electric vector is crucial in experimental procedures.

[0003] In quantum precision measurement experiments, half-wave plates are frequently used to change the laser electric vector. However, this coarse method of manual adjustment is complex and cannot guarantee control precision or long-term stable output of the laser electric vector. Quantum precision measurement experiments often use high-power lasers. Compared to other power lasers, commonly used electrically controlled fiber optic attenuators are prone to wear and tear and may become inoperable. Existing technologies struggle to maintain a stable high-power laser lock for extended periods, failing to meet the experimental requirements of high-power lasers and representing a significant technological shortcoming. Therefore, there is an urgent need for a high-power laser electric vector locking device and method that can rapidly and precisely adjust the laser electric vector. Summary of the Invention

[0004] This invention addresses the problems of existing manual adjustment of half-wave plates, which is a coarse method with complex processes and cannot guarantee control precision and long-term stable output of laser electric vector. It also addresses the issues of existing technologies being unable to lock the laser to a high-power state stably for a long period of time, thus failing to meet the experimental requirements of high-power lasers and having serious technical shortcomings.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] On one hand, the present invention provides a high-power laser electric vector locking method, which is implemented by a high-power laser electric vector locking device. The device includes a collimator, an actuator module, a beam splitting detection module, and a control processing module arranged sequentially along the laser propagation direction. The method includes:

[0007] S1. The collimator receives the laser light generated by the laser through an optical fiber, forming the incident laser light.

[0008] S2. The incident laser sequentially passes through the actuator module and the beam splitting detection module to obtain a feedback signal, which is then sent to the control processing module.

[0009] S3, the control processing module processes the feedback signal, generates servo control commands, and sends them to the actuator module.

[0010] S4, the actuator module executes servo control commands to achieve real-time closed-loop control of the high-power laser electric vector.

[0011] Optionally, the actuator module includes a half-wave plate and a piezoelectric inertial rotary table.

[0012] A piezoelectric inertial rotary table is used to rotate the optical axis of a half-wave plate to adjust the direction of the laser electric vector.

[0013] The half-wave plate is placed on a piezoelectric inertial rotary table.

[0014] Optionally, the beam splitting detection module includes a GlanTeller prism, a photodetector, a non-polarizing beam splitter prism, and an NI acquisition card.

[0015] Optionally, the control processing module includes a PC-based controller and a rotary displacement stage controller.

[0016] Optionally, the incident laser in S2 passes sequentially through the actuator module and the beam splitting detection module to obtain a feedback signal, which is then sent to the control processing module, including:

[0017] S21. The incident laser beam passes through a half-wave plate and a Glan Taylor prism in sequence, forming ordinary light and anomalous light.

[0018] S22. Anomalous light passes through an unpolarized beam splitter to form transmitted light and reflected light; the transmitted light serves as the output laser, and the reflected light serves as the detection laser.

[0019] S23. The photodetector converts the detection laser into an electrical signal, which is then acquired by the NI acquisition card to obtain a feedback signal and send it to the PC controller in the control processing module.

[0020] Optionally, the control processing module in S3 processes the feedback signal, generates servo control commands, and sends them to the actuator module, including:

[0021] S31. The PC-side controller in the control processing module calculates the difference between the feedback signal and the set value to generate an error signal.

[0022] The S32 and PC-side controllers process error signals using point-by-point difference comparison or target shooting methods, generate servo control commands, and send them to the actuator module.

[0023] Optionally, the PC controller in S32 processes the error signal using a point-by-point difference comparison method or a target shooting method, generates servo control commands, and sends them to the actuator module, including:

[0024] The PC-side controller obtains the desired constant parameter and determines whether the constant parameter is within the adjustable range. If it is not within the adjustable range, an error is reported and a prompt is displayed; if it is within the adjustable range, the control process proceeds.

[0025] The control process includes:

[0026] When the constant parameter is near the nonlinear region, the error signal is processed by the shooting method, servo control commands are generated and sent to the actuator module.

[0027] When the constant parameter is within the linear region, the error signal is processed using the point-by-point difference comparison method, servo control commands are generated and sent to the actuator module.

[0028] Optionally, the actuator module in S4 executes servo control commands to achieve real-time closed-loop control of the high-power laser electric vector, including:

[0029] After receiving the servo control command, the rotary displacement stage controller in the actuator module instructs the piezoelectric inertial rotary stage to drive the half-wave plate to rotate, so that the electric vector direction of the incident laser and the polarization axis of the Glan Taylor prism form the required angle, thereby realizing real-time closed-loop control of the electric vector of the high-power laser.

[0030] On the other hand, the present invention provides a high-power laser electric vector locking device, which is used to realize a high-power laser electric vector locking method. The device includes a collimator, an actuator module, a beam splitting detection module and a control processing module arranged sequentially along the laser propagation direction.

[0031] The collimator is used to receive the laser light generated by the laser through an optical fiber, forming the incident laser light.

[0032] The actuator module is used to execute servo control commands to achieve real-time closed-loop control of the high-power laser electric vector.

[0033] The beam splitting detection module is used to obtain feedback signals and send them to the control processing module.

[0034] The control processing module is used to process the feedback signals, generate servo control commands, and send them to the actuator module.

[0035] Optionally, the actuator module includes a half-wave plate and a piezoelectric inertial rotary table.

[0036] A piezoelectric inertial rotary table is used to rotate the optical axis of a half-wave plate to adjust the direction of the laser electric vector.

[0037] The half-wave plate is placed on a piezoelectric inertial rotary table.

[0038] Optionally, the beam splitting detection module includes a GlanTeller prism, a photodetector, a non-polarizing beam splitter prism, and an NI acquisition card.

[0039] Optionally, the control processing module includes a PC-based controller and a rotary displacement stage controller.

[0040] Optionally, the actuator module and the beam splitting detection module are further used for:

[0041] S21. The incident laser beam passes through a half-wave plate and a Glan Taylor prism in sequence, forming ordinary light and anomalous light.

[0042] S22. Anomalous light passes through an unpolarized beam splitter to form transmitted light and reflected light; the transmitted light serves as the output laser, and the reflected light serves as the detection laser.

[0043] S23. The photodetector converts the detection laser into an electrical signal, which is then acquired by the NI acquisition card to obtain a feedback signal and send it to the PC controller in the control processing module.

[0044] Optionally, the control processing module is further used for:

[0045] S31. The PC-side controller in the control processing module calculates the difference between the feedback signal and the set value to generate an error signal.

[0046] The S32 and PC-side controllers process error signals using point-by-point difference comparison or target shooting methods, generate servo control commands, and send them to the actuator module.

[0047] Optionally, the control processing module is further used for:

[0048] The PC-side controller obtains the desired constant parameter and determines whether the constant parameter is within the adjustable range. If it is not within the adjustable range, an error is reported and a prompt is displayed; if it is within the adjustable range, the control process proceeds.

[0049] The control process includes:

[0050] When the constant parameter is near the nonlinear region, the error signal is processed by the shooting method, servo control commands are generated and sent to the actuator module.

[0051] When the constant parameter is within the linear region, the error signal is processed using the point-by-point difference comparison method, servo control commands are generated and sent to the actuator module.

[0052] Optionally, the execution element module is further used for:

[0053] After receiving the servo control command, the rotary displacement stage controller in the actuator module instructs the piezoelectric inertial rotary stage to drive the half-wave plate to rotate, so that the electric vector direction of the incident laser and the polarization axis of the Glan Taylor prism form the required angle, thereby realizing real-time closed-loop control of the electric vector of the high-power laser.

[0054] The above technical solution has at least the following advantages compared with the existing technology:

[0055] The above scheme establishes a constant-value control system that can lock the electric vector of a high-power laser. This system can automatically eliminate or weaken the influence of various disturbances on the controlled variable, and the controlled variable (high-power laser electric vector) can quickly recover to its original set steady-state value under any disturbance. It is particularly suitable for high-power, high-single-photon-energy laser systems where electrically controlled fiber optic attenuators cannot be used, and features high precision, high speed, and high sensitivity. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a schematic diagram of the high-power laser electric vector locking method provided in an embodiment of the present invention;

[0058] Figure 2 This is a loop flowchart for high-power laser electric vector locking provided in an embodiment of the present invention;

[0059] Figure 3 This is a diagram illustrating the control effect of locking high-power laser power in a nonlinear region, provided by an embodiment of the present invention.

[0060] Figure 4 This is a diagram illustrating the effect of laser power control in a linear region, provided by an embodiment of the present invention.

[0061] Figure 5 This is a diagram illustrating the control effect of high-power laser polarization state locking provided in an embodiment of the present invention;

[0062] Figure 6 This is a diagram illustrating the effect of adjusting the power accuracy of a high-power laser according to an embodiment of the present invention;

[0063] Figure 7 This is a block diagram of a high-power laser electric vector locking device provided in an embodiment of the present invention.

[0064] Explanation of reference numerals in the attached figures:

[0065] 101-Collider; 102-Piezoelectric inertial rotary stage; 103-Half-wave plate; 104-Glan Taylor prism; 105-Non-polarizing beam splitter prism; 106-Photodetector; 107-NI acquisition card; 108-PC terminal controller; 109-Rotary displacement stage controller. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0067] like Figure 1 As shown, this embodiment of the invention provides a high-power laser electric vector locking method, which can be implemented by a high-power laser electric vector locking device. This device includes a collimator, an actuator module, a beam splitting detection module, and a control processing module arranged sequentially along the laser propagation direction. Figure 1 The flowchart shown is for a high-power laser electric vector locking method. The processing flow of this method may include the following steps:

[0068] Optionally, the actuator module includes a half-wave plate and a piezoelectric inertial rotary table.

[0069] A piezoelectric inertial rotary table is used to rotate the optical axis of a half-wave plate to adjust the direction of the laser electric vector.

[0070] The half-wave plate is placed on a piezoelectric inertial rotary table.

[0071] Optionally, the beam splitting detection module includes a GlanTeller prism, a photodetector, a non-polarizing beam splitter prism, and an NI acquisition card.

[0072] Optionally, the control processing module includes a PC-based controller and a rotary displacement stage controller.

[0073] S1. The collimator receives the laser light generated by the laser through an optical fiber, forming the incident laser light.

[0074] In one feasible implementation, the laser generates laser light with certain polarization (electric vector direction) characteristics, which is transmitted through polarization-maintaining fiber and then coupled into free space through a collimator to form a collimated device for incident laser light.

[0075] This invention is based on the principle that rotating polarized light using a half-wave plate changes the electric vector of the laser. The electric vector of the laser can be represented by the Stokes vector S, where S = [S0, S1, S2, S3], where S0 represents the total light intensity, and S1, S2, and S3 represent the polarization intensity relationship in three-dimensional space. After normalizing the Stokes vector, its three-dimensional coordinates on the Poincaré sphere are obtained, with each coordinate corresponding to a polarization state. This invention achieves precise adjustment and accurate locking of the laser electric vector through a closed-loop feedback system formed by a high-resolution sampling circuit and high-precision actuators.

[0076] S2. The incident laser sequentially passes through the actuator module and the beam splitting detection module to obtain a feedback signal, which is then sent to the control processing module.

[0077] Optionally, step S2 above may include S21-S23:

[0078] S21. The incident laser beam passes through a half-wave plate and a Glan Taylor prism in sequence, forming ordinary light and anomalous light.

[0079] In one feasible implementation, the incident laser passes through a half-wave plate connected to a piezoelectric inertial rotating stage. The direction of the laser electric vector can be adjusted by adjusting the piezoelectric inertial rotating stage. Then, it passes through a Glan Taylor prism to separate the two different polarization components of the light. The o-ray (ordinary light) undergoes total internal reflection and is emitted to one side where it is absorbed, while the e-ray (anomalous light) continues to propagate.

[0080] S22. Anomalous light passes through an unpolarized beam splitter to form transmitted light and reflected light; the transmitted light serves as the output laser, and the reflected light serves as the detection laser.

[0081] In one feasible implementation, the direction of the polarization axis of the Glan Taylor prism sets the direction of the output laser electric vector, and the angle between the polarization axis and the direction of the incident laser electric vector determines the transmittance, thereby determining the amplitude of the output laser electric vector; after the e-beam passes through the unpolarized beam splitter prism, the transmitted light serves as the output laser, and the reflected light serves as the probe laser, with a constant power ratio between the transmitted and reflected light.

[0082] S23. The photodetector converts the detection laser into an electrical signal, which is then acquired by the NI acquisition card to obtain a feedback signal and send it to the PC controller in the control processing module.

[0083] S3, the control processing module processes the feedback signal, generates servo control commands, and sends them to the actuator module.

[0084] Optionally, step S3 above may include S31-S32:

[0085] S31. The PC-side controller in the control processing module calculates the difference between the feedback signal and the set value to generate an error signal.

[0086] S32. The PC-side controller obtains the desired constant parameter and determines whether the constant parameter is within the adjustable range. If it is not within the adjustable range, an error is reported and a prompt is displayed; if it is within the adjustable range, the control process is initiated.

[0087] One feasible implementation method is, for example Figure 2 As shown, the control processing module is first initialized: Since rotating the optical axis of the half-wave plate can rotate the light polarization, it changes the electric vector direction of the emitted laser, which is also the electric vector direction of the incident laser through the GlanTaylor prism. In the Stokes vector, S0 is related to the laser power, and the transmission power S of the GlanTaylor prism is... 0t The change conforms to Malus's law S 0t =S 0i cos 2 θ, (θ is the angle between the polarization of the incident light and its polarization axis in the GlanTaylor prism, S) 0i (This refers to the laser power incident on the GlanTeller prism). Figure 3 In the middle, the curve-unidirectional rotating waveplate output optical power S 0t As shown in the curve, the displacement of the piezoelectric inertial rotary table is positively correlated with the horizontal axis time. Therefore, this curve can be regarded as the displacement and power (i.e., S) of the piezoelectric inertial rotary table. 0t (θ) change relationship diagram, the area with near linear change in the diagram is defined as the linear region, and the area near the peak and valley values ​​is defined as the non-linear region.

[0088] The control processing module drives the half-wave plate to rotate 360° in one direction. The beam splitting detection module collects the feedback voltage signal during the rotation process to obtain the controllable and adjustable range, the positive adjustment direction (which direction increases power), the linear region, the nonlinear region, and other system self-calibration parameters required for the system initialization parameter control process.

[0089] Furthermore, to demonstrate the locking effect, the stability of the laser electric vector amplitude is characterized by the stability of the S0 stability in the Stokes vector, and the stability of the laser electric vector direction is characterized by the stability of the three-dimensional coordinates of the Stokes vectors S1, S2, and S3 (which determine the direction of the electric vector) on the Poincaré sphere and their angular distance from the set point, as measured in real time.

[0090] Furthermore, precise adjustment and constant value stabilization are performed. The process includes: setting the desired constant value parameter; the control processing module determines whether the parameter is within the adjustable range; if it is not within the range, an error is reported and a prompt is displayed; otherwise, the control process proceeds.

[0091] Optionally, when the constant parameter is near the nonlinear region, i.e. when the high-power electric vector (more than 95% of the highest power) is locked, the rotary table is first controlled to rotate the half-wave plate in one direction to reach the nonlinear region where the constant value is located; the control processing module uses the target shooting method to process the error signal, and the execution element module performs the processing to obtain the servo control parameters to adjust the laser electric vector. Figure 3 To establish a high-power stable performance diagram for the desired constant value in the nonlinear region, the high-power output laser power is set to 99% of the maximum power (0.2W), i.e., S. 0t =0.198W, the high-power output laser power stability accuracy can reach 0.001W.

[0092] In one feasible implementation, a part of the approach of using the target-shooting method to solve the root of the differential equation is employed to address the problem of locking the laser electric vector in the nonlinear region. When the voltage signal (feedback signal) is in the nonlinear region, the correspondence between the rotation direction of the half-wave plate (i.e., the motion direction of the rotary table) and the change direction of the amplitude (laser power) of the laser electric vector will frequently change. Therefore, the single adjustment positive direction parameter obtained during the initialization process in the point-by-point difference comparison method cannot meet the locking requirements in this region. It is necessary to use the idea of ​​the target-shooting method to lock the laser electric vector in the nonlinear region.

[0093] First, the rotation step size of the rotary table is set to the minimum, and the voltage value V is set. 设定 Real-time voltage value V after rotation with the rotary table i实时 The absolute value of the difference, i.e., the error signal V. i The absolute value is |V i |=|V 设定 -V i实时 First, n real-time voltage signals (V) are collected during the n rotations of the rotary table. i实时 V (i+1)实时 ,…,V (i+n-1)实时 ), and calculate n judgment values ​​(|V) i |,|V i+1 |,…,|V i+n-1 |), for |V i |Calculate the difference to obtain Δ|V i |=|V i+n-1 |-|V i |, by judging Δ|V i | to determine the direction of motion, if Δ|V i If |≤0, then maintain the original direction of motion; if Δ|V i |>0, changes the direction of movement.

[0094] For example, in the first judgment, the n error signals are V 1实时 V2实时 ,…,V n实时 Δ|V1|=|V n The direction of motion is determined by Δ|V1|. If Δ|V1|≤0, the original direction of motion is maintained; if Δ|V1|>0, the direction of motion is changed.

[0095] After repeating the above process multiple times, the absolute value of the error signal will approach the error accuracy, thus achieving the goal of constant value stability.

[0096] Optionally, within the linear region, the constant parameter is processed using a point-by-point difference comparison method to obtain new servo control parameters such as Step and λ. The actuator module then executes these new servo control parameters to adjust the laser electric vector.

[0097] In one feasible implementation, the point-by-point difference comparison method is a successive approximation algorithm. The general idea is to first provide an initial iterative value, then repeatedly iterate the selected initial value until an iterative value meeting the accuracy requirements is obtained. This control method, applied to a high-power laser electric vector locking device, can quickly, accurately, and stably lock the laser electric vector in the linear region to a set value over a long period, and can overcome the interference of external conditions such as ambient temperature and vibration on the laser electric vector. Furthermore, this control method has the following advantages, such as overcoming a series of errors affecting displacement accuracy generated during the rotation of the piezoelectric rotary table. The piezoelectric rotary table rotates using static friction, and the presence of sliding friction leads to hysteresis errors during rotation.

[0098] Furthermore, after the laser passes through the Glan Taylor prism, the e-ray passes through the non-polarizing beam splitter prism. The transmitted light becomes the output laser, and the reflected light becomes the probe laser. The power ratio of the transmitted light and the reflected light is constant. The photodetector converts the probe laser into a voltage signal, and the NI acquisition card acquires the electrical signal and sends it to the PC controller as a feedback signal.

[0099] Since the power ratio of the probe laser (reflected light) and the output laser (transmitted light) is constant, when the output laser is output at a set constant power, the value of the feedback signal (voltage signal) is also the corresponding set constant voltage value. This set constant voltage value V... 设定 The actual voltage value V after rotating with the rotary table i实时 The difference V i =V 设定 -V i实时 This serves as both an error signal and an iterative value for the point-by-point difference comparison method, with the iteration step size being the voltage change ΔV after each rotation. i The iterative formula is shown in equation (1) below:

[0100] V i=V i-1 +ΔV i (1)

[0101] In the formula, V i Let ΔV be the iteration value after the i-th rotation. i Let be the change in voltage after the i-th rotation.

[0102] Based on the absolute value of the error signal |V i The linear region is divided into different intervals, and within each interval, a different rotation parameter (λ) is used. j and Step j Control the rotary table. Step j For |V i | The step size of the rotary table during rotation in interval j; λ j For |V i In interval j, the voltage-step proportionality coefficient corresponds to the rotation of the rotary table, taking positive values ​​in the positive direction and negative values ​​in the negative direction. Rotation parameters (|λ) for different intervals. j | and Step j As shown in Table 1 below:

[0103] Table 1

[0104] interval <![CDATA[|V i |]]> <![CDATA[|λ i |]]> <![CDATA[Step i <!-- 6 -->]]> Interval 0 <![CDATA[|V i |≤Error Precision]]> 0 0 Interval 1 <![CDATA[Error precision < |V i | ≤ V 区间1 > <![CDATA[λ1]]> <![CDATA[Step1]]> Interval 2 <![CDATA[V 区间1 <|V i |≤V 区间2 ]]> <![CDATA[λ2]]> <![CDATA[Step2]]> … … … … interval j <![CDATA[V 区间(j-1) <|V i |≤V 区间j ]]> <![CDATA[λ j ]]> <![CDATA[Step j ]]>

[0105] In interval j, the theoretical voltage change λ after each rotation j ×Step j With iteration step size ΔV i Error exists i Error i This refers to the error caused by treating the approximately linear region as a linear region during the i-th rotation, due to theoretical errors and other external disturbances. Therefore:

[0106] ΔV i =λ j ×Step j Error i (2)

[0107] Error generated per rotation i Due to uncertainty, the point-by-point interpolation method is used for control, which can mitigate the errors generated by each rotation. i Accumulated to ΔV i In this way, the error signal V is accumulated. i In the middle, minimize errors as much as possible. i The impact.

[0108] First, during the first rotation of the rotary table, the initial iteration value (set as a constant voltage value V) is... 设定 The initial voltage V sampled in real time before the rotary table rotates 0实时 The difference is V0. Based on |V0|, the first rotation is in interval j. Therefore, the step size Step when the rotary table performs the first rotation is... j The voltage and step size proportionality coefficient λ during the first rotation of the rotary table j If the error in the first rotation process is Error1, then the iteration value after the first rotation of the rotary table is as follows (3):

[0109] V1=V0+ΔV1=V0+λ j ×Step j +Error1 (3)

[0110] When the rotary table performs its second rotation, it is determined based on |V1| that the second rotation occurs within interval j, i.e., during the second iteration:

[0111] V2=V1+ΔV2=V1+λ j ×Step j +Error2 (4)

[0112] This process is repeated iteratively, with the iteration value V. i The numbers are V3, V4…V in sequence. n Until the i-th rotation, V i-1 Let |V| be the iteration value after the (i-1)th rotation. i |≤ Error Accuracy, located in the interval 0, the step size of the rotary table during the i-th rotation is 0 and the voltage-step proportionality coefficient is 0, therefore the iteration value V after the i-th rotation of the rotary table is 0. i for:

[0113] V i =V i-1 +ΔV i =V i-1 Error i (5)

[0114] After stopping the iteration, the change in the error signal is determined by Error. i Dominant, real-time monitoring of error signal V i This is to determine whether point-by-point interpolation control needs to be performed again.

[0115] like Figure 4 The image shows the power stabilization effect when the desired constant value is set in the linear region, with the output laser power S... 0t The output laser power is set to fluctuate between approximately 50% and 45% of the maximum output laser power (0.2W), i.e., S. 0t=0.0985W, and its output laser power stability accuracy can reach 0.001W.

[0116] Through the above constant-value stabilization process, the transmission power S of the Glan Taylor prism corresponding to the current constant parameter can be quickly and accurately determined. 0t The system is stable and simultaneously locks the angle between the incident laser electric vector direction corresponding to the current constant parameter and the polarization axis of the GlanTeller prism, thus achieving locking of the laser electric vector amplitude and direction. It can quickly and accurately lock the electric vector corresponding to the current constant parameter, that is, lock the laser power related to the laser electric vector amplitude to a constant value of ±0.0005W, and can also lock the laser polarization state related to the laser electric vector direction. By adjusting the constant parameter, the system can respond rapidly, change the laser power and polarization state, and lock them, thereby achieving precise adjustment of the laser electric vector of arbitrary intensity.

[0117] The polarization state of a laser (the direction of its electric vector) can be represented by a Stokes vector. A normalized Stokes vector corresponds to a point on a Poincaré sphere; different points on the Poincaré sphere correspond to different Stokes vectors, i.e., different polarization states. Therefore, the angular distance between a measured point and a set point on the Poincaré sphere can be used to measure the deviation between the actual polarization state and the set polarization state. Figure 5 As shown, compared with the input laser, the angular distance between the measured point and the set point on the Poincaré sphere of the output laser is significantly reduced, the deviation between the polarization state of the output laser and the set value is reduced, and the fluctuation of the polarization state of the output laser is significantly reduced.

[0118] By adjusting the constant parameters, the system can respond rapidly, changing and locking the laser power and polarization state, thereby achieving precise adjustment of the laser electric vector. Figure 6 The diagram illustrates the effect of precise adjustment of high-power laser power, with output optical power S. 0t Adjust from 0.1975W to 0.1955W.

[0119] S4. After receiving the servo control command, the rotary displacement stage controller in the actuator module commands the piezoelectric inertial rotary stage to drive the half-wave plate to rotate, so that the electric vector direction of the incident laser and the polarization axis of the Glan Taylor prism form the required angle, thereby realizing real-time closed-loop control of the high-power laser electric vector.

[0120] In one feasible implementation, after receiving the servo signal, the rotary displacement stage controller instructs the piezoelectric inertial rotary stage to drive the half-wave plate to rotate, thereby forming a suitable angle between the incident laser electric vector direction and the polarization axis of the Glan Taylor prism, achieving constant real-time closed-loop control of the high-power laser electric vector (direction and amplitude).

[0121] In this embodiment of the invention, a constant-value control system is established that can lock the electric vector of a high-power laser. This system can automatically eliminate or weaken the influence of various disturbances on the controlled quantity, and the controlled quantity (high-power laser electric vector) can quickly recover to its original set steady-state value under any disturbance. It is particularly suitable for high-power, high-single-photon-energy laser systems where electrically controlled fiber optic attenuators cannot be used, and features high precision, high speed, and high sensitivity.

[0122] like Figure 7 As shown, this embodiment of the invention provides a high-power laser electric vector locking device, which is used to implement a high-power laser electric vector locking method. The device includes a collimator 101, an actuator module, a beam splitting detection module, and a control processing module arranged sequentially along the laser propagation direction.

[0123] The collimator 101 is used to receive the laser generated by the laser through an optical fiber to form an incident laser.

[0124] The actuator module is used to execute servo control commands to achieve real-time closed-loop control of the high-power laser electric vector.

[0125] The beam splitting detection module is used to obtain feedback signals and send them to the control processing module.

[0126] The control processing module is used to process the feedback signals, generate servo control commands, and send them to the actuator module.

[0127] Optionally, the actuator module includes a half-wave plate 103 and a piezoelectric inertial rotary table 102.

[0128] The piezoelectric inertial rotary stage 102 is used to rotate the optical axis of the half-wave plate 103 to adjust the direction of the laser electric vector.

[0129] The half-wave plate 103 is mounted on the piezoelectric inertial rotary table 102.

[0130] Optionally, the beam splitting detection module includes a Glan Taylor prism 104, a photodetector 106, a non-polarizing beam splitter prism 105, and an NI acquisition card 107.

[0131] Optionally, the control processing module includes a PC-side controller 108 and a rotary displacement stage controller 109.

[0132] Optionally, the actuator module and the beam splitting detection module are further used for:

[0133] S21. The incident laser beam passes sequentially through the half-wave plate 103 and the Glan Taylor prism 104 to form ordinary light and anomalous light.

[0134] S22. Anomalous light passes through the non-polarized beam splitter 105 to form transmitted light and reflected light; among them, the transmitted light serves as the output laser and the reflected light serves as the detection laser.

[0135] S23, the photodetector 106 converts the detection laser into an electrical signal, which is then acquired by the NI acquisition card 107 to obtain a feedback signal and send it to the PC-side controller 108 in the control processing module.

[0136] Optionally, the control processing module is further used for:

[0137] S31. The PC-side controller 108 in the control processing module calculates the difference between the feedback signal and the set value to generate an error signal.

[0138] S32 and PC-side controller 108 process the error signal using point-by-point difference comparison method or target shooting method, generate servo control commands and send them to the actuator module.

[0139] Optionally, the control processing module is further used for:

[0140] The PC-side controller 108 acquires the desired constant parameter and determines whether the constant parameter is within the adjustable range. If it is not within the adjustable range, an error is reported and a prompt is displayed; if it is within the adjustable range, the control process is initiated.

[0141] The control process includes:

[0142] When the constant parameter is near the nonlinear region, the error signal is processed by the shooting method, servo control commands are generated and sent to the actuator module.

[0143] When the constant parameter is within the linear region, the error signal is processed using the point-by-point difference comparison method, servo control commands are generated and sent to the actuator module.

[0144] Optionally, the execution element module is further used for:

[0145] After receiving the servo control command, the rotary displacement stage controller 109 in the actuator module commands the piezoelectric inertial rotary stage 102 to drive the half-wave plate 103 to rotate, so that the electric vector direction of the incident laser and the polarization axis of the Glan Taylor prism 104 form the required angle, thereby realizing real-time closed-loop control of the electric vector of the high-power laser.

[0146] In this embodiment of the invention, a constant-value control system is established that can lock the electric vector of a high-power laser. This system can automatically eliminate or weaken the influence of various disturbances on the controlled quantity, and the controlled quantity (high-power laser electric vector) can quickly recover to its original set steady-state value under any disturbance. It is particularly suitable for high-power, high-single-photon-energy laser systems where electrically controlled fiber optic attenuators cannot be used, and features high precision, high speed, and high sensitivity.

[0147] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0148] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-power laser electric vector locking method, characterized in that, The method is implemented by a high-power laser electric vector locking device, which includes a collimator, an actuator module, a beam splitting detection module, and a control processing module arranged sequentially along the laser propagation direction. The method includes: S1. The collimator receives the laser generated by the laser through an optical fiber to form an incident laser. S2. The incident laser sequentially passes through the actuator module and the beam splitting detection module to obtain a feedback signal, which is then sent to the control processing module. S3. The control processing module processes the feedback signal, generates servo control commands, and sends them to the execution element module. S4. The actuator module executes the servo control command to achieve real-time closed-loop control of the high-power laser electric vector; The beam splitting detection module includes a GlanTell prism, a photodetector, a non-polarizing beam splitter prism, and an NI acquisition card. The incident laser in S2 sequentially passes through the actuator module and the beam splitting detection module to obtain a feedback signal, which is then sent to the control processing module, including: S21. The incident laser beam passes sequentially through a half-wave plate and a Glan Taylor prism to form ordinary light and anomalous light. S22. The anomalous light passes through a non-polarized beam splitter to form transmitted light and reflected light; wherein, the transmitted light serves as the output laser, and the reflected light serves as the detection laser. S23. The photodetector converts the detection laser into an electrical signal, which is then acquired by the NI acquisition card to obtain a feedback signal and send it to the PC controller in the control processing module. The control processing module in S3 processes the feedback signal, generates servo control commands, and sends them to the actuator module, including: S31. The PC-side controller in the control processing module calculates the difference between the feedback signal and the set value to generate an error signal. S32. Treat the output optical power variation curve of the unidirectional rotating waveplate as a relationship diagram of displacement and power variation of the piezoelectric inertial rotary table, and delineate the linear and nonlinear regions based on the relationship diagram. The PC-side controller acquires the desired constant value parameter and determines whether the constant value parameter is within the adjustable range. If it is not within the adjustable range, an error is reported and a prompt is displayed; if it is within the adjustable range, the control process is initiated. The control process includes: When the constant parameter is near the nonlinear region, the rotary table is first controlled to rotate the half-wave plate in one direction until it reaches the nonlinear region where the constant parameter is located. The error signal is then processed by the target shooting method to generate servo control commands and send them to the actuator module. The error signal is processed using a target-shooting method, which includes: setting the motion step size of the rotary table to a minimum and setting a voltage value. Real-time voltage value after rotation with the rotary table The absolute value of the difference, i.e., the error signal. The absolute value is First, collect During the rotation of the secondary rotary table A real-time voltage signal was obtained, and the result was calculated. Each judgment value is used to calculate the difference. By judgment To determine the direction of movement, if If ≤0, then maintain the original direction of motion; if Change the direction of movement; When the constant parameter is within the linear region, the error signal is processed by the point-by-point difference comparison method to generate servo control commands and send them to the actuator module. The error signal is processed using a point-by-point difference comparison method, including: setting a constant voltage value. Actual voltage value after rotation with the rotary table The difference This serves as the error signal and as the iterative value for the point-by-point difference comparison method, with the iteration step size being the voltage change after each rotation. Based on the absolute value of the error signal The linear region is divided into different intervals, and the rotary table is controlled with different rotation parameters in the different intervals. The rotation parameters include the proportional coefficient between voltage and step size when the rotary table rotates, and the step size when the rotary table rotates.

2. The method according to claim 1, characterized in that, The actuator module includes a half-wave plate and a piezoelectric inertial rotary table; The piezoelectric inertial rotary table is used to rotate the optical axis of the half-wave plate to adjust the direction of the laser electric vector. The half-wave plate is disposed on the piezoelectric inertial rotating platform.

3. The method according to claim 1, characterized in that, The control processing module includes a PC-based controller and a rotary displacement stage controller.

4. The method according to claim 1, characterized in that, The actuator module in S4 executes the servo control command to achieve real-time closed-loop control of the high-power laser electric vector, including: After receiving the servo control command, the rotary displacement stage controller in the actuator module instructs the piezoelectric inertial rotary stage to drive the half-wave plate to rotate, thereby forming the required angle between the electric vector direction of the incident laser and the polarization axis of the Glan Taylor prism, thus realizing real-time closed-loop control of the high-power laser electric vector.

5. A high-power laser electric vector locking device, said device being used to implement the high-power laser electric vector locking method as described in any one of claims 1-4, characterized in that, The device includes a collimator, an actuator module, a beam splitting detection module, and a control processing module arranged sequentially along the laser propagation direction; The collimator is used to receive laser light generated by the laser through an optical fiber to form incident laser light. The actuator module is used to execute the servo control command to achieve real-time closed-loop control of the high-power laser electric vector; The beam splitting detection module is used to obtain feedback signals and send them to the control processing module; The control processing module is used to process the feedback signal, generate servo control commands, and send them to the actuator module.

6. The apparatus according to claim 5, characterized in that, The actuator module includes a half-wave plate and a piezoelectric inertial rotary table; The piezoelectric inertial rotary table is used to rotate the optical axis of the half-wave plate to adjust the direction of the laser electric vector. The half-wave plate is disposed on the piezoelectric inertial rotating platform.

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