Virtual simulation method and system for simulating Raman pulse laser generation process

Abstract

According to the virtual simulation method and system for simulating the Raman pulse laser generation process, based on the pulse slicing technology, the Runge-Kutta algorithm is used for numerical simulation of the Raman pulse generation process, the shape, width, peak intensity, monopulse energy and other output characteristics of the Raman pulse can be simulated, and the real-time performance of the Raman pulse laser generation process is improved. The time domain relation between the pump pulse and the Raman pulse can be reflected, and theoretical guidance is provided for experimental research.

Description

Technical Field

[0001] This invention belongs to the field of virtual simulation technology, and particularly relates to a virtual simulation method and system for simulating the generation process of Raman pulsed lasers. Background Art

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Traditional lasers are mostly based on rare-earth ion-doped laser crystals, which have limited wavelength radiation range. In order to expand the laser wavelength range, Raman lasers based on stimulated Raman scattering have been extensively studied and have broad application value in lidar, laser medicine, laser nanoguides, and laser displays.

[0004] To date, various crystalline Raman media have been grown, such as diamond, nitrates, vanadates, tungstates, molybdates, and iodates. Raman lasers offer flexible wavelength conversion, with the Raman output wavelength depending only on the pump wavelength. They possess advantages such as automatic phase matching, pulse compression, and beam cleaning, making them particularly advantageous for high-brightness, special-wavelength laser output. External cavity Raman lasers, in particular, facilitate the addition of frequency-doubling crystals within the cavity, enabling visible light laser output through further wavelength conversion. However, there are currently few reports on theoretical simulation software for the external cavity Raman pulse generation process. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a virtual simulation method and system for simulating the Raman pulse laser generation process. Based on pulse slicing technology, the Raman pulse generation process is numerically simulated using the Runge-Kutta algorithm, which can simulate the Raman pulse output characteristics and provide theoretical guidance for experimental research.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a virtual simulation method for simulating the Raman pulse laser generation process, comprising:

[0008] The pump light intensity density and Raman light intensity density are obtained when the pump pulse front reaches the Raman input mirror position. Combined with the coupled wave equation, the Raman light intensity density when it reaches the Raman output mirror position is calculated using the Runge-Kutta algorithm.

[0009] By using pulse slicing technology, the above process is repeated based on the round-trip characteristics of Raman light in the laser cavity to obtain the simulated Raman pulse shape.

[0010] Secondly, the present invention provides a virtual simulation system for simulating the Raman pulse laser generation process, comprising:

[0011] a calculation module configured to obtain the pump light intensity density and the Raman light intensity density when the pump pulse front reaches the Raman input mirror position, and calculate the Raman light intensity density when it reaches the Raman output mirror position using the Runge-Kutta algorithm in combination with the coupled wave equation;

[0012] The simulation module is configured to use pulse slicing technology to repeat the above process based on the round-trip characteristics of Raman light in the laser cavity to obtain the simulated Raman pulse shape.

[0013] In a third aspect, the present invention provides an electronic device comprising a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein the computer instructions, when executed by the processor, perform the method described in the first aspect.

[0014] Fourthly, the present invention provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in the first aspect.

[0015] Fifthly, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.

[0016] One or more of the above technical solutions have the following beneficial effects:

[0017] Based on pulse slicing technology, the present invention utilizes the Runge-Kutta algorithm to numerically simulate the generation process of Raman pulses. It can simulate the output characteristics of Raman pulses, such as shape, width, peak intensity, and single pulse energy, and can reflect the time domain relationship between pump pulses and Raman pulses, providing theoretical guidance for experimental research.

[0018] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 In (a), (b), and (c), the values ​​are 40 MW / cm². 2 、50MW / cm 2 60MW / cm 2 Simulation results of Raman pulse envelope under pump intensity density;

[0021] Figure 2 This is a schematic diagram of the Raman laser in Embodiment 1 of the present invention;

[0022] Figure 3 This is a schematic diagram of the pump Gaussian pulse slice in Embodiment 1 of the present invention;

[0023] Figure 4 This is a flowchart illustrating the algorithmic concept of pulse slicing technology in Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] It should be noted that the terms used herein are for describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention.

[0026] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0027] Example 1

[0028] This embodiment discloses a virtual simulation method for simulating the Raman pulse laser generation process, including:

[0029] The pump light intensity density and Raman light intensity density are obtained when the pump pulse front reaches the Raman input mirror position. Combined with the coupled wave equation, the Raman light intensity density when it reaches the Raman output mirror position is calculated using the Runge-Kutta algorithm.

[0030] By using pulse slicing technology, the above process is repeated based on the round-trip characteristics of Raman light in the laser cavity to obtain the simulated Raman pulse shape.

[0031] To theoretically explain the generation and compression of Raman pulses, a first-order Stokes Raman model was first established based on the plane wave approximation. This model can be extended to second-order and even higher-order modes. This embodiment uses pulse slicing technology and the Runge-Kutta algorithm to numerically simulate the generation process of Raman pulses. It can simulate the output characteristics of Raman pulses, such as shape, width, peak intensity, and single-pulse energy, and can also determine the time-domain relationship between pump pulses and Raman pulses, providing theoretical guidance for experimental research.

[0032] Equation for the strong coupling wave of first-order Raman light and pump light:

[0033]

[0034] Among them, I p and I s represents the intensity density of pump light and Raman light; λ p and λs Indicates the wavelength of the pump light and Raman light; g R K represents the Raman gain coefficient; α represents the Raman loss coefficient; K sp This represents the spontaneous Raman scattering factor.

[0035] Assume the pump pulse shape is Gaussian and the width is 155ns. Figure 1 Images (a), (b), and (c) show a capacity of 40 MW / cm². 2 、50MW / cm 2 and 60MW / cm 2 The simulation results of Raman pulse envelope under different pump intensity densities show the generation process of Raman pulses very well. As the pump light intensity increases, the Raman pulse width also increases accordingly from 27.3ns, 65.2ns to 88ns.

[0036] like Figure 2 As shown in the figure, a KYW Raman crystal is pumped with 1064nm pump light, generating first-order Raman light at 1178nm. To simplify the model, it is assumed that the distance between the Raman laser cavity mirror and the two end faces of the Raman crystal is negligible, and the cavity length is the crystal length L. IC is the Raman input mirror, coated with an anti-reflection coating for 1064nm (AR) and a high-reflection coating for 1178nm (HR); OC is the Raman output mirror, coated with a low-reflection coating with a reflectivity of 75% at 1178nm.

[0037] The idea of ​​pulse slicing technology is: Assuming that the pump pulse shape is Gaussian and the time for Raman light to travel back and forth in the cavity is △t, then the pump pulse is divided into N parts in the time domain, where N represents the maximum number of parts, such as Figure 3 As shown, where T n = n × Δt, where n represents an integer value between 0 and N. At time T0, the leading edge of the pump pulse reaches the input mirror position, and the pump light intensity density I at this time is taken. P0 , the Raman light intensity density is I S0 = 0 is brought into the coupled wave equation, and after propagation of length L, the Raman light intensity density I at the output mirror position is calculated using the Runge-Kutta algorithm. SL0 The pump light intensity density is I PL0 The time is T S0 = Δt / 2, where 25% of the Raman light is transmitted, and the output Raman light intensity density is I. SC0 =I SL0 ×25%, the reflected Raman light intensity density in the cavity is I SR0 =I SL0×75%. The reflected Raman light continues to propagate in the reverse direction. If the effect of the reflected pump light is ignored, the intensity of the return pump light can be considered to be 0. When the reflected Raman light reaches the input mirror again, it has completed one round trip within the laser cavity. Total internal reflection occurs at the input mirror, at which point the Raman light intensity density is I. S1 , time T1 = 1 × △t, and the pump light intensity density I at time T1 P1 The coupling effect continues, and the process goes back and forth again as above. The time is now T2 = 2 × △t, and the above process is repeated until the cycle ends N times. S0 , T S1 , T S2 …T SN ) and Raman output light intensity density (I SC0 , I SC1 , I SC2 …I SCN By plotting the image, the shape of the generated Raman pulse can be obtained. The flowchart of the pulse slicing technique algorithm is shown below. Figure 4 shown.

[0038] Example 2

[0039] The purpose of this embodiment is to provide a virtual simulation system for simulating the Raman pulse laser generation process, including:

[0040] The calculation module is configured to: obtain the pump light intensity density and Raman light intensity density when the leading edge of the pump pulse reaches the position of the Raman input mirror, and calculate the Raman light intensity density when it reaches the position of the Raman output mirror by combining the coupled wave equation and using the Runge-Kutta algorithm.

[0041] The simulation module is configured to: utilize pulse slicing technology to repeat the above process according to the round-trip characteristics of Raman light in the laser cavity to obtain a simulated Raman pulse shape.

[0042] In further embodiments, the following is also provided:

[0043] An electronic device includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor. When executed by the processor, the computer instructions perform the method described in Embodiment 1. For brevity, further details are omitted here.

[0044] It should be understood that in this embodiment, the processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0045] The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0046] A computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in Embodiment 1.

[0047] The method in Embodiment 1 can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, a detailed description is not provided here.

[0048] A computer program product includes a computer program that, when executed by a processor, implements the method described in Embodiment 1.

[0049] The present invention also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules, which execute in a device on a target real or virtual processor to perform the processes / methods described above. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of program modules can be combined or divided among program modules as needed. The machine-executable instructions for the program modules can execute within a local or distributed device. In a distributed device, the program modules can reside in both local and remote storage media.

[0050] The computer program code used to implement the methods of the present invention may be written in one or more programming languages. This computer program code may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the computer or other programmable data processing device, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a computer, partially on a computer, as a stand-alone software package, partially on a computer and partially on a remote computer, or entirely on a remote computer or server.

[0051] In the context of the present invention, computer program code or related data can be carried by any appropriate carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, and the like. Examples of signals include electrical, optical, radio, acoustic, or other forms of propagated signals, such as carrier waves, infrared signals, and the like.

[0052] Those skilled in the art will appreciate that the units and algorithm steps of the various examples described in conjunction with this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0053] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A virtual simulation method for simulating the Raman pulse laser generation process, characterized in that: include: Obtain the pump light intensity density and Raman light intensity when the front edge of the pump pulse reaches the Raman input mirror position, and combine the coupled wave equation to calculate the Raman light intensity density when it reaches the Raman output mirror position using the Runge-Kutta algorithm; By using pulse slicing technology, the above process is repeated according to the round-trip characteristics of Raman light in the laser cavity to obtain a simulated Raman pulse shape.

2. A virtual simulation method for simulating a Raman pulse laser generation process as claimed in claim 1, characterized in that: The pump light intensity density and Raman light intensity density when the front edge of the pump pulse reaches the Raman input mirror position are substituted into the coupled wave equation, and the Raman light intensity density when it reaches the Raman output mirror position is calculated using the Runge-Kutta algorithm; based on the fact that the reflected Raman light reaches the Raman input mirror again and makes a round trip in the laser cavity, the Raman light goes back and forth in the laser cavity multiple times, and the corresponding Raman output light intensity density and time are obtained respectively, and the corresponding Raman output light intensity and time are plotted to obtain the simulated Raman pulse shape.

3. A virtual simulation method for simulating a Raman pulse laser generation process as claimed in claim 1, characterized in that: The wave equation for the first-order Raman light and pump light intensity coupling is: Among them, I p and I s represents the intensity density of pump light and Raman light; λ p and λ s represents the wavelength of pump light and Raman light; g R represents the Raman gain coefficient; α represents the loss coefficient of Raman light; K sp represents the spontaneous Raman scattering factor.

4. A virtual simulation method for simulating a Raman pulse laser generation process as claimed in claim 1, characterized in that: The pump pulse shape is Gaussian.

5. A virtual simulation method for simulating a Raman pulse laser generation process as claimed in claim 2, characterized in that: The distance between the Raman laser cavity mirror and the two end faces of the Raman crystal is ignored, and the Raman laser cavity length is used as the crystal length for calculation.

6. A virtual simulation system for simulating the Raman pulse laser generation process, characterized in that: include: A calculation module is configured to: obtain the pump light intensity density and the Raman light intensity density when the pump pulse front reaches the Raman input mirror position, and calculate the Raman light intensity and the Raman light intensity when the pump pulse front reaches the Raman output mirror position by using the Runge-Kutta algorithm in combination with the coupled wave equation; The simulation module is configured to: utilize pulse slicing technology to repeat the above process according to the round-trip characteristics of Raman light in the laser cavity to obtain a simulated Raman pulse shape.

7. A virtual simulation system for simulating the Raman pulse laser generation process as claimed in claim 6, characterized in that: In the simulation module, when the reflected Raman light reaches the Raman input mirror again, the Raman light goes back and forth in the laser cavity for one round trip. The Raman light goes back and forth in the laser cavity for multiple times to obtain the corresponding Raman output light intensity density and time, and the corresponding Raman output light intensity density and time are plotted to obtain the simulated Raman pulse shape.

8. An electronic device, characterized in that: The method comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method according to any one of claims 1 to 5 is completed.

9. A computer-readable storage medium, characterized in that: Used to store computer instructions, which, when executed by a processor, complete the method described in any one of claims 1 to 5.

10. A computer program product, characterized in that The invention comprises a computer program, which, when executed by a processor, implements the method according to any one of claims 1 to 5.

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