Non-collinear polychromatic laser drive system and method

Abstract

The application provides a non-collinear multicolor laser driving system and method. The system comprises a pump light generator, a fundamental light generator and a nonlinear crystal. The pump light generator is configured to emit pump light to the nonlinear crystal according to received first optical path parameters. The fundamental light generator is configured to emit at least two beams of fundamental light to the nonlinear crystal according to received second optical path parameters, and the frequency of each two beams of fundamental light is different. The nonlinear crystal is configured to generate a non-collinear multicolor laser for driving inertial confinement fusion through a sum frequency method. The non-collinear multicolor laser comprises at least two beams of sub-beams, the number of the sub-beams is the same as the number of the fundamental light, the angle range of the included angle between each two beams of sub-beams is 0.1°-5°, and the frequency difference range is 0.3%-2% of the central frequency. In this way, the intensity of laser plasma instability can be effectively suppressed when driving inertial confinement fusion, and the system design is simplified and the system difficulty is reduced.

Description

Technical Field

[0001] This application relates to the field of inertial confinement fusion technology and fusion energy, and in particular to a non-collinear multicolor laser driving system and method. Background Technology

[0002] Inertial confinement fusion (ICF) is one of the important pathways to achieve controlled nuclear fusion. ICF utilizes a high-power laser to directly or indirectly irradiate a target pellet. The resulting plasma is rapidly ejected outwards, and due to the rocket effect, the nuclear fuel is compressed inwards. Once ignition conditions are met, a controlled fusion reaction occurs. Ultimately, sustainable clean energy is generated by increasing the energy gain of nuclear fusion.

[0003] Various instabilities exist during fusion, leading to reduced laser energy conversion efficiency and decreased implosion quality. Laser plasma instabilities (LPI) are one of the main limiting factors. In indirect-drive configurations, existing methods suppress LPI by reducing the gas density in the black cavity. However, this causes high-Z atoms from the black cavity walls to mix into the target pellet, resulting in a significant decrease in the final implosion efficiency, or even failure to ignite. Therefore, reducing the impact of LPI without compromising black cavity performance is crucial.

[0004] Currently, schemes for suppressing LPI using broadband light have been proposed. A series of large-scale simulations have confirmed that if the laser bandwidth is much larger than the LPI growth rate, the linear growth of LPI can be reduced. However, due to the strong coupling between different frequency components of narrowband continuous-spectrum incoherent lasers over long timescales, uncontrollable plasma turbulence is generated, resulting in poor actual suppression effects. Meanwhile, there is currently no mature technology to efficiently generate high-power broadband third-harmonic lasers. Therefore, the collinear polychromatic light (CPL) scheme has been proposed, which faces no technical difficulties. However, the CPL scheme requires at least four beams of light of different frequencies incident along the same direction, which is a very complex engineering problem in practical applications.

[0005] Therefore, finding a solution that can effectively suppress LPI while reducing engineering difficulty is crucial for achieving efficient and robust ICF. Summary of the Invention

[0006] The purpose of this application is to address at least one of the aforementioned technical deficiencies, particularly to find a solution that can effectively suppress LPI while reducing engineering difficulty for achieving efficient and robust ICF.

[0007] In a first aspect, this application provides a non-collinear multicolor laser driving system, the system comprising: a pump light generator, a fundamental frequency light generator, and a nonlinear crystal;

[0008] The pump light generator is used to emit pump light to the nonlinear crystal according to the received first optical path diagram parameters;

[0009] The fundamental frequency light generator is used to emit at least two fundamental frequency beams to the nonlinear crystal according to the received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency beams are different.

[0010] The nonlinear crystal is used to generate non-collinear multicolor lasers for driving inertial confinement fusion via a sum-frequency method; the non-collinear multicolor lasers include at least two sub-beams, the number of which is the same as the number of the fundamental frequency light, the angle between each pair of sub-beams is in the range of 0.1° to 5°, and the frequency difference is in the range of 0.3% to 2% of the center frequency.

[0011] In one embodiment, the non-collinear multicolor laser comprises 2 to 20 sub-beams.

[0012] In one embodiment, the intensity range of each sub-beam in the non-collinear multicolor laser is 10. 12 W / cm 2 Up to 10 15 W / cm 2 .

[0013] In one embodiment, the non-collinear multicolor laser has a wavelength range from visible light to ultraviolet light.

[0014] In one embodiment, the pump light has a wavelength of 526.5 nm.

[0015] Secondly, this application provides a non-collinear multicolor laser driving method, which is applied to the non-collinear multicolor laser driving system described in any of the above embodiments; the method includes:

[0016] The pump light generator emits pump light toward the nonlinear crystal according to the received first optical path diagram parameters;

[0017] The fundamental frequency light generator emits at least two beams of fundamental frequency light to the nonlinear crystal according to the received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency light beams are different.

[0018] The nonlinear crystal generates non-collinear multicolor lasers for driving inertial confinement fusion via a sum-frequency method; the non-collinear multicolor lasers include at least two sub-beams, the number of which is the same as the number of the fundamental frequency light, the angle between each pair of sub-beams is in the range of 0.1° to 5°, and the frequency difference is in the range of 0.3% to 2% of the center frequency.

[0019] In one embodiment, the non-collinear multicolor laser comprises 2 to 20 sub-beams.

[0020] In one embodiment, the intensity range of each sub-beam in the non-collinear multicolor laser is 10. 12 W / cm 2 Up to 10 15 W / cm 2 .

[0021] In one embodiment, the non-collinear multicolor laser has a wavelength range from visible light to ultraviolet light.

[0022] In one embodiment, the pump light has a wavelength of 526.5 nm.

[0023] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0024] This application provides a non-collinear multicolor laser driving system, the system comprising: a pump light generator, a fundamental frequency light generator, and a nonlinear crystal; the pump light generator is used to emit pump light to the nonlinear crystal according to received first optical path diagram parameters; the fundamental frequency light generator is used to emit at least two fundamental frequency beams to the nonlinear crystal according to received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency beams are different; the nonlinear crystal is used to generate a non-collinear multicolor laser for driving inertial confinement fusion by a sum-frequency method; the non-collinear multicolor laser comprises at least two sub-beams, the number of sub-beams being the same as the number of fundamental frequency beams, the angle between each pair of sub-beams ranging from 0.1° to 5°, and the frequency difference ranging from 0.3% to 2% of the center frequency. In non-collinear multicolor lasers, the angle between any two sub-beams ranges from 0.1° to 5°, and the frequency difference ranges from 0.3% to 2% of the center frequency. This can effectively suppress the intensity of laser plasma instability when driving inertial confinement fusion, thereby significantly improving the fusion gain of inertial confinement fusion. At the same time, non-collinear multicolor lasers only require two sub-beams to maintain the same suppression effect as collinear multicolor laser schemes, simplifying system design and reducing system complexity. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a non-collinear multicolor laser driving system provided in an embodiment of this application;

[0027] Figure 2 Theoretical models of stimulated Raman scattering excited by collinear and non-collinear multicolor lasers are provided for embodiments of this application;

[0028] Figure 3 Theoretical model of stimulated Brillouin scattering excited by single-frequency light and non-collinear multicolor laser provided in the embodiments of this application;

[0029] Figure 4 The results of LPI two-dimensional particle simulation (PIC) for single-frequency light, collinear multicolor laser and non-collinear multicolor laser excitation provided in the embodiments of this application;

[0030] Figure 5 The results of three-dimensional PIC simulation of LPI excited by single-frequency light and non-collinear multicolor laser provided in the embodiments of this application;

[0031] Figure 6 This is a schematic flowchart of a non-collinear multicolor laser driving method provided in an embodiment of this application. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] like Figure 1 As shown, this application provides a non-collinear multicolor laser driving system, the system comprising: a pump light generator 101, a fundamental frequency light generator 102, and a nonlinear crystal 103.

[0034] The pump light generator 101 is used to emit pump light to the nonlinear crystal 103 according to the received first optical path diagram parameters.

[0035] Specifically, the pump light generator 101 refers to a device used to emit pump light. The pump light generator 101 can set relevant parameters of the pump light according to the received first optical path diagram parameters. It is understood that the specific implementation principle and / or specific circuit of the pump light generator 101 can be determined according to actual conditions, and this application does not impose specific limitations in this regard. The positions of the pump light generator 101 and the fundamental frequency light generator 102 can be determined according to the required angle of the emitted light, and the number of fundamental frequency light generators 102 can be selected according to actual conditions, and is not limited to... Figure 1 The quantity and location are shown. The first optical path diagram parameters may include the wavelength, frequency, and intensity of the pump light, as well as the angle at which it is emitted towards the nonlinear crystal 103. In one embodiment, the wavelength of the pump light is 526.5 nm.

[0036] The fundamental frequency light generator 102 is used to emit at least two fundamental frequency beams to the nonlinear crystal 103 according to the received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency beams are different.

[0037] Specifically, the fundamental frequency light generator 102 refers to a device used to emit fundamental frequency light. The fundamental frequency light generator 102 can set relevant parameters of the fundamental frequency light according to the received second optical path diagram parameters. It is understood that the specific implementation principle and / or specific circuit of the fundamental frequency light generator 102 can be determined according to actual conditions, and this application does not impose specific limitations in this regard. The second optical path diagram parameters may include the frequency and intensity of the fundamental frequency light, as well as the angle at which it is emitted towards the nonlinear crystal 103. The fundamental frequency light generator 102 emits at least two beams of fundamental frequency light towards the nonlinear crystal 103, and each pair of fundamental frequency light beams has a different frequency to generate non-collinear multicolor laser. The placement position of the fundamental frequency light generator 102 can be determined according to the required angle of the emitted light, and the number of fundamental frequency light generators 102 can be determined according to the number of fundamental frequency light beams, and is not limited to... Figure 1 The quantities and positions are shown.

[0038] The nonlinear crystal 103 is used to generate non-collinear multicolor laser for driving inertial confinement fusion via a sum-frequency method. The non-collinear multicolor laser comprises at least two sub-beams, the number of which is the same as the number of the fundamental frequency beam. The angle between any two sub-beams ranges from 0.1° to 5°, and the frequency difference ranges from 0.3% to 2% of the center frequency. The number of nonlinear crystals 103 can be selected according to actual conditions and is not limited to this. Figure 1 The quantity shown.

[0039] Specifically, the nonlinear crystal 103 refers to a nonlinear medium that can be used to generate non-collinear multicolor lasers via a sum-frequency method. The sum-frequency method refers to a nonlinear optical processing method that primarily eliminates two photons with angular frequencies ω1 and ω2, while simultaneously generating a photon with an angular frequency ω3. For example, when two beams of light with frequencies ω1 and ω2 propagate in a nonlinear optical medium, the photoelectric field induces polarization in the medium. This second-order nonlinear polarization contains components with different frequencies such as ω1+ω2, 2ω1, 2ω2, and ω1-ω2(ω1,ω2), where the (ω1+ω2) component is called the sum-frequency. It is understood that the specific type of nonlinear crystal 103 can be selected according to actual conditions, and this application does not impose specific limitations on it; for example, it could be a DKDP crystal (potassium dideuterium phosphate). The pump light generated by pump light generator 101 and the fundamental frequency light generated by fundamental frequency light generator 102 have a certain angle between them. When emitted to nonlinear crystal 103, the pump light and fundamental frequency light can generate non-collinear multicolor laser light through sum-frequency generation in nonlinear crystal 103. This non-collinear multicolor laser light is used to drive inertial confinement fusion. When the non-collinear multicolor laser light includes at least two sub-beams, the angle between each pair of sub-beams ranges from 0.1° to 5°, and the frequency difference between each pair of sub-beams ranges from 0.3% to 2% of the center frequency, the non-collinear multicolor laser light can effectively suppress LPI (Limited Peripheral Interference) during inertial confinement fusion. The number of sub-beams in the non-collinear multicolor laser light is the same as the number of fundamental frequency lights generated by fundamental frequency light generator 102.

[0040] It is understood that the number of sub-beams included in a non-collinear multicolor laser can be determined according to the actual situation. In one embodiment, a non-collinear multicolor laser can include 2 to 20 sub-beams, for example, 3, 5, 6, 9, 13, 15, or 20 beams.

[0041] In a non-collinear multicolor laser, the intensity of the sub-beams needs to play a driving role, and the intensity of the sub-beams within the non-collinear multicolor laser can be determined based on the actual situation. In one embodiment, the intensity range of each sub-beam in the non-collinear multicolor laser is 10. 12 W / cm 2 Up to 10 15 W / cm 2 For example, it could be 10 12 W / cm 2 10 13 W / cm 2 10 14 W / cm 2 Or 10 15 W / cm 2 .

[0042] Non-collinear multicolor lasers are generated by pump light and fundamental frequency light, and therefore have a certain wavelength range. The wavelength range of a non-collinear multicolor laser can be determined according to the actual situation. In one embodiment, the wavelength range of the non-collinear multicolor laser is from visible light to ultraviolet light, for example, it can be the visible light band or the ultraviolet light band.

[0043] Understandably, when the angle between any two sub-beams in a non-collinear multicolor laser exceeds the critical angle, the mass dynamics of the LPI driven by the non-collinear multicolor laser decreases by 15%, and correspondingly, the saturation gain of the LPI driven by the non-collinear multicolor laser in a non-uniform plasma decreases by 24%. Therefore, under the same conditions, non-collinear multicolor lasers have a better suppression effect than collinear multicolor lasers. In the construction of a non-collinear multicolor laser driving system, each collinear multicolor laser requires at least four sub-beams, while a non-collinear multicolor laser only requires two sub-beams to achieve the same suppression effect, thus simplifying the non-collinear multicolor laser driving system. The plasma in this system is a coronal plasma at or below the critical density.

[0044] For example, a physical model of non-collinear multicolor laser LPI is described below, and a parameter design scheme for non-collinear multicolor lasers is proposed based on this. The effect of this scheme on suppressing LPI is analyzed under these parameter conditions. Assuming the wave vectors and frequencies of the two beams are (k1, ω1) and (k2, ω2) respectively, the center frequency of the two beams is ω0 = (ω1 + ω2) / 2, the corresponding center wave vector is k0, and the frequency difference between the two beams is δ. ω =|ω1-ω2|. Without loss of generality, the following discussion mainly uses stimulated Raman scattering (SRS) as an example to discuss the suppression conditions of LPI by non-collinear polychromatic light (NCPL). This application also discusses the effects of non-collinear polychromatic light on stimulated Raman scattering (SBS) and cross-beam energy transfer (CBET).

[0045] When the frequency difference between the two beams of light is δ ω Less than or equal to The unstable growth rate of SRS by a factor of 1 (Γ SRS When representing the SRS growth rate, if two beams completely share the scattered light they each produce, then the two beams are said to be collinear. When two beams are collinear, they share all wavelets. Based on the dispersion relation of multicolor laser SRS, under ICF conditions, if the angle between two beams is between 1° and 5°, then the two beams are non-collinear. Under non-collinear conditions, the difference in the transverse wave vectors of the scattered light is large enough that they cannot be completely shared.

[0046] By comparing the SRS dispersion relations of CPL and NCPL excitations, it can be found that the mass driving force for NCPL to excite LPI in a homogeneous plasma is 85% that of CPL under the same conditions. This is because the higher-order terms in the shared wavelet mode are mismatched in the interaction between NCPL and the plasma. Through numerical and analytical solutions to the dispersion relations under NCPL conditions, the maximum growth rate of SRS can be found. It decreases as the angle α between the light rays increases; however, when the angle α is much greater than 5°, The rate of decrease is very slow. Therefore, under ICF conditions, a sub-beam angle of 4° for NCPL is sufficient to effectively suppress LPI.

[0047] In a non-uniform plasma, the unstable saturation gain G is proportional to the square of the maximum growth rate, i.e. Therefore, when the maximum growth rate decreases by 85%, the corresponding unstable saturation gain will also decrease accordingly. Assuming a growth rate... Reduce to ε represents any value greater than 0 and less than 1, then the unstable saturation threshold is reduced to... Therefore, the LPI saturation gain driven by NCPL in non-uniform plasma is reduced by at least 24% compared to CPL.

[0048] Therefore, in both uniform and non-uniform plasmas, a dual-color NCPL with a frequency difference of 1% of the center frequency is sufficient to effectively suppress the intensity of LPI. Similar to the generation of CPL, a third-harmonic NCPL can be generated in a nonlinear crystal via a sum-frequency method using a 526.5nm pump light and two fundamental light beams of different frequencies with a certain angle between them.

[0049] To facilitate understanding of the solution proposed in this application, specific examples will be provided below.

[0050] like Figure 2 As shown, Figure 2 (a) shows the maximum growth rate as a function of the NCPL angle at different densities, where the dotted line represents the numerical solution of the SRS dispersion relation, the connecting line represents the approximate analytical solution, the amplitudes of the two beams are a1=a2=0.03, and the plasma density is n. e =0.2n c0 n c0 The critical density corresponds to the center frequency ω0. The five lines in the figure, from top to bottom, represent n... e =0.1n c0 n e =0.08n c0 n e =0.07n c0 n e =0.06nc0 n e =0.05n c0 Approximate analytical solution; Figure 2 (b) and Figure 2 (c) are respectively at the frequency difference δ ω =0 and frequency difference δ ω Numerical solution of the SRS dispersion relation of NCPL under the condition of 1%ω0, with the angle between the two beams being 20°; Figure 2 (d) is the numerical solution of the SRS dispersion relation under CPL, with the angle between the two beams being 0°.

[0051] Figure 2 (a) The numerical and analytical solutions of the SRS dispersion equation for NCPL-excited plasmas with respect to the maximum unstable growth rate were compared. The relationship between the maximum growth rate and the angle α was described by varying the plasma density. Here, the amplitude α of the light... i With Intensity I i The relationship between them is:

[0052] a i ={I i (W / cm 2 )[λ i (μm)] 2 / 1.37×10 18} 2

[0053] In the formula, λ i λ is the wavelength of light in a vacuum. Figure 2 (a) It can be seen that, under the same density, when angle α >> α c At this point, the maximum unstable growth rate decreases with increasing angle, but the rate of decrease is very slow. Therefore, the maximum growth rate can be reduced by introducing a non-zero angle between the two beams, and the optimal angle only needs to satisfy α ~ α c That is, α~4°. Where α c Used to determine whether two beams of light are collinear; if less than α... c This indicates that the two beams are collinear. If the value is greater than α... c This indicates that the two beams of light are not collinear.

[0054] Figure 2 (b) shows the distribution of SRS instability in wave vector space when two laser beams of the same frequency are angled at α = 20°, obtained by numerically solving the SRS dispersion relation of NCPL-excited lasers. It can be observed that the two beams couple their scattered light through a shared plasma wave, forming an unstable region distribution with one shared mode and two sub-modes. The frequency difference between the two beams is δ. ω =0, the amplitudes of the two beams are the same, i.e., a1 = a2 = 0.03, and the density of the plasma is n.e =0.2n c0 .

[0055] Figure 2 (c) relative to Figure 2 (b) In other words, the frequency difference between the two beams is increased to δ ω =1%ω0. As can be seen from the figure, introducing a sufficient frequency difference can achieve partial decoupling of the scattered light, and the intensity of the unstable sub-mode is reduced.

[0056] Figure 2 (d) relative to Figure 2 (b) In this case, the included angle is α = 0°, and the frequency difference remains unchanged δ. ω =1%ω0. It can be seen that the unstable regions excited by the two beams of light completely overlap, forming a continuous unstable distribution, indicating that the two beams of light achieve strong coupling through the coupling of electron plasma waves.

[0057] The above analysis shows that introducing a certain angle into the two-color light can partially decouple the scattered light, thereby reducing or even completely suppressing the generation of unstable sub-modes.

[0058] like Figure 3 As shown, Figure 3 (a) and 3(b) represent frequency differences of δ ω =0 and δ ω Numerical solution of the SBS dispersion relation under the condition of 1%ω0, with the angle between the two beams being 10° and the plasma density n e =0.7n c0 The ion mass is 1836 times the electron mass.

[0059] Figure 3 (a) The SBS phase diagram of two incident beams of the same frequency excited at an angle of α = 10° is given. The amplitudes of the two beams are the same, a1 = a2 = 0.03, and the plasma density is n. e =0.7n c0 The ion mass is 1836 times the electron mass. From Figure 3 As can be seen in (a), there are multiple strong sub-mode excitations, and strong coupling occurs between the scattered light and the incident light.

[0060] Figure 3 (b) relative to Figure 3 (a) added frequency difference δ ω =1%ω0, at this point the overlapping part of the unstable region becomes smaller, leaving only one shared mode, and its strength is also weakened.

[0061] The above results indicate that, under the condition that the two beams have a certain angle between them, δ ωA frequency difference of 1%ω0 is sufficient to effectively suppress the excitation of SBS and the intensity of CBET.

[0062] like Figure 4 As shown, Figure 4 (a) illustrates the configuration of the NCPL incident beam in a two-dimensional simulation. Beam1 is one NCPL beam, Beam2 is the other, the angle between the NCPL sub-beams is α = 4°, and the frequency difference between the two sub-beams is δ. ω =0.7%ω0, the included angle between the two NCPL beams is θ = 30°; Figure 4 (b) Figure 4 (c) and Figure 4 (d) shows the electron plasma phase diagrams excited by two single-frequency beams, two CPL beams, and two NCPL beams in a non-uniform plasma, respectively, and represents the integral over a time interval from 1000T to 8000T. T is the optical period of the incident laser. Figure 4 (e) Comparison of the hyperthermal electron spectra of different types of incident light at time t = 8000T; Figure 4 (f) shows the evolution of the transverse component of the ion wavenumber driven by different types of intersecting incident beams. In the simulation, the plasma density ranges from 0.19n. c0 up to 0.21n c0 .

[0063] Figure 4 (b) presents the phase diagram of electron plasma excited by two single-frequency laser incident beams. It can be seen that three modes are greatly excited, including a common mode and two sub-modes.

[0064] Figure 4 (c) and Figure 4 (b) By comparison, a frequency difference δ is introduced for each incident beam. ω =0.7%ω0. Compared with the case of two single-frequency light incident beams, the instability intensity is significantly reduced at this time, and the two sub-modes are in a weak coupling state, indicating that the CPL with a sufficient frequency difference can suppress the intensity of LP to a certain extent.

[0065] Figure 4 (d) and Figure 4 (c) In comparison, an angle α = 4° was introduced between the sub-beams of each beam. It can be clearly seen that the SRS instability regions excited by the two beams were separated, and the instability intensity was much lower. Therefore, the NCPL with a certain angle has the best suppression effect on LPI. The comparison shows that the NCPL has the most significant suppression of SRS, i.e., at α = 4° and δ... ω Under the condition of 0.7%ω0, the saturation amplitude of SRS is the lowest.

[0066] Figure 4(e) presents the electronic energy spectra of monochromatic light, CPL, and NCPL excitations at the same time. It can be found that, at the same frequency difference, NCPL has a better suppression effect on the fraction and temperature of superthermal electrons. At δ... ω When ω = 0.7%, the decoupled NCPL produces almost no superheated electrons.

[0067] Figure 4 (f) presents the evolution of CBET ion modes excited by monochromatic light, CPL, and NCPL. It can be seen that the frequency difference is δ ω A CPL of 0.5%ω0 significantly suppressed the excitation of the CBET mode. However, for an NCPL with the same frequency difference, almost no CBET generation was observed.

[0068] The results above demonstrate that NCPL can effectively suppress the intensity of SRS and CBET, as well as the temperature and fraction of superthermal electrons.

[0069] like Figure 5 As shown, Figure 5 (a) shows the configuration of non-collinear polychromatic light in a three-dimensional simulation, where the angle between NCPL sub-beams is α = 4° and the angle between two coplanar NCPL beams is θ = 30°. Figure 5 (b) represents the reflectivity of a single-frequency laser and non-collinear polychromatic light; Figure 5 (c) is the energy ratio of incident energy converted into hot electrons with energy greater than 50 keV; Figure 5 (d) represents the transmittance of single-frequency laser light and non-collinear polychromatic light in a non-uniform plasma. The plasma density ranges from 0.225n. c0 up to 0.257n c0 .

[0070] Figure 5 (b) The reflectivity comparison results of single-frequency light and NCPL are presented. It can be seen that compared with single-frequency laser, NCPL greatly suppresses reflectivity, with its average reflectivity being only 14% of that of single-frequency light. This indicates that NCPL can greatly reduce the energy loss of incident laser and improve beam-target coupling efficiency.

[0071] Figure 5 (c) shows the proportions of superthermal electrons generated by single-frequency light and NCPL. It can be seen that NCPL generates even fewer superthermal electrons with energies greater than 50 keV. At t = 1600T, the proportion of superthermal electrons generated by NCPL is only 0.27%, accounting for only 14.56% of the proportion of superthermal electrons generated by single-frequency light. Therefore, NCPL can effectively suppress the generation of superthermal electrons, thereby reducing the preheating of the target pellet.

[0072] Figure 5(d) shows the energy transmission efficiency of single-frequency light and NCPL. It can be seen that the transmission efficiency of single-frequency light decreases sharply from t=420T and saturates at 34.02%. NCPL, on the other hand, increases the transmission efficiency of the incident laser by more than two times, which greatly improves the beam-target coupling efficiency.

[0073] In summary, in non-collinear multicolor lasers, if the angle between any two sub-beams ranges from 0.1° to 5° and the frequency difference ranges from 0.3% to 2% of the center frequency, energy loss, superheated electron generation, and energy transfer between beams can be effectively suppressed, thereby significantly improving the fusion gain of ICF. At the same time, non-collinear multicolor lasers only require two sub-beams to maintain the same suppression effect as collinear multicolor laser schemes, simplifying system design and reducing system complexity.

[0074] The following describes a non-collinear multicolor laser driving method provided in the embodiments of this application. The non-collinear multicolor laser driving method described below can be referred to in correspondence with the non-collinear multicolor laser driving system described above. The non-collinear multicolor laser driving method provided in this application is applied to the non-collinear multicolor laser driving system described in any of the above embodiments; such as... Figure 6 As shown, the method includes:

[0075] S201: The pump light generator emits pump light to the nonlinear crystal according to the received first optical path diagram parameters;

[0076] S202: The fundamental frequency light generator emits at least two beams of fundamental frequency light to the nonlinear crystal according to the received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency light beams are different.

[0077] S203: The nonlinear crystal generates non-collinear multicolor laser for driving inertial confinement fusion by means of sum-frequency generation; the non-collinear multicolor laser includes at least two sub-beams, the number of sub-beams is the same as the number of fundamental frequency beams, the angle between each two sub-beams is in the range of 0.1° to 5°, and the frequency difference is in the range of 0.3% to 2% of the center frequency.

[0078] In one embodiment, the non-collinear multicolor laser comprises 2 to 20 beams.

[0079] In one embodiment, the intensity range of each sub-beam in the non-collinear multicolor laser is 10. 12 W / cm 2 Up to 10 15 W / cm 2 .

[0080] In one embodiment, the wavelength range of the non-collinear multicolor laser is from visible light to ultraviolet light.

[0081] In one embodiment, the pump light has a wavelength of 526.5 nm.

[0082] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, "a," "an," "the," "the," and "its" may also include plural forms unless the context clearly indicates otherwise. "Multiple" refers to at least two, such as 2, 3, 5, or 8, etc. "And / or" includes any and all combinations of the related listed items.

[0083] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A non-collinear multicolor laser driving system, characterized in that, The system includes: a pump light generator, a fundamental frequency light generator, and a nonlinear crystal; The pump light generator is used to emit pump light to the nonlinear crystal according to the received first optical path diagram parameters; The fundamental frequency light generator is used to emit at least two fundamental frequency beams to the nonlinear crystal according to the received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency beams are different. The nonlinear crystal is used to generate non-collinear multicolor lasers for driving inertial confinement fusion via a sum-frequency method; the non-collinear multicolor lasers include at least two sub-beams, the number of which is the same as the number of the fundamental frequency light, the angle between each pair of sub-beams is in the range of 0.1° to 5°, and the frequency difference is in the range of 0.3% to 2% of the center frequency.

2. The non-collinear multicolor laser driving system according to claim 1, characterized in that, The non-collinear multicolor laser comprises 2 to 20 sub-beams.

3. The non-collinear multicolor laser driving system according to claim 1, characterized in that, The intensity range of each sub-beam in the non-collinear multicolor laser is 10. 12 W / cm 2 Up to 10 15 W / cm 2 .

4. The non-collinear multicolor laser driving system according to claim 1, characterized in that, The wavelength range of the non-collinear multicolor laser is from visible light to ultraviolet light.

5. The non-collinear multicolor laser driving system according to any one of claims 1 to 4, characterized in that, The pump light has a wavelength of 526.5 nm.

6. A method for driving non-collinear multicolor lasers, characterized in that, The method is applied to the non-collinear multicolor laser driving system according to any one of claims 1 to 5; the method includes: The pump light generator emits pump light toward the nonlinear crystal according to the received first optical path diagram parameters; The fundamental frequency light generator emits at least two beams of fundamental frequency light to the nonlinear crystal according to the received second optical path diagram parameters, wherein the frequencies of each pair of fundamental frequency light beams are different. The nonlinear crystal generates non-collinear multicolor lasers for driving inertial confinement fusion via a sum-frequency method; the non-collinear multicolor lasers include at least two sub-beams, the number of which is the same as the number of the fundamental frequency light, the angle between each pair of sub-beams is in the range of 0.1° to 5°, and the frequency difference is in the range of 0.3% to 2% of the center frequency.

7. The non-collinear multicolor laser driving method according to claim 6, characterized in that, The non-collinear multicolor laser comprises 2 to 20 sub-beams.

8. The non-collinear multicolor laser driving method according to claim 6, characterized in that, The intensity range of each sub-beam in the non-collinear multicolor laser is 10. 12 W / cm 2 Up to 10 15 W / cm 2 .

9. The non-collinear multicolor laser driving method according to claim 6, characterized in that, The wavelength range of the non-collinear multicolor laser is from visible light to ultraviolet light.

10. The non-collinear multicolor laser driving method according to any one of claims 6 to 9, characterized in that, The pump light has a wavelength of 526.5 nm.

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