CN205139479U - Based on even smooth device of light kerr effect's radial light beam in inertial confinement fusion device - Google Patents
Based on even smooth device of light kerr effect's radial light beam in inertial confinement fusion device Download PDFInfo
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Abstract
The utility model relates to a based on even smooth device of light kerr effect's radial light beam in inertial confinement fusion device. The device is in laser -driven inertial confinement fusion device optical transmission chain, in adding one in advance between magnification system and the main magnification system based on the even smooth device of light kerr effect's radial light beam, and sexual periodicity gaussian pulse interact production sexual periodicity sphere phase is modulated in utilizing smooth ke er medium and the even smooth device of radial light beam, to carrying out periodic modulation before the laser beam penetrated wave in the inertial confinement fusion device optical transmission chain, the size of its far field focal spot of real -time change, realize zooming fast, zoom the radial sweeping who further causes the scattered spot in far field fast, realize that laser beam far field focal spot in radial square ascending even cunning, realizing laser beam far field irradiation homogeneity in the weak point integration time, improves the homogeneity of its target surface irradiation promptly.
Description
Technical field
The utility model relates to beam smoothing technology in a kind of Laser Driven inertially confinement fusion device, is specifically related to the radial beam smoothing device based on optical kerr effect in a kind of inertial confinement fusion (ICF) device.
Background technology
In Laser Driven inertial confinement fusion (ICF) device, because Physical Experiment requires that device of high power laser can precise hard_drawn tuhes target surface optical field distribution, thus various spatial domains beam smoothing technology and time domain beam smoothing technology is widely used, to realize the control to laser beam far-field focus homogeneity in ICF device, that is improve its homogeneity to target surface irradiation.In the beam smoothing technology of existing spatial domain, normal employing continuous phase plate (ContinuousPhasePlate, CPP) control laser beam far-field focus profile, but due to the coherence stack between the inner beamlet of laser beam, there is pattern in its far-field focus inside; This class pattern can cause the generation of various parametric instability effect in laser beam and pellet interaction process, thus reduce laser beam to the compression symmetry of pellet, thus need to adopt time domain beam smoothing technology to suppress the existence of speckle, reduce the harm of various parametric instability effect.The technology such as existing time domain beam smoothing technology mainly comprises that the even cunning of reduced space incoherent bundle, optical space are level and smooth, polarization smoothing and the even cunning of spectral modeling dispersion.
The even sliding technology of described reduced space incoherent bundle utilizes broadband laser source to come irradiation far field, fabulous focal spot homogeneity can be obtained, but it can only be applicable to gas excimer laser as lasing light emitter, and under needing to make gas excimer laser operate in little energy, when transmitting in the amplifier to avoid laser beam, produce nonlinear optics distortion.
Described optical space smoothing technique utilizes optical dispersion element to be converted into space incoherent by incoherent for the time of wideband light source, interference speckle separate is in a large number superimposed upon on target surface simultaneously, to obtain uniform far-field intensity distribution.The generation that the method for this reduction front end light source coherence can suppress the high frequency spatial of laser beam in far field to be modulated, but can destroy the burst length waveform generation of laser, affect transmission and the amplification characteristic of laser beam.
Described polarization smoothing technology utilizes birefringent wedge, polarization to rotate to pull etc. optical element to change polarization state in beam cross section, realizes the eliminating coherence superposition of the inner beamlet of light beam, to reduce far-field focus contrast.The advantage of this method is the instantaneous even cunning realizing focal spot of energy, fruitful for the far-field focus homogeneity improving the target surface irradiation initial stage, but birefringent wedge is mainly used in the even cunning of single light beam, and can be subject to the damage that stimulated Raman scattering brings, it is then only just have even sliding effect when multiple beam superposes that polarization rotates the shortcoming of pulling.
Described spectral modeling dispersion (SmoothingbySpectralDispersion, SSD) even sliding technology is by carrying out Temporal modulation to laser beam and utilizing grating to carry out spectral modeling dispersion, realize sweeping of laser beam speckle, thus improve far-field focus homogeneity within the plasma heat even sliding time.At present, the shortcoming of one dimension SSD (1D-SSD) only can realize laser beam far field speckle in grating dispersion direction, i.e. the sweeping of x direction or y direction, cause its far-field focus inside appearance along the intensity modulation of the striated in grating dispersion direction, thus also been proposed the even sliding technology of two-dimentional SSD, achieve the beam smoothing of laser beam at two orthogonal directionss in x direction and y direction simultaneously; But because in two-dimentional SSD, laser beam exists inevitable coherent phenomena in far field, and then also been proposed the even sliding technology of three direction SSD, this even sliding technology is tending towards random by making the frequency of near field laser beam, further increases target surface irradiation uniformity.But there is light channel structure complexity, regulate the shortcomings such as difficulty in the even sliding technology of three direction SSD.
Summary of the invention
The purpose of this utility model is just in order to overcome defect existing in prior art and deficiency, radial beam smoothing (RadialSmoothing based on optical kerr effect in a kind of inertially confinement fusion device is provided, RS) new equipment, described radial beam smoothing device is added between preamplifier system in inertially confinement fusion device optical transport chain and main amplification system, adding of this radial beam smoothing device, laser beam far-field focus even cunning in radial directions in optical transport chain can be realized, thus within shorter integral time, realize the homogeneity of laser beam remote irradiation, that is improve the homogeneity of its target surface irradiation.
Based on the radial beam smoothing device of optical kerr effect in the inertially confinement fusion device that the utility model proposes, can be used for Direct driver and indirectly drive inertially confinement fusion device, to improve the homogeneity to target surface irradiation.
For achieving the above object, the utility model adopts the technical scheme be made up of following technical measures to realize.
Design concept of the present utility model is: the preamplifier system in the inertially confinement fusion device optical transport chain of Laser Driven and between main amplification system, add one based on the radial beam smoothing device of optical kerr effect, described radial beam smoothing device is made up of picosecond laser, pulse pile-up unit, lens, dichroic mirror, light kerr medium and filter element; Wherein pulse pile-up unit is made up of beam splitter, multi-channel optical fibre and bundling device; The Gauss pulse that described picosecond laser exports, through fiber pulse stacked units, is divided into multiple sub-Gauss pulse by beam splitter, and each sub-Gauss pulse to bundling device through the different Optical Fiber Transmission of respective length, closes after bundle through bundling device and obtain periodicity Gauss pulse; Periodically Gauss pulse is coupled in the optical transport chain of inertially confinement fusion device through lens, dichroic mirror, and after light kerr medium by filter element filtering; The periodicity sphere Spatial transmission that the periodicity Gauss pulse interaction utilizing light kerr medium and picosecond laser to export produces, to carry out periodic modulation to the laser beam transmission wavefront in described optical transport chain, the size of real-time its far-field focus of change, realizes fast zoom; Fast zoom causes the radial direction of the inner speckle of far-field focus to sweep further, realize laser beam far-field focus even cunning in radial directions further, thus within shorter integral time, realize the homogeneity of laser beam remote irradiation, namely improve the homogeneity of laser beam target surface irradiation.
Based on the radial beam smoothing device of optical kerr effect in a kind of inertially confinement fusion device that the utility model provides, comprise seed light output unit, preamplifier system, main amplification system, catoptron, continuous phase plate, condenser lens, target surface; Also comprise radial beam smoothing device according to the utility model, this radial beam smoothing device by picosecond laser, fiber pulse stacked units, lens, dichroic mirror, light kerr medium and filter element composition; Wherein, fiber pulse stacked units is made up of beam splitter, multi-channel optical fibre and bundling device; Describe according to light path: from seed light output unit export laser beam successively through preamplifier system, dichroic mirror, light kerr medium, after filter element, main amplification system, catoptron and continuous phase plate, then line focus lens focus is on target surface; The Gauss pulse exported from picosecond laser obtains periodically Gaussian beam through fiber pulse stacked units, be coupled in inertially confinement fusion device optical transport chain through lens, dichroic mirror again, after light kerr medium, its effect being subject to periodically Gauss pulse and pump light produces periodically sphere Spatial transmission, the transmission wavefront of the laser beam in optical transport chain described in modulated in real time; Periodicity Gauss pulse is by filter element filtering simultaneously; After in described optical transport chain, the transmission wavefront of laser beam is subject to periodicity sphere Spatial transmission, successively through main amplification system, catoptron and continuous phase plate, then line focus lens focus is to target surface; Its far-field spot size generating period changes, and causes the inner speckle of far-field focus sweeping fast in radial direction, realizes the even cunning of radial direction of target surface, namely improve target surface irradiation uniformity within shorter integral time.
In such scheme, described radial beam smoothing device is in inertially confinement fusion device optical transport chain between preamplifier system and main amplification system.
In such scheme, described smooth kerr medium is Graphene or carbon disulphide.
In such scheme, the picosecond laser in described radial beam smoothing device, selects tunable picosecond laser, or Ti∶Sapphire laser picosecond laser, or mixes Yb
3+optical fiber picosecond laser device.
In such scheme, picosecond laser described in described radial beam smoothing device exports the pulsewidth T of the full width at half maximum of Gauss pulse
wshould be close with described integral time; Described integral time is between 10ps to 1ns.
In such scheme, described filter element is optical rotation plate or optical filter, or the one of spatial filter.
Radial beam smoothing technology described in the utility model, namely be that laser beam speckle is radially swept at target surface, to realize the even cunning of laser beam focal spot in radial direction, described radial direction refers in the direction of target surface along radius, vertical one-tenth " I " font.
Based on the radial beam smoothing device of optical kerr effect in inertially confinement fusion device described in the utility model, use the prerequisite of continuous phase plate in inertially confinement fusion device optical transport chain under, can be used alone, also can sliding device conbined usage even with existing 1D-SSD, to realize the far field speckle of laser beam in the optical transport chain even cunning in radial direction and grating dispersion direction simultaneously.
The advantage that the utility model is compared with prior art had and useful technique effect as follows:
1, the utility model proposes the radial beam smoothing device based on optical kerr effect in the Laser Driven system of inertially confinement fusion device first, to achieve in optical transport chain laser beam speckle at the beam smoothing of radial direction.
2, in inertially confinement fusion device described in the utility model based on the radial beam smoothing device of optical kerr effect, it is the periodicity sphere Spatial transmission utilizing light kerr medium and the periodically rear generation of Gauss pulse interaction, further periodic modulation is carried out to the transmission wavefront of laser beam in optical transport chain, thus change the size of its far-field focus in real time, realize fast zoom; Fast zoom causes the radial direction of far field speckle to sweep further, within shorter integral time, finally improve the remote irradiation homogeneity of laser beam.
3, in inertially confinement fusion device described in the utility model based on the radial beam smoothing device of optical kerr effect compared with existing 1D-SSD, laser beam can be avoided in far field to produce the generation of the intensity modulated of striated, thus the far-field spot size generating period change of laser beam, i.e. fast zoom, thus cause the inner speckle of far-field focus sweeping fast in radial direction, and then the even cunning of the radial direction realizing target surface within shorter integral time.
4, in inertially confinement fusion device described in the utility model based on the radial beam smoothing device of optical kerr effect, after this device and existing SSD, CPP conbined usage, the homogeneity of laser beam target surface irradiation can be improved significantly.
Accompanying drawing explanation
Fig. 1 is the structural representation based on the radial beam smoothing device of optical kerr effect in inertially confinement fusion device described in the utility model;
Fig. 2 is based on the fiber pulse stacked units structural representation in the even sliding device of the radial direction bundle of optical kerr effect in inertially confinement fusion device described in the utility model;
Fig. 3 is based on when in the even sliding device of the radial direction bundle of optical kerr effect, light kerr medium is subject to pump light effect in inertially confinement fusion device described in the utility model, the sphere phase mehtod figure of generation;
Fig. 4 be in inertially confinement fusion device described in the utility model based in the even sliding device of the radial direction bundle of optical kerr effect without beam smoothing direction during continuous phase plate and focal spot thereof, wherein, a () is the even sliding direction of radial light beam and focal spot thereof, (b) is existing 1D-SSD beam smoothing direction and focal spot thereof;
Fig. 5 is based on focal spot when having continuous phase plate in the even sliding device of the radial direction bundle of optical kerr effect in inertially confinement fusion device described in the utility model, wherein, a () is the focal spot of radial beam smoothing device, b () is the focal spot of existing 1D-SSD beam smoothing, (c) is focal spot when radial beam smoothing device and existing 1D-SSD conbined usage;
Fig. 6 is based on when having continuous phase plate in the radial beam smoothing device of optical kerr effect in inertially confinement fusion device described in the utility model, under three kinds of beam smoothing schemes of radial beam smoothing device, existing 1D-SSD, radial beam smoothing device and existing 1D-SSD conbined usage, the FOPAI curve of its focal spot;
Fig. 7 is based on when having continuous phase plate in the radial beam smoothing device of optical kerr effect in inertially confinement fusion device described in the utility model, wherein, a, under the two schemes of () radial beam smoothing device, radial beam smoothing device and existing 1D-SSD conbined usage, luminous flux contrast C ontrast is with pump light peak strength I
pchange curve, under three kinds of schemes of (b) radial beam smoothing device, existing 1D-SSD, radial beam smoothing device and existing 1D-SSD conbined usage, luminous flux contrast C ontrast is with the change curve of Δ t integral time.
In figure, 1 seed light output unit, 2 preamplifier systems, 3 dichroic mirrors, 4 smooth kerr mediums, 5 filter elements, 6 main amplification systems, 7 catoptrons, 8 continuous phase plates, 9 condenser lenses, 10 target surfaces, 11 picosecond lasers, 12 fiber pulse stacked units, 13 lens, 14 beam splitters, 15 bundling devices, 16 multi-channel optical fibres.
Embodiment
The utility model to be described in further detail with specific embodiment below in conjunction with accompanying drawing; be necessary to herein means out be described embodiment just for further describing of the present utility model, and be not meant to be any restriction to the utility model protection domain.
The radial beam smoothing device based on optical kerr effect in a kind of inertially confinement fusion device described in the utility model, its structure as shown in Figure 1.Comprise seed light output unit 1, preamplifier system 2, main amplification system 6, catoptron 7, continuous phase plate 8, condenser lens 9, target surface 10; Also comprise radial beam smoothing device, this radial beam smoothing device by dichroic mirror 3, light kerr medium 4, filter element 5, picosecond laser 11, fiber pulse stacked units 12, lens 13 are formed; Wherein, fiber pulse stacked units 12 is made up of beam splitter 14, multi-channel optical fibre 16 and bundling device 15.Describe by light path: the laser beam that seed light output unit 1 exports, successively through preamplifier system 2, dichroic mirror 3, light kerr medium 4, filter element 5, main amplification system 6, catoptron 7, continuous phase plate 8, condenser lens 9, finally focuses on and arrives target surface 10; Further by Fig. 1, the cycle Gauss pulse produced by picosecond laser 11 and fiber pulse stacked units 12 is coupled in optical transport chain through lens 13, dichroic mirror 3, this cycle Gauss pulse acts on light kerr medium 4 and produces periodically sphere Spatial transmission, finally by filter element 5 filtering; And the laser beam in optical transport chain is when light kerr medium 4, its transmission wavefront is periodicity sphere position phase; After in described optical transport chain, the transmission wavefront of laser beam is subject to periodicity sphere Spatial transmission, successively through main amplification system 6, catoptron 7 and continuous phase plate 8, target surface 10 is focused on finally by condenser lens 9, thus focused spot size changes along with the change of periodicity sphere position phase, i.e. fast zoom, thus cause the inner speckle of far-field focus sweeping fast in radial direction, within shorter integral time, realize the even cunning of radial direction of target surface.
By Fig. 2, the Gauss pulse that described picosecond laser 11 exports is when fiber pulse stacked units 12, first be divided into the sub-Gauss pulse of multi beam by beam splitter 14, sub-Gauss pulse after the multi-channel optical fibre 16 of respective different length, then synthesizes periodically Gauss pulse by bundling device 15.
Embodiment 1
In the present embodiment use light kerr medium to be Graphene, have the characteristics such as high light Kerr coefficient, high damage threshold and large clear aperture because of it, the parameter of Graphene is: light Kerr coefficient n
2=6 × 10
-8cm
2/ W, thickness d=0.5nm, size 40 × 40mm; Picosecond laser 11 selects tunable picosecond laser, its Gauss pulse wavelength X=808nm exported, and the pulsewidth of full width at half maximum is T
w=2.2ps, peak value of pulse intensity I
p=0.2GW/cm
2, the time delay factor h=3.3 in fiber pulse stacked units 12 between multi-channel optical fibre, integral time Δ t=10ps, optical rotation plate selected by described filter element 5.
Adopt radial beam smoothing device of the present utility model to realize laser beam far-field focus even cunning in radial directions in inertially confinement fusion device optical transport chain, its concrete operation step is as follows:
(1) first in inertially confinement fusion device optical transport chain, add radial beam smoothing device, selection output light wavelength is the tunable picosecond laser 11 of λ=808nm, regulates the pulsewidth of its full width at half maximum to be T
w=2.2ps, peak value of pulse intensity I
p=0.2GW/cm
2; Choosing described smooth kerr medium 4 is Graphene, and its parameter is: light Kerr coefficient n
2=6 × 10
-8cm
2/ W, thickness d=0.5nm, size 40 × 40mm;
(2) be coupled in radial beam smoothing device in fiber pulse stacked units 12 by the Gauss pulse that described for step (1) tunable picosecond laser 11 exports, the beam splitter 14 of this Gauss pulse in fiber pulse stacked units is divided into the sub-Gauss pulse of multichannel; The length L of multi-channel optical fibre in fiber pulse stacked units 12 described in adjustment
iwherein, i represents the optical fiber of different light paths, and the length between the optical fiber of Shi Ge road meets L
i+1-L
i=chT
wwherein, c is the light velocity in vacuum, even if each sub-Gauss pulse is through different time delays, synthesizes periodically Gauss pulse, i.e. pump light finally by the bundling device 15 in fiber pulse stacked units 12;
(3) by described in step (2), periodically the lens 13 of Gauss pulse in radial beam smoothing device and dichroic mirror 3 are coupled in described inertially confinement fusion device optical transport chain;
(4) the periodicity Gauss pulse described in step (3) is in radial beam smoothing device during light kerr medium 4, light kerr medium produces periodic sphere Spatial transmission, the transmission wavefront of the laser beam in optical transport chain described in modulated in real time after being subject to the effect of periodically Gauss pulse and pump light; Meanwhile, periodically Gauss pulse after light kerr medium by filter element 5 filtering in radial beam smoothing device, to avoid having an impact to the transmission of laser beam in optical transport chain;
(5) laser beam that seed light output unit 1 exports in inertially confinement fusion device optical transport chain, successively through preamplifier system 2, dichroic mirror 3, light kerr medium 4, filter element 5, main amplification system 6, catoptron 7 and continuous phase plate 8, focuses on target surface 10 finally by condenser lens 9; When laser beam through described in step (4) light kerr medium, its transmission wavefront changes along with the periodicity sphere Spatial transmission of light kerr medium, is also periodically sphere position phase;
(6) laser beam in the optical transport chain described in step (5) is when condenser lens 9 focuses on, and because its transmission wavefront is periodically sphere position phase, thus the size of target surface focal spot also can cyclical variation thereupon; Due to the pulsewidth T of the full width at half maximum of periodicity Gauss pulse
wshorter, its cycle is tens of picoseconds, and thus periodically the cycle of sphere position phase is also tens of picoseconds, and the period of change of described target surface focal spot size is also tens of picoseconds, thus realizes the fast periodic change of focal spot size, i.e. fast periodic zoom;
(7) the fast periodic zoom described in step (6) causes the inner speckle of target surface focal spot sweeping in radial direction; Within shorter integral time, speckle sweeping the intensity modulation of floating target surface focal spot in radial direction, thus the target surface irradiation uniformity improving laser beam.
Fig. 3 give single Gauss pulse in the periodicity Gauss pulse that tunable picosecond laser exports act on light kerr medium 4 described in embodiment 1 on Graphene time, the sphere phase mehtod of generation.
For convenience of comparison, the radial beam smoothing device of embodiment 1 and typical existing one dimension 1D-SSD are compared, wherein the parameter of 1D-SSD is according to document (S.Skupsky, R.W.Short, T.Kessler, etal..Improvedlaserbeamuniformityusingtheangulardispersi onoffrequencymodulatedlight.J.Appl.Phys.66,3456 (1989) .) choose, i.e. the modulating frequency ω of Temporal Phase Modulation
m=2.5GHz, depth of modulation is δ=12, and grating dispersion coefficient is
Fig. 4 ~ Fig. 7 shows the improvement effect of radial beam smoothing device to far-field focus homogeneity in embodiment 1, and from figure, acquired results has absolutely proved validity, the feasibility of the use radial beam smoothing device based on optical kerr effect described in the utility model.
Shown in Fig. 4, when compared for continuous phase plate 8, the even sliding direction of radial even sliding device and existing 1D-SSD and focal spot thereof.Wherein, (a) is the focal spot distribution after using the even sliding device of radial direction described in the utility model, and its even sliding direction is radial, all exists along all directions; B () is the focal spot distribution after typical 1D-SSD, its even sliding direction is y direction.
Shown in Fig. 5, when compared for continuous phase plate 8, the focal spot distribution under three kinds of schemes of radial even sliding device, existing 1D-SSD, radial even sliding device and existing 1D-SSD conbined usage.Wherein, (a) is the focal spot after the even sliding device of described radial direction, and the inner speckle of focal spot obtains even cunning in radial direction; B () is the focal spot of existing 1D-SSD, focal spot obtains even cunning in y direction, there is the intensity modulation of obvious striated; C () is the focal spot after radial even sliding device and existing 1D-SSD coupling, focal spot all obtains even cunning in radial and y direction.It is worthy of note, focal spot size does not obviously change.
In order to the improvement degree of quantitative test focal spot homogeneity, adopt focal spot luminous flux contrast (Contrast) to evaluate, focal spot luminous flux contrast is less shows that focal spot homogeneity is better; Its formula is expressed as follows:
In formula, I
i,j(x
f, y
f) be (x
f, y
f) light intensity of position; I
meanfor average intensity.
In order to the improvement degree of the inner hot spot of the even sliding technology focal spot of quantitative test bundle, adopt FractionalPoweraboveIntensity (FOPAI) curve to evaluate, FOPAI curve shows that to moving to left the improvement effect of the inner hot spot of focal spot is better; Its formula is expressed as follows:
In formula, A is focal spot area, I
meanfor average intensity.
When the improvement degree of focal spot homogeneity and inner hot spot carries out quantitative test, the region for 90% energy circle rate calculates.
Utilize formula (1) and (2) to calculate its luminous flux contrast and FOPAI curve respectively to the light distribution of the focal spot shown in Fig. 5, obtain Fig. 6 and Fig. 7.
Shown in Fig. 6, when employing continuous phase plate 8, under radial beam smoothing device, existing 1D-SSD, the luminous flux contrast of focal spot is close, and it is suitable to restraint even sliding effect; Under radial beam smoothing device and existing 1D-SSD conbined usage, the luminous flux contrast of focal spot obviously reduces, and restraints even sliding effect and is greatly improved.
Shown in Fig. 6, when employing continuous phase plate 8, under radial beam smoothing device and existing 1D-SSD conbined usage, the FOPAI curve of focal spot is to moving to left, and shows compared to the even sliding scheme of other two kinds of light beam bundles, the inner hot spot of focal spot obviously reduces, and restraints even sliding effect and is greatly improved.
Utilize formula (1), (2) calculate when employing continuous phase plate, under the two schemes of radial beam smoothing device, radial beam smoothing device and existing 1D-SSD conbined usage, under different pumping peak strength, the luminous flux contrast of focal spot, obtains shown in Fig. 7 (a); When employing continuous phase plate by calculating, under three kinds of schemes of radial beam smoothing device, existing 1D-SSD, radial beam smoothing device and existing 1D-SSD conbined usage, FOPAI curve under different integration times, obtains shown in Fig. 7 (b).
Shown in Fig. 7 (a), when employing continuous phase plate 8, under the two schemes of radial beam smoothing device, radial beam smoothing device and existing 1D-SSD conbined usage, focal spot luminous flux contrast reduces along with the increase of pump light peak strength, and the latter reaches the better even sliding effect of bundle within the shorter time.
Shown in Fig. 7 (b), when employing continuous phase plate 8, under two schemes for existing 1D-SSD, radial beam smoothing device and existing 1D-SSD conbined usage, focal spot luminous flux contrast reduces gradually along with the growth of integral time, and finally tend towards stability value; And for the even focal spot slided of radial light beam, luminous flux contrast declines rapidly, the then disturbance near some values along with the growth of integral time.Fig. 7 (b) shows, radial beam smoothing device can improve the initial uniform of focal spot sooner, better; And after radial beam smoothing device and existing 1D-SSD conbined usage, fully in conjunction with radial beam smoothing device and existing 1D-SSD feature separately, thus even cunning can be carried out in multi-direction focal spot, improve target surface irradiation uniformity.
By the displaying of above-described embodiment 1 and accompanying drawing, indicate the radial beam smoothing device based on optical kerr effect in inertially confinement fusion device described in the utility model and can realize the effective even cunning of target surface in Δ t=10ps in integral time.
Embodiment 2
In the present embodiment use light kerr medium to be carbon disulphide (CS
2), its parameter is: light Kerr coefficient n
2=2.1 × 10
-15cm
2/ W, thickness d=0.45mm, size 40 × 40mm; The Gauss pulse wavelength adopting tunable picosecond laser to export is the pulsewidth T of λ=800nm, full width at half maximum
w=2.2ps, peak value of pulse intensity I
p=63.5GW/cm
2, fiber pulse stacked units time delay factor h=3.3, integral time Δ t=10ps; Optical filter selected by described filter element 5.Other operation stepss and operating process identical with embodiment 1, the improvement effect of the far-field focus homogeneity to laser beam identical with embodiment 1 can be obtained equally.
Embodiment described in the utility model only gives concrete example application, but for the researchist in the Laser Driven system being engaged in inertial confinement fusion, also can design multiple for the even Slipped Clove Hitch structure of the radial light beam based on optical kerr effect in inertially confinement fusion device according to above enlightenment, this is still considered to be covered by among the utility model.
Claims (6)
1. in an inertially confinement fusion device based on the radial beam smoothing device of optical kerr effect, comprise seed light output unit (1), preamplifier system (2), main amplification system (6), catoptron (7), continuous phase plate (8), condenser lens (9), target surface (10); Characterized by further comprising radial beam smoothing device, this radial beam smoothing device is by picosecond laser (11), fiber pulse stacked units (12), lens (13), dichroic mirror (3), light kerr medium (4) and filter element (5) composition; Wherein, described fiber pulse stacked units (12) is made up of beam splitter (14), multi-channel optical fibre (16) and bundling device (15); Describe according to light path: the laser beam exported from seed light output unit (1) is successively through preamplifier system (2), dichroic mirror (3), light kerr medium (4), after filter element (5), main amplification system (6), catoptron (7) and continuous phase plate (8), then line focus lens (9) focus on target surface (10); The Gauss pulse exported from picosecond laser (11) obtains periodically Gaussian beam through fiber pulse stacked units (12), be coupled in inertially confinement fusion device optical transport chain through lens, dichroic mirror again, after light kerr medium (4), its effect being subject to periodically Gauss pulse and pump light produces periodically sphere Spatial transmission, the transmission wavefront of the laser beam in optical transport chain described in modulated in real time; Periodicity Gauss pulse is by filter element (5) filtering simultaneously; After in described optical transport chain, the transmission wavefront of laser beam is subject to periodicity sphere Spatial transmission, successively through main amplification system (6), catoptron (7) and continuous phase plate (8), then line focus lens (9) focus on target surface (10); Its far-field focus size generating period changes, and causes the inner speckle of far-field focus sweeping fast in radial direction, thus the even cunning of the radial direction realizing target surface within shorter integral time.
2. according to claim 1 in inertially confinement fusion device based on the radial beam smoothing device of optical kerr effect, it is characterized in that described radial beam smoothing device is arranged between inertially confinement fusion device optical transport chain preamplifier system (2) and main amplification system (6).
3. in inertially confinement fusion device according to claim 1 or 2 based on the radial beam smoothing device of optical kerr effect, it is characterized in that described smooth kerr medium (4) is Graphene or carbon disulphide.
4. in inertially confinement fusion device according to claim 1 or 2 based on the radial beam smoothing device of optical kerr effect, it is characterized in that the picosecond laser (11) in described radial beam smoothing device, select tunable picosecond laser; Or select Ti∶Sapphire laser picosecond laser, or mix Yb
3+optical fiber picosecond laser device.
5. according to claim 1 in inertially confinement fusion device based on the radial beam smoothing device of optical kerr effect, it is characterized in that picosecond laser (11) described in described radial beam smoothing device exports the pulsewidth T of the full width at half maximum of Gauss pulse
wshould be close with described integral time; Described integral time is between 10ps to 1ns.
6. in inertially confinement fusion device according to claim 1 or 2 based on the radial beam smoothing device of optical kerr effect, it is characterized in that described filter element (5) is for optical rotation plate or optical filter, or the one of spatial filter.
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| CN105259662A (en) * | 2015-11-13 | 2016-01-20 | 四川大学 | Optical Kerr effect-based beam radially smoothing method in inertial confinement fusion device |
| CN109581682A (en) * | 2019-01-15 | 2019-04-05 | 四川大学 | Based on the quick beam smoothing method of light beam dynamic interference pattern in inertially confinement fusion device |
| CN110515216A (en) * | 2019-07-19 | 2019-11-29 | 四川大学 | It a kind of light intensity and polarizes atwirl light field and regulates and controls method |
| CN111221135A (en) * | 2020-03-19 | 2020-06-02 | 中国工程物理研究院激光聚变研究中心 | System and method for beam polarization smoothing |
-
2015
- 2015-11-13 CN CN201520907538.0U patent/CN205139479U/en not_active Withdrawn - After Issue
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105259662A (en) * | 2015-11-13 | 2016-01-20 | 四川大学 | Optical Kerr effect-based beam radially smoothing method in inertial confinement fusion device |
| CN105259662B (en) * | 2015-11-13 | 2017-08-11 | 四川大学 | Radial direction beam smoothing method based on optical kerr effect in inertially confinement fusion device |
| CN109581682A (en) * | 2019-01-15 | 2019-04-05 | 四川大学 | Based on the quick beam smoothing method of light beam dynamic interference pattern in inertially confinement fusion device |
| CN110515216A (en) * | 2019-07-19 | 2019-11-29 | 四川大学 | It a kind of light intensity and polarizes atwirl light field and regulates and controls method |
| CN110515216B (en) * | 2019-07-19 | 2021-03-26 | 四川大学 | Light field regulation and control method for fast rotation of light intensity and polarization |
| CN111221135A (en) * | 2020-03-19 | 2020-06-02 | 中国工程物理研究院激光聚变研究中心 | System and method for beam polarization smoothing |
| CN111221135B (en) * | 2020-03-19 | 2024-04-12 | 中国工程物理研究院激光聚变研究中心 | System and method for beam polarization smoothing |
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