CN104575656B - Multi-inclination-angle composite multi-film Laue lens and design method thereof - Google Patents

Abstract

The invention discloses a multi-inclination angle compound multi-layer Laue lens. The lens of the present invention comprises m inclined multilayer film Laue lenses arranged along the direction perpendicular to the incident light; wherein, all film layers in each said inclined multilayer film Laue lens have the same clamping distance as the incident light angle; the multi-inclination angle compound multilayer Laue lens can achieve diffraction-limited focusing; m is greater than 2; the film thickness of the inclined multilayer Laue lens near the central area is relatively large, and its film layer has a relatively large relationship with the incident light Small included angle; the inclined multilayer Laue lens near the outer layer has a smaller film thickness, and its film layer has a larger included angle with the incident light. It has a focusing performance close to that of Wedge MLL, and is easy to process and realize.

Description

A multi-tilt angle composite multilayer Laue lens and its design method

technical field

The invention relates to a hard X-ray nano-focusing optical element and a design method thereof, in particular to a multilayer Laue lens, belonging to the fields of synchrotron radiation beamline engineering and synchrotron radiation optics

Background technique

The third-generation synchrotron radiation has the characteristics of high brightness and high collimation, and the unique properties of hard X-rays, such as strong penetrating ability, sensitivity to structural information and chemical information, insensitivity to electromagnetic fields, etc. , making hard X-ray microscopes widely used in many fields such as materials science, medicine, biology and environmental science. The performance of an X-ray microscope depends on the intensity and size of the focused spot. So far, a variety of focusing optics using reflection, refraction, and diffraction have been able to focus hard X-rays down to the order of tens of nanometers. Among these focusing optical elements, the diffractive focusing element—Multilayer Laue lens (MLL) is the most promising to achieve true nanoscale (1nm) focusing (reference: H.Yan et al., Multilayer Laue Lens: A Path Toward One Nanometer X-RayFocusing, X-ray Opt.Instrum.2010, 401845(2010)). At present, MLL has experimentally realized one-dimensional focusing of hard X-rays with the highest resolution of about 11nm, with an efficiency of about 15%; two-dimensional focusing of 25×27nm, with an efficiency of about 2%.

Since the MLL has a very large aspect ratio (the ratio of the depth along the incident light direction to the thickness of the outermost layer), the propagation of X-rays in it must be described by diffraction dynamics. At this time, whether each layer of the film layer Satisfying the Bragg condition is the key to whether MLL can obtain high efficiency and high resolution. According to the degree to which the film layer satisfies the Bragg condition, the multilayer Laue lens can be divided into four types: horizontal (Flat), inclined (Tilted), wedge (wedge) and curved (Curved) (reference: H . Yan et al., Takagi-Taupin description of x-ray dynamical diffraction from diffractive optics with large numerical aperture, Phys. Rev. B 76, 115438 (2007)). Among these four types, the structure of Flat and Tilted MLL is essentially the same, the difference is that the angle between all layers of Flat MLL and the incident light is 0, and all layers do not satisfy the Bragg condition, while Tilted MLL All its layers have the same angle with the incident light, and only a part of the layers satisfy the Bragg condition. Therefore, for Tilted MLL, in order to achieve diffraction-limited focusing, the depth must be reduced to minimize the influence of diffraction dynamics, which will inevitably lead to lower efficiency (reference: Hanfei Yan et al., Optimization of multilayer Laue lenses for ascanning X-ray microscope, J. Synchrotron Rad. 20, 89(2013)). Each film layer of Wedge MLL has a different tilt angle, and all film layers approximately satisfy the Bragg condition. Theoretical calculation results show that it can achieve high-efficiency diffraction-limited focusing. The plating process of Tilted MLL is relatively simple, and the MLLs reported in experiments basically belong to this type. However, due to the complexity of its structure, the plating process of Wedge MLL is relatively difficult, and no experimental reports have been seen so far.

Contents of the invention

The purpose of the present invention is to propose a new MLL structure - multi-tilt angle composite MLL to solve the problems of low efficiency when TiltedMLL realizes diffraction-limited focusing and difficult Wedge MLL plating process.

The present invention can be realized through the following technical solutions:

A multi-tilt composite MLL is characterized in that: the multi-tilt composite MLL is formed by a series of Tilted MLLs arranged along a direction perpendicular to the incident light; for a single Tilted MLL, all of its film layers have the same The included angle of the Tilted MLL with thicker film near the central area has a smaller angle between the film and the incident light; the Tilted MLL with smaller film thickness near the outer area has a relatively small angle between the film and the incident light Large included angle; the multi-tilt-angle composite MLL can achieve diffraction-limited focusing, and has a focusing performance close to that of Wedge MLL.

Each of the Tilted MLLs has an equal or approximately equal number of film layers.

In the single Tilted MLL, the included angle θ between the film layer and the incident light makes the two adjacent film layers whose film layer number is the middlemost in the Tilted MLL satisfy the Bragg condition.

The incident plane and the outgoing plane of the multi-tilt composite MLL are parallel to each other and perpendicular to the incident light.

Described multi-inclination composite MLL, its specific structural parameters can be realized through the following steps:

(1) First, select the appropriate focal length f according to the energy of the incident X-ray (wavelength λ), the ability of the coating (total thickness L of the film layer) and the focusing resolution r, f can be obtained by the Rayleigh criterion formula, r=0.5λ/ NA≈λf/L; then choose a compromise solution according to the required working distance w _d and the accuracy of the actual coating, and determine the thickness of the outermost layer, the innermost layer, and the total number of layers N in Flat MLL And the number n of each film layer, specifically, first obtain ε through the working distance formula w _d = fε, where ε=(x _o -L)/x _o , x _o refers to the outermost film layer At this time, according to the zone plate formula, the thickness of the outermost layer, the thickness of the innermost layer, the total number of layers N and the number n of each layer can be obtained. What needs to be pointed out here is that in this technical solution, the number n of each film layer in Flat MLL is fixed, which is determined by the zone plate formula x(n) ² =nλf, x(n) refers to the number is the position of the film layer of n; and the number of each film layer in the multi-slope composite MLL is the same as that of the Flat MLL, that is, the number of the i-th film layer in the multi-slope composite MLL and the i-th film layer in the Flat MLL are the same, and their total number of film layers N is also the same.

(2) According to the wavelength, focal length, outermost layer and innermost layer thickness, use the Takagi-Taupin description of dynamical diffraction theory (TTD) or Coupledwave theory (CWT) to calculate the different depths of Wedge MLL The wavefront distribution and diffraction efficiency (references: H.Yan et al., Takagi-Taupin description of x-ray dynamical diffraction from diffractiveoptics with large numerical aperture, Phys.Rev.B 76,115438(2007); J.Maser et al ., Coupled wave description of the diffraction by zone plates with highaspect ratios, Opt.Commun.89, 355(1992)), to obtain the optimal depth (the depth corresponding to the maximum diffraction efficiency); at the same time, according to the wave on the exit surface at the optimal depth Then use the Fresnel-Kirchhoff diffraction integral to calculate the light intensity distribution near the focus, and get the strongest peak near the focus.

(3) Calculate the thickness of each film layer in the Flat MLL according to the zone plate formula, d(n)=x(n)-x(n-1), where d(n) refers to the number n The thickness of the film layer.

(4) Assume that the multi-tilt composite MLL is composed of m Tilted MLLs, and the number of layers of each Tilted MLL is N/m. If N/m is not an integer, it is rounded to an integer Int(N/m+0.5), and the extra or missing layers are counted on the Tilted MLL in the outermost area, and the number of layers is N-( m-1)×Int(N/m+0.5), and the number of layers of other Tilted MLLs is Int(N/m+0.5).

(5) For the i-th Tilted MLL, the angle θ _i between its film layer and the incident light makes the two adjacent film layers whose film layer number is the middlemost in the Tilted MLL satisfy the Bragg condition. The included angle θ _i can be obtained by Bragg's formula, 2[2d(i _m )] sinθ _i =λ, where i _m is the serial number of the most middle film layer in the Tilted MLL, i _m =(i _f +i _l )/2 ,if and _{i l are} the numbers of the first and last layers of the Tilted MLL respectively, d(i _m ) is the thickness of the film layer numbered i _m , and its value is given by step (3).

(6) For the first Tilted MLL (the Tilted MLL in the innermost region) in the multi-tilt composite MLL, the position of the first film layer (assuming that the film layer number is k) on the exit surface is determined by the zone plate formula Given, x _re (k)=(kλf) ^1/2 , the position x _in (k)=x _re (k)+w×tan(θ ₁ ) on the incident surface, where w is calculated according to Wedge MLL The best depth obtained, θ ₁ is the angle between the film layer and the incident light in the first Tilted MLL. The position of the second film layer on the outgoing surface is x _re (k+1)=x _re (k)+d(k+1)/cos(θ ₁ ), and the position on the incident surface is x _in (k +1)=x _in (k)+d(k+1)/cos(θ ₁ ), and so on for the positions of subsequent film layers.

(7) For the second Tilted MLL in the multi-tilt composite MLL, the position of the first film layer (assuming the film layer number is p) on the exit surface, x _re (p) = x _re (p-1) +d(p)/cos(θ ₁ ), the position x _in (p) on the incident plane=x _re (p)+w×tan(θ ₂ ). The position of the second film layer on the outgoing surface is x _re (p+1)=x _re (p)+d(p+1)/cos(θ ₂ ), and the position on the incident surface is x _in (p +1)=x _in (p)+d(p+1)/cos(θ ₂ ), and so on for the positions of subsequent film layers.

(8) For the second and subsequent Tilted MLLs in the multi-tilt angle composite MLL, the derivation of the film layer position is the same as that of the second Tilted MLL.

(9) According to the principle of dichotomy, first calculate the situation when the multi-tilt composite MLL is composed of two (2 ¹ ) Tilted MLLs. Specifically, m = 2 ¹ is first substituted into steps (4), (5), (6), (7) and (8) to obtain the specific structural parameters of the multi-tilt composite MLL, and then use TTD or CWT to calculate the The wavefront distribution at the optimal depth, and then use the Fresnel-Kirchhoff diffraction integral to calculate the light intensity distribution near the focus and the strongest peak near the focus; judge whether there is obvious interference in the light intensity distribution near the focus Stripe, determine whether the Strehl Ratio is greater than 0.8, where the Strehl Ratio refers to the ratio of the strongest peak of the multi-tilt composite MLL to the strongest peak of the Wedge MLL (calculated by step (2)). If there are obvious interference fringes near the focal point and Strehl Ratio<0.8, then calculate the situation when the multi-tilt composite MLL is composed of 2 ² , 2 ³ , 2 ⁴ ,..., 2 ^j ,... Tilted MLLs. If there is no obvious interference fringe near the focus and the Strehl Ratio>0.8 when the multi-tilt composite MLL is composed of 2 ^j Tilted MLLs, stop the calculation. At this time, the multi-tilt composite MLL is composed of 2 ^j Tilted MLLs, and the position parameters of each film layer on the incident surface and the outgoing surface can be obtained through the aforementioned steps. What needs to be pointed out here is that according to the principle of dichotomy, m is usually equal to 2 ^l (l=1,2,3,...), but this is not absolute, it can take any positive integer value, as long as it meets the requirements of this step That is, whether there are obvious interference fringes in the light intensity distribution near the focus, and whether the Strehl Ratio is greater than 0.8.

(10) According to the calculation results of step (9), use CWT or TTD to calculate the diffraction efficiency of the multi-tilt composite MLL composed of 2 ^j Tilted MLLs at different depths, and obtain a new optimal depth value. Calculate the wavefront distribution on the exit surface at the optimum depth, use the Fresnel-Kirchhoff diffraction integral to calculate the light intensity distribution near the focus and the strongest peak near the focus, and obtain the corresponding multi-tilt angle composite MLL Efficiency, focus resolution, and Strehl Ratio.

Compared with the prior art, the present invention has the following advantages:

1. In the case of the same physical aperture, compared with a single Tilted MLL, the multi-tilt composite MLL has higher efficiency in achieving diffraction-limited focusing.

2. Compared with Wedge MLL, multi-tilt angle composite MLL has only a few layers with different tilt angles, so it can greatly reduce the process difficulty, and at the same time has similar efficiency to Wedge MLL.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a distribution diagram of the diffraction efficiency on the exit surface of a single Tilted MLL, Wedge MLL, and multi-tilt composite MLL when diffraction-limited focusing is achieved.

Figure 3 is the intensity distribution near the focal point of different MLLs when diffraction-limited focusing is achieved, z is along the direction of incident light, and x is perpendicular to the direction of incident light; Figure (a) is a single Tilted MLL, Figure (b) is a single Wedge MLL, Figure (c) is a composite MLL with multiple tilt angles.

Figure 4 shows the light intensity distribution curves of a single Tilted MLL, Wedge MLL, and multi-tilt composite MLL on the best focal plane when diffraction-limited focusing is achieved, and x is perpendicular to the direction of incident light.

Figure 5 is the intensity distribution diagram of multi-tilt composite MLL composed of different MLLs near the focus. It consists of 4 Tilted MLLs, and Figure (c) consists of 8 Tilted MLLs.

Among them, 1, 2, and 3 are the first, second, and third Tilted MLLs in the multi-tilt angle composite MLL; 6 and 7 are the positions of the first film layer in the second TiltedMLL on the incident surface and the outgoing surface respectively; 8 is the incident X-ray.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Example:

1. Assume that the incident X-ray energy is 12.0keV, and the required diffraction-limited focusing resolution is 10nm. According to the coating ability, the focal length f is selected as 4mm. At this time, the total thickness of the coating is about 41.3 microns; according to the coating accuracy and working distance , the outermost film thickness is selected as 4nm, its film number is 6458, the innermost film thickness is 20nm, the film number is 258, and the total film number N is 6200 layers.

2. Using TTD to calculate the diffraction efficiency of Wedge MLL at different depths, the best depth value is about 12 microns. The diffraction efficiency distribution is shown in Figure 2, the total efficiency is about 47.06%, the intensity distribution near the focus is shown in Figure 3, the light intensity distribution curve on the best focal plane is shown in Figure 4, and the strongest peak is about 1944.

3. Calculate the thickness of each film layer in the Flat MLL according to the zone plate formula.

4. First assume that the multi-tilt composite MLL is composed of 2 Tilted MLLs, and the number of layers of each Tilted MLL is 3100 layers. The included angle between the film layer and the incident X-ray in the first Tilted MLL is 3.42mrad, and the positions of the first and second film layers on the incident surface are 10.36699 and 10.38698 microns respectively, and the positions on the exit surface are 10.32599 and 10.32599 microns respectively. 10.34599 microns; the angle between the second Tilted MLL film layer and the incident light is 5.63mrad, the positions of the first and second film layers on the incident surface are 37.32636 and 37.33191 microns respectively, and the positions on the exit surface are respectively 37.25881, 37.26435 microns. Using CWT to calculate the wavefront distribution on the exit surface at the optimal depth of 12 microns, using the Fresnel-Kirchhoff diffraction integral to calculate the light intensity distribution near the focus and the strongest peak near the focus, the light intensity near the focus The distribution is shown in Figure 5. The strongest peak is about 422.5. It can be seen from Figure 5 that there are obvious interference fringes near the focus, and the Strehl Ratio is about 0.217. Therefore, the multi-tilt composite MLL composed of two Tilted MLLs does not meet the requirements.

5. Continue to calculate the situation when the multi-tilt composite MLL is composed of 4 Tilted MLLs, and the number of layers of each Tilted MLL is 1550 layers. The angle between the film layer and the incident X-ray in the first Tilted MLL is 2.58mrad, and the positions of the first and second film layers on the incident surface are 10.35698 and 10.37697 microns respectively, and the positions on the exit surface are 10.32599 and 10.32599 microns respectively. 10.34599 microns; the angle between the second Tilted MLL film layer and the incident light is 4.08mrad, the positions of the first and second film layers on the incident surface are 27.39176 and 27.39932 microns respectively, and the positions on the exit surface are respectively 27.34276, 27.35031 microns; the angle between the third Tilted MLL film layer and the incident light is 5.17mrad, the positions of the first and second film layers on the incident surface are 37.32078, 37.32633 microns, and the position on the exit surface They are 37.25879 and 37.26434 microns respectively; the angle between the film layer of the fourth Tilted MLL and the incident light is 6.06mrad, and the positions of the first and second film layers on the incident surface are 45.11504 and 45.11963 microns respectively, and on the exit surface The positions are 45.04235, 45.04693 microns, respectively. The light intensity distribution near the focus is shown in Figure 5, and the strongest peak is about 848.7. From Figure 5, it can be seen that there are obvious interference fringes near the focus, and the Strehl Ratio is about 0.437. Therefore, the multi-tilt composite MLL composed of four Tilted MLLs does not meet the requirements.

6. Continue to calculate the situation when the multi-tilt composite MLL is composed of 8 Tilted MLLs. The number of layers of the first 7 Tilted MLLs is 776 layers, and the number of layers of the last Tilted MLL is 768 layers. The angle between the film layer and the incident X-ray in the first Tilted MLL is 2.04mrad, and the positions of the first and second film layers on the incident surface are 10.35049 and 10.37049 microns respectively, and the positions on the exit surface are 10.32599 and 10.32599 microns respectively. 10.34599 microns; the angle between the eighth Tilted MLL film layer and the incident X-ray is 6.23mrad, the positions of the first and second film layers on the incident surface are 48.57265 and 48.57691 microns respectively, and the positions on the exit surface are respectively For 48.49747, 48.50173 microns. The light intensity distribution near the focus is shown in Figure 5, and the strongest peak is about 1328. It can be seen from Figure 5 that there are certain interference fringes near the focus, and the Strehl Ratio is about 0.683. Therefore, the multi-tilt composite MLL composed of eight Tilted MLLs does not quite meet the requirements.

7. Continue to calculate the situation when the multi-tilt composite MLL is composed of 16 Tilted MLLs. The first 15 Tilted MLLs have 388 layers, and the last Tilted MLL has 380 layers. The angle between the film layer and the incident X-ray in the first Tilted MLL is 1.71mrad, the positions of the first and second film layers on the incident surface are 10.34648 and 10.36648 microns respectively, and the positions on the exit surface are 10.32599 and 10.32599 microns respectively. 10.34599 microns; the angle between the film layer of the 16th Tilted MLL and the incident X-ray is 6.36mrad, the positions of the first and second film layers on the incident surface are 50.19983 and 50.20395 microns respectively, and the positions on the exit surface are respectively 50.12346, 50.12758 microns. The light intensity distribution near the focus is shown in Figure 3, and the strongest peak is about 1746. It can be seen from Figure 3 that there are basically no interference fringes near the focus, and the Strehl Ratio is about 0.898. Therefore, the multi-tilt composite MLL composed of 16 Tilted MLLs meets the requirements.

8. Recalculate the optimal depth of the multi-tilt composite MLL composed of 16 Tilted MLLs, which is still 12 microns.

9. Diffraction efficiency distribution on the exit plane, intensity distribution near the focal point, and light intensity distribution on the best focal plane when a single Tilted MLL, Wedge MLL, and multi-tilt composite MLL composed of 16 Tilted MLLs achieve diffraction-limited focusing As shown in Figures 2, 3 and 4, here a single Tilted MLL achieves diffraction-limited focusing with maximum efficiency at a depth of 5 microns and a tilt angle of 4.85 mrad. It can be seen from the figure that when achieving diffraction-limited focusing, the multi-tilt compound MLL has much higher diffraction efficiency and peak intensity of the focused spot than a single Tilted MLL, and its focusing performance is close to that of Wedge MLL, while having a simpler structure , can greatly reduce the difficulty of the process.

The present application is not limited to the embodiments described in detail in the present invention, and those skilled in the art can make various modifications to this, such as changing the focal length, focusing resolution, etc., but as long as these modifications do not deviate from the spirit and intent of the present invention, they are still Within the protection scope of the present invention.

Claims (8)

1. a kind of many inclinations angle composite multilayer membrane Laue lens are it is characterised in that include m along perpendicular to the arrangement of incident light direction Apsacline multilayer film Laue lens, after each described apsacline multilayer film Laue lens arrangement film layer numbering and thicknesses of layers press Determine according to zone plate formula；Positioned at first film layer of central area apsacline multilayer film Laue lens described in first, its volume Number be k, the position on the plane of incidence is by formula x_in(k)=x_re(k)+w×tan(θ₁) determine, w is according to wedge shape multilayer film Laue The calculated optimum depth of lens design, θ₁It is the folder of the film layer of apsacline multilayer film Laue lens described in first and incident illumination Angle, x_inK () is film layer k in the position of the plane of incidence, x_reK () is film layer k in the position of exit facet, x_re(k)=(k λ f)^1/2, λ is Lambda1-wavelength, f is selected focal length, second film layer exit facet position x_re(k+1)=x_re(k)+d(k+1)/cos(θ₁), Position on the plane of incidence is x_in(k+1)=x_in(k)+d(k+1)/cos(θ₁), d (k+1) is the thickness of second film layer, subsequently The position of film layer is by that analogy；The ground floor film layer of apsacline multilayer film Laue lens described in i-th, it is numbered is p, in outgoing Position x on face_re(p)=x_re(p-1)+d(p)/cos(θ_i-1), the position x on the plane of incidence_in(p)=x_re(p)+w×tan (θ_i), position on exit facet for the second layer film layer is x_re(p+1)=x_re(p)+d(p+1)/cos(θ_i), the position on the plane of incidence It is set to x_in(p+1)=x_in(p)+d(p+1)/cos(θ_i), d (p+1) is the thickness of the second film layer, and the position of subsequent film is with such Push away；θ_iIt is the angle of the film layer of apsacline multilayer film Laue lens described in i-th and incident illumination, i value is 2～m；Wherein, often All film layers in apsacline multilayer film Laue lens described in and incident illumination have identical angle；This many inclination angle is combined many Tunic Laue lens are capable of diffraction limit and focus on；M is more than 2.

2. as claimed in claim 1 many inclinations angle composite multilayer membrane Laue lens it is characterised in that each described apsacline is many In tunic Laue lens, two neighboring film layer middle meets Bragg condition：2[2d(i_m)]sinθ_i=λ, i_m=(i_f+i_l)/ 2,i_fAnd i_lIt is the film layer numbering of described apsacline multilayer film Laue lens ground floor and last layer respectively, d (i_m) for numbering be i_mFilm layer thickness.

3. as claimed in claim 2 many inclinations angle composite multilayer membrane Laue lens it is characterised in that each described apsacline multilamellar There is between film Laue lens the equal number of plies or the number of plies of film layer quantity difference minimum.

4. as claimed in claim 2 many inclinations angle composite multilayer membrane Laue lens it is characterised in that each described apsacline multilamellar The plane of incidence of film Laue lens and exit facet are parallel to each other, and perpendicular to incident illumination.

5. a kind of many inclinations angle composite multilayer membrane Laue lens design method, its step is：

1) according to zone plate formula x (n)²=n λ f determines that the film layer of all film layers in the composite multilayer membrane Laue lens of many inclinations angle is compiled Number and thicknesses of layers, and the initial position of each film layer；Wherein, x (n) refers to the initial position of film layer numbering n, λ be into Penetrate optical wavelength, f is selected focal length；

2) according to 1) given wavelength, focal length and film layer numbering, calculate wedge shape multilayer film Laue lens under different depth Wavefront distribution and diffraction efficiency, the optimum depth obtaining；Calculate burnt further according to the wavefront distribution on exit facet at optimum depth Strongest I near point₁；

3) adjustment film layer and the angle of incident illumination, all film layers are divided into m along the inclination perpendicular to the arrangement of incident light direction Type multilayer film Laue lens, wherein, all film layers in each described apsacline multilayer film Laue lens have phase with incident illumination Same angle, m is more than 2；

4) calculate 3) gained apsacline multilayer film Laue lens near focal point strongest I₂；Judge ratio I₂/I₁Whether big In given threshold；If it is not, then change m value, repeat step 3), 4), until ratio I₂/I₁More than given threshold.

6. method as claimed in claim 5 is it is characterised in that be divided into m along perpendicular to incident light direction by all film layers The apsacline multilayer film Laue lens of arrangement, the method calculating film layer position and angle in described apsacline multilayer film Laue lens For：Being set in first film layer of apsacline multilayer film Laue lens described in the first of central area, to number be k, and it is in the plane of incidence On position by formula x_in(k)=x_re(k)+w×tan(θ₁) determine, w is to be calculated according to wedge shape multilayer film Laue lens design The optimum depth arriving, θ₁It is the angle of the film layer of apsacline multilayer film Laue lens described in first and incident illumination, x_inK () is film layer K is in the position of the plane of incidence, x_reK () is film layer k in the position of exit facet, x_re(k)=(k λ f)^1/2, λ is lambda1-wavelength, and f is The focal length selected, second film layer exit facet position x_re(k+1)=x_re(k)+d(k+1)/cos(θ₁), the position on the plane of incidence It is set to x_in(k+1)=x_in(k)+d(k+1)/cos(θ₁), d (k+1) is the thickness of second film layer, and the position of subsequent film is with this Analogize；The ground floor film layer of apsacline multilayer film Laue lens described in i-th, it is numbered is p, the position x on exit facet_re (p)=x_re(p-1)+d(p)/cos(θ_i-1), the position x on the plane of incidence_in(p)=x_re(p)+w×tan(θ_i), the second tunic Position on exit facet for the layer is x_re(p+1)=x_re(p)+d(p+1)/cos(θ_i), the position on the plane of incidence is x_in(p+1) =x_in(p)+d(p+1)/cos(θ_i), d (p+1) is the thickness of the second film layer, and the position of subsequent film is by that analogy；θ_iIt is i-th The film layer of individual described apsacline multilayer film Laue lens and the angle of incident illumination, i value is 2～m.

7. the method as described in claim 5 or 6 is it is characterised in that have between each described apsacline multilayer film Laue lens The equal number of plies or the number of plies of film layer quantity difference minimum；In each described apsacline multilayer film Laue lens, middle Two neighboring film layer meets Bragg condition：2[2d(i_m)]sinθ_i=λ, i_m=(i_f+i_l)/2,i_fAnd i_lIt is described inclination respectively The film layer numbering of type multilayer film Laue lens ground floor and last layer, d (i_m) it is i for numbering_mFilm layer thickness.

8. method as claimed in claim 5 is it is characterised in that change described m value using two way classification.