TWI270689B - Unsymmetrical fourier transform optical system and volume holographic data storage optical system using the same - Google Patents

Abstract

This invention relates to a compact unsymmetrical Fourier transform optical system in an order from an object side to a Fourier transform plane including a first lens group having a negative power, a second lens group having a positive power. The first lens group has a first meniscus lens and a second meniscus lens both having a negative power respectively. The first meniscus lens has a convex surface on the object side and an opposite concave surface. The second meniscus negative power lens has a convex surface on the Fourier transform plane side and an opposite concave surface. The second lens group has of a lens having a positive power, and the lens has a convex surface on the object side. The invention also provides a volume holographic data storage optical system using the unsymmetrical Fourier transform optical system.

Description

1270689 IX. Description of the Invention: [Technical Field] The present invention relates to a Fourier transform optical system for recording and reproducing Fourier transform hologram. [Prior Art] A m is a holographic storage technology for two-dimensional storage technology. It has become the focus of storage technology development due to its advantages of large data storage density, high transmission rate and short readout time. In volume holographic storage systems, data is typically accessed using a Fourier transform optical system. a typical volume holographic storage optical system comprising a front group Fourier transform lens and a rear group inverse Fourier transform lens; the input surface, generally a Spatiai Ught Modulator (SLM) , placed on the focal plane of the front group Fourier transform lens, parallel light is incident on the transmission surface, and the diffracted light is imaged on the back focal plane through the front group Fourier transform lens, and the back focal plane is also called the spectrum surface. The recording medium is placed on the focal plane of the back-group inverse Fourier transform lens, and the spectrum of the spectrum surface is imaged on the back focal plane by the post-group inverse Fourier transform lens, and the back & The output surface is generally CCD (Charge-C〇upled Dev (4) or CMOS (C〇mplememary-Metal-〇xide S coffee iconductor Transistor) 在' In the holographic storage optical system, the front group Fourier transform lens and the latter group The inverse Fourier transform lens can use two different mirrors m or the same lens system. The forward optical path structure of the lens system is used as the front group Fourier transform lens, and the reverse optical path structure is used as the rear group inverse Fuli.茱 transform lens, the reverse The structure of the road is the flipping of its forward optical path structure. The lion of the Fourier transform mirror fill light imaging, the lens of the mosquito must meet the control position of the ί 兰 like Wei position; the first - the total position of the object image: the object is infinite Far, = in the other focal plane 'like in the back focal plane; the second pair of objects like the total position: the object in the front focal plane is on the top of the image like 'in the distance of the silk. (2) the main axis parallel to the optical axis Satisfy the sinusoidal stop. (3) Eliminate various monochromatic aberrations and achieve diffraction limitation. (4) Pieces, (3) 隹i makes =_ high-density information storage, requires Fourier transform lens to have a shorter ... distance, for the US two storage Density, it is required to increase the object surface and reduce the diffracted light into a Fourier transform optical system using an asymmetric structure. ^', 'P', however, the asymmetric Fourier transform lens generally uses an asymmetrical spherical surface of more than 5 In the form of the lens 1270689, which is difficult to be full-storage storage technology, the structure of the Fourier lens is compact. In view of this, it is necessary to provide an asymmetric Fourier and the preparation of the system. Holographic storage system, which may have a more compact image group, wherein The second ii^ir has a positive power of the second lens and the second meniscus type read i if the surface is opposite to the first meniscus type negative lens and a first surface of the lens surface is convex. The orientation of the lens is not the same as the condition of 'other', which is beneficial to the spherical aberration and the off-axis aberration correction. The tea buds should satisfy the constraint conditions (1)~(3): 0.1<RlR/f<0.4 (1) •〇*4<R2F/f<-0.1 ...... (2) 0.1<di2/f<0.3 ...... (3) where f : focal length of an asymmetric Fourier transform optical system; • concave radius of curvature of the first meniscus negative lens;

Rzf · Concave radius of curvature of the first lunar-type negative lens ·, p-bow 戸 戸 ^ · ί The air on the optical axis between the meniscus-type negative lens and the second meniscus-type negative lens ° The distance between the two negative concave lenses and the second meniscus negative lens on the optical axis; the second two Rm generous, the upper limit of the condition (1), the spherical aberration of the positive optical path and the sinusoidal difference to the negative direction The off-axis aberration of the reverse path increases. When Rir is less than the lower limit of the strip, the opposite is true. 1270689 When R2F is greater than the upper limit of condition (2), the spherical aberration and sinusoidal difference of the forward optical path increase in the positive direction, and the off-axis aberration of the reverse optical path increases. When Rw is less than the lower limit of the condition (2), a phenomenon opposite to the above is caused. f As can be seen from the above, by using the change of Rm, the spherical aberration and sine difference of the forward optical path can be corrected. When R and r are arbitrarily changed outside the range of conditions (1) and (2), the spherical aberration and sine of the forward optical path are corrected. The difference is easy to correct, and the off-axis aberration of the reverse path is excessively increased in the negative or positive direction, and the correction is very difficult. When R1R and r2F satisfy the conditions (1) and (2), the reverse axis can be corrected. When the mountain 2 is greater than the upper limit of the condition (3), the positive direction of the spherical aberration of the positive optical path increases, and the negative direction of the sinusoidal difference increases, so the dispersion of the spherical aberration and the sinusoidal difference is too large, resulting in difficulty in correction, and the reverse optical path The off-axis county is also difficult to correct. When dl2 is less than the lower limit of the condition (3), the relationship between the nucleus and the above is greater than the upper limit of the condition (3). If the radius of curvature ‘and &&&&&&&&&&&&&&&&&&&&&&&&&&&& ', therefore, the asymmetric Fourier transform optical system satisfies the constraint bar with a larger number of hunger Wei Xiaoxiao, its Natong with the sister money value aperture and ^ bundle bar New good correction field #, the tear _ Liye light The system should also satisfy about η3>1·7..... η3·ϋ2>〇·15 where η2 : (4) (5) Material refractive index of the second meniscus negative lens: second lens group Material refractive index; = medium n lens group riding Qi% is smaller than face lying scale H (four) 贞 麟 骑 骑 „ „ „ „ „ „ „ „ „ „ „ „ „ 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限 下限And material _Wei _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ F3/f<〇.9 (6) where f3 is the focal length of the second lens group; , wherein, when the focal length of the second lens group & is greater than the upper limit of the condition (6), the second If the lens component is too small, the out-of-axis aberration of the 'reverse _ optical path is difficult to correct; when the focal length (10) of the second lens group is positive and the positive component, the lens table _ is too large, and the spherical aberration is preferred. The positive lens is a double convex Lens. The object side is finely braided—the first lens group is a meniscus positive lens to the ==== group, and the meniscus positive lens is facing the spectrum: two _=(four), and === and - The second meniscus mirror, the convex surface of the relative -th meniscus type negative lens moon type negative lens faces the spectrum surface; the first == face = surface: the second corner faces the object surface, and the lens surface is convex. And including a positive lens, the positive lens ensures that the sinusoidal condition is satisfied on the one hand, and the front set of the sinusoidal light-changing material satisfies about the miscellaneous pieces (1)I corrected spherical aberration _b aberration, 0.1<RiR/f<;0.4...... (1) ' -0.4<R2p/f<-〇# 1 ...... (2) 〇*l<d]2/f<0.3...... (3) where the 'f·· ^ Fu-transformed silk money n n'f month-type negative lens concave curved second-moon type negative lens concave curvature half-two interval 'that is the first _ meniscus type negative month The distance between the air on the optical axis between the negative lenses, the optical axis of the two concave surfaces opposite to the lens and the second arm-shaped negative lens. 1 1270689 bundle i (t(5) calibrated lion, the former _里叶降减« The system should also satisfy about η3>1·7 • · · ♦•Lu (4) η3-η2>0.15 where (5) η2 3 The refractive index of the material of the second meniscus negative lens; the refractive index of the material of the first lens group; the silk of the test 1 , the fine #里__ 〇.55<f3/f<〇.9... (6) where 'f3 ·· the focal length of the second lens group; preferably, the positive lens is a double convex positive lens. Na is fine------------------------------- The Liye exchange optical system is a pre-extension technology of the front group Fourier transform optical system, and the asymmetric Fourier transform silk system provided by the technical solution, the domain light (10), the shape of the positive forward machine seam value The smaller field of view reverse optical path has a smaller numerical aperture and a larger field of view; various monochromatic aberrations such as spherical aberration, off-axis aberration and field curvature of the forward optical path and the reverse optical path can be better corrected; The positive optical path of the asymmetric Fu-Chao transform optical system can be used as the Fourier transform, and the reverse optical path can be used as the inverse Fourier transform; it can meet the requirements of the holographic multiplex county. [Embodiment] Hereinafter, embodiments of the present invention will be described in further detail with reference to the accompanying drawings. In a first embodiment, as shown in the figure, an asymmetric Fourier transform optical system 10, from the object surface to the frequency surface 15, includes a _ lens group having a negative filament and a large positive power. The second lens 10 is a group of 1270689. Wherein, the first lens group is composed of two concave surfaces opposite to one of the meniscus type negative lens 12 and one meniscus type negative lens 13 , and the convex surface of the meniscus type negative lens 12 faces the object surface 11 and the meniscus type negative lens] The convex surface faces the spectral surface 15; the second lens group consists of a double convex positive lens 14. The focal length f = 5 〇 mm of the asymmetric Fourier transform optical system 10, incident light (positive optical path) on the object side, and the angle of view 2ω = 5.72. The F-number of the incident light (reverse optical path) on the side of the spectrum surface 15 is F/#=10, the angle of view is 2ω: 20·72°, and the wavelength is ua532^. The structural parameters of the asymmetric Fourier transform optical system 1 详 are shown in Table 1; where R is the radius of curvature of each lens surface from the object side, and 0 is the green distance of each lens surface from the object side, n secret The refractive index of the pair of her lenses is λ = α532μπι. In order to ensure that the sinusoidal condition is satisfied on the one hand, and to correct the spherical aberration and the off-axis aberration on the other hand, the asymmetric Fourier transform optical system 1 should satisfy the following conditions: 〇.l <R]R/f<0.4 ...... (!) •〇-4<R2F/f<-0.1 ...... (2) 0.1<d]2/f<0.3...... (3) In the target example, R1R = R3 = 13 82753 mm; R2F = R4 = 11 8 〇 158 mm; Mountain 2 = d3 = 6.772233 mm; which satisfies the conditions (1) to (3). For the better correction of the field curvature, the asymmetric Fourier transform optical system 1〇 should also meet the following constraints: ιΐ3>1.7...... (4) n3-n2>0.15..... (5) In the present embodiment, 'n3=l.7643G9; n2=1.517591: conditions (4) to (5). / Better _ 'To ensure a reasonable power distribution of the system, the asymmetric Fourier transform optical system 10 should further satisfy the constraint (6): 0.55 <f3/f<0.9... (6) In the present embodiment, f3/f = 〇.7〇; which satisfies the condition (6). The first graph and m are the positive optical path sinusoidal difference and the optical path difference respectively; the fourth and fifth graphs are respectively ί reverse optical path sinusoidal difference and optical path difference. From the second picture and the _ can be seen, regardless of the forward optical path retreat, the reverse Yao chord difference is very good,], to meet the ball condition. It can be seen from the third and fifth graphs that regardless of the forward optical path, the optical path difference of the reverse optical path is limited by diffraction requirements. 1270689

-------------- 一丨-40.68527 45.32936 The pair of positive-optical-transform optical systems ig's positive and reverse optical paths meet the sinusoidal condition' and meet the Na-restricted requirements. Therefore, the forward optical path can be changed as 'the reverse optical path can be used as the inverse Fourier transform; and the asymmetric Fu 〇ϊ 〇ϊ 〇ϊ 冓 冓 冓 冓 路 可 可 可 换 换 换 换 换 换 换 换 换 换Subsystem and post-group inverse Fourier transform optical system. The second embodiment 25 number I-Asymmetric Fourier transform optical system 2G, from the object surface 21 to the spectral surface fineness - the first and the second lens having a large positive degree The lens group consists of two concave surfaces opposite to one of the meniscus type negative lens 22 and the convex surface of the -f month type negative lens 22 toward the object surface 21, and the convex shape of the f-type negative lens 23: toward the frequency lion 25 4 two lens group by - double The convex positive lens 24 is composed. The asymmetric Fu-changing optical system has a focal spot of 55mm, and the object emits light (positive light tentacles, touches the _man-shot system (slightly light path), the field of view I m ^ 长Μ 532"" The structural parameters of the leaf-transformed optical purity 20 are detailed iii丄, the radius of curvature of each lens surface from the object side, d is the distance on the optical axis of each surface from the object side, and n is the number of lenses from the object side. The corresponding wavelength is again = 〇 532 之 折射 Μ Μ Μ Μ , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 校正 校正 校正 校正 校正 校正 校正 校正 校正 校正 校正 校正<Rir/f<(X4 ...... (1) -0.4<R2F/f<-ai ······· (2) (3) 〇.l<d12/f<〇.3 12 Ϊ 270689 d In this reed and 虼 example, r1r = R3 = 15 〇 836 imm ; 129 〇 65 mm ; π & 7 · 469536 _ ; which satisfies the condition (1) ~ (3). The 'for better correction field curvature, the _ lin The Lie Lai optical line 2G should also satisfy the following constraints: " ^3^1.7..... Π3-η2>0.15 (4) (5) The real (four) '中 'n3=L7643Q9; such as 1507225; Condition (4) ~ (5). 〇.55<f3/f<〇.9 (6) ^Implementation Example towel '._; its riding (6). Reverse light:: The string is the sine difference and the optical path difference of the i-direction optical path; Figure 9 and the tenth figure are the sine of the optical path «彳M, \;^^ and ®9 can Seeing the miscellaneous job, the road is also reversed, and the reverse path is also seen by the reverse ship.

The sinusoidal condition is satisfied, and */▼-the tea transforms the optically pure 2G Zhenggu road and the reverse optical path with the same leaf transformation, and the inverse ^2 diffraction threshold is required. Shame, its positive (four) road structure can be used as the Fourier system of the Fourier system (four) for the Liye Μ; the head 赖 _ «transformation optics before the group Fourier transform ^ to the optical path structure can be divided into two - the implementation of the volume holographic hybrid optical system Two pre- and post-group inverse Fourier transform optical systems. R(mm) infinity—22.17936—15.08361 •12.9065 :16.91654 63.07369 —_^8.4945 It can be seen from the above that 'the asymmetric Fuli is the eleventh figure you;; ', #symmetric Fourier^change optical system 3G, from the object 31 to The spectrum 13 1270689 ' includes a first lens group having an indifference degree, a third lens group having a recorded refractive power, and a third lens group having a small nuclear positiveness placed on the first-Wei side. Wherein, the first lens group is composed of two concave surfaces opposite to one of the meniscus type negative lens 32 and one convex type negative lens 32 facing the object surface 31, and the convex surface of the f-type negative lens is formed toward the ^^36 It consists of a double convex positive lens %, a third lens group consisting of a meniscus positive "6, and a slanting face of the positive lens 36 and a lens surface (four) convex surface. The Fourier transform optical system The focal length of 30 is f=4〇mm, the F-number of incident light (positive light path) on the object side is F/#,25, and the angle of view is 2ω=5.72. The incident light on the side of the spectrum side (reverse light path) is fine. , angle 2ω=2ό 'wavelength λ=α532μ^. The structure of the miscellaneous Fourier transform optical secret 3() is shown in Table 3 '· where R is the radius of curvature of each lens surface from the object side, d In order to count from the object side, the optical axis of each lens is _, n is the refractive index of each lens from the object weaving = α. ^ " Stay sine condition, on the other hand, it is good for correcting spherical aberration and For the off-axis aberration, the asymmetric Fourier transform optical system 3〇 satisfies the following constraints: 〇.1<R]R/f<0.4...(1) ~〇-4< R2F /f<-0.1 . ..... (2) 0 .1<d12/f<0.3...... (3) In the present embodiment, R1R is as (10) (four) 4 mm; R2f = R6 = i2 32391 coffee; Α 2 = (^7·182503πιπι; which satisfies the conditions (1) to (3). Preferably, in order to better correct the curvature of field, the non-pair _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ In the present embodiment, (4). (10) (10); η2 = 1 551456; which satisfies the condition (4Μ5). More preferably, the asymmetric Fourier transform optical system 30 should further satisfy the constraint condition to ensure a reasonable power distribution of the system ( 6): 0.55 <f3/f<0.9 (6) In the present embodiment, f3/f=a76; which satisfies the condition (6). The twelfth and thirteenth drawings are the forward optical paths, respectively. Sinusoidal difference and optical path difference·, pin four figure, 14 1270689 reach the sinusoidal difference and light green of the divergent optical path. From the twelfth picture and the second ΐΓ ΐΓ 向 reverse path, the sine difference is very small, satisfying the sine condition. Restricted to ^. To see that (9) is the positive optical path, the optical path difference of the reverse optical path is very small,

------,. Display 20.01926 ~ wit knows that the Fourier transform light (four) unified 3G positive (four) road and reverse optical path sine condition, and reached the thief _ seeking. , the forward light tin reverse light material is inverse Fourier Wei; domain miscellaneous (four) light change «the system and the rear group · the inner leaf transform light „ system. The “system of the difference Fourier transform fourth embodiment” if ten Six-indicator--Asymmetric Fourier transform optical system 4G, from the object surface _ frequency and ... two include a lens group with negative power, a second i ΐ two with larger positive power: a third lens group having a smaller positive power on the lens group side; the second lens is formed by a concave surface opposite to the f-type negative lens 42 and the f f positive lens 44 One of the lens faces of the positive lens 44 facing the object surface 41 is a convex surface. The third lens group is composed of a - (four) type positive lens 46 which faces the object surface 41. The lens surface is convex. The asymmetric Fourier transform ^ E, Ef =44mm,^^^W^f/#=2 2 , ^#^ω=5 ;〇,frequency: F-number of face-side incident light (four) optical path F/#=11, field of view 2ω=256. ^ (4) The structure of the 轮 Q Q Q 轮 & &&; 从 从 从 从 从 从 从 从 从 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 η is the correspondence of each lens from the object The wavelength λ=α532μηι is used for the sine condition. On the other hand, it is beneficial to correct the spherical aberration and the non-pair _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (i) -0.4< R2F /f<-0.1 O.kcWMU ... In this embodiment (2) (3) Rir :~=10·06888ππή ; R2F=R6=-i4.21〇65_ ; d12=d5= 5.2516mm; it satisfies the conditions (1)~(3). The following is the secret 彳山# 曲转形傅傅_丝料统(10) should also satisfy Π3>1·7... (4) ^3~^2> 0.15 ...... (5) Medium ' „3=1·7_9; η2=1551456; full of secret parts (4)~(5). /Preferred 'To ensure a reasonable power distribution of the system, the asymmetric Fourier transform light wind system 40 should further satisfy the constraint condition (6): VIII, first 0.55 <f3/f<〇.9... (6) In the present embodiment, 〇·84; which satisfies the condition (6). The seven figure and the eighteenth figure are the positive optical path sinusoidal difference and the optical path difference respectively; the nineteenth figure, the m two-dimensional drawing & are not the reverse optical path sinusoidal difference and the optical path difference. From the seventeenth and the nineteenth figure can be = no matter whether it is the forward light path or not, it is said that the m2 ί difference is very small, full ^ sine condition. From the eighteenth shot limit requirement 1 to see that the optical path difference of the optical path is very small, regardless of the forward optical path.

16 1270689

It can be seen from the above that the sinusoidal optical path and the reverse optical path of the salty Fourier transform optical system 40 satisfy the sinusoidal condition I at the same time. Therefore, the forward optical path can be Fourier transformed, and the reverse optical path can be inverse Fourier transform; and the asymmetric Fourier transform optical turn _ the positive optical path] and the inverse _ sigma split _ body Holographic storage optical secrets before the group of Fourier transform optical New Zealand (four) touch leaves Lai fresh. θ additionally Table 5 is the optical characteristics corresponding to the above four embodiments, including the aperture (for f), the field of view (2ω), the bribe, and the value corresponding to each of the preceding conditions.

In addition, with respect to each of the first, second, third, and fourth embodiments, the asymmetric optical path structure and the reverse optical path structure may be combined to form a white-two-turn. The system uses the positive Fourier transform optical (four) system of the asymmetric Fourier transform optical system of the second embodiment, and the first-actual asymmetric asymmetric Fourier transform reverse optical path structure as the subsequent inverse Fourier transform An optical system; or a forward optical path structure called a Fourier transform optical system as a pre-group Fourier third real _^^ structure as a post-group inverse Fourier transform optical system, etc. For example, the structure of the asymmetric Fourier transform optical system is shown in Fig. 17 1270689. The path difference chord difference path difference graph. Sinusoidal difference chord difference path difference graph. Sinusoidal difference Thirteenth diagram Optical path difference. The second optical system of the invention is a positive optical path of the asymmetric Fourier transform optical system of the first embodiment of the present invention. The first optical system of the asymmetric optical path of the asymmetric Fourier transform optical system The fifth embodiment of the reverse optical path of the asymmetric Fourier transform optical system of the first embodiment of the present invention is a second embodiment of the present invention. Structure of a Symmetric Fourier Transform Optical System A schematic diagram of a positive Fourier transform optical system of a second embodiment of the present invention The ninth diagram of the forward optical path light is the reverse optical path of the second embodiment of the present invention, which is called the Fourier transform optical system. The reverse optical path of the asymmetric Fourier transform optical system of the second embodiment of the present invention 10 is a schematic diagram of the structure of the asymmetric Fourier transform optical system of the third embodiment of the present invention. The second embodiment is a third embodiment of the asymmetric optical path system of the asymmetric Fourier transform optical system of the third embodiment of the present invention. Example Asymmetric Fourier transform optical system, the forward optical path sinusoidal 1 cut chart is the same as the third embodiment, the surface is called the Fourier problem optical money, the reverse light path wire 2 5® system, the third real compensation of the invention _ Liye Transformation optics Wei Zhi reverse light path tenth county invention fourth # 关非_傅里叶赖丝绪's structure diagram 18 1270689 The seventeenth embodiment is a fourth embodiment of the invention asymmetric asymmetry sine difference. The forward optical path of the leaf-converting optical system Fig. 18 is an asymmetrical cross-leaf optical path difference of the fourth embodiment of the present invention. ', the positive optical path of the transform optical system. Figure 19 Sinusoidal difference. The fourth real aspect of the invention is _Liye_Optical New Zealand's reverse optical path. According to the fourth embodiment of the present invention, the reverse optical path of the optically pure optical

[Major component description] Asymmetric Fourier transform optical system object meniscus type negative lens double convex JL lens spectrum surface JL lens 10, 20, 30, 40 11, 21, 31, 41 12, 13, 22, 23, 32, 33, 42, 43 14, 24, 34 15, 25, 35, 45 44 meniscus positive lens 46

19

Claims (1)

1270689 X. Patent application scope ···--Asymmetric Fourier transform optical system, from the object plane to the spectrum surface, including a 1 - negative lens - lens group and - with positive power a two lens group, wherein the second lens - the first meniscus type negative lens and the second type _ negative lens, the convex surface of the two I two meniscus type negative lens faces the "two T lenses" The direction of the lens toward the object surface 透 Γ π Γ The Fourier transform optical system satisfies the constraints (1) ~ (3): U. 1 < K] r / I < U.4 ...... (i) -0.4 <R2F/f<-0·1 0.1<d]2/f<0.3 ··· where (2) (3) f: focal length of the asymmetric Fourier transform optical system; R]r: first The radius of curvature of the concave surface of the meniscus negative lens; R2F • the radius of curvature of the concave surface of the second meniscus negative lens; the mountain 2: the air between the first meniscus negative lens and the second moon type negative lens Π3&gt ;1·7...... (4) n3*^2>0.15 ...... (5) where η2·the second meniscus negative lens material refractive index; two%: second The refractive index of the lens group material. 3. As described in the patent application section The Fourier transform wire _ satisfies about the non-contrast-55<f3/f<〇.9 (6) where f3·the focal length of the second lens group. The symmetry system, wherein the non-symmetric Fourier transform optical system described in the non-parameters is viewed on the side of the 敎 lens group 20 1270689 and has a positive power The third through 6. As described in the fifth paragraph of the patent application scope, the lens _-bend and the fine (10) are replaced by the money, and the third of the towel is convex. Xie Wei, do (four) Zheng Wei read the object Face-Lens Surface 7 - Front Secret Age and New - Back Group Negative, including the optical system 'from the object to the 'group, one of the second meniscus negative lenses, the Η * 3 months without The convex surface of the lens and meniscus _ towards the spectrum:; the second === mirror:: ΪΪΪ = ^, the surface is convex; the front set of Fourier transform optics two 0.1 < R1R / f < 〇 e4. .....(1) *〇.4<R2F/f<-0.1 ...... (2) 0.1<di2/f<0.3 where f: (3) f •• former group Fourier The focal length of the transform optical system; Rm: the first meniscus negative lens Concave radius of curvature; If · concave radius of curvature of the second meniscus negative lens; spacer d12 · between the -f month type negative lens and the second meniscus type negative lens between the air on the optical axis 8 · as in the patent model M7 The volume holography-optical system according to the item, wherein the front set Fourier transform optical system satisfies the constraint condition (4)~(5) ··Π3>1·7... (4) η3- Η2 > 0.15 (5) where η2 η3 · the refractive index of the material of the first write, the moon type negative lens, and the refractive index of the material of the first lens group. 9. The volume holographic storage optical system of claim 7, wherein the front group of Fourier wheat for optical music meets the constraint condition (6): (6) 〇.55<f3/f<〇.9 21 1270689 where & is the focal length of the second lens group. 10. The volume holographic storage optical system of claim 7, wherein the double lenticular positive lens. The volume holographic storage optical system of claim 7, wherein the front tea conversion optical system further comprises a three lens group having positive refractive power disposed on the side of the first lens group. . The volume holographic storage optical system according to Item 11, wherein the third lens (four) is a positive parent, and the meniscus positive lens faces the object surface through the convex surface. 13'^Γ^ " Reading silk H riding series _ Liye Yiguang material system turning structure. twenty two