JP6876189B1

JP6876189B1 - Frenerrom, measuring device and optical attenuator equipped with Frenerrom

Info

Publication number: JP6876189B1
Application number: JP2020136037A
Authority: JP
Inventors: 保明 ▲柳▼澤
Original assignee: KOGAKUGIKEN CORP.
Current assignee: KOGAKUGIKEN CORP.
Priority date: 2020-08-11
Filing date: 2020-08-11
Publication date: 2021-05-26
Anticipated expiration: 2040-08-11
Also published as: JP2022032352A

Abstract

【課題】位相差がλ／２（１８０°）であり、真空紫外から近赤外の波長領域で使用可能であるフレネルロムを提供する。【解決手段】等方性材料で形成された平行四辺形状の第一菱面体１０及び第二菱面体２０を備えるフレネルロムＨＷＰであって、第一全反射面１３、第二全反射面１４、第三全反射面２３及び第四全反射面２４の少なくとも１つ以上の面には、多層膜Ｍが形成されており、多層膜Ｍは、等方性材料よりも屈折率の大きい高屈折率材料で形成性された高屈折率膜ＭＨと、等方性材料よりも屈折率の小さい低屈折率材料で形成性された低屈折率膜ＭＬと、が交互に積層されており、真空紫外から近赤外の波長領域において入射光線Ｉに対して略１８０°の位相差を与える。【選択図】図１ＡPROBLEM TO BE SOLVED: To provide a frenerrom having a phase difference of λ / 2 (180 °) and being usable in a wavelength region from vacuum ultraviolet to near infrared. SOLUTION: This is a Frenerrom HWP having a parallel quadrilateral first rhombic body 10 and a second rhombic body 20 formed of an isotropic material, and has a first total reflection surface 13, a second total reflection surface 14, and a second. A multilayer film M is formed on at least one or more surfaces of the total internal reflection surface 23 and the fourth total reflection surface 24, and the multilayer film M is a high refractive index material having a higher refractive index than an isotropic material. The high refractive index film MH formed in the above and the low refractive index film ML formed of a low refractive index material having a refractive index smaller than that of the isotropic material are alternately laminated, and are close to vacuum ultraviolet. It gives a phase difference of approximately 180 ° with respect to the incident light I in the infrared wavelength region. [Selection diagram] FIG. 1A

Description

本発明は、フレネルロム、該フレネルロムを備えた計測装置及び光アッテネーターに係り、特に入射光線に対して１８０度の位相差を与えるλ／２フレネルロム、該フレネルロムを備えた計測装置及び光アッテネーターに関する。 The present invention relates to a frenerrom, a measuring device and an optical attenuator equipped with the frenerrom, and more particularly to a λ / 2 frenerrom that gives a phase difference of 180 degrees to an incident light beam, and a measuring device and an optical attenuator equipped with the frenerrom.

波長板は、直交する２つの偏光成分に所定の位相差（光路差）を与えて、入射偏光の状態を変える光学素子である。一般的に、波長板としては、１／２波長板（λ／２板）と１／４波長板（λ／４板）の２種類がよく利用されている。 The wave plate is an optical element that changes the state of incident polarized light by giving a predetermined phase difference (optical path difference) to two orthogonal polarized light components. In general, two types of wave plates, a 1/2 wave plate (λ / 2 plate) and a 1/4 wave plate (λ / 4 plate), are often used.

１／４波長板（Ｑｕａｒｔｅｒ−ｗａｖｅｐｌａｔｅ：ＱＷＰ）は、入射光線に対して１／４の位相差を与える波長板であり、具体的には、入射光線の電界振動方向（偏光面）にλ／４（９０°）の位相差を与える光学素子である。１／４波長板は、入射光線に対して位相差をλ／４（９０°）与え、直線偏光を円偏光に変えたり、円偏光を直線偏光に変えたりするために用いられる。 The 1/4 wave plate (QWP) is a wave plate that gives a 1/4 phase difference to the incident light beam, and specifically, λ in the electric field vibration direction (polarizing plane) of the incident light beam. It is an optical element that gives a phase difference of / 4 (90 °). The 1/4 wave plate is used to give a phase difference of λ / 4 (90 °) to an incident light ray and change linearly polarized light to circularly polarized light or circularly polarized light to linearly polarized light.

１／２波長板（Ｈａｌｆ−ｗａｖｅｐｌａｔｅ：ＨＷＰ）は、入射光線に対して１／２の位相差を与える波長板であり、具体的には、入射光線の電界振動方向（偏光面）にλ／２（１８０°）の位相差を与える光学素子である。１／２波長板は、入射光線に対して位相差をλ／２（１８０°）与え、直線偏光を回転させて出射させるために用いられる。 The 1/2 wave plate (HWP) is a wave plate that gives a phase difference of 1/2 with respect to the incident light ray, and specifically, λ in the electric field vibration direction (polarizing plane) of the incident light ray. It is an optical element that gives a phase difference of / 2 (180 °). The 1/2 wave plate is used to give a phase difference of λ / 2 (180 °) to the incident light beam and rotate the linearly polarized light to emit it.

特許文献１には、２つの平行四辺形状の菱面体を組み合わせた位相差が１１６〜１３６°のフレネル菱面体（フレネルロム）に関して、菱面体を溶融石英製とし、４つの全反射面の上に、菱面体を構成する溶融石英よりも屈折率の低いＭｇＦ_２を３０〜４５ｎｍの範囲の厚みでコーティングすることで、１９０〜１７００ｎｍの波長範囲にわたって使用されることが記載されている。 In Patent Document 1, regarding a Fresnel rhombohedron (Fresnel rhombohedron) having a phase difference of 116 to 136 °, which is a combination of two parallel quadrilateral rhombohedra, the rhombohedron is made of fused silica and is placed on four total reflection surfaces. _{It is described that MgF 2} having a refractive index lower than that of fused silica constituting the rhombohedron is coated with a thickness in the range of 30 to 45 nm so that it can be used in the wavelength range of 190 to 1700 nm.

特許文献２には、ピンホールアレイ板と試料の間にコリメータレンズおよびフレネルロムを備えた共焦点顕微鏡に関し、プリズム面内で２回の全反射によって両偏光成分の間にπ／２の位相差を生じさせるように形成されたフレネルロムや、キング型のフレネルロムを用いること、フレネルロムに多層膜をコーティングすることで、可視光域（４００〜８００ｎｍ）で波長依存性の極めて少ない位相子として働くことが可能となることが記載されている。 Patent Document 2 relates to a confocal microscope provided with a collimator lens and Frenerrom between a pinhole array plate and a sample, and causes a phase difference of π / 2 between both polarization components by two total reflections in the prism plane. By using a frenerrom formed to generate or a king-type frenerrom, or by coating the frenerrom with a multilayer film, it is possible to work as a phaser with extremely little wavelength dependence in the visible light region (400 to 800 nm). It is stated that

特許文献３には、測定光路中にフレネルロムと偏光子を有する反射率測定装置に関して、フレネルロムがλ／２（１８０°）遅れの位相関係を有することが記載されている。 Patent Document 3 describes that Frenellom has a phase relationship with a delay of λ / 2 (180 °) with respect to a reflectance measuring device having Frenelrom and a polarizer in the measurement optical path.

特許第５４３８７８９号公報Japanese Patent No. 5438789 特開平６−２３５８６５号公報Japanese Unexamined Patent Publication No. 6-235856 特開昭６１−９５２３０号公報Japanese Unexamined Patent Publication No. 61-95230

近年、半導体などの高精度、高密度化に伴い、微小領域の偏光解析や高分解能な面内情報の分析が重要性を増しており、（１）位相差がλ／２（１８０°）であり、（２）使用可能な波長帯域が真空紫外から近赤外の波長領域（λ＝１９０〜２０００ｎｍ）と広帯域である汎用性の高い光学素子が必要とされているが、上記（１）及び（２）の特性を備える光学素子は存在していなかった。 In recent years, with the increase in precision and density of semiconductors, polarization analysis of minute regions and analysis of in-plane information with high resolution have become more important. (1) The phase difference is λ / 2 (180 °). Yes, (2) a highly versatile optical element having a wavelength band that can be used from vacuum ultraviolet to near infrared (λ = 190 to 2000 nm) and a wide band is required. There was no optical element having the characteristic of (2).

特許文献１のフレネルロムでは、４つの全反射面にＭｇＦ_２単層膜をコーティングすることで１９０ｎｍ〜１７００ｎｍの波長領域と広帯域化が可能となっているが、これは、位相差を１２６°（１１６〜１３６°）としているためである。このことは、特許文献１がエリプソメーターやポラリメーターといった測定装置を前提としており、フレネルロムで生じる位相差が、汎用性が高く、原理的には使いやすい位相差λ／４（９０°）ではなくても、装置側の調整で使用できるためである。また、特許文献１のフレネルロムは、位相差がλ／２ではない。 In Frenerlom of Patent Document 1, by coating the four total reflection surfaces with an MgF ₂ monolayer film, it is possible to widen the wavelength region from 190 nm to 1700 nm, which makes the phase difference 126 ° (116 °). This is because it is set to ~ 136 °). This is because Patent Document 1 presupposes a measuring device such as an ellipsometer or an ellipsometer, and the phase difference generated by frenerrom is not a phase difference λ / 4 (90 °) which is highly versatile and easy to use in principle. This is because it can be used for adjustment on the device side. Further, the phase difference of Frenerrom in Patent Document 1 is not λ / 2.

特許文献２のフレネルロムでは、１つの平行四辺形状の菱面体を用いる場合、その構造上、入射光線と出射光線の光軸にズレが発生するため、光学系を組む際に、入射光線と出射光線の光軸のズレに合わせて、後の部品もずらして配置しなければならない。また、フレネルロムを回転させながら使用すると、出射光線の位置も回転してしまい、使用し難いという課題がある。さらに、キング型のフレネルロムでは、その構造上、特定の一か所以外は、入射光線と出射光線の光軸にズレが発生し光線の上下が逆転してしまうため、光線の上下を修正する部品を追加する必要があるなど使用し難いという課題がある。また、特許文献２のフレネルロムは、位相差がλ／２ではない。 In Frenerrom of Patent Document 2, when one parallel quadrilateral rhombic body is used, the optical axes of the incident light rays and the emitted light rays are deviated due to the structure. Therefore, when the optical system is assembled, the incident light rays and the emitted light rays are displaced. The rear parts must be shifted and arranged according to the deviation of the optical axis of. Further, if Frenelrom is used while being rotated, the position of the emitted light beam is also rotated, which causes a problem that it is difficult to use. Furthermore, in the king type Frenerrom, due to its structure, except for a specific place, the optical axis of the incident light ray and the outgoing light ray shifts and the top and bottom of the light ray are reversed, so a part that corrects the top and bottom of the light ray. There is a problem that it is difficult to use, such as the need to add. Further, the phase difference of Frenerrom in Patent Document 2 is not λ / 2.

特許文献３のフレネルロムは可視光用であり、真空紫外から近赤外の波長領域で使用可能な性能を有するものではない。 The Frenerrom of Patent Document 3 is for visible light and does not have the performance that can be used in the wavelength region from vacuum ultraviolet to near infrared.

本発明は、上記の課題に鑑みてなされたものであり、本発明の目的は、位相差がλ／２（１８０°）であり、真空紫外から近赤外の波長領域で使用可能であるフレネルロム、該フレネルロムを備えた計測装置及びアッテネーターを提供することにある。 The present invention has been made in view of the above problems, and an object of the present invention is Frenerlom, which has a phase difference of λ / 2 (180 °) and can be used in the wavelength region from vacuum ultraviolet to near infrared. , To provide a measuring device and an attenuator equipped with the Frenerrom.

本発明者らは、上記課題を解決すべく鋭意研究した結果、菱面体を形成する等方性材料よりも屈折率の大きい高屈折率膜と、菱面体を形成する等方性材料よりも屈折率の小さい低屈折率膜と、が交互に積層した多層膜を、フレネルロムの全反射面に形成することを見出し、本発明を完成するに至った。 As a result of diligent research to solve the above problems, the present inventors have found a high refractive index film having a higher refractive index than the isotropic material forming the rhombus and a refraction than the isotropic material forming the rhombus. We have found that a multilayer film in which low refractive index films having a low refractive index and a low refractive index film are alternately laminated is formed on the total reflection surface of Frenerrom, and the present invention has been completed.

前記課題は、本発明のフレネルロムによれば、等方性材料で形成された平行四辺形状の第一菱面体及び第二菱面体を備えるフレネルロムであって、前記第一菱面体は、第一入射端面と、前記第一入射端面と平行に配置された第一出射端面と、前記第一入射端面及び前記第一出射端面と交わる第一全反射面と、前記第一全反射面と平行に配置された第二全反射面と、を有し、前記第二菱面体は、第二入射端面と、前記第二入射端面と平行に配置された第二出射端面と、前記第二入射端面及び前記第二出射端面と交わる第三全反射面と、前記第三全反射面と平行に配置された第四全反射面と、を有し、前記第一入射端面に入射した入射光線は、前記第一全反射面、前記第二全反射面、前記第三全反射面及び前記第四全反射面で全反射して、前記第二出射端面から出射光線として出射し、前記第一全反射面、前記第二全反射面、前記第三全反射面及び前記第四全反射面の少なくとも１つ以上の面には、多層膜が形成されており、前記多層膜は、前記等方性材料よりも屈折率の大きい高屈折率材料で形成された高屈折率膜と、前記等方性材料よりも屈折率の小さい低屈折率材料で形成された低屈折率膜と、が交互に積層されており、１９０ｎｍ以上２０００ｎｍ以下の波長領域において前記入射光線に対して１８０°±１０°の位相差を与えること、により解決される。 According to the Frenerrom of the present invention, the subject is a Frenerrom having a parallel quadrilateral first rhombus and a second rhombus formed of an isotropic material, and the first rhombus is the first incident. The end face, the first emission end face arranged parallel to the first incident end face, the first total reflection surface intersecting the first incident end face and the first emission end face, and the first total reflection surface arranged parallel to the first total reflection surface. The second total reflection surface has a second total reflection surface, and the second rhombic body has a second incident end surface, a second exit end surface arranged in parallel with the second incident end surface, the second incident end surface, and the above. The incident light beam having a third total reflection surface intersecting with the second emission end surface and a fourth total reflection surface arranged in parallel with the third total reflection surface, and incident light incident on the first incident end surface is the first. (1) Total internal reflection surface, the second total reflection surface, the third total reflection surface, and the fourth total reflection surface are totally reflected and emitted as emitted light from the second emission end surface, and the first total reflection surface, A multilayer film is formed on at least one or more surfaces of the second total reflection surface, the third total reflection surface, and the fourth total reflection surface, and the multilayer film is more than the isotropic material. and the high refractive index film made form a high refractive index material having a large refractive index, and a low refractive index film than the isotropic material made form a small refractive index and low refractive index material, but alternatively are stacked, to provide a phase difference of 1 80 ° ± 10 ° with respect to the incident light in the 2000nm or less in the wavelength region above 190 nm, it is solved by.

このように、等方性材料で形成された平行四辺形状の第一菱面体及び第二菱面体を備えるフレネルロムにおいて、フレネルロムの４つの全反射面の少なくとも１つ以上の面に、菱面体を形成する等方性材料よりも屈折率の大きい高屈折率膜と、菱面体を形成する等方性材料よりも屈折率の小さい低屈折率膜と、が交互に積層した多層膜を形成することで、位相差がλ／２（１８０°）であり、真空紫外から近赤外の波長領域で使用可能であるフレネルロムを提供することが可能となる。 As described above, in the Frenerrom having the parallel quadrilateral first rhombus and the second rhombus formed of the isotropic material, the rhombus is formed on at least one or more of the four total reflection planes of the Frenerrom. By forming a multilayer film in which a high refractive index film having a higher refractive index than the isotropic material and a low refractive index film having a lower refractive index than the isotropic material forming the rhombus are alternately laminated. , The phase difference is λ / 2 (180 °), and it is possible to provide a Frenerrom that can be used in the wavelength region from vacuum ultraviolet to near infrared.

このとき、前記第一全反射面、前記第二全反射面、前記第三全反射面及び前記第四全反射面の１つ又は２つの面に前記多層膜が形成されているとよい。
このとき、前記低屈折率材料がＭｇＦ_２であり、前記高屈折率材料がＧｄＦ_３、ＬａＦ_３及びＮｄＦ_３からなる群から選択される少なくとも一種であるとよい。
このとき、前記等方性材料が石英又はＣａＦ_２であるとよい。 At this time, it is preferable that the multilayer film is formed on one or two surfaces of the first total reflection surface, the second total reflection surface, the third total reflection surface, and the fourth total reflection surface.
At this time, it is preferable that the low refractive index material is MgF ₂ and the high refractive index material is at least one selected from the group consisting of _{GdF 3} , LaF ₃ and NdF _3.
At this time, it is preferable that the isotropic material is quartz or CaF ₂ .

このとき、前記等方性材料が石英であり、前記第一菱面体及び前記第二菱面体の楔角が５３°であるとよい。
このとき、前記多層膜が４層膜であり、１９０ｎｍ以上１２５０ｎｍ以下の波長領域において前記入射光線に対して１８０°±１０°の位相差を与えるとよい。
このとき、前記多層膜が１０層膜であり、１９０ｎｍ以上１６３０ｎｍ以下の波長領域において前記入射光線に対して１８０°±１０°の位相差を与えるとよい。 At this time, it is preferable that the isotropic material is quartz and the wedge angles of the first rhombohedron and the second rhombohedron are 53 °.
At this time, it is preferable that the multilayer film is a four-layer film and a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1250 nm or less.
At this time, it is preferable that the multilayer film is a 10-layer film and a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1630 nm or less.

このとき、前記等方性材料がＣａＦ_２であり、前記第一菱面体及び前記第二菱面体の楔角が５４°であるとよい。
このとき、前記多層膜が４層膜であり、１９０ｎｍ以上１１５０ｎｍ以下の波長領域において前記入射光線に対して１８０°±１０°の位相差を与えるとよい。
このとき、前記多層膜が１０層膜であり、１９０ｎｍ以上１８６０ｎｍ以下の波長領域において前記入射光線に対して１８０°±１０°の位相差を与えるとよい。 At this time, it is preferable that the isotropic material is CaF ₂ and the wedge angles of the first rhombohedron and the second rhombohedron are 54 °.
At this time, it is preferable that the multilayer film is a four-layer film and a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1150 nm or less.
At this time, it is preferable that the multilayer film is a 10-layer film and a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1860 nm or less.

また、前記課題は、本発明の計測装置によれば、上記のフレネルロムを備えること、により解決される。
また、前記課題は、本発明の光アッテネーターによれば、上記のフレネルロムを備えること、により解決される。 Further, according to the measuring device of the present invention, the above-mentioned problem is solved by providing the above-mentioned Frenelrom.
Further, according to the optical attenuator of the present invention, the above-mentioned problem is solved by providing the above-mentioned Frenelrom.

本発明によれば、等方性材料で形成された２つの平行四辺形状の菱面体を備えるフレネルロムにおいて、菱面体を形成する等方性材料よりも屈折率の大きい高屈折率膜と、菱面体を形成する等方性材料よりも屈折率の小さい低屈折率膜と、が交互に積層した多層膜を、４つの全反射面の少なくとも１つ以上の面に形成することで、位相差がλ／２（１８０°）であり、真空紫外から近赤外の波長領域で使用可能となる。 According to the present invention, in Frenerrom having two parallel quadrilateral rhombuses formed of an isotropic material, a high refractive index film having a higher refractive index than the isotropic material forming the rhombus and a rhombus. By forming a multilayer film in which low refractive index films having a refractive index smaller than that of the isotropic material forming the above are alternately laminated on at least one or more of the four total reflection surfaces, the phase difference is λ. It is / 2 (180 °) and can be used in the wavelength region from vacuum ultraviolet to near infrared.

また、本発明のフレネルロムは、上記の特性を備えているため、各種の測定装置、分析装置、検査装置、観察装置を含む計測装置に適用することで、微細領域の検査、微小領域を観察、様々な偏光計測を行うことが可能となる。さらに、本発明のフレネルロムは、光アッテネーターに適用することで、レーザー装置の発振光の光量や、白色光の光量を調整することも可能となる。 Further, since the frenerrom of the present invention has the above-mentioned characteristics, it can be applied to a measuring device including various measuring devices, an analyzer, an inspection device, and an observation device to inspect a minute area and observe a minute area. It is possible to perform various polarization measurements. Further, by applying the Frenerrom of the present invention to an optical attenuator, it is possible to adjust the amount of oscillating light of the laser device and the amount of white light.

本発明の一実施形態に係るフレネルロムの概略構成図である。It is a schematic block diagram of Frenellom which concerns on one Embodiment of this invention. フレネルロムの各全反射面に施された多層膜の構成を示す模式的断面図である。It is a schematic cross-sectional view which shows the structure of the multilayer film applied to each total reflection surface of Frenellom. 石英製フレネルロムの各全反射面への入射角と位相差の関係を波長毎に示したグラフであり、各全反射面に多層膜が無い状態での計算値である。It is a graph which showed the relationship between the angle of incidence on each total reflection surface of quartz frenerrom and the phase difference for each wavelength, and is the calculated value in the state where there is no multilayer film on each total reflection surface. フレネルロムにおける入射角と楔角の説明図である。It is explanatory drawing of the incident angle and the wedge angle in Frenellom. 石英よりも小さい屈折率をもつＭｇＦ_２材料による膜を全反射面に施した場合の位相差の変化の様子を示すグラフである。It is a graph which shows the state of the change of the phase difference when a film made of the _{MgF 2} material which has a refractive index smaller than quartz is applied to the total reflection surface. 石英よりも大きい屈折率をもつＧｄＦ_３材料による膜を全反射面に施した場合の位相差の変化の様子を示すグラフである。The membrane according to GdF ₃ material having a refractive index greater than quartz is a graph showing changes in phase difference when subjected to total reflection surface. 全反射面に施した膜の構成と位相差について示すグラフである。It is a graph which shows the composition and the phase difference of the film applied to the total reflection surface. 図５の紫外光から可視光領域を拡大したグラフである。It is a graph which enlarged the visible light region from the ultraviolet light of FIG. 実施例１で検討を行った石英製のλ／２フレネルロムの概要図である。It is a schematic diagram of the quartz λ / 2 Frenerrom examined in Example 1. 実施例１−１の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-1. 実施例１−２の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-2. 実施例１−３の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-3. 実施例１−４の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-4. 実施例１−５の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-5. 実施例１−６の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-6. 実施例１−７の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-7. 実施例１−８の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-8. 実施例１−９の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-9. 実施例１−１０の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-10. 実施例１−１１の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 1-11. 実施例２で検討を行ったＣａＦ_２製のλ／２フレネルロムの概要図である。It is a schematic diagram of the λ / 2 Frenerlom made of _{CaF 2} examined in Example 2. 実施例２−１のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-1. 実施例２−２のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-2. 実施例２−３のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-3. 実施例２−４のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-4. 実施例２−５のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-5. 実施例２−６のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-6. 実施例２−７のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-7. 実施例２−８のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-8. 実施例２−９のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-9. 実施例２−１０のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-10. 実施例２−１１のＣａＦ_２製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in λ / 2 frenerrom made by _{CaF 2 of} Example 2-11. ４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を有する石英製とＣａＦ_２製のλ／２フレネルロムにおける位相差の波長特性について示すグラフである。Four total reflection surface is a graph showing the wavelength characteristics of the phase difference in the quartz and CaF ₂ made of lambda / 2 Fresnel rhomb having a 50-layered film by _GdF 3 / MgF _2. ４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を有する本実施形態のフレネルロムＨＷＰと、従来から存在する各種フレネルロムによる位相差の波長特性について比較したグラフである。It is a graph which compared the wavelength characteristic of the phase difference by the Frenellom HWP of this embodiment which has the 50-layer film by _{GdF 3} / MgF ₂ on all four reflection surfaces, and the phase difference by various conventional Frenelloms. 石英製の膜無しλ／２フレネルロムと、全反射面にＭｇＦ_２単層膜を形成した従来のフレネルロム（ＭｇＦ_２単層膜）の概要図である。No quartz film and lambda / 2 Fresnel rhomb is a schematic view of a conventional forming the MgF ₂ monolayer film Fresnel rhomb (MgF ₂ monolayer film) on the total reflection surface. ４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を有する本実施形態のフレネルロムＨＷＰと、石英製の膜無しλ／２フレネルロムと、全反射面にＭｇＦ_２単層膜を形成した従来のフレネルロム（ＭｇＦ_２単層膜）と、全反射面にＧｄＦ_３単層膜を形成した従来のフレネルロム（ＧｄＦ_３単層膜）の位相差の波長特性を比較したグラフである。The Frenellom HWP of the present embodiment having a 50-layer film _{of GdF 3} / MgF ₂ on all four total reflection surfaces, the _{λ / 2 Frenelrom without a film made of quartz, and the conventional MgF 2} single-layer film formed on all reflection surfaces. It is a graph which compared the wavelength characteristic of the phase difference of Frenellom (MgF ₂ monolayer film) and the conventional Frenelrom (GdF ₃ _{monolayer film) which formed the GdF 3 monolayer film on the total reflection surface.} 石英製λ／２フレネルロム１個型の概要図である。It is a schematic diagram of a quartz λ / 2 Frenerrom 1-piece type. 石英製の膜無しλ／２フレネルロム１個型と、４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を有する本実施形態のフレネルロムＨＷＰの位相差の波長特性を比較したグラフである。It is a graph comparing the wavelength characteristics of the phase difference of the Frenerrom HWP of the present embodiment having a 50-layer film _{of GdF 3} / MgF ₂ on all four reflection surfaces of a quartz filmless λ / 2 Frenerrom single type. 石英製λ／２フレネルロムキング型の概要図である。It is a schematic diagram of a quartz λ / 2 Fresnel Rom King type. 石英製の膜無しλ／２フレネルロムキング型と４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を有する本実施形態のフレネルロムＨＷＰの位相差の波長特性を比較したグラフである。It is a graph comparing the wavelength characteristics of the phase difference of the Fresnelrom HWP without a film made of quartz and _{the Fresnelrom HWP of the present embodiment having a 50-layer film of GdF 3} / MgF _{2 on four total reflection surfaces.} 実施例３−１−１の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-1-1. 実施例３−１−２の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-1-2. 実施例３−１−３の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-1-3. 実施例３−１−４の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-1-4. 実施例３−２−１の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-2-1. 実施例３−２−２の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-2-2. 実施例３−２−３の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-2-3. 実施例３−２−４の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 3-2-4. 実施例４−１の石英製λ／２フレネルロムにおける位相差の波長特性について示すグラフである。It is a graph which shows the wavelength characteristic of the phase difference in the quartz λ / 2 frenerrom of Example 4-1.

以下、図１Ａ乃至図４４を参照しながら、本発明の一実施形態（以下、本実施形態）に係るフレネルロムについて説明する。本実施形態に係るフレネルロムＨＷＰは、真空紫外から近赤外の波長領域において位相差の波長依存性が小さい多層膜付きのλ／２フレネルロム（位相子）である。 Hereinafter, the frenerrom according to one embodiment of the present invention (hereinafter, the present embodiment) will be described with reference to FIGS. 1A to 44. The Frenerrom HWP according to the present embodiment is a λ / 2 Frenerrom (phaser) with a multilayer film having a small wavelength dependence of phase difference in the wavelength region from vacuum ultraviolet to near infrared.

本願明細書において、○ｎｍ〜△ｎｍは、○ｎｍ以上△ｎｍ以下を意味する。
本明細書において、「コンタクト」とは、一対の隣接するプリズムが相互に接触して配置されていることをいい、直接接合されているオプティカル・コンタクトのほか、接着による接合も含まれる。
また、本明細書において、プリズム素子（菱面体）が「対向」するとは、直接接合されているオプティカル・コンタクトの場合と、接着剤など、何かを介在させて接合されている接着の場合、空気層を介在させている場合とを含む。 In the specification of the present application, ◯ nm to Δnm means ◯ nm or more and Δnm or less.
As used herein, the term "contact" means that a pair of adjacent prisms are arranged in contact with each other, and includes not only an optical contact that is directly bonded but also a bonding by adhesion.
Further, in the present specification, the prism elements (rhombohedrons) are "opposed" in the case of an optical contact that is directly bonded and in the case of an adhesive that is bonded by interposing something such as an adhesive. Including the case where an air layer is interposed.

［１．本実施形態のフレネルロムＨＷＰの構造］
本実施形態のフレネルロムＨＷＰ（λ／２フレネルロム、λ／２波長板）は、平行四辺形状のプリズム素子を２つ組み合わせた構造（ダブル型のフレネルロム）であり、具体的には、図１Ａに示すように、断面（図１Ａの面と平行な断面、つまり、後述する各入射端面、出射端面、全反射面と直交する断面）が平行四辺形の平行四辺形状の第一菱面体１０及び第二菱面体２０を備えている。第一菱面体１０及び第二菱面体２０は、同一形状であり、等方性材料で形成されている。 [1. Structure of Frenerrom HWP of the present embodiment]
The Frenerrom HWP (λ / 2 Frenerrom, λ / 2 wavelength plate) of the present embodiment has a structure (double type Frenerrom) in which two parallelogram prism elements are combined, and is specifically shown in FIG. 1A. As described above, the first rhombic body 10 and the second rhombus having a parallelogram whose cross section (the cross section parallel to the plane of FIG. 1A, that is, the cross section orthogonal to each incident end face, exit end face, and total reflection surface described later) is a parallelogram. It has a rhombic body 20. The first rhombohedron 10 and the second rhombohedron 20 have the same shape and are made of an isotropic material.

（第一菱面体１０）
第一菱面体１０は、第一入射端面１１と、第一入射端面１１と平行に配置された第一出射端面１２と、第一入射端面１１及び第一出射端面１２と交わる第一全反射面１３と、第一全反射面１３と平行に配置された第二全反射面１４と、を有している。 (First rhombohedron 10)
The first rhombohedron 10 is a first total reflection surface that intersects the first incident end surface 11, the first emitting end surface 12 arranged in parallel with the first incident end surface 11, the first incident end surface 11, and the first emission end surface 12. It has 13 and a second total reflection surface 14 arranged in parallel with the first total reflection surface 13.

第一菱面体１０において、第一入射端面１１及び第一出射端面１２は互いに平行であり、かつ、第一全反射面１３及び第二全反射面１４は互いに平行である。また、第一菱面体１０において、第一入射端面１１と第一全反射面１３との間、及び、第一出射端面１２と第二全反射面１４との間は、互いに９０度よりも小さい角度（楔角α）で交わっている。さらに、第一菱面体１０において、第一入射端面１１と第二全反射面１４との間、及び、第一出射端面１２と第一全反射面１３との間は、互いに９０度よりも大きい角度で交わっている。 In the first rhombohedron 10, the first incident end surface 11 and the first exit end surface 12 are parallel to each other, and the first total reflection surface 13 and the second total reflection surface 14 are parallel to each other. Further, in the first rhombohedron 10, the distance between the first incident end surface 11 and the first total reflection surface 13 and the distance between the first emission end surface 12 and the second total reflection surface 14 are smaller than 90 degrees. They intersect at an angle (wedge angle α). Further, in the first rhombohedron 10, the distance between the first incident end surface 11 and the second total reflection surface 14 and the distance between the first emission end surface 12 and the first total reflection surface 13 are larger than 90 degrees with each other. It intersects at an angle.

（第二菱面体２０）
第二菱面体２０は、第二入射端面２１と、第二入射端面２１と平行に配置された第二出射端面２２と、第二入射端面２１及び第二出射端面２２と交わる第三全反射面２３と、第三全反射面２３と平行に配置された第四全反射面２４と、を有している。 (Second rhombohedron 20)
The second rhombohedron 20 is a third total reflection surface that intersects the second incident end face 21, the second emitting end face 22 arranged parallel to the second incident end face 21, the second incident end face 21, and the second emitting end face 22. It has a 23 and a fourth total reflection surface 24 arranged in parallel with the third total reflection surface 23.

第二菱面体２０において、第二入射端面２１及び第二出射端面２２は互いに平行であり、かつ、第三全反射面２３及び第四全反射面２４は互いに平行である。また、第二菱面体２０において、第二入射端面２１と第三全反射面２３との間、及び、第二出射端面２２と第四全反射面２４との間は、互いに９０度よりも小さい角度（楔角α）で交わっている。さらに、第二菱面体２０において、第二入射端面２１と第四全反射面２４との間、及び、第二出射端面２２と第三全反射面２３との間は、互いに９０度よりも大きい角度で交わっている。 In the second rhombohedron 20, the second incident end surface 21 and the second exit end surface 22 are parallel to each other, and the third total reflection surface 23 and the fourth total reflection surface 24 are parallel to each other. Further, in the second rhombohedron 20, the distance between the second incident end surface 21 and the third total reflection surface 23 and the distance between the second emission end surface 22 and the fourth total reflection surface 24 are smaller than 90 degrees with each other. They intersect at an angle (wedge angle α). Further, in the second rhombohedron 20, the distance between the second incident end surface 21 and the fourth total reflection surface 24 and the distance between the second emission end surface 22 and the third total reflection surface 23 are larger than 90 degrees with each other. It intersects at an angle.

第一菱面体１０及び第二菱面体２０は、第一菱面体１０の第一出射端面１２と、第二菱面体２０の第二入射端面２１とが互いに平行になるように対向して配置されている。第一出射端面１２と第二入射端面２１は、オプティカル・コンタクトによる直接接合とすることが好適であるが、紫外線透過接着剤を用いた接着固定とすることや、接合を行わずに隙間を空けて配置することも可能である。 The first rhombohedron 10 and the second rhombohedron 20 are arranged so that the first exit end surface 12 of the first rhombohedron 10 and the second incident end surface 21 of the second rhombohedron 20 are parallel to each other. ing. The first exit end face 12 and the second incident end face 21 are preferably directly bonded by optical contact, but may be bonded and fixed using an ultraviolet transmissive adhesive, or a gap may be left without joining. It is also possible to arrange them.

上述したように第一菱面体１０の第一入射端面１１と第一全反射面１３（第一出射端面１２と第二全反射面１４）は楔角αをなしており、同様に、第二菱面体２０の第二入射端面２１と第三全反射面２３（第二出射端面２２と第四全反射面２４）も楔角αをなしている。ここで、楔角αは、第一菱面体１０及び第二菱面体２０を構成する等方性材料の種類に応じて適宜設定することが可能であり、等方性材料が石英の場合には楔角α＝５３°とし、等方性材料がＣａＦ_２の場合には楔角α＝５４°とすればよい。 As described above, the first incident end surface 11 and the first total reflection surface 13 (first emission end surface 12 and second total reflection surface 14) of the first rhombohedron 10 form a wedge angle α, and similarly, the second The second incident end surface 21 and the third total reflection surface 23 (second emission end surface 22 and fourth total reflection surface 24) of the rhombohedron 20 also form a wedge angle α. Here, the wedge angle α can be appropriately set according to the type of the isotropic material constituting the first rhombohedron 10 and the second rhombohedron 20, and when the isotropic material is quartz, the wedge angle α can be appropriately set. The wedge angle α = 53 ° may be set, and when the isotropic material is CaF ₂ , the wedge angle α = 54 ° may be set.

（等方性材料）
第一菱面体１０及び第二菱面体２０は、等方性材料から形成されており、上述した図１Ａは、等方性材料として石英を使用した場合を示している（楔角α＝５３°）。等方性材料としては、真空紫外から近赤外の波長領域を透過する材料であれば良く、入手性の観点から石英（溶融石英：屈折率ｎ＝１．４６＠５５０ｎｍ）やフッ化カルシウム（ＣａＦ_２：屈折率ｎ＝１．４４＠５４６ｎｍ）を用いると好適である。なお、用いる等方性材料については、位相差を劣化させてしまうような素材の欠陥や歪などがないことも重要であり、ＣａＦ_２よりも石英（溶融石英）を用いることが好ましい。 (Isotropic material)
The first rhombohedron 10 and the second rhombohedron 20 are formed of an isotropic material, and FIG. 1A described above shows a case where quartz is used as the isotropic material (wedge angle α = 53 °). ). The isotropic material may be any material that transmits the wavelength region from vacuum ultraviolet to near infrared, and from the viewpoint of availability, quartz (fused quartz: refractive index n = 1.46 @ 550 nm) or calcium fluoride ( CaF ₂ : Refractive index n = 1.44 @ 546 nm) is preferably used. As for the isotropic material to be used, it is important that there are no defects or distortions of the material that deteriorate the phase difference, and it is preferable to use quartz (fused quartz) rather than _{CaF 2.}

第一菱面体１０の第一入射端面１１に入射した入射光線Ｉは、第一全反射面１３、第二全反射面１４、第三全反射面２３、第四全反射面２４の順で全反射して（反射光線Ｒ）、第二出射端面２２から出射光線Ｅとして出射する。フレネルロムＨＷＰでは、真空紫外から近赤外の波長領域において入射光線Ｉに対して略１８０°（具体的には、１８０°±１０°）の位相差を与えた出射光線Ｅが出射される。 The incident light rays I incident on the first incident end surface 11 of the first rhombic body 10 are all in the order of the first total reflection surface 13, the second total reflection surface 14, the third total reflection surface 23, and the fourth total reflection surface 24. It is reflected (reflected ray R) and is emitted as an emitted ray E from the second emission end face 22. In Frenerlom HWP, an emitted ray E having a phase difference of approximately 180 ° (specifically, 180 ° ± 10 °) with respect to an incident ray I in a wavelength region from vacuum ultraviolet to near infrared is emitted.

フレネルロムＨＷＰを使用する時、第一菱面体１０の第一入射端面１１に対して、外部から実質的に垂直に入射させられた入射光線Ｉは、次のように進む。入射光線Ｉは、第一菱面体１０の第一全反射面１３及び第二全反射面１４において内部反射し、反射光線Ｒは、第一菱面体１０の第一出射端面１２から第二菱面体２０の第二入射端面２１へと出射する。そして、第一菱面体１０の第一出射端面１２から第二菱面体２０の第二入射端面２１へと入射した反射光線Ｒは、第三全反射面２３と第四出射端面２４において内部反射し、反射光線Ｒは、第二菱面体２０の第二出射端面２２から出射光線Ｅとして出射する。 When Frenerlom HWP is used, the incident light ray I incident substantially perpendicular to the first incident end surface 11 of the first rhombohedron 10 proceeds as follows. The incident ray I is internally reflected by the first total reflection surface 13 and the second total reflection surface 14 of the first rhombohedron 10, and the reflected ray R is from the first emission end surface 12 to the second rhombohedron of the first rhombohedron 10. It exits to the second incident end face 21 of 20. Then, the reflected light rays R incident on the second incident end surface 21 of the second rhombohedron 20 from the first exit end surface 12 of the first rhombohedron 10 are internally reflected by the third total reflection surface 23 and the fourth emission end surface 24. , The reflected ray R is emitted as an emission ray E from the second emission end surface 22 of the second rhombohedron 20.

本実施形態のフレネルロムＨＷＰは、同一の平行四辺形状のプリズム素子を２つ組み合わせた構造であり、入射光線Ｉと出射光線Ｅの光軸がずれない。換言すると、入射光線Ｉと出射光線Ｅが一直線になり、入射光線Ｉと出射光線Ｅの光軸が（略）同軸となる。つまり、本実施形態のフレネルロムＨＷＰを光軸Ｘの周りで回転させても、出射光線Ｅの位置が変わらないという特長がある。 The Frenerrom HWP of the present embodiment has a structure in which two prism elements having the same parallel quadrilateral shape are combined, and the optical axes of the incident light ray I and the outgoing light ray E do not deviate from each other. In other words, the incident ray I and the emitted ray E are aligned, and the optical axes of the incident ray I and the emitted ray E are (omitted) coaxial. That is, even if the Frenerrom HWP of the present embodiment is rotated around the optical axis X, the position of the emitted light beam E does not change.

（多層膜Ｍ）
第一全反射面１３、第二全反射面１４、第三全反射面２３及び第四全反射面２４は、その面上に、第一菱面体１０及び第二菱面体２０を構成する等方性材料とは異なる屈折率の多層膜Ｍがコーティングされている（図１Ｂ）。 (Multilayer film M)
The first total reflection surface 13, the second total reflection surface 14, the third total reflection surface 23, and the fourth total reflection surface 24 form an isotropic body 10 and a second rhombus 20 on the surfaces thereof. A multilayer film M having a refractive index different from that of the sex material is coated (FIG. 1B).

ここで、多層膜Ｍは、第一菱面体１０及び第二菱面体２０を構成する等方性材料よりも屈折率の大きい高屈折率材料で形成された高屈折率膜Ｍ_Ｈと、第一菱面体１０及び第二菱面体２０を構成する等方性材料よりも屈折率の小さい低屈折率材料で形成された低屈折率膜Ｍ_Ｌと、が交互に積層されている。高屈折率膜Ｍ_Ｈと低屈折率膜Ｍ_Ｌの積層の順序は図１Ｂに示すように、基板となる等方性材料の上に、高屈折率膜Ｍ_Ｈ、低屈折率膜Ｍ_Ｌの順で積層されていてもよいし、基板となる等方性材料の上に、低屈折率膜Ｍ_Ｌ、高屈折率膜Ｍ_Ｈの順で積層されていてもよい。 Here, the multilayer film M has a high refractive index film M _H was made form a high refractive index material having a large refractive index than isotropic material constituting the first rhomb 10 and the second rhombohedral 20, and a low refractive index film M _L was made form a small low-refractive index material having a refractive index higher than isotropic material constituting the first rhomb 10 and the second rhombohedral 20, are alternately stacked. The order of lamination of the high-refractive-index film M _H and the low refractive index film M _L, as shown in FIG. 1B, on the isotropic material comprising a substrate, a high refractive index film M _H, the low refractive index film M _L may be stacked in this order, on the isotropic material comprising a substrate, a low refractive index film M _L, may be stacked in this order of the high-refractive-index film M _H.

入射光線Ｉは、第一全反射面１３、第二全反射面１４、第三全反射面２３及び第四全反射面２４で全反射し、同時にｐ偏光とｓ偏光に位相差が発生する。通常、全反射に伴って生じる位相差は、波長が短くなるにつれて大きくなってしまう。そこで、フレネルロムＨＷＰでは、第一菱面体１０及び第二菱面体２０を構成する等方性材料（石英やＣａＦ_２）よりも大きい屈折率の高屈折率膜Ｍ_Ｈと、小さい屈折率の低屈折率膜Ｍ_Ｌからなる２種類の膜材料が交互に積層された多層膜Ｍを４つの全反射面の少なくとも１つ以上の面に施している。 The incident light ray I is totally reflected by the first total reflection surface 13, the second total reflection surface 14, the third total reflection surface 23, and the fourth total reflection surface 24, and at the same time, a phase difference is generated between the p-polarized light and the s-polarized light. Usually, the phase difference caused by total reflection increases as the wavelength becomes shorter. _{Therefore, in Frenerlom HWP, a high refractive index film MH} having a higher refractive index than the _{isotropic materials (quartz or CaF 2} ) constituting the first rhombic body 10 and the second rhombic body 20 and a low refractive index with a small refractive index are used. two membrane material made of Ritsumaku M _L is subjected to at least one surface of the total reflection surface 4 multilayer film M that are alternately stacked.

高屈折率膜Ｍ_Ｈを構成する高屈折率材料としては、フッ化ガドリニウム（ＧｄＦ_３：屈折率ｎ＝１．５９＠５５０ｎｍ）、フッ化ランタン（ＬａＦ_３：屈折率ｎ＝１．５９＠５５０ｎｍ）及びフッ化ネオジム（ＮｄＦ_３：１．６１＠５５０ｎｍ）が例示されるが、これらの物質に限定されるものではない。また、低屈折率膜Ｍ_Ｌを構成する低屈折率材料としては、フッ化マグネシウム（ＭｇＦ_２：屈折率ｎ＝１．３８〜１．４０＠５５０ｎｍ）が例示されるが、これに限定されるものではない。 Examples of the high refractive index material constituting the high refractive index film _MH _{include gadolinium fluoride (GdF 3} : refractive index n = 1.59 @ 550 nm) and lanthanum fluoride (LaF ₃ : refractive index n = 1.59 @ 550 nm). ) And neodymium fluoride (NdF ₃ : 1.61 @ 550 nm), but are not limited to these substances. As the low refractive index material constituting the low refractive index film _{M L,} magnesium fluoride (MgF _2: refractive index N=1.38～1.40Atto550nm) but is exemplified, it is not limited thereto It's not a thing.

高屈折率膜Ｍ_Ｈ及び低屈折率膜Ｍ_Ｌは、真空蒸着、ＣＶＤ、スパッタリング等の方法により形成することが可能である。高屈折率膜Ｍ_Ｈ及び低屈折率膜Ｍ_Ｌの膜厚は、材料の種類に依存し、例えば、１００Å以上６５０Å以下とすればよいが、この範囲に限定されるものではない。 High refractive index film M _H and the low refractive index film M _L is capable of forming a vacuum vapor deposition, CVD, by a method such as sputtering. The film thickness of the high refractive index layer M _H and the low refractive index film M _L depends on the type of material, for example, it may be less 650Å than 100 Å, but is not limited to this range.

フレネルロムＨＷＰは、４つの全反射面の少なくとも１つ以上の面が、上述の多層膜Ｍを有していることで、真空紫外から近赤外の波長領域（例えば、１９０ｎｍ以上２０００ｎｍ以下の波長領域）において位相差の波長依存性を小さくする事を可能となっている。 In Frenerlom HWP, at least one or more of the four total reflection surfaces have the above-mentioned multilayer film M, so that the wavelength region from vacuum ultraviolet to near infrared (for example, wavelength region of 190 nm or more and 2000 nm or less) ), It is possible to reduce the wavelength dependence of the phase difference.

（素子のサイズについて）
本実施形態のフレネルロムＨＷＰについて、素子の幅Ｗ（素子の厚み）、素子の開口Ｋ、素子の高さＨ、素子の長さＬを、図１Ａに示すように定義する。第一菱面体１０及び第二菱面体２０を構成する等方性材料が石英であるとき、楔角α＝５３°であり、素子の幅Ｗ：素子の開口Ｋ：素子の高さＨ：素子の長さＬ＝１０ｍｍ：１０ｍｍ：２２．８ｍｍ：３３．９ｍｍとなる。また、第一菱面体１０及び第二菱面体２０を構成する等方性材料がＣａＦ_２であるとき、楔角α＝５４°であり、素子の幅Ｗ：素子の開口Ｋ：素子の高さＨ：素子の長さＬ＝１０ｍｍ：１０ｍｍ：２３．１ｍｍ：３６．０ｍｍとなる。 (About the size of the element)
For the Frenerrom HWP of the present embodiment, the width W (thickness of the element), the opening K of the element, the height H of the element, and the length L of the element are defined as shown in FIG. 1A. When the isotropic material constituting the first rhombohedron 10 and the second rhombohedron 20 is quartz, the wedge angle α = 53 °, the width of the element W: the opening of the element K: the height of the element H: the element. The length L = 10 mm: 10 mm: 22.8 mm: 33.9 mm. Further, when the isotropic material constituting the first rhombohedron 10 and the second rhombohedron 20 is CaF ₂ , the wedge angle α = 54 °, the width of the element W: the opening of the element K: the height of the element. H: The length of the element L = 10 mm: 10 mm: 23.1 mm: 36.0 mm.

このように、本実施形態のフレネルロムＨＷＰでは、素子の幅Ｗ又は素子の開口Ｋの比を１としたときに、素子の高さＨや素子の長さＬの比が約２．２〜３．６、つまり、２．２以上３．６以下となり、素子の高さが高くなることや、素子の長さが長くなってしまうことが無く、素子のサイズを小型なものにすることが可能である。 As described above, in the Frenerlom HWP of the present embodiment, when the ratio of the width W of the element or the opening K of the element is 1, the ratio of the height H of the element and the length L of the element is about 2.2 to 3. It is possible to reduce the size of the element to 0.6, that is, 2.2 or more and 3.6 or less, without increasing the height of the element or increasing the length of the element. Is.

［２．全反射面への多層膜の適用による位相差への効果］
図２Ａは、石英における各全反射面への入射角と位相差の関係を波長毎に示したものである。図２Ｂは、フレネルロムにおける入射角θと楔角αの説明図である。フレネルロムに光線を垂直入射した場合、楔角α＝入射角θとなる。各全反射面に多層膜が無い状態での計算値である。フレネルロムは、光線が全反射する際にｐ偏光とｓ偏光に位相差が生じる事を利用した位相子であり、生じる位相差は、素材の屈折率と全反射角に依存する。屈折率には、波長依存性がある為、生じる位相差にも、波長依存性が出てしまう。 [2. Effect on phase difference by applying multilayer film to total reflection surface]
FIG. 2A shows the relationship between the angle of incidence on each total reflection surface and the phase difference of quartz for each wavelength. FIG. 2B is an explanatory diagram of the incident angle θ and the wedge angle α in Frenerrom. When a light ray is vertically incident on Frenerrom, the wedge angle α = incident angle θ. It is a calculated value when there is no multilayer film on each total reflection surface. Frenerrom is a phaser that utilizes the fact that a phase difference occurs between p-polarized light and s-polarized light when a light beam is totally reflected, and the generated phase difference depends on the refractive index and total reflection angle of the material. Since the refractive index has a wavelength dependence, the resulting phase difference also has a wavelength dependence.

図１Ａに示すフレネルロムＨＷＰのような、４回全反射させる屋根型（ダブル型）と呼ばれる構造の場合、位相差１８０°（λ／２）を得る為には、全反射１回当たりの位相差が、４５°になるような楔角にする必要がある。しかし、図１Ａに示すフレネルロムＨＷＰの場合、可視から近赤外の波長領域では、図２Ａに示すように位相差を４５°にすることが出来ない。また、図３や図４に示すように、波長が長くなるほど、膜によって位相差を調整することが難しくなるため、楔角は、可視から近赤外の波長領域で位相差が４５°に近くなる５３°としている。 In the case of a structure called a roof type (double type) that totally reflects four times, such as Frenerrom HWP shown in FIG. 1A, the phase difference per total reflection is required to obtain a phase difference of 180 ° (λ / 2). However, it is necessary to make the wedge angle so that it becomes 45 °. However, in the case of Frenerlom HWP shown in FIG. 1A, the phase difference cannot be set to 45 ° in the visible to near-infrared wavelength region as shown in FIG. 2A. Further, as shown in FIGS. 3 and 4, the longer the wavelength, the more difficult it is to adjust the phase difference by the film. Therefore, the wedge angle has a phase difference close to 45 ° in the visible to near infrared wavelength region. It is set to 53 °.

図３に、石英よりも小さい屈折率をもつＭｇＦ_２材料による膜を全反射面に施した場合の位相差の変化の様子を示す（楔角α＝５３°のフレネルロム）。石英よりも小さい屈折率を持つ材料の膜では、膜厚を厚くすると、全体的な位相差は小さくなる傾向にある。 _{FIG. 3 shows how the phase difference changes when a film made of MgF 2} material having a refractive index smaller than that of quartz is applied to the total reflection surface (Frenerlom with a wedge angle α = 53 °). For a film of a material having a refractive index smaller than that of quartz, the overall phase difference tends to decrease as the film thickness increases.

図４に、石英よりも大きい屈折率をもつＧｄＦ_３材料による膜を全反射面に施した場合の位相差の変化の様子を示す（楔角α＝５３°のフレネルロム）。大きな屈折率を持つ材料の膜では、膜厚を厚くすると、全体的な位相差は大きくなる傾向にある。更に、膜厚を厚くしていくと、８００Åの場合で示されるように、紫外領域の位相差にうねりが発生する。 Figure 4 shows a change of the phase difference when subjected to membrane by GdF ₃ material having a refractive index greater than quartz on the total reflection surface (Fresnel rhomb of the wedge angle α = 53 °). In a film made of a material having a large refractive index, the overall phase difference tends to increase as the film thickness increases. Further, as the film thickness is increased, undulations occur in the phase difference in the ultraviolet region, as shown in the case of 800 Å.

図５及び図６に、全反射面に施した膜の構成と位相差について示す。図５及び図６に示すように、位相差１８０°±１０°の範囲を見ていくと、ＧｄＦ_３膜／ＭｇＦ_２膜の積層数を増やすことで、うねりの数が増えて行き、位相差が１８０°±１０°となる波長範囲が広がっていくことがわかる。このように、多層膜Ｍを２０層や５０層と積層させることで、波長λ＝１９０〜２０００ｎｍで位相差が１８０°±１０°となる。
多層膜Ｍの積層数を増やすと、素子の作製に手間がかかるため、多層膜Ｍを４層〜１０層程度とすることが好適である。多層膜Ｍが４層膜である場合でも、波長λ＝１９０〜１０００ｎｍで位相差が１８０°±１０°となり、従来技術にはない優れた位相差性能を持った実用的な位相子を実現することが可能となる。 5 and 6 show the structure and phase difference of the film applied to the total reflection surface. As shown in FIGS. 5 and 6, looking at the range of the phase difference of 180 ° ± 10 °, the number of waviness increases by increasing the number of laminated _{GdF 3} film / MgF _{2 film, and the phase difference} It can be seen that the wavelength range in which is 180 ° ± 10 ° is expanding. By laminating the multilayer film M with 20 layers or 50 layers in this way, the phase difference becomes 180 ° ± 10 ° at a wavelength λ = 190 to 2000 nm.
If the number of multilayer films M is increased, it takes time to manufacture the device. Therefore, it is preferable to increase the number of multilayer films M to about 4 to 10 layers. Even when the multilayer film M is a four-layer film, the phase difference is 180 ° ± 10 ° at a wavelength of λ = 190 to 1000 nm, and a practical phase element having excellent phase difference performance not found in the prior art is realized. It becomes possible.

［３．本実施形態のフレネルロムＨＷＰの応用例］
本実施形態のフレネルロムＨＷＰの応用例について、以下に示す。本実施形態のフレネルロムＨＷＰは、計測装置に応用可能である。ここで、「計測装置」とは、各種の測定装置、分析装置、検査装置、観察装置を含むものとする。 [3. Application example of Frenerrom HWP of this embodiment]
An application example of Frenerlom HWP of this embodiment is shown below. The Frenerrom HWP of the present embodiment can be applied to a measuring device. Here, the "measuring device" includes various measuring devices, analyzers, inspection devices, and observation devices.

半導体検査装置は、微細領域の検査を行う装置であり、紫外光を積極的に利用するため、真空紫外から近赤外の波長領域で使用可能な本実施形態のフレネルロムＨＷＰを用いると好適である。白色光の偏光を利用している半導体検査装置であれば、本実施形態のフレネルロムＨＷＰが利用可能である。 The semiconductor inspection device is a device that inspects a fine region, and since it actively uses ultraviolet light, it is preferable to use the Frenerlom HWP of the present embodiment that can be used in the wavelength region from vacuum ultraviolet to near infrared. .. The Frenerlom HWP of the present embodiment can be used as long as it is a semiconductor inspection apparatus using polarized light of white light.

また、本実施形態のフレネルロムＨＷＰを、微小領域を観察するための観察装置に適用することも可能である。偏光を制御することでコントラストを向上できる場合がある。より微細な観察を行うためには、短い波長も使った観察が必要になるため、本実施形態のフレネルロムＨＷＰを使用するメリットがある。 It is also possible to apply the Frenerrom HWP of the present embodiment to an observation device for observing a minute region. In some cases, the contrast can be improved by controlling the polarization. Since observation using a short wavelength is required for finer observation, there is a merit of using Frenerrom HWP of the present embodiment.

さらに、異物検知を行うため、異物からの散乱光の偏光状態が正常な部分と異なる特性を利用した観察装置や検査装置、具体的には、半導体ウエハー上の配線パターンの偏光状態を観察して異物を発見する装置に本実施形態のフレネルロムＨＷＰを適用することができる。装置によって、偏光の利用方法は異なるが、偏光情報から半導体の各プロセスで発生した異常（不良）を発見する際に、本実施形態のフレネルロムＨＷＰを位相差９０°（λ／４）の位相子と組み合わせることで、様々な偏光計測が可能となる。 Furthermore, in order to detect foreign matter, an observation device or inspection device that utilizes characteristics that the polarization state of scattered light from the foreign matter is different from the normal part, specifically, the polarization state of the wiring pattern on the semiconductor wafer is observed. The Frenerrom HWP of the present embodiment can be applied to a device for detecting a foreign substance. Although the method of using polarized light differs depending on the device, when anomalies (defects) generated in each semiconductor process are found from the polarized light information, the Frenerrom HWP of the present embodiment is used as a phaser with a phase difference of 90 ° (λ / 4). By combining with, various polarization measurements are possible.

また、膜厚計に本実施形態のフレネルロムＨＷＰを適用することができる。膜厚計は、主に半導体プロセス中の検査などに用いられるが、フィルム厚、塗装厚等を測定するなど、他の膜状の物の検査にも使われている。膜厚計の測定原理は、様々であるが、エリプソメーター同様の偏光解析で膜厚を測定する装置もある。 Further, the Frenerrom HWP of the present embodiment can be applied to the film thickness meter. The film thickness meter is mainly used for inspection during a semiconductor process, but is also used for inspection of other film-like objects such as measuring film thickness, coating thickness, and the like. There are various measurement principles of the film thickness meter, but there are also devices that measure the film thickness by ellipsometry similar to the ellipsometer.

その他、本実施形態のフレネルロムＨＷＰは、機器偏光を低減させるための偏光解消素子の代わりに使用することができる。反射光学系では、ｐ偏光とｓ偏光の反射率が異なるため、入射光線の偏光状態が異なる場合や変動する場合、透過率が異なったり、変動したりする。このことを防止するために、入射光線の偏光状態を一定にしたり、光学系からの出射光線の偏光状態を一定にしたりすることがある。精密な計測を行う装置の場合には、入射光線や出射光線の偏光状態を一定にすることが必要になる。本実施形態のフレネルロムＨＷＰを位相差９０°（λ／４）の位相子と組み合わせることで、いかなる偏光状態も作り出すことができるため、入射光線や出射光線の偏光状態を一定にすることが可能となる。 In addition, the Frenerlom HWP of the present embodiment can be used instead of the depolarizing element for reducing the polarization of the device. In the catadioptric system, since the reflectances of p-polarized light and s-polarized light are different, the transmittance may be different or fluctuate when the polarization state of the incident light beam is different or fluctuates. In order to prevent this, the polarization state of the incident light rays may be made constant, or the polarization state of the light rays emitted from the optical system may be made constant. In the case of a device that performs precise measurement, it is necessary to keep the polarization state of the incident light beam and the outgoing light ray constant. By combining the Frenerrom HWP of the present embodiment with a phase element having a phase difference of 90 ° (λ / 4), any polarized state can be created, so that the polarized state of the incident light beam and the outgoing light ray can be made constant. Become.

また、本実施形態のフレネルロムＨＷＰは、光アッテネーターに応用可能である。レーザー装置の発振光の光量調整は、安定性確保のため、レーザー装置外部で波長板と偏光子を組み合わせた光アッテネーターで行う事がある。この光アッテネーターに用いられる波長板を、本実施形態のフレネルロムＨＷＰとすることで、光量を調整することが可能となる。加えて、本実施形態のフレネルロムＨＷＰは、広帯域偏光子と組み合わせる事で、従来には実現できなかった、真空紫外〜赤外域までの光を一緒に調光することが出来る広帯域な光アッテネーターを構成することが可能である。 Further, the Frenerrom HWP of the present embodiment can be applied to an optical attenuator. In order to ensure stability, the amount of oscillating light of the laser device may be adjusted by an optical attenuator that combines a wave plate and a polarizer outside the laser device. By using the Frenerrom HWP of the present embodiment as the wave plate used for this optical attenuator, the amount of light can be adjusted. In addition, the Frenerrom HWP of the present embodiment constitutes a wideband optical attenuator capable of dimming light from the vacuum ultraviolet to the infrared region together, which was not possible in the past, by combining with a wideband polarizer. It is possible to do.

以下、実施例に基づき、本発明の多層膜付きλ／２フレネルロムについて更に詳細に説明するが、本発明は、以下の実施例に限定されるものではない。 Hereinafter, the λ / 2 Frenerrom with a multilayer film of the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples.

以下の実施例では、菱面体を形成する等方性材料として石英又はＣａＦ_２を用い、フレネルロムＨＷＰに多層膜Ｍを形成した際の位相差の波長特性を示す。具体的には、石英製とＣａＦ_２製のフレネルロムＨＷＰの４つの全反射面の少なくとも１つ以上の面に、膜材料が異なる３種類の多層膜（２〜５０層膜）をそれぞれ成膜したものを示す。 _{In the following examples, quartz or CaF 2} is used as the isotropic material for forming the rhombohedron, and the wavelength characteristics of the phase difference when the multilayer film M is formed on Frenerlom HWP are shown. Specifically, three types of multilayer films (2 to 50 layers) having different film materials were formed on at least one or more of the four total reflection surfaces of Frenerlom HWP made of quartz and CaF _2. Show things.

＜実施例１．多層膜付き石英製λ／２フレネルロム＞
石英製のλ／２フレネルロムの４つ全ての全反射面に、ＧｄＦ_３／ＭｇＦ_２、ＬａＦ_３／ＭｇＦ_２、ＮｄＦ_３／ＭｇＦ_２の多層膜を成膜した場合における位相差の波長特性を実施例１−１．〜１−１１．に示す。図７は、石英製のλ／２フレネルロムの概要図で、多層膜の種類（構成）によらず同一の形状である。なお、２つの菱面体をオプティカル・コンタクトした場合と、互いに離して平行に並べた場合の位相差に違いはない。また、図７に示す石英製のλ／２フレネルロムは、同一の平行四辺形状のプリズム素子を２つ組み合わせた構造であり、入射光線Ｉと出射光線Ｅの光軸がずれない。換言すると、入射光線Ｉと出射光線Ｅが一直線になり、入射光線Ｉと出射光線Ｅの光軸が（略）同軸となる。 <Example 1. Quartz λ / 2 Frenerrom with multilayer film>
Performed the wavelength characteristics of the phase difference when a multilayer film of _{GdF 3} / MgF ₂ , LaF ₃ / MgF ₂ , and NdF ₃ / MgF ₂ was formed on all four total reflection surfaces of quartz λ / 2 frenerrom. Example 1-1. ~ 1-11. Shown in. FIG. 7 is a schematic view of λ / 2 Frenerrom made of quartz, and has the same shape regardless of the type (configuration) of the multilayer film. There is no difference in the phase difference between the case where the two rhombohedrons are in optical contact and the case where they are arranged in parallel apart from each other. Further, the quartz λ / 2 frenerrom shown in FIG. 7 has a structure in which two prism elements having the same parallel quadrilateral shape are combined, and the optical axes of the incident light ray I and the emitted light ray E do not deviate. In other words, the incident ray I and the emitted ray E are aligned, and the optical axes of the incident ray I and the emitted ray E are (omitted) coaxial.

（実施例１−１．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の２層膜）
図８に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による２層膜を成膜した場合の位相差の波長特性について示す。また、表１に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の２層膜を成膜する事で、波長λ＝１９０〜１１３５ｎｍの範囲で１７０〜１９０°の位相差にする事が可能になる。 (Example 1-1. Quartz λ / 2 Frenerrom, GdF ₃ / MgF ₂ two-layer film)
FIG. 8 shows the wavelength characteristics of the phase difference when a two-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 1 shows the film thickness of the multilayer film and the like. _{By forming a two-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 190 ° in the wavelength range of λ = 190 to 1135 nm.

（実施例１−２．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の４層膜）
図９に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表２に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の４層膜を成膜する事で、波長λ＝１９０〜１２５０ｎｍの範囲で１７０〜１８２．３°の位相差にする事が可能になる。 (Example 1-2. Quartz λ / 2 Frenerrom, GdF ₃ / MgF ₂ 4-layer film)
FIG. 9 shows the wavelength characteristics of the phase difference when a four-layer film made _{of GdF 3} / MgF _{2 is formed on the four total reflection surfaces.} Table 2 shows the film thickness of the multilayer film and the like. _{By forming a four-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 182.3 ° in the wavelength range of λ = 190 to 1250 nm.

（実施例１−３．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の１０層膜）
図１０に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表３に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の１０層膜を成膜する事で、波長λ＝１９０〜１６３２ｎｍの範囲で１７０〜１８２．６°の位相差にする事が可能になる。 (Example 1-3. Quartz λ / 2 Frenerrom, GdF ₃ / MgF ₂ 10-layer film)
FIG. 10 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 3 shows the film thickness of the multilayer film and the like. _{By forming a 10-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 182.6 ° in the wavelength range of λ = 190 to 1632 nm.

（実施例１−４．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の２０層膜）
図１１に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による２０層膜を成膜した場合の位相差の波長特性について示す。また、表４に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の２０層膜を成膜する事で、波長λ＝１９０〜１８７２ｎｍの範囲で１７０〜１８７．６°の位相差にする事が可能になる。 (Example 1-4. Quartz λ / 2 Frenerrom, GdF ₃ / MgF ₂ 20-layer film)
FIG. 11 shows the wavelength characteristics of the phase difference when a 20-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 4 shows the film thickness of the multilayer film and the like. _{By forming a 20-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 187.6 ° in the wavelength range of λ = 190 to 1872 nm.

（実施例１−５．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の５０層膜）
図１２に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表５に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の５０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７４．９〜１８７．８°の位相差にする事が可能になる。 (Example 1-5. 50-layer film of λ / 2 frenerrom made of quartz and GdF ₃ / MgF ₂₎
FIG. 12 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 5 shows the film thickness of the multilayer film and the like. _{By forming a 50-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 174.9 to 187.8 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例１−６．石英製λ／２フレネルロム、ＬａＦ_３／ＭｇＦ_２の２層膜）
図１３に４つの全反射面にＬａＦ_３／ＭｇＦ_２による２層膜を成膜した場合の位相差の波長特性について示す。また、表６に多層膜の膜厚などを示す。全反射面にＬａＦ_３／ＭｇＦ_２の２層膜を成膜する事で、波長λ＝１９０〜１２３３ｎｍの範囲で１７０〜１９０°の位相差にする事が可能になる。 (Example 1-6. Quartz λ / 2 Frenerrom, LaF ₃ / MgF ₂ two-layer film)
FIG. 13 shows the wavelength characteristics of the phase difference when a two-layer film made _{of LaF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 6 shows the film thickness of the multilayer film and the like. _{By forming a two-layer film of LaF 3} / MgF _{2 on} the total reflection surface, it is possible to achieve a phase difference of 170 to 190 ° in the wavelength range of λ = 190 to 1233 nm.

（実施例１−７．石英製λ／２フレネルロム、ＬａＦ_３／ＭｇＦ_２の４層膜）
図１４に４つの全反射面にＬａＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表７に多層膜の膜厚などを示す。全反射面にＬａＦ_３／ＭｇＦ_２の４層膜を成膜する事で、波長λ＝１９０〜１６１８ｎｍの範囲で１７０〜１８２．８°の位相差にする事が可能になる。 (Example 1-7. Quartz λ / 2 Frenerrom, LaF ₃ / MgF ₂ 4-layer film)
FIG. 14 shows the wavelength characteristics of the phase difference when a four-layer film made _{of LaF 3} / MgF _{2 is formed on the four total reflection surfaces.} Table 7 shows the film thickness of the multilayer film and the like. _{By forming a four-layer film of LaF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 182.8 ° in the wavelength range of λ = 190 to 1618 nm.

（実施例１−８．石英製λ／２フレネルロム、ＬａＦ_３／ＭｇＦ_２の１０層膜）
図１５に４つの全反射面にＬａＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表８に多層膜の膜厚などを示す。全反射面にＬａＦ_３／ＭｇＦ_２の１０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７４．１〜１８６．６°の位相差にする事が可能になる。 (Example 1-8. Quartz λ / 2 Frenerrom, LaF ₃ / MgF ₂ 10-layer film)
FIG. 15 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of LaF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 8 shows the film thickness of the multilayer film and the like. _{By forming a 10-layer film of LaF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 174.1 to 186.6 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例１−９．石英製λ／２フレネルロム、ＮｄＦ_３／ＭｇＦ_２の２層膜）
図１６に４つの全反射面にＮｄＦ_３／ＭｇＦ_２による２層膜を成膜した場合の位相差の波長特性について示す。また、表９に多層膜の膜厚などを示す。全反射面にＮｄＦ_３／ＭｇＦ_２の２層膜を成膜する事で、波長λ＝１９０〜１２４０ｎｍの範囲で１７０〜１９０°の位相差にする事が可能になる。 (Example 1-9. Quartz λ / 2 Frenerrom, NdF ₃ / MgF ₂ two-layer film)
FIG. 16 shows the wavelength characteristics of the phase difference when a two-layer film made _{of NdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 9 shows the film thickness of the multilayer film and the like. _{By forming a two-layer film of NdF 3} / MgF _{2 on} the total reflection surface, it is possible to achieve a phase difference of 170 to 190 ° in the wavelength range of λ = 190 to 1240 nm.

（実施例１−１０．石英製λ／２フレネルロム、ＮｄＦ_３／ＭｇＦ_２の４層膜）
図１７に４つの全反射面にＮｄＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表１０に多層膜の膜厚などを示す。全反射面にＮｄＦ_３／ＭｇＦ_２の４層膜を成膜する事で、波長λ＝１９０〜１７１１ｎｍの範囲で１７０〜１８３．２°の位相差にする事が可能になる。 (Example 1-10. Quartz λ / 2 Frenerrom, NdF ₃ / MgF ₂ 4-layer film)
FIG. 17 shows the wavelength characteristics of the phase difference when a four-layer film made _{of NdF 3} / MgF _{2 is formed on the four total reflection surfaces.} Table 10 shows the film thickness of the multilayer film and the like. _{By forming a four-layer film of NdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 183.2 ° in the wavelength range of λ = 190 to 1711 nm.

（実施例１−１１．石英製λ／２フレネルロム、ＮｄＦ_３／ＭｇＦ_２の１０層膜）
図１８に４つの全反射面にＮｄＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表１１に多層膜の膜厚などを示す。全反射面にＮｄＦ_３／ＭｇＦ_２の１０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７５．５〜１８７．１°の位相差にする事が可能になる。 (Example 1-11. Quartz λ / 2 Frenerrom, NdF ₃ / MgF ₂ 10-layer film)
FIG. 18 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of NdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 11 shows the film thickness of the multilayer film and the like. _{By forming a 10-layer film of NdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 175.5 to 187.1 ° in the wavelength range of λ = 190 to 2000 nm.

＜実施例２．多層膜付きＣａＦ_２製λ／２フレネルロム＞
ＣａＦ_２製のλ／２フレネルロムの４つ全ての全反射面に、ＧｄＦ_３／ＭｇＦ_２、ＬａＦ_３／ＭｇＦ_２、ＮｄＦ_３／ＭｇＦ_２の多層膜を成膜した場合における位相差の波長特性を実施例２−１．〜２−１１．に示す。図１９は、ＣａＦ_２製のλ／２フレネルロムの概要図で、多層膜の種類（構成）によらず同一の形状である。なお、２つの菱面体をオプティカル・コンタクトした場合と、互いに離して平行に並べた場合の位相差に違いはない。また、図１９に示すＣａＦ_２製のλ／２フレネルロムは、同一の平行四辺形状のプリズム素子を２つ組み合わせた構造であり、入射光線Ｉと出射光線Ｅの光軸がずれない。換言すると、入射光線Ｉと出射光線Ｅが一直線になり、入射光線Ｉと出射光線Ｅの光軸が（略）同軸となる。 <Example 2. _{CaF 2} with multilayer film λ / 2 Frenerrom>
The wavelength characteristics of the phase difference when a multilayer film of _{GdF 3} / MgF ₂ , LaF ₃ / MgF ₂ , and NdF ₃ / MgF ₂ is formed on all four total reflection surfaces of λ / 2 Frenerrom made of CaF _2. Example 2-1. ~ 2-11. Shown in. FIG. 19 is a schematic view _{of λ / 2 Frenerrom made of CaF 2} , and has the same shape regardless of the type (constitution) of the multilayer film. There is no difference in the phase difference between the case where the two rhombohedrons are in optical contact and the case where they are arranged in parallel apart from each other. _{Further, the CaF 2} λ / 2 frenerrom shown in FIG. 19 has a structure in which two prism elements having the same parallel quadrilateral shape are combined, and the optical axes of the incident light ray I and the emitted light ray E do not deviate from each other. In other words, the incident ray I and the emitted ray E are aligned, and the optical axes of the incident ray I and the emitted ray E are (omitted) coaxial.

（実施例２−１．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の２層膜）
図２０に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による２層膜を成膜した場合の位相差の波長特性について示す。また、表１２に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の２層膜を成膜する事で、波長λ＝１９０〜７６４ｎｍの範囲で１７０〜１９０°の位相差にする事が可能になる。 (Example 2-1. Two-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and GdF 3} / MgF ₂₎
FIG. 20 shows the wavelength characteristics of the phase difference when a two-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 12 shows the film thickness of the multilayer film and the like. _{By forming a two-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to achieve a phase difference of 170 to 190 ° in the wavelength range of λ = 190 to 764 nm.

（実施例２−２．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の４層膜）
図２１に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表１３に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の４層膜を成膜する事で、波長λ＝１９０〜１１５５ｎｍの範囲で１７０〜１８５．６°の位相差にする事が可能になる。 (Example 2-2. 4-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and GdF 3} / MgF ₂₎
FIG. 21 shows the wavelength characteristics of the phase difference when a four-layer film made _{of GdF 3} / MgF _{2 is formed on the four total reflection surfaces.} Table 13 shows the film thickness of the multilayer film and the like. _{By forming a four-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 185.6 ° in the wavelength range of λ = 190 to 1155 nm.

（実施例２−３．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の１０層膜）
図２２に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表１４に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の１０層膜を成膜する事で、波長λ＝１９０〜１８６６ｎｍの範囲で１７０〜１８９．１°の位相差にする事が可能になる。 (Example 2-3. 10-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and GdF 3} / MgF ₂₎
FIG. 22 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 14 shows the film thickness of the multilayer film and the like. _{By forming a 10-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 189.1 ° in the wavelength range of λ = 190 to 1866 nm.

（実施例２−４．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の２０層膜）
図２３に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による２０層膜を成膜した場合の位相差の波長特性について示す。また、表１５に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の２０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７０．９〜１８８．９°の位相差にする事が可能になる。 (Example 2-4. 20-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and GdF 3} / MgF ₂₎
FIG. 23 shows the wavelength characteristics of the phase difference when a 20-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 15 shows the film thickness of the multilayer film and the like. _{By forming a 20-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170.9 to 188.9 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例２−５．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２の５０層膜）
図２４に４つの全反射面にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表１６に多層膜の膜厚などを示す。全反射面にＧｄＦ_３／ＭｇＦ_２の５０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７５．４〜１８９°の位相差にする事が可能になる。 (Example 2-5. 50-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and GdF 3} / MgF ₂₎
FIG. 24 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 16 shows the film thickness of the multilayer film and the like. _{By forming a 50-layer film of GdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 175.4 to 189 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例２−６．ＣａＦ_２製λ／２フレネルロム、ＬａＦ_３／ＭｇＦ_２の２層膜）
図２５に４つの全反射面にＬａＦ_３／ＭｇＦ_２による２層膜を成膜した場合の位相差の波長特性について示す。また、表１７に多層膜の膜厚などを示す。全反射面にＬａＦ_３／ＭｇＦ_２の２層膜を成膜する事で、波長λ＝１９０〜７８８ｎｍの範囲で１７０〜１９０°の位相差にする事が可能になる。 (Example 2-6. Two-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and LaF 3} / MgF ₂₎
FIG. 25 shows the wavelength characteristics of the phase difference when a two-layer film made _{of LaF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 17 shows the film thickness of the multilayer film and the like. _{By forming a two-layer film of LaF 3} / MgF _{2 on} the total reflection surface, it is possible to achieve a phase difference of 170 to 190 ° in the wavelength range of λ = 190 to 788 nm.

（実施例２−７．ＣａＦ_２製λ／２フレネルロム、ＬａＦ_３／ＭｇＦ_２の４層膜）
図２６に４つの全反射面にＬａＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表１８に多層膜の膜厚などを示す。全反射面にＬａＦ_３／ＭｇＦ_２の４層膜を成膜する事で、波長λ＝１９０〜１２２１ｎｍの範囲で１７０〜１８５．６°の位相差にする事が可能になる。 (Example 2-7. 4-layer film of λ / 2 _{Frenerlom made of CaF 2} _{and LaF 3} / MgF ₂₎
FIG. 26 shows the wavelength characteristics of the phase difference when a four-layer film made _{of LaF 3} / MgF _{2 is formed on the four total reflection surfaces.} Table 18 shows the film thickness of the multilayer film and the like. _{By forming a four-layer film of LaF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 185.6 ° in the wavelength range of λ = 190 to 1221 nm.

（実施例２−８．ＣａＦ_２製λ／２フレネルロム、ＬａＦ_３／ＭｇＦ_２の１０層膜）
図２７に４つの全反射面にＬａＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表１９に多層膜の膜厚などを示す。全反射面にＬａＦ_３／ＭｇＦ_２の１０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７２．６〜１８７．７°の位相差にする事が可能になる。 (Example 2-8. 10-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and LaF 3} / MgF ₂₎
FIG. 27 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of LaF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 19 shows the film thickness of the multilayer film and the like. _{By forming a 10-layer film of LaF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 172.6 to 187.7 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例２−９．ＣａＦ_２製λ／２フレネルロム、ＮｄＦ_３／ＭｇＦ_２の２層膜）
図２８に４つの全反射面にＮｄＦ_３／ＭｇＦ_２による２層膜を成膜した場合の位相差の波長特性について示す。また、表２０に多層膜の膜厚などを示す。全反射面にＮｄＦ_３／ＭｇＦ_２の２層膜を成膜する事で、波長λ＝１９０〜７７７ｎｍの範囲で１７０〜１９０°の位相差にする事が可能になる。 (Example 2-9. Two-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and NdF 3} / MgF ₂₎
FIG. 28 shows the wavelength characteristics of the phase difference when a two-layer film made _{of NdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 20 shows the film thickness of the multilayer film and the like. _{By forming a two-layer film of NdF 3} / MgF _{2 on} the total reflection surface, it is possible to achieve a phase difference of 170 to 190 ° in the wavelength range of λ = 190 to 777 nm.

（実施例２−１０．ＣａＦ_２製λ／２フレネルロム、ＮｄＦ_３／ＭｇＦ_２の４層膜）
図２９に４つの全反射面にＮｄＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表２１に多層膜の膜厚などを示す。全反射面にＮｄＦ_３／ＭｇＦ_２の４層膜を成膜する事で、波長λ＝１９０〜１２５２ｎｍの範囲で１７０〜１８４．７°の位相差にする事が可能になる。 (Example 2-10. 4-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and NdF 3} / MgF ₂₎
FIG. 29 shows the wavelength characteristics of the phase difference when a four-layer film made _{of NdF 3} / MgF _{2 is formed on the four total reflection surfaces.} Table 21 shows the film thickness of the multilayer film and the like. _{By forming a four-layer film of NdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 170 to 184.7 ° in the wavelength range of λ = 190 to 1252 nm.

（実施例２−１１．ＣａＦ_２製λ／２フレネルロム、ＮｄＦ_３／ＭｇＦ_２の１０層膜）
図３０に４つの全反射面にＮｄＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表２２に多層膜の膜厚などを示す。全反射面にＮｄＦ_３／ＭｇＦ_２の１０層膜を成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７３．７〜１８６．３°の位相差にする事が可能になる。 (Example 2-11. 10-layer film of λ / 2 _{Frenerrom made of CaF 2} _{and NdF 3} / MgF ₂₎
FIG. 30 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of NdF 3} / MgF ₂ is formed on the four total reflection surfaces. Table 22 shows the film thickness of the multilayer film and the like. _{By forming a 10-layer film of NdF 3} / MgF _{2 on} the total reflection surface, it is possible to obtain a phase difference of 173.7 to 186.3 ° in the wavelength range of λ = 190 to 2000 nm.

＜比較例．従来のフレネルロムとの比較＞
本実施形態の多層膜付きλ／２フレネルロムと従来のフレネルロムとの比較を以下に示す。本実施形態の多層膜付きλ／２フレネルロムは、波長λ＝１９０〜２０００ｎｍと真空紫外から近赤外の波長領域において、位相差を１８０±１０°にする事が可能な位相子である。第一菱面体１０及び第二菱面体２０を構成する素材は、上記の波長帯域を透過する等方性材料で安定的な入手が可能な石英又はＣａＦ_２となる。図３１に示すように、位相差特性は、石英製の方が若干劣っている為、以下に示す比較は、等方性材料として石英を用いた場合で行う。なお、以下の比較では、多層膜Ｍが５０層膜である例を示して行っているが、積層数によらず、概ね同様の結果となる。 <Comparative example. Comparison with conventional Frenerrom>
A comparison between the λ / 2 frenerrom with a multilayer film of the present embodiment and the conventional frenerrom is shown below. The λ / 2 Frenerrom with a multilayer film of the present embodiment is a phaser capable of having a phase difference of 180 ± 10 ° in a wavelength region of λ = 190 to 2000 nm and a wavelength region from vacuum ultraviolet to near infrared. The material constituting the first rhombohedron 10 and the second rhombohedron 20 is quartz or CaF ₂ , which is an isotropic material that transmits the above wavelength band and can be stably obtained. As shown in FIG. 31, the phase difference characteristic is slightly inferior to that of quartz, so the comparison shown below is performed when quartz is used as the isotropic material. In the following comparison, an example in which the multilayer film M is a 50-layer film is shown, but the results are substantially the same regardless of the number of layers.

図３２は、全反射面に多層膜を有する本実施形態のフレネルロムＨＷＰと、従来から存在する各種フレネルロムによる位相差の波長特性について比較したものである。フレネルロムは、位相差の波長特性に優れた素子で、素材に石英を使用する事で、真空紫外から近赤外領域までの波長領域に対応可能な位相子とする事が可能である。位相差の平坦性や使用時の使い勝手などは、構造によって異なり、これらを鑑みた際に、優れた位相差性能を持ち、使い勝手が良く、現実的なフレネルロムは、従来存在していなかった。 FIG. 32 compares the wavelength characteristics of the phase difference between the Frenerrom HWP of the present embodiment, which has a multilayer film on the total reflection surface, and various conventional Frenerroms. Frenerrom is an element with excellent phase difference wavelength characteristics, and by using quartz as the material, it is possible to make a phaser that can handle the wavelength region from the vacuum ultraviolet region to the near infrared region. The flatness of the phase difference and the usability at the time of use differ depending on the structure, and in view of these, there has not been a realistic Frenerrom having excellent phase difference performance and being easy to use.

（比較例１．石英製λ／２フレネルロム膜無し、ＭｇＦ_２単層膜フレネルロム（従来品）との比較）
図３３Ａに石英製の膜無しλ／２フレネルロムと、全反射面にＭｇＦ_２単層膜又はＧｄＦ_３単層膜を形成した従来のフレネルロム（ＭｇＦ_２単層膜フレネルロム又はＧｄＦ_３単層膜フレネルロム）の概要図を示し、図３３Ｂに位相差の波長特性の比較を示す。なお、ＭｇＦ_２単層膜フレネルロムは、特許文献１を参考にλ／２フレネルロムとして検討し直したものである。ここで示した３つの従来品と本実施形態のフレネルロムＨＷＰは、基本形状は同一であり、違いは全反射面の膜構成のみとなっている。このような屋根型（ダブル型）と言われる構造の場合、入射光線と出射光線の光軸にズレなどが起こらない為、光学系を組み立てる際や、素子を回転させて使用する際に非常に便利である。また、開口と長さの比が１０：３０程度と偏光用素子としては、一般的な大きさである。位相差特性は、波長λ＝１９０〜２０００ｎｍにおいて、本実施形態のフレネルロムＨＷＰ以外は、１８０°±１０°を超えてしまう。 (Comparative Example 1 quartz lambda / 2 Fresnel rhomb film without a comparison of the MgF ₂ monolayer film Fresnel rhomb (conventional product))
FIG. 33A shows a quartz filmless λ / 2 frenerrom and _{a conventional frenerrom having an MgF 2} monolayer film or a GdF ₃ monolayer film formed on the _{total reflection surface (MgF 2} monolayer film frenerrom or GdF ₃ monolayer film frenerrom). A schematic diagram of the above is shown, and FIG. 33B shows a comparison of the wavelength characteristics of the phase difference. Incidentally, MgF ₂ monolayer film Fresnel rhomb is obtained again studied as lambda / 2 Fresnel rhomb Patent Document 1 as a reference. The three conventional products shown here and the Frenerrom HWP of the present embodiment have the same basic shape, and the only difference is the film configuration of the total reflection surface. In the case of such a roof type (double type) structure, the optical axes of the incident light rays and the emitted light rays do not shift, so it is extremely difficult to assemble the optical system or rotate the element. It's convenient. Further, the ratio of the aperture to the length is about 10:30, which is a general size for a polarizing element. The phase difference characteristic exceeds 180 ° ± 10 ° at a wavelength of λ = 190 to 2000 nm, except for Frenerrom HWP of the present embodiment.

（比較例２．石英製λ／２フレネルロム１個型との比較）
図３４Ａに石英製λ／２フレネルロム１個型（従来品）の概要図を示し、図３４Ｂに位相差の波長特性の比較を示す。１個型の場合、１回の全反射で得られる位相差が最大約４０°〜４５°程度である為、２回の全反射で得られる位相差は、９０°程度になる。素子を長くして全反射回数を４回にする事も可能であるが、位相差の性能は、屋根型（ダブル型）にして４回反射させる場合と同じである。その上、１個型の場合、構造上、入射光線と出射光線の光軸にズレが発生するという特徴があり、素子を長くすればする程ズレが大きくなってしまい、光学系を組む際に、光線のズレに合わせて、後の部品もずらして配置しなければならなくなったり、１個型フレネルロムを回転させながら使用すると、出射光線の位置も回転してしまい、使用し難くなってしまう。 (Comparative example 2. Comparison with quartz λ / 2 Frenerrom 1-piece type)
FIG. 34A shows a schematic diagram of a quartz λ / 2 Frenerrom single type (conventional product), and FIG. 34B shows a comparison of wavelength characteristics of phase difference. In the case of the single type, the phase difference obtained by one total reflection is about 40 ° to 45 ° at the maximum, so that the phase difference obtained by two total reflections is about 90 °. It is possible to lengthen the element so that the total number of reflections is four, but the performance of the phase difference is the same as when the roof type (double type) is used to reflect four times. In addition, the one-piece type has the characteristic that the optical axes of the incident light and the emitted light are displaced due to their structure, and the longer the element, the larger the deviation. , It is necessary to shift the rear parts according to the deviation of the light beam, or if the single-type Frenerrom is used while rotating, the position of the emitted light beam also rotates, making it difficult to use.

（比較例３．石英λ／２フレネルロムキング型との比較）
図３５Ａに石英λ／２フレネルロムキング型（従来品）の概要図を示し、図３５Ｂに位相差の波長特性の比較を示す。キング型の場合、３回の全反射で得られる位相差が、最大約１００°前後と位相差を１８０°にする事が出来ない。また、キング型は、その構造上、図３５Ａに図示した一か所の位置以外では、入射光線と出射光線の光軸にズレが発生し光線の上下が逆転する。この為、光線の上下を修正する部品を追加する必要があり、使用し難いという問題がある。 (Comparative example 3. Comparison with quartz λ / 2 Fresnel Rom King type)
FIG. 35A shows a schematic view of the quartz λ / 2 Fresnel Rom King type (conventional product), and FIG. 35B shows a comparison of the wavelength characteristics of the phase difference. In the case of the king type, the phase difference obtained by three total reflections is about 100 ° at the maximum, and the phase difference cannot be 180 °. Further, due to the structure of the king type, the optical axes of the incident light beam and the outgoing light ray are deviated from each other except at one position shown in FIG. 35A, and the light rays are turned upside down. Therefore, it is necessary to add a part that corrects the top and bottom of the light beam, which causes a problem that it is difficult to use.

＜実施例３．多層膜の成膜面数を１つ〜３つとした多層膜付きλ／２フレネルロム＞
石英製又はＣａＦ_２製λ／２フレネルロムに多層膜を成膜した際の位相差の波長特性を以下に示す。具体的には、石英製又はＣａＦ_２製のフレネルロムの１つ〜３つの全反射面に、膜材料ＧｄＦ_３とＭｇＦ_２の、多層膜を成膜した場合に、位相差特性が広帯域となることを示す例である。 <Example 3. Λ / 2 Frenerrom with multi-layer film with 1 to 3 multi-layer film formation surfaces>
The wavelength characteristics of the phase difference when a multilayer film is formed on λ / 2 frenerrom made of quartz or CaF _{2 are shown below.} Specifically, when _{a multilayer film of the film materials GdF 3} and MgF ₂ is formed on one to three total reflection surfaces of Frenellom made of _{quartz or CaF 2} , the phase difference characteristic becomes wide band. This is an example showing.

（実施例３−１．多層膜付き石英製λ／２フレネルロム）
石英製のλ／２フレネルロムの１つ〜３つの全反射面に、ＧｄＦ_３／ＭｇＦ_２による多層膜を成膜した場合の位相差波長特性を実施例３−１−１〜３−１−４に示す。具体的には、図７に示す石英製のλ／２フレネルロムにおいて、４つの全反射面の任意の１つ〜３つの面に多層膜を成膜した例を示す。 (Example 3-1. Quartz λ / 2 frenerrom with multilayer film)
Examples 3-1 to 1-3-1-4 phase difference wavelength characteristics when a multilayer film made of _{GdF 3} / MgF _{2 is formed on} one to three total reflection surfaces of quartz λ / 2 frenerrom. Shown in. Specifically, in the quartz λ / 2 Frenerrom shown in FIG. 7, an example in which a multilayer film is formed on any one to three surfaces of the four total reflection surfaces is shown.

（実施例３−１−１．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：１面、５０層膜）
図３６にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表２３に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の５０層膜を３つの全反射面に成膜する事で、波長λ＝１９０〜１７５３ｎｍの範囲で１７０〜１８１．６°の位相差にする事が可能になる。 (Example 3-1-1. Quartz λ / 2 frenerrom, GdF ₃ / MgF ₂ , number of film formations: 1, 50-layer film)
FIG. 36 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 23 shows the film thickness and the like. By _{forming a 50-layer film of GdF 3} / MgF ₂ on all three reflective surfaces, it is possible to achieve a phase difference of 170 to 181.6 ° in the wavelength range of λ = 190 to 1753 nm.

（実施例３−１−２．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：２面、１０層膜）
図３７にＧｄＦ_３／ＭｇＦ_２による１０層膜を成膜した場合の位相差の波長特性について示す。また、表２４に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の１０層膜を２つの全反射面に成膜する事で、波長λ＝１９０〜１９０５ｎｍの範囲で１７０〜１８６°の位相差にする事が可能になる。 (Example 3-1-2. Quartz λ / 2 frenerrom, GdF ₃ / MgF ₂ , number of film-forming surfaces: 2 surfaces, 10-layer film)
FIG. 37 shows the wavelength characteristics of the phase difference when a 10-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 24 shows the film thickness and the like. By _{forming a 10-layer film of GdF 3} / MgF _{2 on} the two total reflection surfaces, it is possible to achieve a phase difference of 170 to 186 ° in the wavelength range of λ = 190 to 1905 nm.

（実施例３−１−３．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：２面、５０層膜）
図３８にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表２５に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の５０層膜を２つの全反射面に成膜する事で、波長λ＝１９０〜１９３４ｎｍの範囲で１７０〜１８３．３°の位相差にする事が可能になる。 (Example 3-1-3. Quartz λ / 2 frenerrom, GdF ₃ / MgF ₂ , number of film formations: 2, 50-layer film)
FIG. 38 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 25 shows the film thickness and the like. By _{forming a 50-layer film of GdF 3} / MgF _{2 on} the two total reflection surfaces, it is possible to obtain a phase difference of 170 to 183.3 ° in the wavelength range of λ = 190 to 1934 nm.

（実施例３−１−４．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：３面、５０層膜）
図３９にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表２６に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の５０層膜を３つの全反射面に成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７５〜１８３°の位相差にする事が可能になる。 (Example 3-1-4. Quartz λ / 2 frenerrom, GdF ₃ / MgF ₂ , number of film formations: 3, 50-layer film)
FIG. 39 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 26 shows the film thickness and the like. By _{forming a 50-layer film of GdF 3} / MgF ₂ on all three reflective surfaces, it is possible to obtain a phase difference of 175 to 183 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例３−２．多層膜付きＣａＦ_２製λ／２フレネルロム）
ＣａＦ_２製のλ／２フレネルロムの１つ〜３つの全反射面に、ＧｄＦ_３／ＭｇＦ_２による多層膜を成膜した場合の位相差波長特性を実施例３−２−１〜３−２−４に示す。具体的には、図１９に示すＣａＦ_２製のλ／２フレネルロムにおいて、４つの全反射面の任意の１つ〜３つの面に多層膜を成膜した例を示す。 (Example 3-2. CaF ₂ with multilayer film λ / 2 Frenerrom)
Examples 3-2-1 to 2-3-2 show the phase difference wavelength characteristics when a multilayer film made of _{GdF 3} / MgF _{2 is formed on} one to three total reflection surfaces of λ / 2 Frenerrom made of CaF _2. Shown in 4. _{Specifically, in the λ / 2 Frenerrom made of CaF 2} shown in FIG. 19, an example in which a multilayer film is formed on any one to three surfaces of four total reflection surfaces is shown.

（実施例３−２−１．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：１面、５０層膜）
図４０にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表２７に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の５０層膜を１つの全反射面に成膜する事で、波長λ＝１９０〜１６８５ｎｍの範囲で１７０〜１８７°の位相差にする事が可能になる。 (Example 3-2-1. CaF ₂ λ / 2 _{Frenerrom, GdF 3} / MgF ₂ , number of film formations: 1, 50-layer film)
FIG. 40 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 27 shows the film thickness and the like. By _{forming a 50-layer film of GdF 3} / MgF _{2 on} one total reflection surface, it is possible to achieve a phase difference of 170 to 187 ° in the wavelength range of λ = 190 to 1685 nm.

（実施例３−２−２．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：２面、８層膜）
図４１にＧｄＦ_３／ＭｇＦ_２による８層膜を成膜した場合の位相差の波長特性について示す。また、表２８に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の８層膜を２つの全反射面に成膜する事で、波長λ＝１９０〜１９０３ｎｍの範囲で１７０〜１８７．２°の位相差にする事が可能になる。 (Example 3-2-2. λ / 2 _{Frenerrom made of CaF 2} _{, GdF 3} / MgF ₂ , number of film-forming surfaces: 2, 8-layer film)
FIG. 41 shows the wavelength characteristics of the phase difference when an 8-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 28 shows the film thickness and the like. By _{forming an 8-layer film of GdF 3} / MgF _{2 on} the two total reflection surfaces, it is possible to obtain a phase difference of 170 to 187.2 ° in the wavelength range of λ = 190 to 1903 nm.

（実施例３−２−３．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：２面、５０層膜）
図４２にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表２９に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の５０層膜を２つの全反射面に成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７５．７〜１８４．７°の位相差にする事が可能になる。 (Example 3-2-3. λ / 2 _{Frenerrom made of CaF 2} _{, GdF 3} / MgF ₂ , number of film-forming surfaces: 2, 50-layer film)
FIG. 42 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 29 shows the film thickness and the like. By _{forming a 50-layer film of GdF 3} / MgF _{2 on} the two total reflection surfaces, it is possible to obtain a phase difference of 175.7 to 184.7 ° in the wavelength range of λ = 190 to 2000 nm.

（実施例３−２−４．ＣａＦ_２製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：３面、５０層膜）
図４３にＧｄＦ_３／ＭｇＦ_２による５０層膜を成膜した場合の位相差の波長特性について示す。また、表３０に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の５０層膜を３つの全反射面に成膜する事で、波長λ＝１９０〜２０００ｎｍの範囲で１７３．４〜１８５．２°の位相差にする事が可能になる。 (Example 3-2-4. λ / 2 _{Frenerrom made of CaF 2} _{, GdF 3} / MgF ₂ , number of film-forming surfaces: 3, 50-layer film)
FIG. 43 shows the wavelength characteristics of the phase difference when a 50-layer film made _{of GdF 3} / MgF _{2 is formed.} Table 30 shows the film thickness and the like. By _{forming a 50-layer film of GdF 3} / MgF ₂ on all three reflective surfaces, it is possible to obtain a phase difference of 173.4 to 185.2 ° in the wavelength range of λ = 190 to 2000 nm.

＜実施例４．多層膜の成膜面数を１つとした多層膜付きλ／２フレネルロム＞
石英製λ／２フレネルロムに多層膜を成膜した際の位相差の波長特性を以下に示す。具体的には、石英製のフレネルロムの１つの全反射面に、膜材料ＧｄＦ_３とＭｇＦ_２の４層膜を成膜した場合に、広帯域性は若干劣るものの、真空紫外域から可視域まで、うねりの少ない平坦な位相差特性が得られることと、膜層数と成膜面数も少なく製造上の誤差が少なくできることを示す例である。 <Example 4. Λ / 2 Frenerrom with multilayer film with one multilayer film formation surface>
The wavelength characteristics of the phase difference when a multilayer film is formed on quartz λ / 2 Frenerrom are shown below. _{Specifically, when a four-layer film of the film materials GdF 3} and MgF ₂ is formed on one total reflection surface of quartz frenerrom, the wide band is slightly inferior, but from the vacuum ultraviolet region to the visible region. This is an example showing that a flat phase difference characteristic with less waviness can be obtained, and that the number of film layers and the number of film-forming surfaces can be reduced to reduce manufacturing errors.

（実施例４−１．石英製λ／２フレネルロム、ＧｄＦ_３／ＭｇＦ_２、成膜面数：１面、４層膜）
石英製のλ／２フレネルロムの１つの全反射面に、ＧｄＦ_３／ＭｇＦ_２による多層膜を成膜した場合の位相差波長特性を実施例４−１に示す。具体的には、図７に示す石英製のλ／２フレネルロムにおいて、４つの全反射面の任意の１つの面に多層膜を成膜した例を示す。 (Example 4-1. Quartz λ / 2 Frenerrom, GdF ₃ / MgF ₂ , number of film formations: 1 and 4 layers)
Example 4-1 shows the phase difference wavelength characteristics when a multilayer film _{made of GdF 3} / MgF ₂ is formed on one total reflection surface of λ / 2 frenerrom made of quartz. Specifically, in the quartz λ / 2 Frenerrom shown in FIG. 7, an example in which a multilayer film is formed on any one of the four total reflection surfaces is shown.

図４４にＧｄＦ_３／ＭｇＦ_２による４層膜を成膜した場合の位相差の波長特性について示す。また、表３１に膜厚などを示す。ＧｄＦ_３／ＭｇＦ_２の４層膜を１つの全反射面に成膜する事で、波長λ＝１９０〜１４３６ｎｍの範囲で１７０〜１８０．７°の位相差にする事が可能になる。 FIG. 44 shows the wavelength characteristics of the phase difference when a four-layer film made _{of GdF 3} / MgF _{2 is formed.} In addition, Table 31 shows the film thickness and the like. By _{forming a four-layer film of GdF 3} / MgF _{2 on} one total reflection surface, it is possible to obtain a phase difference of 170 to 180.7 ° in the wavelength range of λ = 190 to 1436 nm.

以上の結果から、多層膜を成膜する全反射面の数が２つ又は３つの場合において、４つの場合と同等か、より少ない多層膜の層数で、より広帯域な位相差特性を得られる場合があることが分かった。原理的には、多層膜を成膜する全反射面の数によらず、多層膜の層数の多い方が広帯域な位相差特性を得られると考えられるが、フレネルロムの構成や目的とする波長範囲によっては、多層膜を成膜する全反射面の数が少ない方が、効果が高い場合があることが分かった。 From the above results, when the number of total reflection surfaces on which the multilayer film is formed is two or three, a wider band phase difference characteristic can be obtained with the same number of layers as four or fewer layers. It turns out that there are cases. In principle, regardless of the number of total reflection surfaces on which the multilayer film is formed, it is considered that the wider the number of layers of the multilayer film, the wider the phase difference characteristic can be obtained. It was found that, depending on the range, the effect may be higher when the number of total reflection surfaces on which the multilayer film is formed is small.

また、１つ又は２つの全反射面に多層膜を成膜する場合、４つの全反射面に多層膜を成膜する場合と比べて成膜回数を１／４又は半分に減らすことができるため、製造誤差を減らせる等、生産上のメリットもある。したがって、多層膜付きλ／２フレネルロムにおいて、少なくとも１つ以上の全反射面に多層膜を形成することにより、位相差の広帯域化が可能であり、２つ以上の面に４層以上の多層膜を形成することがより好ましい Further, when a multilayer film is formed on one or two total reflection surfaces, the number of times of film formation can be reduced to 1/4 or half as compared with the case where a multilayer film is formed on four total reflection surfaces. There are also production merits such as reduction of manufacturing error. Therefore, in λ / 2 Frenerrom with a multilayer film, by forming a multilayer film on at least one or more total reflection surfaces, it is possible to widen the wavelength of the phase difference, and it is possible to widen the wavelength of the retardation. Is more preferable to form

ＨＷＰフレネルロム
１０第一菱面体
１１第一入射端面
１２第一出射端面
１３第一全反射面
１４第二全反射面
２０第二菱面体
２１第二入射端面
２２第二出射端面
２３第三全反射面
２４第四全反射面
Ｍ多層膜
Ｍ_Ｈ高屈折率膜
Ｍ_Ｌ低屈折率膜
θ 入射角
α 楔角
Ｗ素子の幅（素子の厚み）
Ｈ素子の高さ
Ｌ素子の長さ
Ｋ素子の開口
Ｉ入射光線
Ｒ反射光線
Ｅ出射光線
Ｘ光軸 HWP Frenerrom 10 1st rhombus 11 1st incident end face 12 1st total reflection end surface 13 1st total reflection surface 14 2nd total reflection surface 20 2nd rhombus 21 2nd incident end face 22 2nd emission end face 23 3rd total reflection surface 24 fourth total reflection surface M multilayer film M _H high refractive index film M _L low refractive index film θ incident angle α width of the wedge angle W element (thickness of the device)
H Element height L Element length K Aperture of element I Incoming ray R Reflected ray E Emitting ray X Optical axis

Claims

A frenerrom having parallel quadrilateral first and second rhombohedrons made of isotropic material.
The first rhombohedron includes a first incident end face, a first exit end surface arranged in parallel with the first incident end face, and a first total reflection surface intersecting the first incident end face and the first exit end face. It has a second total reflection surface arranged in parallel with the first total reflection surface, and has.
The second rhombohedron includes a second incident end face, a second emitting end face arranged parallel to the second incident end face, and a third total reflection surface intersecting the second incident end face and the second emitting end face. It has a fourth total reflection surface arranged in parallel with the third total reflection surface, and has.
The incident light rays incident on the first incident end face are totally reflected by the first total reflection surface, the second total reflection surface, the third total reflection surface, and the fourth total reflection surface, and the second emission end surface. Emitted as an emitted ray from
A multilayer film is formed on at least one or more of the first total reflection surface, the second total reflection surface, the third total reflection surface, and the fourth total reflection surface.
The multilayer film includes a high refractive index film than the isotropic material made form a high refractive index material having a large refractive index, shape formed with a small refractive index and low refractive index material than the isotropic material The low-refractive index film and the low-refractive index film are alternately laminated.
Fresnel rhomb, characterized in that at 2000nm or less in the wavelength region above 190nm gives a phase difference of 1 80 ° ± 10 ° with respect to the incident beam.

The claim is characterized in that the multilayer film is formed on one or two surfaces of the first total reflection surface, the second total reflection surface, the third total reflection surface, and the fourth total reflection surface. Frenerrom according to 1.

The low refractive index material is MgF ₂ ,
The frenerrom according to claim 1 or 2, wherein the high refractive index material is at least one selected from the group consisting of _{GdF 3} , LaF ₃ and NdF _3.

The frenerrom according to claim 3, wherein the isotropic material is quartz or CaF _2.

The isotropic material is quartz
The frenerrom according to claim 3, wherein the wedge angle of the first rhombohedron and the second rhombohedron is 53 °.

The multilayer film is a four-layer film, and the multilayer film is a four-layer film.
The frenerrom according to claim 5, wherein a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1250 nm or less.

The multilayer film is a 10-layer film.
The frenerrom according to claim 5, wherein a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1630 nm or less.

The isotropic material is CaF ₂ and
The frenerrom according to claim 3, wherein the wedge angle of the first rhombohedron and the second rhombohedron is 54 °.

The multilayer film is a four-layer film, and the multilayer film is a four-layer film.
The frenerrom according to claim 8, wherein a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1150 nm or less.

The multilayer film is a 10-layer film.
The frenerrom according to claim 8, wherein a phase difference of 180 ° ± 10 ° is given to the incident light beam in a wavelength region of 190 nm or more and 1860 nm or less.

A measuring device comprising the Frenerrom according to any one of claims 1 to 10.

An optical attenuator comprising the frenerrom according to any one of claims 1 to 10.