DE1772690A1 - Optical element with multiple reflections - Google Patents

Description

"Optical element with multiple reflection"

My invention also relates to an optical element with Liehrfciciireflexion, the one elongated, almost "completely radiolucent body, with high Refractive index and flat at a short distance ■ from each other has lying interfaces.

In articles in "Physical Review Letters" of Larz 1, 1960, Pages 224-226, and in "Physical Review", Volume 124, i.r. 4, 1962, pages 1165-1170 are a gate direction Ulm -fein 'procedure has been described, which leads to Investigation of physical and chemical properties, of surfaces with the help of frustrated total reflection. In this device there is ultrared radiation Directed onto the end face of an optical element that is ground at such an angle is that 'the radiation beam on one of the. Interfaces this element occurs at an angle which is greater than the critical angle, so that total reflection occurs and the beam is reflected to an opposing reflective interface onto which it is also occurs at an angle that is greater than the critical angle, so that total reflection occurs again,

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etc. In the articles mentioned above, be? scn.riG-ben been, daia the bundle that is caused by refuse reflection spreads at the interfaces through the entire optical element, each time also in the vicinity a reflective interface, into the thinner, i.e. the optically less dense medium adjoining the optical element penetrates, with at or in the xi '-'. he of molecular resonance frequencies an interaction between the radiation and e.g. 'impurities the mentioned surfaces occurs within the penetration depth. For example, an ultrared absorption spectrum which are characteristic of the

™ Settlement of the material on the surface of a semiconductor is. Eo has also been proposed, such a device for the ultra-red analysis of gases under Use of the principle of gas chromatography. When the gas flowing through the chromatograph is exposed to a cooled, semi-conductive reflector plate is brought into contact, a part condenses on the surface. As a result of the many reflections, which result in the plate when the ultrared beam passes through, each reflection being an interaction Means with the condensate, a thin film of condensate provides a spectrum that is strong enough to

) easy to identify relatively small amounts of a component contained in the gas.

In these known devices, the usual shape is the refuse reflection plate has a thin flat sheet with it bevelled, cut at an angle of 4'j> End up. By directing the bundle perpendicular to one of the beveled ends, it is achieved that the bundle at angles that are slightly larger than the critical angle .fills onto the boundary surfaces. These known devices have the nactibeil that the direction of the incident beam and thus the

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Number of '.reflections in the l-irefaelireflexionsplatte ■

iiaiiezu completely through ..the. given shape of the abs dir-i gt «i end of the noble reflection element. v / ground, thereby determining the size of the interaction and the number of possible interactions are.

However, known elements of this type are quite complex and expensive. ' It is the object of the invention therefore to create a simple and cheap optical element with ijehrfr-Ciireflexioix.

According to:?. ·: = The invention this is in an optical Element of the type mentioned achieved in that the -StraLlungsbüiidel. at the same end in drs element in and out of it; .-.

The GtraJvlenbündel l '"UFT liierbei eiirnal by the optioc': ^ //!.c-nent Iiinöu :: c:., V / obei it before the." Entry surface opposite Oberfläclie total reflc ^j jctie3: tv, ^T IRD. The increased number of wedge-exiles means an increased number of interactions with the substance to be analyzed. 3iLne v / additional sequence is, ο.-) ;? one end of the optical element is free

and sG ^ it simply, immersed in the liquid (

whose absorption spectrum is desired, or, weiui it is necessary to arrange dos.-optical element in a closed envelope. That .only a Θχηι: 1 _Γ ΐθβ window at the .combined end is required for exiting and entering.

Preferably, the erwJ-ihnte end Y ~ is the optical element according to the invention formed ffirmig, wob ^ i c i> - ^ rJe ENVOL factories V ungleidi Icng be köiuien. ^

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According to another embodiment of the element According to the invention, the end has the shape of a half-cylinder and runs the axis of the cylinder almost parallel to the interfaces. The diameter of the cylinder is useful here greater than the distance between the interfaces. A device with an optical element this kind has c.as characteristic a.uf that d ??. s element is rotatable about the axis of the cylinder ', so the · Λ the The number of reflections at the interfaces of the element is variable.

The. Invention is now based on some in the Drawing of illustrated embodiments explained in more detail:

Fig. 1 shows schematically !! a view of a filling form from an element according to the invention, the is suitable for obtaining optical spectra of various substances.

In Pig. 2 is a modified embodiment of the Element shown in Fig. 1, which makes it possible to adjust the angle of incidence and the number of reflections | to deliver.

Fig. 3 is a modified embodiment of the element according to Fig. 2, in which there is a much larger number of internal reflections.

Fig. T) shows a further modified aur> f!?. Irnnij, \ vi.rorm of the element ni'oh the figures 1,? and;>, at which the radiation reduction ; -. te be limited.

Dan El'inert t after } <i>:. 1. Consists of a flat plate of CTiWre i ■ - ■ - · ■ i, .- ;; -, u ν (YJ.Ii.;.; -Permeable;, ;; material with a

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V-shaped end, the left surface 16 of which is the entrance surface is for the radiation and its right surface serves as an exit surface for the radiation, as through the beam 18 is indicated, the radiation travels the enters through the entry surface 16, by total reflection down through the element '1ί? and then run back up again through the same element, to finally exit through the exit surface 17. The Eleiaenb 15 can be immersed in a vessel 19 or -in be hung on him, which is a suitable sample 20 des liquid (or in a "different physical state") to be analyzed contains. '

ji'ig. 2 shows a modified embodiment in which an ifacnteil of the element according to I'ig. 1 is avoided, which consists in the fact that the angle of incidence of the beam and the 'Δ & ηΐ of the reflections are almost completely fixed / If the end receiving the radiation 2? of the optical, ■ il3mei "1; oH .'-- '* i-.ekri.imnb formed and the element is only the j, ittöl;.' and slightly change the xchl of the reflections. The radiation bundle 26 shown as a solid line indicates an oxt angle of incidence at which there are seven reflections a on the surface of the element 23, while the bundle 2? shows a smaller angle of incidence associated with an increase in the number of reflections on the surface. The admissible ΐ-, ηπavail ?; the angle of incidence is bescj-ir-iruct by the requirement that the incident and the exiting bundle only! '.Uiii ^ go through an infjamen pressure point 24 kiLinseu, -V / parent must be taken into account that if the angle of incidence changes, the length of the StranLuu ™ w :! ^r / - '<i in the element and thus the position of the outer width ~ \,' Λ (ΐχ \\,!: ίΏ changes. This can be - required: mi "alls <\\ wo i'iLn'i , ^ o.sondertft Eiiüi division of the focal points of the €: 1η1Ή11 · .. · χι ~

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the .Bändels by hand or using a suitable coupling compensate by tilting or rotating the element 23 with the usual mirrors in the spectrometers connected isb, so there. 3 sicli a. automatic .'iUü'.leioh results,

'Fig. 3 shows an embodiment in which it is possible to change the angle of incidence luacl the number of Hexl ^r ;: <. Iojien au, whereby the total number of iielle ^ ioLOu r. ;; ark can be increased. This is made possible by using a very thin plate 34. As a result of the many

"Reflections fills the radiation, the ganae Plante Consequently, the inlet uad outlet-if laughing as ürennflachen effective, and the fact d '· ;; they ehp a common irr oint 33 hi;. Bva, it much easier night, the set j-ilei ^ ent in Spekt ^ üiueter or AInc ;. · andereu au used device correctly, uei in L ¹ Mg:. 5 Darge & töilteri / Uisfuhrungsforn are to facilitate the entry of the ütrahlenbüuclels 36 optical liittel in Forr: two Viertelajlin ' 30 and 31 are provided, which are opposite each other in optical contact with the extension of the garden areas 32 h? Mi. at the end of the element 34. This embodiment

But k has the iiacL part that ^ 30 γ> of the radiation is lost because half of the radiation emerges in such a way, that it is again reduced to the source, so> i: ·; it is not available for detection. If this is partially disruptive, it can be avoided by the fact that f .; the entrance surface 33 is made smaller than the exit surface ^: 'c; ue "> ^f -j, as shown in Figure 4. This is particularly suitable for outer optical Mt be L, in which it is a question of the imaging of a slit and the like .uidelt, which is generally narrow in relation to the radiation source and the surface of the optisciu-'i. ',' l ^ riontes.

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_ 7 -

en / Ε «should make sense, dal? the Ausitüirungsfoivi according to the

Are 1 to 4 not only in i'alle liquids advantageous but also offer .then-benefits "when the aua a gas chromatograph effluent gas and for studying Eeststoffen, particularly in l ^|! Orm Dänner .Schichten or iliederschlngen, Find use.

The pictures in the! Bit. 1 to 4 are side views of the panels showing their length and thickness. The JjreitenabmesBun.; -: stands perpendicular to the plane of the sienna. Particularly suitable dimensions for a plate like those in the J? Ig. 1 and 2 eats _s are: length 6ü mm, width 15 na IMD thickness ''}: RMI. The .L ^: l? .Tten iiE.ch den i ' ¹ ! ;;. ^r > and 4 "

icöunten eivic dieice of 1 mm.

Bio-detected radiation -Icaiui in a normal recording device working with a paper strip recorded in the form of a curve indicating the intensity of the detected radiation as a function of its wavelength. In In practice, the detector can be a tne3: moelektriseh ^ E Clement or dex ^ like, for example an indium antimonide trowel liquid (or in another state of aggregation) i a, d < ^r β ^ n the optical element grenat, v / whether the mentioned uediura is ontic thinner than the element. The depth of penetration of the bundle into the thinner ixediura is etifa one wavelength '. .and depends on the angle of incidence depending on the V / avelength ■' · he radiation can interact between d'ir ütrahlm: g and the thinner tied ium within the _Sindrir;; tie:. f '": T.-ei or in the ^ Mjie of raole lcular resonance frenuenrrer .-- ¹ ua "kick. For example, a sum Ultrarotstrnhlimg lltr- 3 "are ot9bsorptionnspektrum ERL ^ lten, the core :: ei ι.ν 'ι .-- κΐ ^i:.': 5r the" ufjmivien set solution drr 1Ί ";; ^ i. r] ze it •. '/ αϊ dor in »rj.J.'lelif-.'! er Γ! .. ti.o is.

Claims (6)

Patent claims: 1. Optical element with multiple reflection, an elongated, almost completely radiolucent body with a high refractive index and has flat at a small distance from one another boundary surfaces, characterized in that the radiation beam enters and exits the element at the same end. 2. Optical element according to claim 1, characterized in that said end is V-shaped. 3. Optical element according to claim 2, characterized in that the legs of the V are of unequal length are. 4. Optical element according to claim 1, characterized in that the end is in the shape of a half cylinder and the axis of the cylinder is almost parallel to the interfaces. 5. Optical element according to claim 4, characterized in that the diameter of the cylinder is larger than the distance between the interfaces. 6. Device with an optical element according to claim 4 or 5, characterized in that the element is rotatable about the axis of the cylinder, so that the number of reflections at the boundary surfaces of the element is variable is. 1098 ?? / n548