Abstract
The present invention relates to an optical component, comprising a substrate having a substrate surface (1), a radiation output element (2) situated on the substrate surface and/or a radiation input element (2) situated on the substrate surface and a beam deflection element (3) having dimensions of below 1 mm in all three spatial directions, which optical component is arranged on the radiation output or input element (2) on the substrate surface (1) and designed such that it deflects electromagnetic radiation exiting the radiation output element (2) substantially vertically with respect to the substrate surface (1) and in so doing forms a beam that has a smaller or even negative angle in comparison with the exit angle that the beam leaving the radiation output element forms with the substrate surface or is oriented parallel to the substrate surface, or that it focuses electromagnetic radiation entering the beam deflection element (3) at a particular angle with respect to the substrate surface and directs it into the beam input element, wherein the beam deflection element (3) has an entry area for entering radiation and an exit area for this radiation and has at least two areas influencing the path of the radiation passing through the element, one of said areas causing a deflection in at least some of the incident radiation and the other causing the beam divergence and/or the beam form to change, wherein at least one of the entry and exit areas of the beam deflection element is in planar form, characterised in that this planar area is located at least to some extent directly on an exit or entry area of said beam output or input element. The invention also relates to a method for producing this component and to beam deflection elements suitable therefor.
Claims
1. A method for producing an optical component, said optical component comprising: a substrate having a substrate surface, a radiation output element and/or a radiation input element arranged on the substrate surface, and a beam deflection element with dimensions of less than 1 mm in all spatial directions which is arranged on the substrate surface on the radiation input element or radiation output element and is designed to deflect electromagnetic radiation exiting the radiation output element essentially vertically with respect to the substrate surface, and thereby forms a beam which is aligned in parallel to the substrate surface or has a smaller or even negative angle with respect to the exit angle formed by the beam exiting the radiation output element with the substrate surface, or such that it focuses electromagnetic radiation entering the beam deflection element with a specific angle with respect to the substrate surface and directs it into the radiation input element, wherein the beam deflection element has an entrance face for incident radiation and an exit face for this radiation and at least two further faces distinct from the entrance face and the exit face, said two further faces affecting the path of the radiation passing through the element, one of said two further faces causing a deflection of at least a part of the incident radiation and the other one of said two further faces causing a change in the beam divergence and/or the beam shape, wherein at least one of the entrance face and exit face of the beam deflection element has a planar shape at least partially arranged directly on an exit face of said radiation output element or on an entrance face of said radiation input element, wherein the beam deflection element is produced directly on-site out of a starting material through photo-induced curing of a photo-structurable material, wherein the photo-induced curing is carried out by two-photon absorption or multi-photon absorption, characterized in that the beam deflection element that causes the beam divergence and/or the beam shape to change is a diffractive optical element, a lens, a lens combination, a thin hologram, a volume hologram, a metamaterial or a combination of several of the specified elements on the inside of the beam deflection element, or wherein there is a diffractive optical element on a reflective face of the beam deflection element, wherein the entrance face for incoming radiation and the exit face for this radiation have an angle of between 70 and 110.
2. The method according to claim 1, wherein the beam deflection element has a two-component or multi-component design, wherein a first part is arranged at least partially directly on a radiation output element or radiation input element on the substrate surface, and a second part is arranged at a position on the substrate surface such that it is necessarily arranged directly in the beam path of the radiation exiting the first part or entering into this part or at least a part thereof, wherein the first part of the beam deflection element has a face which causes a deflection of at least a part of the incident radiation, and the second part of the beam deflection element has a surface which causes a change of the beam divergence and/or the beam shape of the incident beam, or vice versa.
3. The method according to claim 1, wherein the beam deflection element is arranged partially directly on a radiation output element, characterized in that the beam deflection element is further arranged partially directly on a radiation input element which is part of a second optical component, and wherein the beam deflection element has at least two faces which cause a deflection of at least a part of the incident radiation, and at least two faces which cause a change of the beam divergence and/or the beam shape, wherein the faces are arranged with respect to one another such that the beam is guided from the radiation output element of the optical component through the beam deflection element into the radiation input element of the second optical component.
4. The method according to claim 1, further comprising a waveguide, which is arranged either directly adjacent to or spaced from a flat radiation entrance face or radiation exit face of the beam deflection element.
5. The method according to claim 4, wherein the waveguide is arranged at a distance from the flat radiation entrance face or radiation exit face of the beam deflection element, and a space between the flat radiation entrance face or the radiation exit face of the beam deflection element and the waveguide is filled with gas, vacuum, a liquid or a solid, wherein the liquid or the solid has a different refractive index than the material which forms the radiation entrance face or radiation exit surface of the beam deflection element and the material from which the waveguide is formed.
6. The method according to claim 1, wherein the beam deflection element is produced through photo-induced curing of a droplet of the photo-structurable material and wherein at least one additional optical component is produced from the same droplet of photo-structurable material.
7. The method according to claim 6, wherein the additional optical component is a waveguide, which is either arranged directly adjacent to or spaced from a flat radiation entrance face or radiation exit face of the beam deflection element.
8. The method according to claim 1, wherein liquid material remaining after the photostructuring of the beam deflection element is washed away.
9. The method according to claim 8, wherein the additional optical component is a waveguide, wherein a space between the flat radiation entrance face or radiation exit face of the beam deflection element and the waveguide is filled with gas, vacuum, a liquid or a solid after washing the liquid material away, wherein the liquid or the solid has a different refractive index than the material which forms the radiation entrance face or radiation exit face of the beam deflection element and the material from which the waveguide is formed.
10. The method according to claim 6, wherein the total material of the droplet is flooded with light and/or thermally treated and cured, prior to and/or after the photostructuring of the beam deflection element.
Description
(1) FIGS. 1-1 to 1-3 show a beam deflection element.
(2) FIGS. 2-1 to 2-4 show basic forms A of a beam deflection element.
(3) FIGS. 3-1 and 3-2 show basic forms B of a beam deflection element.
(4) FIGS. 4-1 and 4-2 show forms C and D of a beam deflection element with two parts.
(5) FIGS. 5-1 to 5-6 show basic forms E of a beam deflection element.
(6) FIGS. 6-1 to 6-5 show basic forms F of a beam deflection element.
(7) FIG. 7-1 shows another embodiment of a beam deflection element.
(8) FIGS. 8-1 to 8-6 show other embodiments of a beam deflection element.
(9) FIG. 9 shows an electron microscope image of beam deflection elements.
(10) An embodiment of a micro-optical component with the basic form (form G) of a beam deflection element is shown in FIG. 1-1, which utilizes a principle of beam deflection known in the art. Beam deflection element 3 has a curved surface that acts as a focusing mirror (mirror plus lens) for the radiation exiting the radiation output element. The light beam collimated by this mirror exits element 3 through an additional face of the deflection element, passes the face plane vertically and therefore does not affect the beam shape, and enters free space. In the prior art, however, such beam deflection elements are also embedded in a solid material having a refractive index differing from that of the material used for the beam deflection element. The beam path does not change because of this. The depicted beam deflection element has a material-saving undercut below the beam exit face which could not be achieved with the previous manufacturing methods for these elements. The form of the beam deflection element is therefore new. However, the undercut is of no significance for the beam path.
(11) FIGS. 1-2 and 1-3 illustrate the technical limits of this beam deflection element: as previously explained, the use of a single face for the deflection and collimation or other shaping of the beam is disadvantageous in that the beam height and the diameter of the beam cannot be adjusted independently; for a desired beam diameter, the height of the beam is automatically fixed. FIG. 1-2 shows an embodiment with which the desired small target diameter is achieved but not the target height of the collimated beam, since the distance between the curved face and the beam source must remain small to form a narrow beam. FIG. 1-3 shows the opposite case; while the target height is achieved, the target diameter is not. Due to the greater distance between the curved surface and the beam source, the produced beam is too wide.
(12) This disadvantage is eliminated with the beam deflection elements according to the invention which are described in further detail with reference to individual embodiments. The descriptions for these embodiments illustrate that different features of the various embodiments can also be combined with each other; as a matter of course, these combinations should likewise be comprised by the invention.
(13) A basic form A of such a beam deflection element is illustratively shown in FIG. 2-1. In this basic form the element has two outer faces affecting the beam shape. Of course, the geometry to be chosen in a specific case also depends on the refractive index of the material of the beam deflection element, and on the refractive index difference to the surrounding space. The beam exiting beam source 2 strikes an optionally mirrored (e.g. with metal), flat inclined (outer) face, on which it is reflected. After reflection, beam expansion necessarily continues within the element. The beam moves in the direction of a second (outer) face which affects the beam and is curved in a lenticular manner. There, the beam is deflected and collimated. It exits the deflection element as a parallel beam 4 and enters the free space (e.g. air, vacuum) in this embodiment, for example in order to strike an element with an optical input at a certain distance, such as a light conductor, a sensor, a detector or a grid. Embedding the beam deflection element in a liquid or solid medium having a refractive index which deviates from that of the material of the deflection element would alternatively be possible. It is immediately clear that a beam having a freely selectable width, even a large width, can be produced with this design, even when the distance between the beam source and the reflective surface is short and the design is correspondingly short and compact.
(14) FIG. 2-2 shows the continued path of the collimated light beam, in this case an optical fiber optical waveguide. It may consist of glass or another transparent material and can be surrounded by a cladding layer. These fibers can be produced, e.g. through structuring with TPA/MPA within a liquid or pre-cured material, as described above. The fiber optical waveguide can be part of the optical component on which deflection element 3 is arranged, and can e.g. be anchored on surface 1 thereof, though this is not necessary (it can connect two of these elements or guide the light to another object).
(15) FIG. 2-3 shows an alternative to this. Here, the collimated light beam 4 exiting the deflection element 3 is guided into a radiation input element 5 which is arranged on the same optical element as the radiation output element 2, namely via a second deflection element 3 which is formed and arranged mirror-inverted.
(16) In a variation to this which is shown in FIG. 2-4, the light beam is guided by free space propagation to a second optical element having a second substrate surface 1 to there enter a radiation input element 5 located on substrate surface 1 of the second optical element, for example a detector or a grid for light coupling, via deflection element 3 which is formed and arranged mirror-inverted.
(17) If both faces affecting the path of the radiation passing through the beam deflection element are outer faces of this element, as shown above for basic form A, beam 4 exiting deflection element 3 does not necessarily have to be parallel. Alternatively, lens can be designed such that it can be focused on any object, as shown with reference to basic form B of FIG. 3-1. It is immediately clear that the geometry of the deflection element and the lens shape can be selected in such a way that instead an expanding beam is produced.
(18) A variation of basic form B is shown in FIG. 3-2, in which the beam is focused on the input of an optical waveguide fiber. Again, suitable fibers are glass fibers of fibers produced, e.g. through structuring with TPA/MPA as specified for FIG. 2-2. This embodiment is particularly suitable for single-mode fibers.
(19) FIG. 4-1 illustrates those designs of the invention in which the beam deflection element is designed with two or more parts, wherein a first part is arranged directly on the radiation input element 2 or on at least one thereof and usually slightly projects over it. In form C shown in this figure, the first part 3 of beam deflection element has a reflective surface as described for forms A and B (FIGS. 2 and 3). However, the light beam is not collimated or focused when exiting this part of the deflection element. It exits from a face where it remains unchanged or slightly diffracted depending on the inclination (vertical to this surface or at an angle different from 90). The required collimation then occurs at a separate lens 4 which can be arranged for example on a shaft directly on the substrate (though this is not mandatory). The beam passes through this lens and is collimated thereby in a desired form (parallelized, as shown in FIG. 4, or focused, as shown in FIG. 4-2 with reference to a design termed form D; or instead the beam can also be expanded).
(20) Forms C and D are again basic forms which can be diversely modified. For example, a multitude of lenses can be used in place of one lens. Alternatively, or in addition, it is also possible to design the exit face of first part 3 of the deflection element in the form of a lens, concavely or in any other suitable manner.
(21) The exiting beam can propagate into the open environment or enter a surrounding liquid or solid medium, as described above for forms A and B.
(22) FIG. 5-1 shows an embodiment (basic form E) in which the lens surface 4 is not an outer face of the beam deflection element 3 or in which a separate lens is arranged in the beam path of the beam coming from a first part of the deflection element, but in which a lens comprising the faces affecting the beam path is located inside the element. This can be achieved by using two optically unequally dense materials for the lens and for the material of the deflection element surrounding the lens. This variation can be produced, e.g. by encapsulating a glass lens in a liquid or pasty organically polymerizable material, which is then polymerized in a suitable form, wherein the formed polymer has a different refractive index than the glass lens. A more elegant manufacturing route is carried out by inscribing a lens by means of TPA/MPA. To this end, the beam deflection element is pre-structured in its exterior form, e.g. through polymerization (through light or heat) in a mold, through a stereolithography process or a printing process. A two-photon or multi-photon polymerization is then carried out within the pre-cured material using a laser, wherein the laser light causes an additional TPA/MPA and thereby curing (a change of the primary or secondary structure as described above). The refractive index difference with respect to the material not exposed to the laser light achieved thereby can be sufficient to cause a deflection of the light beam.
(23) It should be clear that the lens does not necessarily have to be located completely inside the deflection element; instead, one of its surfaces can form that (outer) face of the beam deflection element through which the light radiation passes. In that case, the beam deflection element may also be assembled from the two components consisting of a different material, by e.g. fitting the lens in a concave recess of the remaining beam deflection element and e.g. adhering or mounting it there in another manner.
(24) In the variation in accordance with FIG. 5-2, the exit face of deflection element 3 is directly connected to an optical waveguide fiber (butt coupling). This optical fiber can be a glass fiber as well, in particularly a multi-mode fiber, or a waveguide structured through TPA/MPA.
(25) Based on FIG. 5-3, it is easy to see that the beam deflection does not necessarily have to proceed in the order first reflection, then beam formation. In this figure, a modification of form E is shown in which the light beam passes through the lens first and only then passes the reflection face.
(26) The purpose of FIG. 5-4 is to demonstrate that not just lenses can be considered as an integral beam deflection element. An element 4 is schematically integrated into the deflection element according to the invention which should stand for any element causing a volume structuring, for example a classical lens, a sequence of multiple lenses, a diffractive optical element, a thin hologram, a volume hologram or a metamaterial. At the same time, this can be a device for combining a beam (fan-in element) or a device for separating a beam (fan-out element).
(27) In the form shown, the light beam exits the beam deflection element through a curved face; depending on the conditions to which the beam has been subjected previously inside of the deflection element, this surface can also be chosen as flat.
(28) The specific case of an integrated diffractive optical element 4 (DOE) in this variation is illustrated in FIG. 5-5.
(29) The variation in FIG. 5-6 shows another specific case. Here, the diffractive optical element (DOE) is integrated into the reflective surface of the beam deflection element. Thus, the beam striking the reflective surface is not only reflected, but simultaneously its phase and/or its amplitude is modulated, whereby interference and/or intensity patterns occur within the beam geometry.
(30) In both cases, the DOE can be for example a phase plate in the form of a Fresnel zone plate for focusing.
(31) Basic form F shown in FIG. 6-1 shows a variation of form E with a lens, wherein the lens is formed in such a way that not a parallel beam but rather a converging light beam exits the deflection element. It can be directed to any optical element or object such as the input of an optical waveguide fiber (shown in FIG. 6-2) or to a separate lens being an integral part of the light deflection element, as explained for forms C and D.
(32) On the basis of basic form F, FIG. 6-3 shows a variation that is designated as a combined element in the general part of the description, i.e. a beam deflection element in which the necessary functions and geometries of single basic element E occur twice, in this case as mirror images (in this case, both outer faces of the lens respectively act as an element changing the beam divergence and/or the beam shape, wherein the one should be assigned to the first part and the other to the second part of the combined element). This element can be used to guide radiation from a radiation output element 2 (a laser or the like) arranged on surface 1 of the substrate to a radiation input element 5 (a detector or the like) arranged on the same surface, wherein the lens (or alternatively a lens sequence or the like) can be used to change the beam shape, direction of coupling-in and coupling-out direction, and the numerical aperture along the path from the light source to the detector. This beam deflection element can of course transport light from a radiation output element on the surface of a first substrate to a radiation input element on the surface of a second substrate in the same way.
(33) In a specific variation of this embodiment, the reflection surface of the element can be simultaneously curved such that the light beam is collimated and is guided parallel to the opposite curved reflection surface. A lens is not required in this case. This variation (shown in FIG. 6-4) can be described as a combined element of basic form G known from the prior art, wherein the further development of the present invention to the combined element does not have the technical disadvantage of the coupled deflection and focusing functions inherent to this basic form, as the light beam does not leave the element on its path from the radiation output element to the radiation input element and thus the target height as well as the target diameter of the beam can be freely selected within the geometrical frame of the deflection element. This variation is also formally comprised by the invention because the deflection element has a first face affecting the radiation, which causes at least a part of the incident radiation to be deflected, and a second face affecting the radiation which causes a change of the beam divergence and/or the beam shape. However, this variation (i.e. a deflection element with only two faces affecting the path of the radiation passing through the element, which are two external, curved reflection faces facing each other) is less preferred than all other variations according to the invention.
(34) The variation shown in FIG. 6-4 does not necessarily have to be symmetrically designed, which also applies for all combined beam deflection elements of the invention. If the radiation of the radiation output element first strikes for example a reflection surface which is curved such that a (e.g. converging) light beam is formed and which has an inclined focus with respect to the substrate surface, this light beam can be captured again on the opposite side by a suitably inclined mirror face and guided into the radiation input elementsee FIG. 6-5. In this embodiment, the emitter can have, e.g. a different beam divergence than accepted by the detector. If, for example, the emitter radiates a 10 cone and the detector only accepts vertical light with 1, the beam bundle on the second mirror must be very narrow to couple all the light into the detector. An asymmetrical beam path requires asymmetrical elements. The beam shape can be adapted analogously. This variation can be for example be used with a beam deflection of a beam from an edge-emitting laser having a square exit facet, as a radiation output element, to a detector with a round entrance facet.
(35) An embodiment of a beam deflection element having a non-curved exit face is shown in FIG. 7-1. Here, the refractive index difference between the material of the deflection element and that of the exterior surroundings in combination with the angle with which the beam strikes these surfaces, causes an additional deflection, namely a stronger convergence of the beam bundle compared to its form inside the deflection element.
(36) In specific embodiments of the invention, the beam deflection element contains additional optically effective elements. One example is a so-called multiplexer which separates the optical paths of the light beam for different wavelengths. This element can be a grid, a DOE, a hologram, a photonic crystal or a dichroic mirror. In some instances, this multiplexer can be inscribed directly into the bulk of the beam deflection element by means of TPA/MPA. Otherwise, it can be embedded into the still not fully cured material of the beam deflection element as a prefabricated element, as described above, e.g. for the lenses of variation E, FIG. 6-1, 6-3.
(37) A potential variation of a deflection element containing a multiplexer is shown in FIG. 8-1. A multiplexer 4 separates the beam into two vertical components 7, 8 with differing wavelengths, which exit the deflection element through lenticular faces 5 and 7. This form requires an extremely high positioning accuracy.
(38) Another variation is shown in FIG. 8-2 with a multiplexer 4 that separates the beam into two horizontal components 7, 8, which exit the deflection element through corresponding lenses 5, 6.
(39) With these variations, a multitude of potential beam shapes can be achieved. Thus, for example, the paths of light of two or more different wavelengths entering the deflection element from two or more radiation output elements arranged beneath a single beam deflection element, can be separated by an element inscribed into the bulk. As such, parallel, focusing or diverging light beams can be formed that are composed of, e.g. light of differing wavelengths, wherein different parts of the beamviewed in the cross-sectioncontain light of different wavelengths in a different manner. Thus, a beam bundle, the core of which forms a common light path for the light leaving both radiation output elements 2 and 3, can be formed by a flat grid or other flat element 5, as schematically shown in FIG. 8-3, wherein both radiation output elements emit light of different wavelengths. At the same time, the deflection element is formed in such a way that the light of wavelength 1 exiting 2 is reflected on a mirror surface such that it forms a wider parallel beam after exiting through the lenticular interface of the deflection element than the light of wavelength 2 emitted from 3, which is reflected on element 5. In this regard, element 5 is formed in such a manner that the light can pass through wavelength 1.
(40) If element 5 has a wavelength-dependent refractive power (dispersion), this dispersion can be chosen such that both paths are identical in position, direction, and diameter. As shown in FIG. 8-4, the collimated beam 6 in this case consists of the same mixture of both wavelengths emitted from 2 and 3 at all positions of its diameter.
(41) Instead of a planar element, it is also possible to provide a complex volume-structured element in the deflection element, such as a photonic crystal, a hologram or a metamaterial. The beam pattern which can be achieved thereby is comparable to that of the planar element, see FIG. 8-5, wherein cuboid 5 symbolizes the volume element.
(42) Of course, both radiation output elements do not have to be arranged in succession with respect to the radiation path, as shown in the examples in FIGS. 8-4 and 8-5, but rather they can also be arranged side by side. A respective example is shown in FIG. 8-6.
(43) Electron microscopic images of two beam deflection elements of basic form A are shown in FIG. 9. The left deflection element is correctly formed, the right one is incomplete (to allow a view to the inside, the uppermost area is cut away and the rest of the element is hollow). A radiation output element is arranged below the rear part of the elements; on its way up, the light beam strikes the inclined surface visible in the back left where it is reflected. It passes diagonally from the back towards the front through the slightly conical body of the element and exits in the front on the curved face.
