DE102020212031A1 - Device and method for determining the intensity of light guided in a planar waveguide IWG(x, y) - Google Patents

Abstract

The invention relates to a device having at least one light source, a coupling grating, a computing unit and a biochip, the biochip having at least one biograting with a focal length f and a waveguide. The waveguide has a waveguiding layer with an upper side and an underside, a substrate being arranged on the underside of the waveguiding layer and a cover layer being arranged on the upper side of the waveguiding layer. The device also has a first lens with a focal length f1, a second lens with a focal length f2, a first pinhole, at least two detectors and an outcoupling grating. The decoupling grid is arranged on the biochip in the propagation direction of the light behind the at least one biogrid and each additional biogrid. According to the invention, the device is set up to detect the elastically scattered light IScat coupled out at refractive index jumps in the waveguiding layer with a detector and at least part of the intensity of the light IWG(x, y) guided in the waveguiding layer at location x=xoutfrom the biochip to couple out the outcoupling grating and to detect the outcoupled light IWG(xout,y) on at least one further detector. Furthermore, the computing unit is set up to calculate the intensity of the light in the waveguide IWG(x, y) at any desired location x, y in the waveguide from the detected elastically scattered light IScat and the detected decoupled light IWG(xout, y).

Description

The invention relates to a device having at least one light source, a coupling grating, a computing unit and a biochip, the biochip having at least one biograting with a focal length f and a waveguide. The waveguide has a waveguiding layer with an upper side and an underside, a substrate being arranged on the underside of the waveguiding layer and a cover layer being arranged on the upper side of the waveguiding layer. The device also has a first lens with a focal length f ₁ , a second lens with a focal length f ₂ , a first pinhole, at least two detectors and a coupling-out grating. The decoupling grid is arranged on the biochip in the propagation direction of the light behind the at least one biogrid and each additional biogrid. According to the invention, the device is set up to detect the elastically scattered light I _Scat coupled out at jumps in the refractive index in the waveguiding layer with a detector and at least part of the intensity of the light _IWG (x, y) guided in the waveguiding layer at location x=x _out from the biochip through the outcoupling grating and to detect the outcoupled light I _WG (x _out , y) on at least one further detector. Furthermore, the computing unit is set up to calculate the intensity of the light in the waveguide I _WG (x, y) at any desired location x, y in the waveguide from the detected elastically scattered light I _Scat and the detected decoupled light I _WG (x _out , y) to calculate.

In the case of molography, mologram foci are read out using suitable devices. With regard to the present invention, the molography concept of Chr. Fattinger/Roche should be mentioned in particular ( WO 2013/107811 A1 , WO 2014/086789 A1 , WO 2014/111521 A1 , WO 2015 004264 A1 ). With this method, coherent light is first coupled into a planar waveguide with the aid of an optical grating. Adsorption of the biomolecules to be detected forms a diffractive biograting with curved lines and a continuously varying grating period (chirp) on the surface of the waveguide. This biolattice interacts with the near-field of the light propagating in the waveguide, thereby bioselectively decoupling part of this light and simultaneously focusing it on a diffraction-limited spot. The diffraction efficiency η of this biogrid is a measure of its mass occupancy and is calculated from the intensity I _Diff coupled out of the waveguide by the biogrid, normalized to the excitation intensity I _WG (x, y) guided in the waveguide at the location of the biogrid: $$n=\frac{I_{Diff}}{I_{WG}\left(x,y\right)}$$

In the context of the present invention, the coordinate system lies with the x-y plane in the plane of the waveguide and z perpendicular to it. The x-axis runs along the propagation direction of the light and y perpendicular to it.

For an exact determination of the diffraction efficiency, and thus the mass occupancy, it is necessary to know both the diffracted intensity I _Diff and the excitation intensity in the waveguide at the location of the biolattice I _WG (x, y).

A device for reading out diffraction-limited mologram foci is the so-called Zeptoreader from Zeptosens [1, 2]. The ceptoreader described in the EP 1 327 135 B1 , is a waveguide-based device with appropriate optics that can be used for imaging and subsequent detection of mologram foci. In this case, the associated zepto chip is designed with an outcoupling grating, which completely outcouples the light guided in the waveguide and directs it onto an approx. 10×10 mm large photodiode on the substrate side. However, this intensity measurement of the out-coupled light is only used to optimize the in-coupling angle and the in-coupling position by adjusting to maximum intensity. In regular operation of the ceptoreader, however, this information is not used to optimize the intensity in the waveguide. Since there is no measurement of I _WG (x, y), the brightness values detected by the ceptoreader are always only relative information, mostly to a brightness standard carried along on the waveguide.

In addition, the intensity measurement in the ceptoreader is only carried out with a photodiode, i.e. a 0-dimensional detector array. It is therefore not possible to carry out an intensity measurement with spatial resolution along the coupler in the y-direction; instead, only an average value of the intensity of the light that is coupled out is measured. The light propagates in the waveguide in the x-direction and is coupled into it in the y-direction over a width of approx. 10 mm (either as a line-shaped light beam or as a collimated beam that is scanned along a line). However, the intensity information along the y-axis is lost on the 0-dimensional detector after the outcoupling grating, which is just as widely illuminated. This is particularly disadvantageous, since the efficiency of the in-coupling grating varies locally due to fluctuations in the production parameters (in particular etching depth, edge steepness, etc.), so that the intensity profile of the light I _WG ( _X , y) coupled into the waveguide is generally not homogeneous. In addition, the in-coupling efficiency also varies along the y-direction due to residual divergence of the usually linear in-coupling light beam, inhomogeneity in the intensity profile of the same and inadvertent rotation of the in-coupling device relative to the long axis of the in-coupling light beam (i.e. around Rz). All of these effects cannot be measured with sufficient accuracy using a 0-dimensional detector.

Another disadvantage of the zeptoreader is that the light is coupled out at the outcoupling grid at a negative angle, ie in the negative x-direction towards the detection area of the biogrid. This is very disadvantageous in particular for the arrangement of subsequent optical elements and detectors.

To avoid the disadvantages of the ceptreader, Frutiger et al. [3] therefore another method to approximately determine I _WG (x, y), namely the measurement of the scattered light background outside of a biogrid: "A suitable intensity reference...is the mean of the speckle background I _Scat , since it is affected in the same manner as the molographic focus by the majority of processes that cause noise or drift” [3].

The disadvantage of this method, however, is that it requires the scattering loss α _S of the waveguide, which determines the scattered light background, to be a fixed, known quantity. However, the scattering loss is subject to production-related fluctuations, so that it has to be measured again for each biochip, which, however, is consistent with the method used by Frutiger et al. used device is not possible. In addition, the scattered light background can change due to environmental influences such as dirt or the applied medium.

The prior art therefore only discloses devices and methods for measuring the diffracted intensity I _Diff in a biochip, but no devices or methods for measuring the intensity of the light in the waveguide I _WG (x, y) with sufficient accuracy. However, this information is of crucial importance for the determination of the diffraction efficiency η of the different biolattices.

The object of the present invention is therefore to provide a device and a method with which the intensity of the light in the waveguide I _WG (x, y) can be determined at any location x, y in the waveguide.

For this purpose, the present invention provides a device having at least one light source, an in-coupling grating, a computing unit and a biochip, the biochip having at least one biograting with a focal length f and a waveguide, the waveguide having a waveguiding layer with a top side and a Has an underside, a substrate being arranged on the underside of the waveguiding layer and a cover layer being arranged on the upper side of the waveguiding layer, characterized in that
the device also has a first lens with a focal length f ₁ , a second lens with a focal length f ₂ , a first pinhole, at least two detectors and a coupling-out grating;
the outcoupling grating is arranged on the biochip in the propagation direction of the light behind the at least one biograting and each additional biograting;
and
the device is set up to use a detector to detect the elastically scattered light I _Scat coupled out at jumps in the refractive index in the waveguiding layer; and
to decouple at least part of the intensity of the light I _WG (x, y) guided in the waveguiding layer at location x=x _out from the biochip through the decoupling grating and the decoupled light I _WG (x _out , y) to at least one further detector to detect and
wherein the computing unit is set up to calculate the intensity of the light in the waveguide I _WG (x, y) at any desired location x, y in the waveguide from the detected elastically scattered light I _Scat and the detected decoupled light I _WG (x _out, y) to calculate.

• • Einkoppeln von Licht aus mindestens einer Lichtquelle in die wellenleitende Schicht;
• • Auskopplung von elastisch gestreutem Licht der Intensität I_Scat an Brechungsindexsprüngen in der wellenleitenden Schicht;
• • Abbilden und messen des elastisch gestreuten Lichts der Intensität I_Scat durch optische Elemente auf einem ersten Detektor;
• • Auskoppeln zumindest eines Teils der Intensität des Lichts I_WG(x_out, y), das im Wellenleiter geführt wird am Ort x_out im Wellenleiter durch das Auskoppelgitter;
• • Abbilden und messen des ausgekoppelten Teils des Lichts I_WG(x_out, y) auf mindestens einen weiteren Detektor.
• • Berechnen des Wellenleiterverlustes α aus dem gemessenen ausgekoppelten elastisch gestreuten Licht I_Scat;
• • Optional berechnen der gesamten Intensität des im Wellenleiter geführten Lichts I_WG(x, y) am Ort x=x_out des Wellenleiters;
• • Berechnen der Intensität des Lichts im Wellenleiter I_WG(_X, y) an jedem beliebigen Ort x, y im Wellenleiter mit der Formel

$$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{out},y\right)}{{\eta }_{ou\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-\alpha \left(y\right)\left(x-x_{out}\right)}.$$

Furthermore, a method for calculating the intensity of the light in the waveguide I _WG (x, y) at any location x, y in the waveguide is described using a device according to any one of claims 1 to 8, characterized in that the method comprises the steps

• • coupling of light from at least one light source into the waveguiding layer;
• • Outcoupling of elastically scattered light of intensity I _Scat at refractive index jumps in the waveguiding layer;
• • imaging and measuring the elastically scattered light of intensity I _Scat by optical elements on a first detector;
• • Outcoupling at least part of the intensity of the light I _WG (x _out , y), which is guided in the waveguide at location x _out in the waveguide, through the outcoupling grating;
• • Imaging and measuring the decoupled part of the light I _WG (x _out , y) on at least one additional detector.
• • Calculation of the waveguide loss α from the measured decoupled elastically scattered light I _Scat ;
• • Optionally calculate the total intensity of the light guided in the waveguide I _WG (x, y) at location x=x _out of the waveguide;
• • Calculate the intensity of the light in the waveguide I _WG ( _X , y) at any location x, y in the waveguide using the formula

$$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{O\mathrm{and}t},y\right)}{n_{O\mathrm{and}\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-a\left(y\right)\left(x-x_{O\mathrm{and}t}\right)}.$$

All features that are described below for the device of the present invention also apply to the method of the present invention and vice versa.

Detailed description

When light propagates in a waveguide, the intensity guided in the waveguide decreases exponentially along the propagation direction (x-direction) due to absorption and scattering. The attenuation constant is referred to here as the waveguide loss α. If the waveguide loss α and the intensity I _WG (x=x ₁ , y) guided in the waveguide are known at a location x=x ₁ , the intensity guided in the waveguide can be calculated at any other location x via the exponential relationship.

In order to eliminate the disadvantages of the prior art, the present invention provides for the light guided in the planar waveguide of a biosensor to be decoupled using a decoupling grating and then to be guided to at least one, at least 1-dimensional, detector array. In this way, the intensity I _WG (x=x _out , y) guided in the waveguide can be measured at one location, namely the position of the outcoupling grating x=x _out .

In addition, the invention provides for a measurement of the waveguide loss α, as described, for example, in [4]. For this purpose, the surface of the planar waveguide is imaged and the detected intensity profile of the scattered light background of the waveguide is exponentially fitted. The decay constant of this exponential function, possibly depending on the position y on the waveguide, is the waveguide loss α(y), which is less than 1 dB/cm for good planar waveguides (eg made of Ta ₂ O ₅ ).

If the two pieces of information I _WG (x=x _out , y) and α(y) are then known, the intensity I _WG ( _X , y) guided in the waveguide can be calculated at any location as follows: $$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{O\mathrm{and}t},y\right)}{n_{O\mathrm{and}\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-a\left(y\right)\left(x-x_{O\mathrm{and}t}\right)}$$

In this case, η _out is the outcoupling efficiency of the outcoupling grating.

According to the present invention, the device has at least one light source, wherein the at least one light source is a coherent light source. Suitable light sources are, for example, lasers, laser diodes, light-emitting diodes, etc. The at least one light source preferably has a wavelength in the range from 400 nm to 1000 nm. In one embodiment, the at least one light source can emit light of one or more wavelengths. The wavelengths of the at least one light source can be individually switched mechanically, e.g. by so-called shutters, or electrically. The wavelength of the at least one light source can thus be adapted to the respective application.

The light from the at least one light source is coupled into the wave-guiding layer of a biochip via a coupling grating. In one embodiment of the present invention, the light of the mind least one light source is coupled into the wave-guiding layer of a biochip via a lens. The lens serves to collimate the light from the light source. Does the light source already emit collimated light, e.g. with a laser, the use of such a lens is not necessary.

The biochip according to the present invention has a waveguiding layer with a top and a bottom, with a substrate being arranged on the bottom of the waveguiding layer. The biochip thus comprises a planar waveguide, with the waveguide in the sense of the invention consisting of a waveguiding layer with a refractive index nw, which is enclosed between two layers that have a lower refractive index. According to the invention, a substrate layer with a refractive index ns and a cover layer with the refractive index _nD adjoin the waveguiding layer.

The waveguiding layer of the biochip has a material from the group containing Ta ₂ O ₅ , Si ₃ N ₄ , SiO _x N _y , TiO ₂ , SiC or combinations thereof. The wave-guiding layer of the biochip particularly preferably has Ta ₂ O ₅ .

The substrate layer has a material from the group containing D263, float glass, Borofloat, Herasil. The substrate layer particularly preferably has D263.

According to the invention, the upper side of the waveguiding layer is adjacent to a cover layer, the cover layer having a material from the group consisting of SiO ₂ , water, DMSO and air or a combination of these.

The in-coupling grating is located on the underside of the wave-guiding layer. In one embodiment of the present invention, a cover layer of SiO ₂ borders the waveguiding layer in the area of the in-coupling grating, while a cover layer of water or air borders the waveguiding layer outside of this area.

Suitable in-coupling gratings used in the device according to the invention have a grating constant Λ _k in the range from 200 nm to 700 nm, preferably from 300 to 500 nm, particularly preferably 360 nm.

The light coupled into the waveguiding layer propagates along the waveguiding layer (x-direction) and decays exponentially outside the waveguiding layer (z-direction). The coupled-in light strikes the at least one biolattice in the waveguiding layer.

In the field of biosensors, gratings for coupling light in and out are known, which have biological materials and act as capture molecules for biomolecules to be examined, also called analyte molecules below. If such biomolecules accumulate on the catcher molecules structured to form a lattice, the biomolecules form an optically effective lattice. Such catcher molecules structured to form a lattice, with or without adsorbing biomolecules, are referred to below as biolattices. A biolattice therefore consists of capture molecules that are attached to the surface of the biochip in a lattice-like manner, ie like the bars of a lattice. Such biogrids are already known from the prior art. Due to the lattice-like accumulation of the analyte molecules on the catcher molecules, a small part of the light propagating in the wave-guiding layer is decoupled as a measuring light bundle I _Diff . The lattice shape of the biolattice is selected according to the invention in such a way that the decoupled measuring light bundle I _Diff is focused onto a small focal area in the focal plane at a distance f. The grating shape thus represents a diffractive lens with the focal length f. A quantitative statement about the mass occupancy can be made on the basis of the measured intensity I _Diff of the diffracted light.

According to the invention, the biochip has at least one biogrid. According to the invention, the biochip can have a large number of biogrids, it being possible for the biogrids to be arranged one-dimensionally or two-dimensionally. For example, the biochip can have 14 biolattices in the propagation direction of the light (x-direction) and 10 in the y-direction. In this case, the biogrids form a two-dimensional biogrid array. The arrangement of more or fewer biogrids in such a biogrid array is possible. Arrangements of biogrids in biochips are known to those skilled in the art.

Only a very small proportion of the light propagating in the wave-guiding layer is coupled out at the first biolattice. In one embodiment of the invention, the major part propagates further to a second (third, etc...) biolattice, which consists of second (third, etc...) scavenger molecules that are in turn connected in a grid-like manner. The lattice shape is identical to the lattice shape of the first biolattice and thus also represents a diffractive lens with the focal length f. The second capture molecules differ from the first capture molecules of the first biolattice and thus bind other specific analyte molecules whose mass occupancy is also to be measured. Due to the lattice-like attachment of the second analyte molecules to the catcher molecules, a small part of the light propagating in the wave-guiding layer is in turn decoupled as the second measuring light bundle I _Diff and focused on the focal plane. In this way, a measurement light bundle I _Diff is decoupled from each of the biogrids and focused on the focal plane of the biogrids.

In addition to the decoupling of measuring light I _Diff at the biogrids, all refractive index jumps occur during the propagation of light in the waveguiding layer, which are caused, for example, by the roughness of the substrate and/or the waveguiding layer, dirt on the waveguide surface, material inhomogeneities, etc , for coupling out elastically scattered light I _Scat , which is also deflected in the direction of the focal plane of the at least one biolattice. These scattering mechanisms contribute (in addition to absorption) to the above-mentioned exponential attenuation of the light guided in the waveguide.

The device according to the invention also has a first lens with a focal length f ₁ , a second lens with a focal length f ₂ , a first pinhole diaphragm, at least two detectors and an outcoupling grating.

A lens is a converging optical system that creates a real optical image of an object. In the simplest case, this is a single converging lens. In practice, lenses are used today that consist of many lenses, so that the aberrations are minimized. Within the scope of the present invention, preference is given to selecting multi-lens objectives with a correspondingly high imaging quality, which are fast (i.e. high numerical aperture), compact and robust. The beam path at the lenses is described using the so-called main planes, these are two defined planes in which the refraction of the light rays can be assumed in simplified terms. The advantage of the principal planes is that a multi-lens system, such as a lens, can be expressed by just one lens with only one equivalent focal length and two principal planes. Correspondingly, each objective of the device according to the invention has two main planes.

Within the scope of the present invention, the detectors of the present device are selected from the group of photosensitive detectors containing photodiodes, photomultiplier tubes, line detectors, camera detectors, avalanche photodiodes or arrays of the same. In one embodiment of the present invention, at least one detector can be designed as a multi-dimensional detector array. This is preferably designed as a 1-dimensional or 2-dimensional detector array. In one embodiment of the present invention, the detectors are therefore selected from a group containing 0-dimensional detectors, 1-dimensional detector arrays and 2-dimensional detector arrays.

In one embodiment of the present invention, the device also has a first partition wall for screening off scattered light when the light is coupled into the waveguiding layer.

In a further embodiment of the present invention, the device also has a beam catcher for absorbing the light component transmitted during coupling.

According to the invention, the device is designed such that the measuring light bundle I _Diff coupled out of the waveguide by the at least one biogrid is focused onto the focal plane of the at least one biogrid. Furthermore, the focal plane of the biogrid, in which the measuring light bundle I _Diff is focused, is imaged with the aid of a first objective (input objective) and a second objective (exit objective) with the respective focal lengths f ₁ and f ₂ onto a first detector, which is is at a distance f ₂ from the image-side main plane H ₂ 'of the second lens. If the focal lengths f ₁ and f ₂ of the first lens and the second lens are the same, ie f ₁ =f ₂ , this results in an image with magnification M=−1.

According to the invention, the first lens is arranged in such a way that its main plane H ₁ ′ on the object side is at a distance f ₁ from the focal plane of the at least one biogrid. A first pinhole diaphragm is arranged between the first objective and the second objective.

The first pinhole diaphragm is preferably arranged at a distance f ₁ from the image-side main plane H ₁ of the first objective and at a distance f ₂ from the object-side main plane H ₂ of the second objective. This arrangement of the first pinhole diaphragm is particularly advantageous since a Fourier plane results at this location. The first pinhole diaphragm thus represents a Fourier diaphragm, so that k-space filtering, ie angle filtering, is implemented. In the context of the present invention, the term Fourier diaphragm is used synonymously with the term first pinhole diaphragm. The first pinhole has an opening through which the measuring light bundle I _Diff passes. The diameter d of the diaphragm opening is selected in such a way that the desired numerical aperture results according to NA=d/2f. In this way, the numerical aperture of the detection optics can be adjusted in such a way that unwanted scattered light I _Scat , which is emitted in modes other than the measurement mode, is at least partially blocked for the measurement of the measurement light beam I _Diff .

The measuring mode thus designates that part of the light that is radiated from the location of the diffractive biogrid in the directions in which the biogrid bends. Light that is radiated from outside or in other directions, e.g. due to the roughness of the waveguide, falls into other modes and should be blocked. The aperture in the Fourier plane thus gives a desirable mode filter.

In one embodiment of the present invention, the first pinhole is mobile. In a preferred embodiment of the present invention, the first perforated diaphragm is designed to be displaceable in the x-direction and/or in the y-direction. In this way, tilting of the measurement light bundle coupled out of the biochip about the R _x and R _y axes can be compensated.

As already described, not only is the measurement light bundle I _Diff coupled out of the wave-guiding layer, but also elastically scattered light I _Scat . In a further embodiment, the first pinhole diaphragm for measuring the elastically scattered light I _Scat can be moved completely out of the beam path.

In one embodiment, both I _Diff and I _Scat are imaged onto a first detector using a second objective (output objective).

In order to calculate the respective image distances b _out for such so-called tandem lens arrangements for a given object distance g _in (distance from the main plane on the object side H ₁ ' of the first lens to the object to be imaged), that is b ₂ (distance from the main plane on the image side H ₂ ' of the second lens to the first detector), the imaging equation is applied twice. The thickness of the substrate through which the light beams pass, which is generally small compared to the focal length of the lenses, is neglected in the following analytical calculation for the sake of clarity. The minor corrections of the corresponding distances caused by them can be compensated within the framework of the usual assembly tolerances. These can be taken into account in advance in the optical design with relevant simulation packages.

If g _in , b _in and f _in are the object distance, image distance and focal length of the first lens O1, then the following applies: $$b_{\text{in}}={\left(\frac{1}{{ƒ}_{\text{in}}}-\frac{1}{G_{in}}\right)}^{-1}$$

If g _out , b _out and f _out are the object distance, image distance and focal length of the second lens, then the following applies: $$b_{\text{out}}={\left(\frac{1}{{ƒ}_{\text{out}}}-\frac{1}{G_{\text{out}}}\right)}^{-1}$$

The image generated by the first lens is imaged again by the second lens, which is at a distance L (each measured from the main plane H ₁ to the main plane H ₂ ), so that the following applies: $$G_{\text{out}}=-\left(b_{\text{in}}-L\right)$$

In the general case, the image width bout is then: $$b_{\text{out}}={\left(\frac{1}{{ƒ}_{\text{out}}}+{\left({\left(\frac{1}{{ƒ}_{\text{in}}}-\frac{1}{G_{\text{in}}}\right)}^{-1}-L\right)}^{-1}\right)}^{-1}$$

For the special case L=f _in +f _out this simplifies to: $$b_{\text{out}}=\frac{{ƒ}_{\text{out}}\left({ƒ}_{\text{in}}\left({ƒ}_{\text{in}}+{ƒ}_{\text{out}}\right)-{ƒ}_{\text{out}}{G}_{\text{in}}\right)}{{ƒ}_{\text{in}}^2}$$

For the special case of a 4f geometry, i.e. f _in =f _out , L= f _in +f _out = 2f _out , this is further simplified to: $$b_{\text{out}}=2{ƒ}_{\text{out}}-G_{\text{in}}$$

In one embodiment of the invention, the common first lens (input lens) is positioned in such a way that its focal plane coincides with the focal plane of the at least one biogrid and each additional biogrid. For imaging the focal plane of the biogrid (diffractive mode), the object distance g _in thus corresponds to the focal length of the first lens, i.e. g _in = f _in . In this way, an infinite beam path is obtained, in which a first perforated diaphragm (Fourier diaphragm) is introduced as a mode filter. At a distance L (measured between the two main planes H ₁ and H ₂ ) from the first objective, a second objective is positioned as the output objective, which produces an image on the first detector. With g _in =f _in it follows for the image distance on the second lens (initial lens) from equations (6), (7), or (8) that b _out =f _out or, specifically for the second lens, b ₂ =f ₂ . The first detector must therefore be positioned in the focal plane of the second lens in order to sharply image the focal plane of the biogrid. In a preferred embodiment of the present invention, the first detector is therefore arranged in the focal plane of the second objective.

Since the intensity profile of the elastically scattered light can be measured via an image of the surface of the waveguide, in one embodiment of the present invention the first detector is used both to measure the measuring light beam I _Diff and to measure the scattered light intensity. The imaging optics, consisting of the first lens and the second lens, are designed in such a way that the focal plane of the at least one biogrid is imaged on the first detector, so that the scattered light intensity I _Scat is not measured at its point of origin, namely the waveguide plane, but in the measured by the distance f distant focal plane. However, the numerical aperture of the imaging optics is chosen so that it roughly corresponds to the numerical aperture of the biogrid. Therefore, the blurring of the image on the waveguide surface at a distance f is approximately the diameter of a biolattice. Since this is generally well below 1 mm, the averaging of the scattered light I _Scat caused by this image blurring is so low that it is possible to calculate the waveguide loss α(y) from the measured intensity profile of the elastically scattered light.

In one embodiment of the present invention, at least one detector is arranged so that it can be moved.

In a further embodiment of the present invention, the first objective and the second objective and/or the first detector are arranged in a variable location. These are preferably variable in location along the beam path of the coupled-out light (z-direction). Due to the fact that the first objective and the second objective and/or the first detector can change location, the imaging optics can be focused on the waveguide plane and the scattered light intensity I _Scat can thus be measured in the plane of the waveguide.

The advantage of this embodiment is that in this way any imaging blurring is avoided and the waveguide loss α(y) can thus be determined more precisely.

Furthermore, in this embodiment, since the Fourier stop FB blocks a large part of the scattered light I _Scat , the first pinhole stop can be made movable so that it can be removed for measuring the surface of the waveguide. In this case, only either the focal plane of the at least one biogrid or the waveguide surface can be sharply imaged, but not both at the same time, which requires two measurements that are separated in time. In one embodiment of the present invention, the device is therefore set up such that the elastically scattered light I _Scat and the first measurement light bundle I _Diff and each further measurement light bundle I _Diff are imaged one after the other on the same detector.

The two measurements that are separated in time slow down the determination of the waveguide loss α(y) and thus also the calculation of the intensity of the light in the waveguide I _WG (x, y). In a further embodiment of the present invention, the device therefore also has a beam splitter with a holder, a third lens with a focal length f ₃ and a third detector. With this embodiment, it is possible to image the focal plane of the at least one biogrid on the first detector and the waveguide surface on the third detector at the same time.

In order to enable the simultaneous imaging of the upper side of the waveguiding layer and the focal plane of the at least one biolattice, the device according to the invention has a beam splitter. This is preferably arranged in the optical path after the first objective and before the first pinhole diaphragm, with each additional objective being arranged after the beam splitter. According to the invention, the beam splitter is a wavelength-independent beam splitter, since the measuring light I _Diff and the elastically scattered light I _Scat have the same wavelength. In one embodiment of the present invention, the beamsplitter has a splitting ratio (reflection:transmission) in the range of 1:99 to 99:1. The beam splitter preferably has a splitting ratio (reflection:transmission) of 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20 or 90:10. In one embodiment of the present invention, the mount of the beam splitter is designed to be movable.

After passing through the first lens, a first part of the light I _Diff and I _Scat is transmitted at the beam splitter and, as already described above, passes through the first pinhole diaphragm, which absorbs a large part of the scattered light I _Scat before it is passed through a second lens (output lens). is imaged onto the first detector. The signals of the at least one diffractive biogrid are detected there. The first objective, the second objective and the first detector are fixed in position according to the calculations for the tandem objective arrangement (equations 3 to 8).

After passing through the first lens, a second part of the light I _Diff and I _Scat is reflected at the beam splitter and imaged onto the third detector with a third lens (output lens). Both images thus share the first lens as a common input lens and each have separate lenses, namely the second lens and the third lens as output lenses. In the following the figure is called First Lens, Second Lens, First Detector referred to and the mapping first lens-third lens-third detector as .

The description of the tandem lens arrangement for the has already been described. Equations 3 through 8 are applied in the same way to the applied, with the object distance g _in (distance from the object-side main plane H ₁ ' of the first lens to the object to be imaged) and image distance bout, in this case b ₃ (distance from the image-side main plane H ₃ ' of the third lens to the third detector).

The imaging of the surface of the waveguiding layer (surface mode) is based on the same, fixedly positioned, first objective as the input objective. The object distance g _in this figure is thus extended by the focal length f of the biogrid, i.e. g _in =f _in +f. At a distance L (measured between the principal planes H ₁ and H ₃ ) from the first objective, a third objective is positioned as the output objective, which produces an image on a third detector. With g _in =f _in +f it follows for the image distance on the third lens from equation (6) b _out =(1/f _out +((f _in ² +ff _in )/fL) ^-1 ) ^-1 or, since in this specific case the starting lens is the third lens, b ₃ =(1/f ₃ +((f ₁ ² +ff ₁ )/fL) ^-1 ) ^-1 . For the special case L=f _in +f _out , this is simplified according to equation (7) to b _out =f _out -f(f _out /f _in ) ² or b ₃ =f ₃ -f(f ₃ /f ₁ ) ² . In the special case of a 4f geometry with f _in =f _out , this is further simplified according to equation (8) to b _out =f _out -f, or b ₃ =f ₃ -f. Since the upper side of the wave-guiding layer is located at a larger object distance g _in relative to the common first lens, the associated image distance b ₃ on the third lens is reduced. Consequently, the third detector must be positioned at a distance smaller than the focal length f ₃ from the third lens in order to be able to image the upper side of the wave-guiding layer sharply. It should be noted here that this is only possible as long as the image distance b ₃ remains sufficiently large so that the image is generated outside the last optical surface of the output lens. With the rear focal length (better known as back focal length) f _bfl,3 of the third lens, this condition is met as long as the following applies: b ₃ >f ₃ -f _bfl,3 .

In a preferred embodiment of the present invention, the third detector is therefore arranged at a distance f ₃ -f(f ₃ /f ₁ ) ² from the image-side main plane H ₃ ′ of the third objective. Furthermore, the third detector is preferably arranged at a distance greater than f _{3 −f bfl,3} from the main plane H ₃ ′ of the third objective on the image side. In one embodiment, the distance between the third detector and the image-side main plane H ₃ ′ of the third objective can be adjusted to a small extent of less than 1%.

If the two optical images are designed according to the invention, then the image consists of the first objective, the second objective and the first detector focused on the focal plane of at least one biolattice (b2=f2, diffractive mode), while those from the first objective, third objective and third detector existing is focused on top of the waveguiding layer (b ₃ =f ₃ -f(f ₃ /f ₁ ) ² , surface mode). This embodiment is particularly advantageous since two different object planes can be imaged simultaneously using the same input objective, namely the first objective.

It is also advantageous that images with different numerical apertures can be realized using the first objective as a common input objective. The numerical aperture of is limited by a first pinhole diaphragm, which acts as a Fourier diaphragm, and is thus adapted to the numerical aperture of the focusing biogrid. In this way, I _Diff can be detected while most of the elastic scattered light I _Scat is blocked by the Fourier stop. In contrast, will designed without a Fourier diaphragm, which leads to a high numerical aperture and thus high light intensity, and enables precise detection of the weak scattered light background on the waveguide. The high numerical aperture of is associated with a low depth of focus, so that it is advantageous to design the third lens and/or the third detector to be adjustable in the x-direction, so that the imaging optics can be focused exactly on the surface of the wave-guiding layer even with mechanical positional tolerances of the biochip.

In one embodiment of the device according to the invention, the third detector and/or the third objective can therefore be moved along the beam path. In this context, mobile means that the third detector and/or the third lens can be moved at least along one axis in space. In a particularly preferred embodiment of the invention, the third detector and/or the third lens can be adjusted in the x-direction, i.e. in the direction of the optical path of the light beam incident on the third detector and/or the third lens.

Alternatively, to increase the depth of field, the numerical aperture of be reduced by a suitable aperture. In one embodiment of the present invention, a second pinhole diaphragm is therefore arranged in the beam path in front of the third objective. In the case of multi-lens lenses, this diaphragm can also be arranged within the lens; corresponding optics with—possibly adjustable—diaphragms are known from the prior art and are commercially available. The diameter d of the diaphragm opening is selected in such a way that the desired numerical aperture results according to NA=d/2f.

It is particularly advantageous that the transmitted at the beam splitter is an infinite beam path with respect to the focal plane between the first objective and the second objective. In this way, no aberrations occur during transmission through the plane-parallel plate of the beam splitter. at because of the increased object distance, it is not an infinite beam path, but this is reflected at the beam splitter, so that no imaging errors occur either.

In principle, the reflected and transmitted beam paths occurring at the beam splitter can also be swapped, so that the reflected portion is guided through the first pinhole and imaged onto the first detector with the second lens, while the transmitted portion is imaged onto the third detector with the third lens. In this case, however, the non-infinity beam path experiences from a transmission through the plane-parallel plate of the beam splitter, which can lead to corresponding disadvantageous aberrations.

In a preferred embodiment of the present invention, the portion of the light transmitted at the beam splitter is directed through the first pinhole diaphragm to the first detector via the second lens, and the reflected portion of the light is directed to the third detector via the third lens.

In a further embodiment of the present invention, the portion of the light reflected at the beam splitter is directed through the first pinhole diaphragm via the second lens onto the first detector and the transmitted portion of the light is directed via the third lens onto the third detector.

The third detector is preferably a 2-dimensional detector array. If the detector is designed as a 2-dimensional detector array, the two-dimensional surface of the waveguide can be imaged.

According to the invention, the elastically scattered light I _Scat coupled out at jumps in the refractive index in the waveguiding layer is detected, as described, with the first or the third detector.

Since the biogratings applied to the waveguide decouple only a small portion of the light propagating in the planar waveguide as I _Diff and high-quality waveguides decouple only little scattered light I _Scat , the majority of the light intensity guided in the waveguide propagates further to the decoupling grating, which is located on the Location x=x _Out is located on the underside of the planar waveguide, and which at least partially decouples the light intensity guided in the waveguide and directs it to at least one further detector.

According to the invention, the device is set up to detect the elastically scattered light I _Scat coupled out at jumps in the refractive index in the waveguiding layer with a detector and at least part of the intensity of the light _IWG (x, y) guided in the waveguiding layer at location x=x _out from the biochip through the outcoupling grating and to detect the outcoupled light I _WG (x _out, y) on at least one further detector.

In one embodiment of the present invention, the device is set up to decouple the entire intensity of the light I _WG (x, y) guided in the waveguiding layer at location x=x _out of the biochip through the decoupling grating and the decoupled light I _WG (x _out, y) to be detected on at least one further detector.

According to the invention, the outcoupling grating is arranged on the biochip, seen in the propagation direction of the light, behind the at least one biograting and each additional biograting, with the outcoupling grating being arranged on the underside of the planar waveguide. It is advantageous to select the lattice constant Λ of the outcoupling grating so that the light I _WG (x _out , y) is outcoupled at a positive angle, ie in the positive x direction away from the detection area of the biogrid. This refinement is particularly advantageous compared to the prior art, since in this way space is gained for the subsequent detection arrangement.

In order to be able to precisely determine the intensity guided in the waveguide at the location of the decoupling grating, it is advantageous to design the decoupling grating in such a way that the entire intensity guided in the waveguide is decoupled. In this case, the outcoupling grating has an outcoupling efficiency η _Out =1. This can be achieved by the outcoupling grating having a sufficient length in the propagation direction of the light in the waveguide (x-direction) and/or modulation depth (in the z-direction) so that the outcoupling efficiency is correspondingly high. Since such a decoupling grating decouples the light guided in the waveguide both in the direction of the substrate and in the direction of the medium, i.e. the cover layer, via the waveguide, the decoupled light can in principle either be emitted on the substrate side I _{WG, Sub} (x _out , y), on the medium side I _{WG, Med} (x _out , y), or in both directions. The efficiency of the outcoupling grating is ideally η _out =η _{out, Med} + η _{out, Sub} =1. In addition, the ratio η _{out, Med} /η _{out, Sub} is constant for given waveguide and grating parameters, so η _{out, Sub} can be considered known, allowing a measurement I _{WG, Sub} (x _out , y) or I _{WG, Med} (x _out ,y) is sufficient. For example, an embodiment with a waveguide made of Ta ₂ O ₅ has η _{out , Sub} ≈0.55, η _{out , Med} ≈0.45. In many cases it proves to be advantageous to measure the substrate-side decoupling, since the media-side decoupling may not be easily accessible due to any fluidic devices etc. that may be present.

In one embodiment of the present invention, the light I _WG (x _out , y) coupled out via the coupling-out grating is detected with a further detector. This is referred to below as the second detector. In one embodiment of the present invention, the second detector is a 1-dimensional detector array that is positioned on the substrate after the outcoupling grating, so that I _{WG, Sub} (x _out , y) can be spatially resolved measured in the y direction. The spatial resolution in the y-direction is particularly advantageous since the intensity guided in the waveguide can fluctuate in the y-direction due to manufacturing and positioning tolerances of the in-coupling grating, which requires y-dependent normalization. In a further embodiment of the present invention, the second detector is a 1-dimensional detector array, which is positioned on the medium side after the outcoupling grating, so that I _WG,Med (x _out , y) can be spatially resolved measured in the y direction. This embodiment also provides the advantages already described.

In a further embodiment, the second detector is designed as a 2-dimensional detector array in the xy plane, which can resolve the intensity I _{WG, Sub} (x _out , y) coupled out at the coupling-out grating on the substrate side in addition to the y-direction. In a further embodiment, the second detector is designed as a 2-dimensional detector array in the xy plane, which can resolve the intensity I _{WG, MED} (x _out , y) coupled out at the coupling-out grating on the medium side in addition to the y-direction. This additional information is advantageous, for example, when the decoupling grating is too weak for the out-coupling grating in the waveguide fully decouple light. In this case, the intensity guided in the waveguide drops exponentially during propagation via the outcoupling grating, but does not disappear completely by the end of the outcoupling grating. In order to be able to deduce the intensity guided in the waveguide at the beginning of the outcoupling grating I _{WG, Sub} (x _out , y), one can resolve the intensity drop at the outcoupling grating in the x-direction, fit it exponentially and extrapolate to x→∞ . The integral under the corresponding curve then gives the full intensity guided in the waveguide at location x=x _out .

The additional information in the x-direction is also advantageous in order to be able to determine the decoupling angle β at which the light leaves the waveguide from the x point of impingement of the decoupled light on the detector. Since the outcoupling angle β is a function of the grating constant Λ of the outcoupling grating, the wavelength λ and the effective refractive index Neff of the waveguiding layer, the effective refractive index can be deduced from fluctuations in the x impingement position on the second detector. The effective refractive index determines both the outcoupling angle of the molograms and the outcoupling angle β at the outcoupling grating. If a change in the x-position of the decoupled light is observed on the detector, the corresponding change in the decoupling angle β can be deduced. Since the decoupling angle of the molograms is influenced to the same extent, this information can be used, for example, to move the Fourier diaphragm in the x-direction to the appropriate location (corresponds to the angle in Fourier space), so that the necessary position adjustment is simplified.

In a further embodiment, the device also has at least one optical element from the group consisting of mirrors, reflecting layers and lenses.

In one embodiment of the present invention, the device also has imaging optics consisting of a fourth objective, a fifth objective and optionally a mirror for beam deflection between the outcoupling grating and the second detector. This embodiment is advantageous because the imaging optics allow free positioning, i.e. in particular a greater distance, of the second detector relative to the outcoupling grating. If the device according to the invention represents part of a larger optical structure, for example, the structural conditions within the optical structure can be taken into account in this way. The lenses are preferably selected from the group containing cylindrical lenses, spherical lenses, aspherical lenses and combinations of these.

In a further embodiment of the present invention, it is possible to detect both the light intensity I _{WG, MED} (x _out , y) coupled out on the medium side and the light intensity I _{WG, Sub} (x _out , y) coupled out on the substrate side. This embodiment is advantageous since the ratio of the coupled-out intensity η _{out, Med} /η _{out, Sub} does not have to be known and fluctuations in the waveguide and out-coupling parameters are therefore permitted without the measurement accuracy being reduced.

In one embodiment of the present invention, the light I _WG (x _out , y) coupled out via the coupling-out grating is therefore detected with two detectors. In this embodiment, the device has a fourth detector, the fourth detector being arranged on the side of the cover layer (medium side) of the biochip. In this embodiment, the light I _WG (x _out , y) coupled out via the coupling-out grating is detected by the second and fourth detectors, the second detector being arranged on the substrate side and the fourth detector on the medium side after the coupling-out grating. In this embodiment, the second and fourth detectors can be designed both as 1-dimensional detector arrays and as 2-dimensional detector arrays in the xy plane. If the detectors are designed as 1-dimensional detector arrays, they measure spatially resolved in the y-direction. In one embodiment, imaging optics consisting of a fourth objective, a fifth objective and optionally a mirror for beam deflection are arranged between the outcoupling grating and the second detector and between the outcoupling grating and the fourth detector. Suitable lenses for this have already been described. This embodiment is advantageous because the imaging optics allow free positioning, ie in particular a greater distance, of the second detector and the fourth detector relative to the outcoupling grating.

In one embodiment, a mirror or a reflecting layer is applied over the outcoupling grating. In this embodiment, the light intensity I _{WG, Sub} (x _out , y) coupled out on the substrate side is detected via a detector, namely the second detector. The second detector is arranged on the substrate side. The mirrors or the reflecting layer can either be applied to the biochip or arranged at a certain distance above it, independently of the biochip. If the biochip is part of a larger structure, such as a fluidic cell, the mirror or the reflecting layer can also be integrated in a part of the larger structure. The mirror or the reflecting layer reflect the light intensity I _{WG, MED} (x _out , y) coupled out from the medium side in such a way that it passes through the wave-guiding layer and the substrate is also guided to the second detector. In this way, the complete intensity I _{WG, Sub} (x _out , y) + I _{WG, MED} (x _out , y) coupled out of the waveguide at the coupling-out grating can be measured with just one detector, namely the second detector, without the The ratio of the decoupled intensity η _{out, Med} /η _{out, Sub} must be known. This embodiment is particularly advantageous since the mirror or the reflecting layer is cheaper and more space-saving than an additional fourth detector for measuring the light I _{WG, MED} (x _out , y) coupled out on the medium side. In order to avoid renewed coupling or scattering at the outcoupler, the mirror is advantageously arranged as a function of the outcoupling angle in such a way that the reflection of the obliquely incident outcoupling light bundle does not shine through the outcoupler again.

The invention also has a computing unit. This is selected from the group containing PCs and tablets.

According to the invention, the computing unit of the device is set up to calculate the intensity of the light in the waveguide I _WG (x, y) at any desired location x, y in the waveguide from the detected elastically scattered light I _Scat and the detected decoupled light I _WG (x _out , y) to calculate. For this purpose, the computing unit has suitable software in order to calculate the waveguide loss α from the detected values of the elastically scattered light I _Scat . The software is also suitable for calculating the total light intensity guided in the waveguide from the detected decoupled light I _WG (x _out , y) at location x=x _out if only part of the intensity of the light in the waveguide at location x=x is present at the decoupling grating _out guided light could be decoupled. Furthermore, the computing unit has software to use equation (2) to calculate the intensity of the light in the waveguide I _WG (x, y) at any location x, y in the waveguide from the detected values of the elastically scattered light I _Scat and the detected decoupled light I _WG (x _out, y) at the location x=x _out to calculate. In a further embodiment, the computing unit has suitable software to calculate the diffraction efficiency of the at least one biolattice from the calculated intensity of the light in the waveguide I _WG (x, y) at any arbitrary location x, y in the waveguide according to equation (1). .

• • Einkoppeln von Licht aus mindestens einer Lichtquelle in die wellenleitende Schicht;
• • Auskopplung von elastisch gestreutem Licht der Intensität I_Scat an Brechungsindexsprüngen in der wellenleitenden Schicht;
• • Abbilden und messen des elastisch gestreuten Lichts der Intensität I_Scat durch optische Elemente auf einem ersten Detektor;
• • Auskoppeln zumindest eines Teils der Intensität des Lichts I_WG(x_out, y), das im Wellenleiter geführt wird am Ort x=x_out im Wellenleiter durch das Auskoppelgitter;
• • Abbilden und messen des ausgekoppelten Teils des Lichts I_WG(x_out, y) auf mindestens einen weiteren Detektor.
• • Berechnen des Wellenleiterverlustes α aus dem gemessenen ausgekoppelten elastisch gestreuten Licht I_Scat;
• • Optional berechnen der gesamten Intensität des im Wellenleiter geführten Lichts I_WG(x_out, y) am Ort x=x_out des Wellenleiters;
• • Berechnen der Intensität des Lichts im Wellenleiter I_WG(_X, y) an jedem beliebigen Ort x, y im Wellenleiter mit der Formel

$$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{out},y\right)}{{\eta }_{ou\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-\alpha \left(y\right)\left(x-x_{out}\right)}.$$

The invention provides a method for calculating the intensity of the light in the waveguide I _WG (x, y) at any location x, y in the waveguide with a device according to any one of claims 1 to 8, characterized in that the method comprises the steps includes

• • coupling of light from at least one light source into the waveguiding layer;
• • Outcoupling of elastically scattered light of intensity I _Scat at refractive index jumps in the waveguiding layer;
• • imaging and measuring the elastically scattered light of intensity I _Scat by optical elements on a first detector;
• • Outcoupling at least part of the intensity of the light I _WG (x _out, y), which is guided in the waveguide at location x=x _out in the waveguide, through the outcoupling grating;
• • Imaging and measuring the decoupled part of the light I _WG (x _out, y) on at least one additional detector.
• • Calculation of the waveguide loss α from the measured decoupled elastically scattered light I _Scat ;
• • Optionally calculate the total intensity of the light guided in the waveguide I _WG (x _out, y) at location x=x _out of the waveguide;
• • Calculate the intensity of the light in the waveguide I _WG ( _X , y) at any location x, y in the waveguide using the formula

$$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{O\mathrm{and}t},y\right)}{n_{O\mathrm{and}\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-a\left(y\right)\left(x-x_{O\mathrm{and}t}\right)}.$$

According to the invention, light from at least one light source is coupled into the wave-guiding layer of the device. Elastically scattered light I _Scat is coupled out at the at least one biogrid and then imaged and measured on a first detector by optical elements. In one embodiment, the elastically scattered light I _Scat is imaged onto the first detector via the first objective, the first pinhole diaphragm and the second objective. In a further embodiment, the elastically scattered light I _Scat is imaged onto the third detector via the first objective, a beam splitter, optionally further optical elements and the third objective.

Furthermore, at least part of the intensity of the light I _WG (x _out, y), which is guided in the waveguide, is coupled out at the location x=x _out in the waveguide through the outcoupling grating. The decoupled part of the light I _WG (x _out, y) is imaged on at least one detector and measured in this way. Embodiments suitable for this have already been described in detail.

The waveguide loss α is calculated from the measured decoupled elastically scattered light I _Scat . For this purpose, the detected intensity profile of the scattered light background of the waveguide I _Scat is exponentially fitted. The decay constant of this exponential function, possibly depending on the position y on the waveguide, is the waveguide loss α(y), which is less than 1 dB/cm for good planar waveguides (eg made of Ta ₂ O ₅ ).

If the entire intensity of the light I _WG (x _out, y) guided in the waveguide at location x=x _out is not coupled out through the decoupling grating, the entire intensity of the light I _WG (x _out, y) guided in the waveguide at location x =x _out of the waveguide is calculated from the detected partial intensity. In this case, as described, I _WG (x _out, y) is measured resolved by a 2-dimensional detector array in the xy plane. The intensity drop in the x-direction can be adjusted exponentially and extrapolated to x→∞. The integral under the corresponding curve then yields the full intensity I _WG (x _out, y) guided in the waveguide at location x=x _out . In a preferred embodiment, the entire intensity of the light I _WG (x _out , y) guided in the waveguide at location x=x _out is coupled out through the out-coupling grating, so that this calculation is not necessary.

The coupled-out intensity I _WG (x _out , y) is determined from the light I _WG (x _out , y) detected by at least one detector. Methods for this are known from the prior art. For example, the coupled-out intensity I _WG (x _out , y) can be determined by integration over all pixels of an image recorded by the at least one detector. The corresponding light intensity can be calculated from the measured digital units, thus the intensity I _WG (x _out, y) guided in the waveguide is obtained for each point on the outcoupling grating.

berechnet.According to the invention, the intensity of the light in the waveguide I _WG (x, y) at any location x, y in the waveguide is given by the formula $$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{O\mathrm{and}t},y\right)}{n_{O\mathrm{and}\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-a\left(y\right)\left(x-x_{O\mathrm{and}t}\right)}$$

calculated.

• • Auskoppeln eines Teils des eingekoppelten Lichts als erstes Mess-Lichtbündel I_Diff durch das mindestens eine Biogitter;
• • Optional auskoppeln je eines weiteren Mess-Lichtbündels durch jedes weitere Biogitter;
• • Abbilden des ersten Mess-Lichtbündels der Intensität I_Diff und jedes weiteren Mess-Lichtbündels mit der ersten Lochblende und dem zweiten Objektiv auf einen Detektor.

In a further embodiment, the method further comprises the steps

• • Coupling out part of the coupled-in light as a first measuring light bundle I _Diff through the at least one biogrid;
• • Optional decoupling of an additional measurement light bundle through each additional biogrid;
• • Imaging of the first measuring light bundle of intensity I _Diff and each further measuring light bundle with the first pinhole and the second lens onto a detector.

As already described, part of the coupled-in light is coupled out at the at least one biogrid as the first measurement light bundle I _Diff . If more than one biogrid is present on the biochip, a further measurement light bundle is coupled out at each additional biogrid. The first measurement light beam of intensity I _Diff and each additional measurement light beam are imaged onto a detector with the first pinhole and the second lens.

In one embodiment of the method according to the invention, the elastically scattered light I _Scat and the first measurement light bundle I _Diff and each further measurement light bundle I _Diff are imaged one after the other on the same detector. As already described, this imaging takes place via the first objective, the first pinhole diaphragm and the second objective onto the first detector.

In a further embodiment, the decoupled elastically scattered light I _Scat and the first measuring light bundle I _Diff and each further measuring light bundle I _Diff are split by a beam splitter into a first and a second beam path, where
the first measuring light bundle I _Diff and each additional measuring light bundle I _Diff via the first beam path the first pinhole and the second lens are imaged onto a first detector;
the elastically scattered light I _Scat is imaged onto a further detector via the second optical beam path with the third objective and optionally at least one further optical element; and wherein the first optical beam path is imaged onto the first detector and the second optical beam path is imaged onto the further detector simultaneously.

In one embodiment of the method according to the invention, the light I _WG (x _out, y) coupled out at location x=x _out is imaged onto a detector via at least one optical element. Examples of suitable elements are mirrors, reflecting layers, lenses and combinations of these. Suitable arrangements of these and their advantages have already been described in detail.

In one embodiment of the present invention, the outcoupled light I _WG (x _out, y) is imaged onto two detectors. Suitable arrangements of these and their advantages have also already been described in detail.

The device according to one of claims 1 to 8 according to the invention, or the method according to one of claims 9 to 15, can be used to calculate the diffraction efficiency of a biolattice using equation (1). Since, according to the invention, the intensity of the light in the waveguide I _WG (x, y) is known at every point of the waveguide and thus also at the point (x, y) of each biolattice arranged on the waveguiding layer, the present invention can diffraction efficiency of each individual biogrid can be calculated.

• 1 stellt den Abfall der im Wellenleiter geführten Intensität in Propagationsrichtung des Lichts dar;
• 2 stellt eine Ausführungsform der vorliegenden Erfindung mit zwei Detektoren dar;
• 3 stellt eine Draufsicht auf eine Ausführungsform der vorliegenden Erfindung dar;
• 4 stellt eine Ausführungsform der vorliegenden Erfindung mit zwei Detektoren dar;
• 5 stellt eine Ausführungsform der vorliegenden Erfindung mit drei Detektoren dar;
• 6 stellt eine Ausführungsform der vorliegenden Erfindung dar, bei der das ausgekoppelte Licht I_WG(x_out, y) mit zwei Detektoren detektiert wird;
• 7 stellt eine Ausführungsform der vorliegenden Erfindung dar, bei der das ausgekoppelte Licht I_WG(x_out, y) mediumsseitig über einen Spiegel auf einen auf den Detektor gelenkt wird;
• 8 stellt eine Ausführungsform der vorliegenden Erfindung dar, bei der das ausgekoppelte Licht I_WG(x_out, y) über optische Elemente auf den Detektor gelenkt wird;
• 9 stellt die unvollständig ausgekoppelte Intensität des Lichts I_WG(x_out, y) am Ort x=x_out über die Länge des Auskoppelgitters dar.

The present invention is explained in more detail below with reference to 9 figures and 2 exemplary embodiments.

• 1 represents the drop in the intensity guided in the waveguide in the direction of propagation of the light;
• 2 Figure 12 illustrates a dual detector embodiment of the present invention;
• 3 Figure 12 illustrates a plan view of an embodiment of the present invention;
• 4 Figure 12 illustrates a dual detector embodiment of the present invention;
• 5 Figure 12 illustrates a three detector embodiment of the present invention;
• 6 Figure 12 illustrates an embodiment of the present invention in which the outcoupled light I _WG (x _out, y) is detected with two detectors;
• 7 represents an embodiment of the present invention, in which the decoupled light I _WG (x _out, y) is directed onto the detector on the medium side via a mirror;
• 8th FIG. 12 shows an embodiment of the present invention in which the decoupled light I _WG (x _out, y) is directed onto the detector via optical elements;
• 9 represents the incompletely decoupled intensity of the light I _WG (x _out, y) at location x=x _out over the length of the decoupling grating.

1 represents the exponential decay of the intensity guided in the waveguide in the direction of propagation. Shown here for the direction of propagation x at a defined position y. Knowing the waveguide loss α and I _WG (x _out, y) at a location x=x _out , the intensity I _WG (x, y) at any other location x can be calculated.

2 12 represents an embodiment of the present invention with a first detector 60 and a second detector 61. In this embodiment, the elastically scattered light I _Scat and the measurement light beams I _Diff of the three biogrids 33, 34, 35 are imaged on the first detector 60. First, light from the light source 10 is coupled into the wave-guiding layer 30 via the lens 15 and the coupling-in grating 20 . Above the in-coupling grating 20 there is a beam catcher 16 which absorbs the portion of light transmitted at the in-coupling grating 20 so that stray light is avoided. The coupled light propagates in the waveguiding layer 30 and hits the first biolattice 33. A part of the propagating light is coupled out there as a measuring light bundle I _Diff . The remaining part of the light propagates further in the waveguiding layer 30 and strikes the second biogrid 34, at which a measuring light bundle I _Diff is also coupled out. The same happens at the third biogrid 35. The decoupled measurement light beams I _Diff are focused on a small focal area in the focal plane of the biogrid 40 at a distance f. The grid shape of the biogrids 33, 34, 35 thus represents a diffractive lens with the focal length f.

At a distance f ₁ from the focal plane of the biogrids 33, 34, 35 is the object-side main plane H ₁ 'of the first lens 50 with the focal length f ₁ . The first lens 50 serves as a common input lens. Downstream of this are the first pinhole 52, the second lens 53 with focal length _f2 and the first detector 60. The first pinhole 52 is at a distance f1 from the main plane _H1 of the _first lens 50 and at a distance _f2 from the main plane H ₂ of the second lens 53.

The first pinhole diaphragm 52 is therefore located in a Fourier plane, so that k-space filtering, ie angle filtering, is implemented. The second lens 53 is located at a distance f ₂ from the first aperture plate 52 in the beam path. In this way, the focal planes of the biogrids 40 and thus the measurement light beams I _Diff are imaged on the first detector D1 60.

In addition to the decoupling of measuring light I _Diff at the biogrids 33, 34, 35, there is contamination during the propagation of light in the waveguiding layer 30 at all refractive index jumps that are caused, for example, by the roughness of the substrate 32 and/or the waveguiding layer 30 on the upper side of the wave-guiding layer 31, material inhomogeneities, etc., to unintentional decoupling of elastically scattered light I _Scat , which is also deflected in the direction of the focal plane of the biogrid 40.

The elastic scattered light I _Scat is imaged onto the first detector 60 via the same optical path. Since the pinhole screen filters a large part of the elastically scattered light I _Scat , the pinhole screen can advantageously be moved out of the beam path for the measurement of the elastically scattered light I _Scat .

In this embodiment, the measurement of the elastically scattered light I _Scat and the measurement light beam I _Diff is carried out one after the other.

Furthermore, a dividing wall 17 can be fitted in the device 200 to shield scattered light from the coupling process.

The decoupling grid 90 is arranged behind the biogrids 33 , 34 , 35 . At least part of the intensity of the light I _WG (x, y) guided in the waveguide is coupled out at location x=x _out via the coupling-out grating 90 . The entire intensity of the light I _WG (x, y) guided in the waveguide is coupled out at the location x=x _out . The coupled-out light is detected by the second detector 61 on the substrate side. Alternatively, the second detector 61 can also be arranged on the medium side.

3 FIG. 12 shows a plan view of an embodiment of the present invention. The in-coupling grating 20, the bio-grids 33a-c, 34a-c and 35a-c and the out-coupling grating 90 are arranged on the substrate 32. FIG. The first detector 60 is arranged below the biogrids 33a-c, 34a-c and 35a-c and the second detector 61 is arranged behind the outcoupling grid 90. The partition wall 17 is arranged under the substrate.

4 FIG. 11 represents a further embodiment of the invention. The device 200 is analogous to the device 200 in FIG 2 built up. The only difference is that in this embodiment, the position of the first detector 60 along the beam path of the decoupled elastically scattered light I _Scat and the measuring light bundle I _Diff can be adjusted. The focal plane 40 of the biogrids 33, 34, 35 is imaged on the first detector 60 for the measurement of the measuring light bundle I _Diff . In this configuration, however, the scattered light intensity I _Scat is not measured at its point of origin, namely the waveguide plane, but in the focal plane at a distance f, resulting in a blurring of the image. Due to the fact that the first detector 60 can vary in location, the imaging optics can be focused on the upper side of the waveguiding layer 31 and the scattered light intensity I _Scat can thus be measured in the plane of the waveguide. Alternatively, the first objective 50 and the second objective 53 can also be designed to be mobile in order to fulfill the stated purpose.

At least part of the intensity of the light I _WG (x, y) guided in the waveguide is in turn coupled out at location x=x _out via the coupling-out grating 90 and detected on the substrate side with the detector 61 . Alternatively, the second detector 61 can also be arranged on the medium side.

5 10 represents an embodiment of the present invention, in which elastically scattered light I _Scat is imaged on the third detector 62 and the measurement light beams I _Diff of the three biogrids 33, 34, 35 are imaged on the first detector 60. First, light from the light source 10 is coupled into the wave-guiding layer 30 via the lens 15 and the coupling-in grating 20 . Above the in-coupling grating 20 there is a beam catcher 16 which absorbs the light component transmitted at the in-coupling grating 20 so that it strays of the scattered light is avoided. The coupled light propagates in the waveguiding layer 30 and hits the first biolattice 33. A part of the propagating light is coupled out there as a measuring light bundle I _Diff . The remaining part of the light propagates further in the waveguiding layer 30 and strikes the second biogrid 34, at which a measuring light bundle I _Diff is also coupled out. The same happens at the third biogrid 35. The decoupled measurement light beams I _Diff are focused on a small focal area in the focal plane of the biogrid 40 at a distance f. The grid shape of the biogrids 33, 34, 35 thus represents a diffractive lens with the focal length f.

At a distance f ₁ from the focal plane of the biogrids 33, 34, 35 is the object-side main plane H ₁ 'of the first lens 50 with the focal length f ₁ . The first lens 50 serves as a common input lens. Downstream of this is the beam splitter 51, which splits the decoupled light into two beam paths. In this embodiment, the beam splitter is a wavelength-independent beam splitter. According to the invention, the first beam path is imaged onto the first detector 60 . In the first beam path, after the beam splitter 51, there is a first pinhole 52, the second objective 53 with focal length f ₂ and the first detector 60. The first pinhole 52 is at a distance f ₁ from the main plane H ₁ of the first objective 50 and in Distance f ₂ from the main plane H ₂ of the second lens 53.

The first pinhole diaphragm 52 is therefore located in a Fourier plane, so that k-space filtering, ie angle filtering, is implemented. The second lens 53 is located at a distance f ₂ from the first aperture plate 52 in the beam path. In this way, the focal planes of the biogrids 40 and thus the measurement light bundles I _Diff are imaged on the first detector 60 .

In addition to the decoupling of measuring light I _Diff at the biogrids 33, 34, 35, there is contamination during the propagation of light in the waveguiding layer 30 at all refractive index jumps that are caused, for example, by the roughness of the substrate 32 and/or the waveguiding layer 30 on the upper side of the wave-guiding layer 31, material inhomogeneities, etc., to unintentional decoupling of elastically scattered light I _Scat , which is also deflected in the direction of the focal plane of the biogrid 40.

The first objective 50 also serves as an input objective for the elastically scattered light I _Scat , the elastically scattered light I _Scat then falls on the beam splitter 51 and is deflected in the direction of the third objective 54 and the third detector 62 . This represents the second beam path. After the beam splitter 51, the elastically scattered light I _Scat falls on the third lens 54 with the focal length f ₃ . The third detector 62 is located at the distance f ₃ −f(f ₃ /f ₁ ) ² from the image-side main plane H ₃ ′ of the third objective 54 .

The high numerical aperture of this image is accompanied by a low depth of focus, so that it is advantageous to design the third lens 54 and/or the third detector 62 to be adjustable in the x-direction, ie in the direction of the beam path. The imaging optics can thus be focused exactly on the upper side of the wave-guiding layer 31 even with mechanical positional tolerances of the biochip. In a further embodiment of the present invention, the numerical aperture of the image can be reduced by a suitable diaphragm in order to increase the depth of field.

The third detector 62 is preferably designed as a 2-dimensional detector array in the x-y direction.

Furthermore, a dividing wall 17 can be fitted in the device 200 to shield scattered light from the coupling process.

The decoupling grid 90 is arranged behind the biogrids 33 , 34 , 35 . At least part of the intensity of the light I _WG (x, y) guided in the waveguide is coupled out at location x=x _out via the coupling-out grating 90 . The entire intensity of the light I _WG (x, y) guided in the waveguide is coupled out at the location x=x _out . The coupled-out light is detected by the second detector 61 on the substrate side. Alternatively, the second detector 61 can also be arranged on the medium side.

6 10 represents an embodiment of the present invention, in which the coupled-out light I _WG (x _out, y) is detected with two detectors 61, 63. The device 200 is similar to the device of FIG 5 constructed, except that the light coupled out at the coupling-out grating 90 is detected on the second detector 61 and the fourth detector 63 . The second detector 61 is arranged on the substrate side behind the coupling-out grating 90 and the fourth detector 63 on the medium-side behind the coupling-out grating 90. In this embodiment, both the light intensity I _{WG, MED} (x _out , y) coupled out on the medium side and the light intensity I _{WG, Sub} (x _out , y) can be detected. These The embodiment is advantageous because the ratio of the coupled-out intensity η _{out, Med} /η _{out, Sub} does not have to be known and fluctuations in the waveguide and coupling-out parameters are therefore permitted without the measurement accuracy being reduced.

7 FIG. 12 represents an embodiment of the present invention, in which the decoupled light I _WG (x _out , y) is directed onto the second detector 61 via a mirror 100 on the medium side. In this embodiment it is also possible to detect both the light intensity I _{WG, MED} (x _out , y) coupled out on the medium side and the light intensity I _{WG, Sub} (x _out , y) coupled out on the substrate side. The use of a mirror 100 compared to the use of a further detector 63 for detecting the light intensity I _{WG, MED} (x _out , y) coupled out on the medium side is more economical and space-saving. The further construction of the device 200 corresponds to the device of FIG 5 .

8th 12 represents an embodiment of the present invention in which the decoupled light I _WG (x _out , y) is directed onto the detector 61 via optical elements. In this embodiment, the light I _WG (x _out, y) coupled out on the substrate side is directed via the objective 110, the mirror 120 and the objective 130 onto the detector 61 and detected there. This embodiment has the advantage that the detector 61 can be positioned freely. The further construction of the device 200 corresponds to the device of FIG 5 .

9 represents the incompletely decoupled intensity of the light I _WG (x, y) at location x=x _out over the length of the decoupling grating. If the second detector 61 is designed as a 2-dimensional detector array in the xy plane, the decoupling grating 90 can be decoupled intensity I _{WG, Sub} (x _out , y) can be resolved in addition to the y-direction in the x-direction. This additional information is advantageous, for example, when the outcoupling grating is too weak to completely outcouple the light guided in the waveguide. In this case, the intensity guided in the waveguide drops exponentially during propagation via the outcoupling grating, but does not disappear completely until the end of the outcoupling grating, as in 9 shown. In order to be able to deduce the intensity guided in the waveguide at the beginning of the outcoupling grating I _{WG, Sub} (x _out , y), one can resolve the intensity drop at the outcoupling grating in the x-direction, fit it exponentially and extrapolate to x→∞ . The integral under the corresponding curve then gives the full intensity guided in the waveguide at location x=x _out .

Alternatively, the second detector 61 can be designed as a 2-dimensional detector array in the xy plane in order to resolve the intensity I _{WG, Med} (x _out , y) coupled out at the coupling-out grating 90 on the medium side in addition to the y-direction.

Example 1

A biochip consisting of a D263 substrate with a wave-guiding layer 30 made of Ta ₂ O ₅ was used. 140 biogrids 33, 34, 35 were arranged on the waveguide surface in a 14×10 grid, each with a center distance of 500 μm (in the x and y direction). Light of a first wavelength λ ₁ =785 nm was coupled into the waveguiding layer 30 via a coupling grating 20 with a grating constant λ=360 nm.

The biogrids 33, 34, 35 had a diameter of d=0.4 mm and a focal length of f=12 mm and accordingly a numerical aperture of NA=d/2f=0.0167. The biogrids 33, 34, 35 produced corresponding diffraction-limited foci in the focal plane 40.

As the first objective 50, second objective 53 and third objective 54, three identical multi-lens objectives with a fixed focal length f ₁ =f ₂ =f ₃ =35 mm were used, which were at a distance of L=f ₁ +f ₂ or L=f ₁ + f ₃ were arranged in opposite directions as tandem lenses. A 4f image with a magnification of M=-1 was thus implemented.

The beam splitter 51 was designed as a wavelength-independent beam splitter with a splitting ratio (reflection:transmission) of 10:90. The majority of the light I _Diff and I _Scat coupled out was transmitted at the beam splitter 51 and reached a Fourier diaphragm. The Fourier stop was positioned at a distance fi=35 mm behind the main plane H ₁ of the first lens 50 on the image side. The aperture had a diameter of D=2f ₁ NA=f ₁ d/f≈1.2 mm, so that the numerical aperture in the figure corresponded to that of the biogrids 33, 34, 35. The majority of the elastically scattered light I _Scat was blocked by the Fourier stop, while the light I _Diff was transmitted and imaged using the second objective 53 onto the first detector 60, which was designed as a CMOS camera sensor with low dark noise.

The smaller part of the light I _Diff , I _Scat was reflected at the beam splitter 51 and imaged with the aid of the third lens 54 onto a third detector 62 which was also designed as a CMOS camera sensor with low dark noise. The distance between this detector 62 and the main plane of the third lens 54 on the image side was b ₃ =f ₃ −f(f ₃ /f ₁ ) ² =35 mm−12 mm=24 mm. This distance could be adjusted slightly by moving the third lens 54 and/or the third detector 62, so that the image could be focused exactly on the upper side of the wave-guiding layer 31 even with mechanical positional tolerances of the biochip.

A large part of the light intensity guided in the waveguide propagates on to the outcoupling grating 90. The outcoupling grating 90 had a grating constant of λ=480 nm. The lattice constant Λ of the outcoupling grating 90 was chosen such that the light I _WG (x _out, y) was outcoupled at a positive angle, i.e. in the positive x-direction away from the detection area of the biogrids 33, 34, 35.

The outcoupling grating 90 had a length of 1 mm in the propagation direction of the light (x-direction) and was therefore designed to be long enough for the entire intensity of the light I _WG (x _out, y) to be outcoupled at location x=x _out . Imaging optics 110 and a mirror 120 were introduced behind the outcoupling grating 90 , which imaged the outcoupled light onto a 2-dimensional detector 61 . A 2-dimensional CMOS sensor served as detector 61 .

Example 2

The elastically scattered light I _Scat and the decoupled light I _WG (x _out, y) were detected in accordance with exemplary embodiment 1. Accordingly, with the aid of the detector 62 and the third lens 54, a recording of the waveguide surface was made. The scattered light intensity determined in this way was fitted exponentially and the waveguide loss α was determined in this way. If necessary, the waveguide loss α can also be determined in the y-direction α(y).

The coupled-out light I _WG (x _out, y) was detected with the detector 61 and the coupled-out intensity I _WG (x _out, y) was determined from the image of the detector 61 by integration over all pixels. The sensitivity of the detector 61 was known, so that a corresponding light intensity could be calculated from the measured digital units. Thus, for each point on the outcoupling grating 90, the intensity I _WG (x _out, y) guided in the waveguide was known.

$$I_{WG}\left(6\text{mm},\text{5 mm}\right)=\frac{1\text{mW}}{\mathrm{0,55}}{10}^{-\text{dB/cm}\left(6\text{mm}-15\text{mm}\right)}\approx 2.24\text{mW}$$

The substrate-side outcoupling efficiency of the outcoupling grating 90 was η _{out, Sub} ≈0.55. The position of the outcoupling grating 90 on the chip was x _out =15 mm. The result of the waveguide attenuation measurement was α=1 dB/cm. If you are now interested in the intensity guided in the waveguide at location x=6 mm, y=5 mm, you need to measure the intensity coupled out at the outcoupling grating 90 at location y=5 mm, which I _WG (x _out, y=5 mm)=1 mW. The intensity guided in the waveguide at location x=6 mm, y=5 mm was calculated according to formula (2) as follows: $$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{O\mathrm{and}t},y\right)}{n_{O\mathrm{and}\mathrm{<figure-callout\; id="10"\; label="t"\; filenames="DE102020212031A1\_0016.png,DE102020212031A1\_0018.png"\; state="\{\{state\}\}">t</figure-callout>}}}{10}^{-a\left(y\right)\left(x-x_{O\mathrm{and}t}\right)}$$

$$I_{WG}\left(6\text{mm},\text{5mm}\right)=\frac{1\text{mW}}{0.55}{10}^{-\text{dB/cm}\left(6\text{mm}-15\text{mm}\right)}\approx 2.24\text{mW}$$

Reference List

10

light source

15

lens

16

Beam catcher for the transmitted light component

17

Partition wall for scattered light

20

coupling grid

30

wave-guiding layer

31

Top of the waveguiding layer

32

substrate

33, 33a-33c

biogrid

34, 34a-34c

biogrid

35, 35a-35c

biogrid

40

focal plane of the biogrid

50

first lens O1

51

beam splitter

52

first pinhole

53

second lens O2

54

third lens O3

60

first detector

61

second detector

62

third detector

63

fourth detector

80

top layer

90

outcoupling grid

100, 120

mirror

110, 130

lenses

200

contraption

literature

1. [1] V. Gatterdam et al., Nature Nanotechnology 12, 1089 (2017)
2. [2] A.M. Reichmuth et al., Anal. Chem. 92, 13, 8983 (2020)
3. [3] Frutiger et al., Phys. Rev. Applied 11, 014056 (2019)
4. [4] F. Zernike, Fabrication and Measurements of Passive Components. In: T. Tamir (eds.) Integrated Optics. Topics in Applied Physics, vol 7. Springer, Berlin, Heidelberg (1975)

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2013/107811 A1 [0002]
• WO 2014/086789 A1 [0002]
• WO 2014/111521 A1 [0002]
• WO 2015004264 A1 [0002]
• EP 1327135 B1 [0005]

Claims (15)

Device (200) having at least one light source (10), a coupling grating (20), a computing unit and a biochip, the biochip having at least one biograting (33, 34, 35) with a focal length f and a waveguide, the waveguide having a has a waveguiding layer (30) with an upper side (31) and an underside, a substrate (32) being arranged on the underside of the waveguiding layer and a covering layer (80) being arranged on the upper side of the waveguiding layer (30), characterized in that the device (200) also has a first objective (50) with a focal length f ₁ , a second objective (53) with a focal length f ₂ , a first pinhole diaphragm (52), at least two detectors (60, 61) and an outcoupling grating (90 ) having; the decoupling grating (90) is arranged on the biochip in the propagation direction of the light behind the at least one biograting (33, 34, 35) and each additional biograting (33, 34, 35); and the device (200) is set up to detect the elastically scattered light I _Scat coupled out at jumps in the refractive index in the waveguiding layer (30) using a detector (60); and decoupling at least part of the intensity of the light I _WG (x, y) guided in the waveguiding layer at location x=x _out from the biochip through the decoupling grating (90) and coupling out the light I _WG (x _out, y) to at least a further detector (61) to detect; and wherein the computing unit is set up to calculate the intensity of the light in the waveguide I _WG (x, y) at any arbitrary location x, y in the waveguide from the detected elastically scattered light I _Scat and the detected decoupled light I _WG (x _out, y ) to calculate. Device (200) according to claim 1 , characterized in that the detectors (60, 61, 62, 64) are selected from a group containing 0-dimensional detectors, 1-dimensional detector arrays and 2-dimensional detector arrays. Device (200) according to one of the preceding claims, characterized in that at least one detector (60, 61, 62, 64) is arranged to be mobile. Device (200) according to one of the preceding claims, characterized in that the first perforated diaphragm 52 is arranged so that it can be moved. Device (200) according to one of the preceding claims, characterized in that the device (200) further comprises a beam splitter (51) with holder, a third objective (54) with a focal length f ₃ and a third detector (62). Device (200) according to one of the preceding claims, characterized in that the device (200) further comprises a fourth detector (64), the fourth detector (64) being arranged on the side of the cover layer (80) of the biochip. Device (200) according to any one of Claims 1 until 5 , characterized in that the device (200) further comprises at least one optical element from the group containing mirrors (100, 120), reflecting layers, lenses (110, 130). Device (200) according to claim 7 , characterized in that the lenses (110, 130) are selected from the group containing cylindrical lenses, spherical lenses, aspherical lenses and combinations of these. Method for calculating the intensity of the light in the waveguide I _WG (x, y) at any location x, y in the waveguide using a device (200) according to one of Claims 1 until 8th , characterized in that the method comprises the steps of • coupling light from at least one light source (10) into the waveguiding layer (30); • Outcoupling of elastically scattered light of intensity I _Scat at refractive index jumps in the waveguiding layer (30); • imaging and measuring the elastically scattered light of intensity I _Scat by optical elements on a first detector; • Outcoupling at least part of the intensity of the light I _WG (x _out, y) that is guided in the waveguide at location x _out in the waveguide through the outcoupling grating (90); • Imaging and measuring the decoupled part of the light I _WG (x _out, y) on at least one other Detector. • Calculation of the waveguide loss α from the measured decoupled elastically scattered light I _Scat ; • Optionally calculate the total intensity of the light guided in the waveguide I _WG (x _out, y) at location x _out of the wave guide; • Calculate the intensity of the light in the waveguide I _WG (x, y) at any location x, y in the waveguide using the formula $$I_{WG}\left(x,y\right)=\frac{I_{WG}\left(x=x_{O\mathrm{and}t},y\right)}{n_{O\mathrm{and}t}}{10}^{-a\left(y\right)\left(x-x_{O\mathrm{and}t}\right)}.$$

procedure after claim 9 , characterized in that the method further comprises the steps • decoupling of part of the coupled-in light as the first measurement light beam I _Diff through the at least one biogrid (33, 34, 35); • Optionally decoupling a further measurement light beam through each further biogrid (33, 34, 35); • Imaging of the first measuring light bundle of intensity I _Diff and each further measuring light bundle with the first pinhole (52) and the second lens (53) onto a detector. procedure after claim 10 , characterized in that the elastically scattered light I _Scat and the first measuring light bundle I _Diff and each further measuring light bundle I _Diff are successively imaged on the same detector. procedure after claim 10 , characterized in that the decoupled elastically scattered light I _Scat and the first measuring light bundle I _Diff and each further measuring light bundle I _Diff are split by a beam splitter into a first and a second beam path, the first measuring light bundle I _Diff and each further measurement light beam I _diff is imaged onto a first detector via the first beam path with the first pinhole diaphragm (52) and the second lens (53); the elastically scattered light I _Scat is imaged onto a further detector via the second optical beam path with the third objective (54) and optionally at least one further optical element; and wherein the first optical beam path is imaged onto the first detector and the second optical beam path is imaged onto the further detector simultaneously. Method according to one of the preceding claims , characterized in that the entire intensity of the light I _WG (x _out, y) of the light guided in the waveguide is coupled out at location x _out in the waveguide through the decoupling grating (90). Method according to one of the preceding claims, characterized in that the decoupled light I _WG (x _out, y) is imaged onto a detector via at least one optical element. Method according to one of the preceding claims, characterized in that the light I _WG (x _out, y) coupled out is imaged on two detectors.

Images