WO2020057890A1

WO2020057890A1 - Sensor device

Info

Publication number: WO2020057890A1
Application number: PCT/EP2019/072449
Authority: WO
Inventors: Maximilian Amberger; Andreas Brenneis; Radoslav Rusanov; Robert Roelver
Original assignee: Robert Bosch Gmbh
Priority date: 2018-09-20
Filing date: 2019-08-22
Publication date: 2020-03-26
Also published as: DE102018216033A1

Abstract

The invention relates to a sensor device (100), comprising: a sensor material layer (105), which comprises at least one color center; an illumination apparatus (103) for optically exciting the at least one color center; and a detection apparatus (104) for detecting electromagnetic radiation that can be emitted by the at least one color center, wherein: the sensor device (100) comprises a first carrier element (101) and a second carrier element (102); the illumination apparatus (103) is arranged on the first carrier element (101) on a first side (101') facing the second carrier element (102); the detection apparatus (104) is arranged on the second carrier element (102) on a second side (102') facing the first carrier element (101); and the sensor material layer (105) is arranged between the illumination apparatus (103) and the detection apparatus (104).

Description

description

title

Sensor device

State of the art

US 2015/0192532 A1 shows an on-chip sensor which comprises a diamond layer with color centers and a diode laser which are applied to a common chip substrate.

Core and advantages of the invention

The use of nitrogen defect defect centers, also called nitrogen vacancy centers or NV centers, in diamond for measuring magnetic fields is a well-known measuring principle. It has been shown in the first basic experiments that NV centers with their high

Magnetic field sensitivity based on the Zeeman splitting of electronic spin states are suitable for use as highly sensitive magnetic field sensor systems. These days, elements such as light sources (e.g. laser light sources), microwave sources and light detectors are usually used in laboratory devices, e.g. Table laser sources, microscopes, table microwave source devices), which are large, expensive and not suitable for mobile applications. For a mass application, for example for industrial, consumer or automotive applications, is a

Sensor system required, which is approximately or maximum 1 cm ^{3 in} size,

is energy efficient and inexpensive.

The invention relates to a sensor device. An advantage of the invention is that a compact, energy-efficient and inexpensive sensor device is provided. This is achieved with a sensor device according to claim 1, wherein the sensor device comprises a sensor material layer. The

Sensor material layer comprises at least one color center. Furthermore, the sensor device comprises an illumination device for the optical excitation of the at least one color center and a detection unit for the detection of electromagnetic radiation which can be emitted by the at least one color center. The sensor device is characterized in that it comprises a first carrier element and a second carrier element, the illumination device being arranged on the first carrier element on a first side facing the second carrier element and the detection device on the second carrier element being on a second side facing the first carrier element Side is arranged. Furthermore, the sensor device is characterized in that the sensor material layer is arranged between the lighting device and the detection device. One advantage is that the sensor device can be manufactured in large numbers and using conventional construction and connection methods. Furthermore, the lighting device and the

Detection device is advantageously protected from external influences, which improves the robustness of the sensor device.

According to one embodiment, the sensor material layer can comprise diamond with at least one negatively charged nitrogen vacancy center. A negatively charged nitrogen vacancy center can be one

Nitrogen storage in a crystal lattice of the diamond and one to the

Nitrogen deposition adjacent defect in the crystal lattice, which has captured an additional electron. The negatively charged nitrogen vacancy center has a sensitivity to a magnetic field, as is also the case, for example, with a current-carrying conductor.

At least one excitation frequency (= irradiated microwave frequency) assigned to a local minimum of fluorescence (= incident microwave frequency) or a spectrum of an optically detected magnetic resonance of the diamond material shifts in proportion to a magnetic field strength of the magnetic field. The Magnetic field strength can, for example, easily be converted into a current strength that causes the magnetic field or another physical quantity that is connected to the magnetic field via a physical connection, for example using a predetermined processing rule.

A similar effect also occurs in silicon vacancy centers or SiV centers in silicon carbide (SiC). Here, too, a Zeeman splitting of individual, quantized energy levels can be detected by changes in the fluorescence at certain irradiated microwave frequencies, and a magnetic field strength can be determined thereon.

In addition to the exemplary color centers or vacancy centers shown here, other color centers, for example in SiC,

Diamond or boron nitride as a sensor material layer, especially for

Magnetic field measurement can be used via the Zeeman effect.

The optical excitation takes place in the sensor device by the

Lighting device, the lighting device for example an LED (light-emitting diode) and / or a surface emitter (VCSEL, English:

vertical-cavity surface-emitting laser).

The detection unit can comprise, for example, a radiation sensor. Semiconductor-based, for example, are suitable as radiation sensors

Detector elements, photodiodes, integrated photodiodes or bolometers.

Depending on a property of the electromagnetic radiation impinging on the radiation sensor, radiation sensors can output an electrical detection signal which is a measure of the radiation property. Radiation sensors can be, for example, an intensity or a

Energy flux density of the electromagnetic radiation coming from the sensor material layer or the at least one color center, for example the fluorescence of the sensor material layer or the at least one

Color center, detect. It is advantageous that the Zeemann splitting of the electronic states on which the measuring principle of the sensor device is based, for example for the NV center in diamond, is extremely high

Field strength range reacts linearly to external magnetic fields and the

Sensor device is therefore also suitable for precise measurement of electrical currents or other physical quantities that are directly or indirectly related to a magnetic field in an extremely large measuring range.

According to one embodiment, the sensor material layer comprises nitrogen defect defect centers in diamond, alternatively or additionally, the sensor material layer comprises silicon carbide with at least one fluorescent defect.

According to one embodiment, the sensor device is characterized in that the first carrier element and the second carrier element have a

Holding structure are spaced apart. An advantage is that the sensor material layer, the lighting device and the

Detection device are protected from external influences and thus a robust implementation of the sensor device is made possible. Furthermore, at least one through-contact can be provided in the holding structure, for example, which transmits electrical signals or currents (e.g. supply current for the lighting device or for the

Detection device) between the two support elements or the components of the sensor device arranged thereon. A very compact, small-sized and inexpensive construction of the sensor device can thus advantageously be realized.

For example, the first carrier element and / or the second

Carrier element can be designed as a carrier plate or carrier layer.

A printed circuit board, also called a printed circuit board, is a carrier for electronic components. It can be used for mechanical fastening and / or electrical connection of components. Printed circuit boards can, for example, be a board comprise electrically insulating material with adhering, conductive connections, so-called conductor tracks. Can be used as an insulating material

For example, fiber-reinforced plastic or hard paper can be used.

The conductor tracks can, for example, be etched from a thin layer of copper. The components that are to be applied to the printed circuit board are soldered on soldering pads (pads) or in pads. In this way, they are mechanically held and electrically connected to these “footprints” at the same time. Examples of printed circuit boards include one-sided, two-sided

Printed circuit boards or multilayer printed circuit boards.

According to a further embodiment, the first carrier element, the second carrier element and / or the holding structure comprise at least one printed circuit board.

An advantage is that PCB-based assembly and connection methods can thus be used in the manufacture of the sensor device. This makes it possible to manufacture large quantities (good scalability) at low costs. In addition, the PCB technology allows the strong

Integration (small size) of commercially available and therefore inexpensive elements, such as B. itself not packaged, d. H. non-packed elements, such as bare-die, as a light source,

Microwave source chip, light detector, etc., so that cost-intensive single-die or hybrid integration is not required. I.e. it is not a separate assembly and connection technology for the manufacture of the sensor device

Components (lighting device, microwave source, possibly optical elements, detection unit, etc.) necessary. Furthermore, for example, microwave antenna elements can also be arranged on the at least one printed circuit board. This not only enables the realization of small-scale, inexpensive sensor devices, but also the protection of the components arranged on the printed circuit boards from external influences. The use of a PCB-based connection and

Construction technology is not only limited to the use of NV centers in diamond sensor material layers, but can also be used in other similar systems. Eg with electrically excited, fluorescent defects in SiC or the systems mentioned above. If a printed circuit board is used as the holding structure, it can have cutouts and thus form a cavity together with the first carrier element and in the second carrier element. Furthermore, the

Holding structure can be realized in a simple manner, a forwarding of electrical signals and electrical currents between the first carrier element and the second carrier element.

In one embodiment, the sensor device comprises a

Microwave generating device for loading the

Sensor material layer with microwave radiation. The

Microwave generating device can, for example, on the first

Carrier element or the second carrier element may be arranged. The

Microwave generation device can comprise, for example, a microwave source chip and at least one microwave guide structure, which couples the microwave radiation into the sensor material layer. Furthermore, the microwave generating device for microwave excitation of the color centers of the sensor material layer can lead between the

Microwave source chip and the at least one microwave antenna. An advantage is that the sensor device can thus be built in a very compact manner and the microwave generating device can be protected against disturbing influences from the environment.

In one embodiment, the microwave generating device can have a first microwave guide structure on the first carrier element and a second one

Include microwave guide structure on the second carrier element, which are arranged in the form of a Helmholtz coil arrangement and are used to couple the microwave radiation into the sensor layer. One advantage is that a homogeneous microwave field can thus be generated between the first carrier element and the second carrier element in the region in which the sensor material layer is arranged, and thus the reliability and

Sensitivity of the measurement results of the sensor device can be increased.

According to one embodiment, the sensor device comprises a

Evaluation device, the evaluation device on the first Carrier element or the second carrier element is arranged. The

Evaluation device can include, for example, a microcontroller or a microcontroller chip. This can be used, for example, to control individual components, such as the lighting device and / or the

Detection device. As an alternative or in addition, the evaluation device can be set up to receive signals from the

Detection device come to evaluate. For example, an electrical signal, which is a measure of the electromagnetic radiation emitted by the sensor material layer, can be evaluated. In particular, the microwave frequency can be determined at which a minimum in

Signal curve, which includes, for example, an application of a variable (eg intensity) representing the electromagnetic radiation above the microwave frequency, occurs. By means of, for example, a characteristic curve, the change of the position of the minimum relative to a reference value or based on the distance between two minima in the signal curve can be used to determine the characteristic curve

Magnetic field strength can be determined. The result can be from the

Evaluation device are output or transmitted to an output unit, such as a display. As an alternative or in addition, the evaluation device can comprise a communication interface in order to transfer data from the sensor device to a unit external to the sensor device, such as a cloud or one relating to the

Sensor device external computing device or an external evaluation device related to the sensor device. In particular, the evaluation device can be arranged on the first carrier element on the same side (first side) as the lighting device or on the second carrier element on the same side (second side) as the detection unit.

According to one embodiment, at least one optical filter is applied to the sensor material layer. One advantage is that a very compact sensor device can thus be implemented. The at least one optical filter can be in the beam path between the lighting device and the sensor material layer and / or in the beam path between the

Sensor material layer and the detection device can be arranged. Alternatively or in addition, the lighting device and / or the detection device can comprise at least one optical filter.

Alternatively or additionally, the at least one optical filter can be a separate component in the beam path between the lighting device and the

Sensor material layer and / or in the beam path between the

Sensor material layer and the detection device can be arranged.

An advantage of an optical filter in the beam path between the

Illumination device and the sensor material layer is that the wavelength of the electromagnetic radiation for optical excitation can thus be controlled or fixed.

An advantage of the at least one optical filter in the beam path between the sensor material layer and the detection device is that the light coming from the lighting device can thus be filtered out, so that only the electromagnetic radiation (fluorescence) emitted by the sensor material layer is detected by the detection device. The reliability and the accuracy of the measurement with the sensor device can thus be increased.

Colored glasses that selectively transmit only the fluorescent light and absorb the excitation light (position of the filter between the sensor material layer and detection device) or a portion of the excitation light that is in the red spectral range (wavelength l> 650 nm) can be used as the material for the filters (Position of the filter between

Illumination device and sensor material layer). Dielectric filter layers (also called Bragg reflector or distributed bragg reflector [DBR]) are also suitable. These are made up of alternating thin dielectrics. The reflection and transmission behavior can be set in a targeted manner from the choice of the respective layer thickness and the alternating indices. Another advantage of these dielectric filter layers is that they can be applied directly to the sensor material layer. This advantageously reduces the overall volume of the entire sensor and reduces the AVT effort. In addition, such scalable technology can save costs.

Brief description of the drawings

Embodiments of the invention are shown in the drawings and are explained in more detail in the following description. Same

Reference symbols in the figures denote identical or equivalent functions

Elements.

Show it

Figure 1 is a schematic representation of a nitrogen defect in a diamond grid.

Figures 2 to 7 energy schemes and diagrams for fluorescence properties according to embodiments; and

8 shows a schematic sectional illustration of a sensor device according to an exemplary embodiment.

Embodiments of the invention

Fig. 1 shows a schematic representation of a nitrogen vacancy 1002 in diamond 1000. In diamond 1000, the carbon atoms 1001 are tetrahedral, i. H. each carbon atom 1001 has four symmetrically aligned bonds to its closest neighboring carbon atoms 1001. A nitrogen vacancy 1002 results from the replacement of a carbon atom 1001 by a nitrogen atom 100, one directly adjacent

Carbon atom 1001 missing in diamond lattice 1000 (Vacancy 1003) A negatively charged nitrogen vacancy has captured an additional electron.

Figures 2, 4, 6 show energy schemes and Figures 3, 5, 7 the associated diagrams of fluorescence properties depending on the the color center acting magnetic field and the frequency of the irradiated microwave field according to an embodiment.

For example, nitrogen vacancies in diamond and silicon vacancy centers (SiV centers) in silicon carbide (SiC) exhibit an energy spectrum shown in the diagram or energy diagram 200 shown in FIG. 2

Room temperature. In the normal state, i.e. H. without microwaves and without a magnetic field, a nitrogen defect shows one with optical excitation

Fluorescence in the red wavelength range or at a wavelength of 630 nm.If microwave radiation 430 or high-frequency signal 430 is radiated in addition to the optical excitation by excitation light 210, the fluorescence will collapse at approx.2.88 GHz, since the

In this case, electrons are raised from the level ms = ± 1 of state ³ A to the level ms = ± 1 of state ³ E and recombine from there in a non-radiative manner. In the case of an external magnetic field, the level ms = ± 1 is split (Zeeman splitting), and when the fluorescence is plotted against the frequency of the microwave excitation, two minima, for example wi and w ₂ , appear in the fluorescence spectrum, the frequency spacing of which is proportional to the magnetic one Field strength B is. A magnetic field sensitivity or magnetic field resolution is achieved by a minimally resolvable one

Frequency shift defined and can reach up to 1 pT or 1 pT / VHz.

Diamond or boron nitride, in particular for magnetic field measurement using the Zeeman effect. Here, too, a Zeeman splitting of individual, quantized energy levels can be detected by changes in the fluorescence at certain irradiated microwave frequencies.

2 shows an energy diagram 200 without high-frequency signal excitation or

Microwave excitation and without magnetic field excitation, whereby excitation light hv 210, a fluorescence signal 220 and three states ³ A, ³ E and ¹ A as well as energy levels ms = 0 and ms = ± 1 are shown for the states ³ A and ³ E electrons. FIG. 3 shows a diagram 300 relating to the energy scheme shown in FIG. 2. In the diagram 300 there is an example on the abscissa axis 302

Microwave frequency in megahertz (MHz) and a fluorescence in arbitrary units is plotted on the ordinate axis 304. In addition, four characteristic curves or graphs 310, 312, 314 and 316 are shown by way of example in FIG. 3, which represent a fluorescence profile for magnetic fields of different strengths, an arrow 306 parallel to the ordinate axis 304 symbolizing that the magnetic field B acting on the system is at the bottom in diagram 300

the first graph 310 entered increases to the top fourth graph 316 entered in the diagram 300. The first graph 310 is sketched for a magnetic field with the strength 0, B = 0; the second graph 312 is sketched for a magnetic field with a strength of 2.8 mT; the third graph 314 shows a fluorescence signal in a magnetic field with the strength of 5.8 mT; the fourth graph 316 represents a fluorescence signal with the strength of an applied one

Magnetic field of 8.3 mT. Minima of the fluorescence signal are designated wi and w ₂ for the second graph 312 only as an example. A

Mark 320 on the first graph 310 marks the parameter combination of the energy scheme shown in FIG. H. without magnetic field (B = 0) and a microwave frequency f ^ 2.9GHz.

If, as shown in the energy diagram in FIG. 4, radiation 430 is emitted in addition to the optical excitation, as shown in FIG. 5 by the marking 520, the fluorescence collapses, since in this case the electrons are from the microwave radiation from the m _s = 0 level to the m _s = + - 1 level of state ³ A and raised to the level ms = ± l of state ³ E by means of laser radiation and recombine from there without radiation.

5 shows a diagram 500 relating to the energy scheme from FIG. 4. The diagram 500 in FIG. 5 corresponds to the diagram from FIG. 3 except for the marking 520. The marking 520 on the first graph 310 marks the

Parameter combination of the energy scheme shown in Fig. 4, i. H. without magnetic field (B = 0) and with a microwave frequency of f = 2.9GHz. The

Marking 520 is arranged in the minimum of the first graph 310. As shown in Fig. 6, it occurs in the presence of an external one

Magnetic field for splitting the m _s = + - 1 level (Zeeman splitting) and it shows up when the fluorescence is plotted over the frequency of the

Microwave excitation (see diagram Fig. 7) two minima wi and w ₂ in

Fluorescence spectrum. The minima are marked by way of example in the second graph 312 in FIG. 7 by the markings 720 and 725. The frequency spacing of the minima is proportional to the magnetic field strength of the external magnetic field. The magnetic field sensitivity is defined by the minimally resolvable frequency shift and can reach a few rTL / Hz.

This method for measuring magnetic field strength is also referred to as ODMR (Optically Detected Magnetic Resonance). If the microwave frequency corresponds to the energy gap between the state ³ A ms = 0 and the level ms = ± 1, the fluorescence collapses. With an external magnetic field the level splits ms = ± 1 and there are two defined microwave frequencies at which the fluorescence decreases or minima are present. The frequency spacing is proportional to the magnetic field B.

8 shows a schematic cross-sectional illustration of a sensor device 100 according to an exemplary embodiment. The sensor device 100 comprises a first carrier element 101 and a second carrier element 102, which are spaced apart from one another by means of a holding structure 108. The first carrier element 101, the second carrier element 102 and the holding structure 108 delimit a cavity in which an illumination device 103, a detection device 104, a sensor material layer 105 and optical filters 1061, 1062 as well as a microcontroller 110 and a microwave generating device 107 are arranged. The lighting device 103 is arranged on a first side 10T of the first carrier element 101 facing the second carrier element 102. Furthermore, a microwave source 1070 and a first microwave guide structure 1071, which in this exemplary embodiment is arranged around the lighting device 103, are arranged on the first side 10T. The detection device 104 is on the first carrier element 101 facing second side 102 'of the second support member 102. Furthermore, the microcontroller 110 and a second microwave conductor structure 1072, which in this exemplary embodiment is arranged around the detection device 104, are arranged on the second side 102 ′. The

In this exemplary embodiment, microwave guide structures 1071, 1072 and the microwave source 1070 form the microwave generating device 107.

The sensor material layer 105 with the at least one color center is arranged between the illumination device 103 and the detection device 104. Between the sensor material layer 105 and the

In this exemplary embodiment, lighting device 103 is arranged a first optical filter 1061. This first optical filter 1061 can be used to increase the wavelength of the excitation light irradiated by the illuminating device 103 onto the sensor material layer 105

control or fix. The first optical filter 1061 can be applied to a surface of the sensor material layer 105 facing the illuminating device 103, arranged on the illuminating device 103 or encompassed by the illuminating device 103. Between the

Detection device 104 and the sensor material layer 105, a second optical filter 1062 is arranged, which filters out the radiation emitted at the illuminating device 103, so that only the light (fluorescent light) emitted by the sensor material layer 105 enters the detection device 104 and is detected. The second optical filter 1062 can be on one of the

Detection device 104 facing surface of the sensor material layer 105 may be applied, arranged on the detection device 104 or be included in the detection device 104.

A printed circuit board can be used as the holding structure 108, which can have cutouts in the region of the cavity, for example. The holding structure 108 serves as a spacer between the first carrier element 101 and the second carrier element 102. Furthermore, the holding structure 108 can serve to transmit electrical signals and currents between the carrier elements 101, 102. Furthermore, the holding structure 108 can be used to form feedthroughs 108 (vias) between the carrier elements 101, 102. The first carrier element 101 and the second carrier element 102 can be embodied as printed circuit boards (PCB elements).

In other words, FIG. 8 shows the sensor device 100 produced using PCB-based production methods and in particular the placement of the sensor material layer 105 together with the corresponding optical filters 1061, 1062 between the light source 103 and the photodetector 104, the light source 103 and the photodetector being two directly opposite PCBs 101, 102 are attached. A third PCB 108, partially with

Recesses, forms a cavity between the first PCB 101 and the second PSB and serves as a spacer and for forwarding the electrical signals between the two PCBs 101, 102. The realization of

Microwave antenna elements 1071, 1072 on the PCBs are possible. The sensor material layer 105, for example diamond with NV centers, is placed between the photodetector 104 and the light source 103, which are each located on one of two PBC elements 101, 102. Between the diamond 105 and the photodetector 104 there is a second optical filter 1062, which filters out the light from the source, so that only the fluorescent light from the sensor material layer 105 can be detected. A first optical filter

1061 is optionally located between the diamond and the light source 103 to control the wavelength of the excitation light. The optical filters 1061,

1062 can be located on the surface of the sensor material layer 105 or on the photodetector 104 and / or the light source 103. The holding structure 108 (preferably PCB) between the first PCB 101 and the second PCB 102 serves to set the correct distance between the light source 103 and the photodetector 104 so that the sensor material layer 105 with the optical filters 1061, 1062 fits between them. The sensor material layer 105 and the detection device 104 and / or the sensor material layer 105 and the lighting device 103 are preferably in mechanical contact with one another directly or via the optional optical filters 1061, 1062. The

The holding structure 108 or the third (PCB) element can be used to form feedthroughs 108 (vias) between the two other PCBs 101, 102. In particular, a microwave source chip 1070 can also be integrated on one of the PCBs 101, 102, 108, together with leads to and from at least one of the microwave antennas 1071, 1072 for microwave excitation of the at least one color center of the sensor material layer 105, for example NV centers in the diamond. In order to generate a homogeneous microwave field, the microwave antennas 1071, 1072 can be implemented on the mutually opposite first and second PCB elements 101, 102 (Helmholtz coils). In addition, the integration of the microcontroller

Chips 1 10 for controlling the individual components, evaluating the signals and communicating externally on one of the PCBs 101, 102, 108 are possible.

Claims

Expectations

1. Sensor device (100) comprising

A sensor material layer (105) which comprises at least one color center,

• a lighting device (103) for optical excitation of the

at least one color center and

A detection device (104) for detecting an electromagnetic radiation emitted by the at least one color center, characterized in that

• That the sensor device (100) comprises a first carrier element (101) and a second carrier element (102), the lighting device (103) on the first carrier element (101) on one of the second

Carrier element (102) facing first side (10T) is arranged and wherein the detection device (104) on the second carrier element

(102) is arranged on a second side (102 ') facing the first carrier element (101), and

• that the sensor material layer (105) between the

Lighting device (103) and the detection device (104) is arranged.

2. Sensor device (100) according to claim 1, characterized in that the sensor material layer (105) comprises nitrogen defect defect centers in diamond and / or silicon carbide, comprising at least one fluorescent defect.

3. Sensor device (100) according to one of the preceding claims,

characterized in that the first carrier element (101) and the second carrier element (102) are spaced apart from one another by a holding structure (108).

4. Sensor device (100) according to one of the preceding claims,

characterized in that the first carrier element (101), the second Carrier element (102) and / or the holding structure (108) comprise at least one printed circuit board.

5. Sensor device (100) according to one of the preceding claims,

characterized in that the sensor device a

Microwave generating device (107) for loading the

Includes sensor material layer (105) with microwave radiation.

6. Sensor device (100) according to claim 5, characterized in that the microwave generating device (107) is arranged on the first carrier element (101) or the second carrier element (102).

7. Sensor device (100) according to claim 5 or 6, characterized in that the microwave generating device (107) a first

Microwave guide structure (1071) on the first support element (101) and a second microwave guide structure (1072) on the second support element (102), which are arranged in the form of a Helmholtz coil arrangement.

8. Sensor device (100) according to one of the preceding claims,

characterized in that the sensor device (100) has a

Evaluation device (1 10), wherein the evaluation device (1 10) is arranged on the first carrier element (101) or the second carrier element (102).

9. Sensor device (100) according to one of the preceding claims,

characterized in that at least one optical filter (1061, 1062) is applied to the sensor material layer (105).

10. Sensor device (100) according to one of the preceding claims,

characterized in that the lighting device (103) and / or the detection device (104) comprise at least one optical filter (1061, 1062).

1 1. Sensor device (100) according to one of claims 9 or 10, characterized

characterized that in the beam path between the

Illumination device (103) and the sensor material layer (105) and / or in the beam path between the sensor material layer (105) and the Detection device (104) which has at least one optical filter (1061, 1062) arranged.