EP3797273A1

EP3797273A1 - Optical arrangement for a spectroscopic imaging method and spectroscopic imaging method

Info

Publication number: EP3797273A1
Application number: EP19726933.5A
Authority: EP
Inventors: Gregor Matz; Bernhard Messerschmidt
Original assignee: Grintech GmbH
Current assignee: Grintech GmbH
Priority date: 2018-05-22
Filing date: 2019-05-20
Publication date: 2021-03-31
Also published as: US11448551B2; WO2019224146A1; US20210215535A1; DE102018112253A1

Abstract

The invention relates to an optical arrangement for a spectroscopic imaging method, comprising a multi-core fibre (7), which has at least one first fibre core (1) for guiding a first illuminating light and a second fibre core (2) for guiding a second illuminating light, and a wavelength-dispersive beam-combining element (12), which is designed to spatially superpose the first illuminating light and the second illuminating light in an object space (14). A spectroscopic imaging method comprising the optical arrangement is also described.

Description

description

Optical arrangement for a spectroscopic imaging method and spectroscopic imaging method

The application relates to an optical arrangement for a spectroscopic imaging method. Furthermore, the application relates to a spectroscopic imaging method in which the optical arrangement is used.

This patent application claims the priority of German Patent Application 10 2018 112 253.5, the disclosure of which is hereby incorporated by reference.

The optical arrangement can be used in particular for a

be provided for the endoscopic probe

spectroscopic imaging on bulky samples, e.g. B.

living biological tissue. As an imaging method, in particular a non-linear,

in particular, coherent anti-Stokes Raman scattering (CARS, Coherent anti-Stokes Raman scattering) or stimulated Raman scattering (SRS, stimulated Raman scattering). To enable this modality, two high peak intensity and different frequency light pulses must be simultaneously superimposed at the same location in the sample.

From the document US Pat. No. 7,414,729 B2 an endoscopic probe for CARS spectroscopy is known in which the

Illuminating light of two different wavelengths, the pump and Stokes wavelength, are passed through the same optical fiber to the sample. In guiding the pump and Stokes wavelength in a single fiber, the problem may arise that the

simultaneous superposition of the high-intensity light pulses leads to a non-linear four-wave mixing process in which light is generated which has the same optical frequency as the signal to be measured of the sample. Achieve this high-intensity, non-resonant underground to

examining sample, it is no longer possible to distinguish it from the low-intensity signal of the sample to be measured. Therefore, it is imperative to have a

Short-pass filter or bandpass filter to put in the beam path, which is optically opaque to the non-resonant ground and passes only the pump and Stokes wavelength to the sample. However, it can be concluded that also the CARS signal from the sample can not be collected by the same beam path from the sample to the fiber, which requires a second beam path for the collection of the sample signal with the anti-Stokes wavelength and thus the

Miniaturization of the system sets limits.

The invention is in one aspect the object of an optical arrangement for a spectroscopic

specify imaging method, which avoids the problem of the occurrence of a non-linear four-wave mixing process and at the same time has a compact design. Furthermore, a spectroscopic imaging method is to be given, which makes use of the optical arrangement.

These objects are achieved by an optical arrangement for a spectroscopic imaging method and a

spectroscopic imaging method according to independent claims solved. Advantageous embodiments are the subject of the dependent claims.

In accordance with at least one embodiment, the optical arrangement for a spectroscopic imaging method comprises a multicore fiber which has at least one first fiber core for guiding a first illumination light and a second fiber core for guiding a second illumination light. The fiber is designed in particular as a double-core fiber and can thus advantageously simultaneously guide the first illumination light and the second illumination light, the first illumination light and the second illumination light

Illumination light in particular have different wavelengths. The fiber cores preferably have different diameters and / or different materials. In this way, the Singlemodigkeit and at the same time a good light guide for each wavelength can be ensured.

For scanning the object space, the multi-core fiber has one according to an embodiment of the optical arrangement

Fiber scanner for the deflection of the multi-core fiber. Of the

Fiber scanner can be designed for example as a piezo scanner. According to an alternative embodiment follows the

Multi-core fiber after a mirror scanner. The mirror scanner can be designed in particular as a MEMS scanner. Through the fiber scanner or the mirror scanner, a time-dependent beam deflection is realized, which allows the imaging.

Furthermore, the optical arrangement comprises a

wavelength-dispersive beam combining element configured to spatially and angularly confine the first illuminating light and the second illuminating light in an object space overlap. The optical arrangement can be part of a microscopic arrangement, in particular the

optical arrangement be integrated into an endoscopic probe that is part of a fiber optic endomicroscope.

Characterized in that the first illumination light and the second illumination light in the optical arrangement by

different fiber cores of the multi-core fiber are guided, a non-linear four-wave mixing process, which can occur in the light guide of both wavelengths in the same fiber, is advantageously prevented. At the same time

advantageously no further beam path in a second fiber is required, so that the optical arrangement can have a particularly compact construction.

The spectroscopic imaging method for which the optical arrangement is provided may be in particular CARS spectroscopy or SRS spectroscopy. In the method, two light pulses of the first illumination light and the second illumination light having different wavelengths are simultaneously superimposed on the same location of a sample in the object space.

In the first fiber core, in particular, the first

Illumination light of the pump wavelength and guided in the second fiber core, the second illumination light of the Stokes wavelength. By separately guiding the pump wavelength and the Stokes wavelength in the two fiber cores, the undesirable four-wave mixing process becomes sufficient

suppressed. The first illumination light and the second

Lighting light are in particular of a

Laser light source generated and in one of the object space opposite end of the multi-core fiber coupled. Of the

Frequency difference of the two wavelengths is advantageous so to be detected molecular trinsische

Vibration vibration of the sample tuned that he coherently drives them and leads to the emission of a third wavelength, the anti-Stokes wavelength, for the

spectroscopic imaging is used. Furthermore, the principle presented allows simultaneous imaging

additional nonlinear imaging processes such as

Higher Harmonic Microscopy and Multiphoton Fluorescence Microscopy.

According to an advantageous embodiment that is

wavelength-selective beam combining element between the fiber scanner or the mirror scanner and the object space arranged. In this case, the first illumination light and the second illumination light are deflected to scan the object space before passing through the wavelength-selective

Beam union element, such as a grid or a prism, are combined. The first illumination light and the second illumination light are deflected by the fiber scanner or the mirror scanner in particular in the same way, wherein the following wavelength-selective

Beam union element is advantageously unmoved.

In one embodiment, a collimating lens is disposed between the fiber scanner or the mirror scanner and the wavelength-selective beam combining element. The collimating lens may be a one-piece or multi-part lens. In a preferred embodiment, the collimating lens comprises a gradient index lens (GRIN lens).

For the beam combination of the first and second

Lighting light by means of the wavelength-selective Beam unification element, it is advantageous if an at least approximate collimation of the illumination lights of both wavelengths before the wavelength-selective

Beam union element takes place. From a local

Offset of the first and second illumination light during

Exit from the multi-core fiber, for example, by means of the collimating lens, an angular offset can be generated. The wavelength-selective beam combination element is advantageously located in the Fourier plane of the imaging optics behind the fiber scanner or mirror scanner, that is, in particular behind the collimating lens.

The optical arrangement described here allows a very good diffraction-limited imaging quality for the CARS imaging over a comparatively large field of view based on the overall diameter of the optical arrangement.

In particular, higher-order aberrations that could limit the usable image field are largely avoided by the optical arrangement.

According to an advantageous embodiment of the optical

Arrangement, the multi-core fiber contains a light-conducting jacket for guiding a coming out of the object space

Obj ectlichts, wherein the photoconductive sheath is surrounded by an outer sheath, the lower one

Refractive index has as the photoconductive sheath. In the multi-core fiber, not only the

Illumination light in the direction of the object space, but advantageously also the object light to be detected in

opposite direction led to an evaluation unit.

According to an advantageous embodiment, the multi-core fiber has an inner jacket, in which the fiber cores are arranged, wherein the inner jacket is surrounded by the photoconductive jacket. The inner jacket advantageously has a lower refractive index than that

Fiber cores and a lower refractive index than the photoconductive sheath on. In particular, a single-mode light-conducting property of the two fiber cores can be achieved by the inner jacket. The inner coat can

in particular be doped with fluorine. The light-conducting

Coat, between the inner coat and the outer coat

Sheath is arranged and has a higher refractive index can be used efficiently for collecting the object light.

The fiber cores of the multi-core fiber are preferably made

Quartz glass formed. The inner cladding and outer cladding of the multicore fiber may be doped with a dopant

For example, be fluorine doped to lower the refractive index. The photoconductive jacket preferably comprises pure quartz glass or, for increasing the refractive index, is doped with a dopant suitable thereto, e.g. Doped germanium oxide.

According to an advantageous embodiment, the multicore fiber is a polarization-maintaining fiber. In order to obtain the polarization-conserved property, the multicore fiber may in particular contain voltage-generating elements which generate a permanent voltage by generating a permanent voltage

cause birefringent property. The

For example, voltage-generating elements may

be bar-shaped.

According to a further embodiment of the multi-core fiber, the fiber cores are arranged asymmetrically in the multi-core fiber. In particular, the fiber cores in this embodiment are arranged asymmetrically to the center of the multi-core fiber. For example, the fiber cores may have different distances from the center of the multi-core fiber. Furthermore, the fiber cores may be arranged one behind the other in the same radial direction as viewed from the center of the multi-core fiber. Depending on how strong this is

Detecting object light from the sample in the wavelength of the wavelengths of the guided in the fiber cores

Illuminating light differs, the object light is deflected by the wavelength-dispersive beam combination element, so that it is not centric on the

Fiber end face meets. As a result, the collection efficiency of the fiber for the object light can be impaired. For this reason, it may be advantageous to dispose the fiber cores asymmetrically in the multicore fiber, in particular eccentrically to the photoconductive jacket.

The wavelength dispersive beam combining element of the optical arrangement may have various configurations

respectively. The beam combination element can in particular be a diffraction grating, for example a

Reflection diffraction grating or transmission diffraction grating. In one embodiment, this is

Beam unification element a reflection diffraction grating, so that the optical axis is angled to the object space.

Alternatively, the beam combining element may comprise at least one prism or grating prism (GRISM), wherein the

Grid prism is a combination of a diffraction grating and a prism. In a further embodiment, the beam combining element is a multiple prism, the optical axis preferably not changing its direction. It is also possible that the beam combining element a Prism or a multiple prism is and changes the direction of the optical axis in the direction of the object space targeted. For example, the wavelength dispersive beam combining element may be disposed between the fiber scanner or mirror scanner and the object space. Alternatively, the

Wavelength dispersive beam combining element between the multi-core fiber and the mirror scanner to be arranged.

The optical arrangement may be in addition to those hitherto

components described contain other elements. In one embodiment, the optical assembly includes

For example, the fiber scanner, a gradient index lens (GRIN lens), the wavelength-sensitive deflecting element and a front lens group facing the object space, the

For example, a spherical achromat, a biconvex lens and a plano-convex lens. In another embodiment, the optical arrangement includes a

Mirror scanner, a GRIN lens, a deflection prism, a spherical meniscus lens, a spherical achromatic lens, the wavelength-sensitive deflection element and a

Front lens group, for example, a spherical

Achromat, a biconvex lens and a plano-convex lens has.

The numerical aperture of the multicore fiber is

preferably between 0.05 and 0.4. The numerical aperture of the optical arrangement to the object space is preferably between 0.2 and 1.1.

According to an advantageous embodiment, the optical arrangement has a diameter of less than 5 mm. The small diameter is made possible in particular by the fact that the optical arrangement between the multi-core fiber and the object space only one beam path for the

Has illumination light and the object light to be detected.

The invention furthermore relates to an endoscopic probe which contains the optical arrangement. The

Endoscopic probe may be part of a fiber optic endomicroscope, in particular the fiber optic

Probe, an illumination light source for generating the first and second illumination light and an evaluation unit.

In the spectroscopic imaging method according to the principle proposed herein, a first

Led illumination light in a first fiber core of a multi-core fiber and a second illumination light in a second fiber core of the multi-core fiber, wherein the first

Illumination light and the second illumination light

have different wavelengths. The first

Illumination light and the second illumination light are spatially superimposed by a wavelength-dispersive beam combination element in an object space. That from the

Object space coming object light is guided in a light-conducting jacket of the multi-core fiber in the direction of an evaluation.

In the method, the multi-core fiber is advantageously integrated into a fiber scanner which moves the fiber perpendicular to the fiber

Discharges exit direction of the light, or the multicore fiber follows a mirror scanner, wherein the object space is scanned by the movement of the fiber scanner or the mirror scanner. In this case, between the multi-core fiber and the object space advantageously only a single optical Beam path formed in which the first and second

Illumination light are guided in the direction of the object space, and in which the object light in the opposite direction to

Multi-core fiber is guided. In particular, the spectroscopic imaging method may be CARS spectroscopy or SRS spectroscopy, wherein the first illumination light has the pump wavelength and the second illumination light has the Stokes wavelength.

Further advantageous embodiments of the method will become apparent from the description of the optical arrangement and

vice versa .

The invention will be described below with reference to

Embodiments in connection with the figures 1 to 10 explained in more detail.

Show it:

1A is a schematic representation of a cross section through a first example of the multi-core fiber,

Figure 1B is a schematic diagram of the

Refractive index profile in the multi-core fiber according to the first example,

Figure IC is a schematic diagram of the

Refractive index profile in another example of the

Multi-core fiber,

Figure ID is a schematic representation of a cross section through another example of the multi-core fiber, Figures 2 to 10 are each a schematic representation of a cross section through an example of the optical arrangement.

Identical or equivalent components are each provided with the same reference numerals in the figures. The

Components shown and the proportions of the components with each other are not to be regarded as true to scale.

The optical arrangement and the method according to the principle proposed here are based in particular on

Use of a multi-core fiber with multiple sheaths, especially a dual-core double-sheath fiber. An example of a multi-core fiber 7 is shown in FIG. 1A. FIG. 1B schematically shows the course of the refractive index n over the cross section of the multicore fiber in the direction x, which is shown in FIG. 1A.

The multi-core fiber 7 has two fiber cores 1, 2. The first fiber core 1 carries a first illumination light, in particular the light of the pump wavelength for CARS spectroscopy or SRS spectroscopy. The second fiber core 2 carries a second illumination light having a wavelength different from the wavelength of the first illumination light, in particular the light of the Stokes wavelength for CARS spectroscopy or SRS spectroscopy.

Both fiber cores 1, 2 preferably have different diameters or materials in order to ensure singlemodidity and, at the same time, good light guidance for the respective wavelength. In addition, if the fiber cores 1, 2 are made of undoped quartz glass, this reduces unwanted multiphoton intrinsic fluorescence in the fiber and thus ensures better contrast, for example, for multiphoton fluorescence microscopy.

These two fiber cores 1, 2 are advantageously embedded in a fluorine-doped inner shell 3, which has a

has lower refractive index than the two fiber cores 1, 2. In this way, in particular a single-mode light conduction property of the two fiber cores 1, 2 can be achieved. Radially outside the inner shell 3 is followed by a middle jacket, which functions as a light-conducting jacket 4 for the object light to be detected in the optical arrangement. The light-conducting jacket 4 has a higher refractive index than the inner jacket 3 and is therefore light-conducting. The photoconductive jacket 4 can be efficiently used for integrally collecting the object light, for example the CARS, SHG or fluorescence signal of a sample, which is generated in a non-linear imaging process.

The photoconductive jacket 4 is surrounded by an outer jacket 5, which has a lower refractive index than the

having light-conducting jacket 4 and thus allows the light conduction of the object light generated in the photoconductive jacket 4.

The multi-core fiber 7 is preferably one

polarization-maintaining fiber. A polarization maintaining fiber is advantageous for a nonlinear imaging process because the use of polarized light minimizes the required peak intensity and thus reduces damage to the object to be examined. The

polarization-maintaining property of the multi-core fiber 7 can in particular by the insertion of voltage-generating Elements 6 can be achieved, which is an asymmetric

Cause light conduction property of the fiber cores 1, 2.

Figure IC shows the refractive index profile in one

alternative embodiment of the multi-core fiber. This

Embodiment of the multi-core fiber contains no internal

Cloak 3. The light pipe in the fiber cores 1, 2 is realized by the higher refractive index with respect to the photoconductive jacket 4, which is realized for example with the aid of a dopant such as germanium.

In Figure ID is another possible embodiment of

Multi-core fiber 7 shown. In this example, the two fiber cores 1, 2 are arranged asymmetrically in the multi-core fiber 7, in particular eccentrically to the photoconductive

Sheath 4. This arrangement of the fiber cores 1, 2 is

Especially advantageous if the object light to be detected by the wavelength dispersive

Beam union element 12 is deflected so that it does not hit the fiber end face centric.

A first example of the optical arrangement for a

spectroscopic imaging method is shown in FIG. In the spectroscopic imaging method, for example, the light of a

Spectrally divided and separately as first illumination light and second illumination light into the fiber cores 1, 2 of the illumination light source

Multi-core fiber 7 coupled. The multi-core fiber 7 emits the light of the two wavelengths with a certain NA and a spatial offset corresponding to the distance between the first fiber core 1 and the second fiber core 2. A subsequent collimating lens 11 leads to a

approximate collimation of the illumination light of both

Wavelengths. The local offset at the fiber exit here becomes a wavelength-specific angular offset, which is then of a laterally wavelength-dispersive

Beam union element 12 is spatially and angularly superimposed. A subsequent front lens group 13 now focuses the beams of the illumination light with a sufficiently high NA in the object space 14 to those for the

Imaging processes required phase matching conditions and necessary peak intensities to meet. The im

Object space generated to be detected object light can

in particular an antistokes signal, a second harmonic generation (SHG) signal and / or a two-photon fluorescence (TPF) signal. The object light is returned in the optical arrangement on the same beam path and integrally aufgesamme11 of the photoconductive jacket of the multi-core fiber 7.

The distal end of multicore fiber 7 is provided with a fiber scanner (not shown) in the example of Figure 2 to deflect the multicore fiber. By a lateral deflection of the fiber end face, z. B. by a piezo fiber scanner or other suitable method, the object space 14 is scanned in accordance with the magnification of the optical arrangement. By coincident movement of the photoconductive jacket of the multi-core fiber 7, it functions as a quasi-confocal optical detector for the signal emitted by the sample in volume around the excitation spot. Depending on how big and with which numerical aperture the

photoconductive sheath 4 of the multi-core fiber 7 is designed, the confocality can be influenced. For a high

Collection efficiency should the middle photoconductive sheath 4th the multicore fiber 7 be as large as possible, so that the volume around the excitation spot, in which the

detecting object light is scattered by the

photoconductive jacket is detected.

Depending on the extent to which the object light of the sample to be detected differs in wavelength from the wavelengths of the illumination light guided in the fiber cores 1, 2, the object light is also deflected by the wavelength-dispersive beam combination element 12 so that it does not strike the fiber end face centrically. Thereby, the collection efficiency of the multi-core fiber 7 for the object light can be impaired. Therefore, it may be advantageous, the area of the two fiber cores 1 and 2 eccentrically to

to arrange light-conducting jacket 4 or to make this asymmetric, as in the example of the multi-core fiber 7 according to FIG ID. On the other hand, this increases the production costs and, in the case of an enlargement of the cross section, the rigidity of the multicore fiber 7, which entails a spatial enlargement and an increased energy consumption of the scanner in order to ensure the necessary lateral deflection for scanning the object space 14. Here is a technically meaningful compromise to find.

For imaging, for example, a photomultiplier tube (PMT) or a spectrometer, which in coordination with the

Stimulation signal is triggered at the proximal end of the

Multi-core fiber 7 can be used as a detector of the light emitted by the sample. It is advantageous that no second beam path in the optical arrangement is necessary to collect the object light, and also no cleaning filter in the optical arrangement must be used, as the

unwanted four-wave mixing process within the multi-core Fiber 7 is sufficiently suppressed by the separate guidance of the illumination light with the Stokes wavelength and the illumination light with the pump wavelength.

A second example of the optical arrangement is shown in FIG. In this example, the multicore fiber 7 follows a collimation unit 8 and a mirror scanner 9. The mirror scanner 9 is a MEMS mirror scanner. A the

Mirror scanner 9 subsequent lens 10 generates

Intermediate image, which is then of a functioning as a further collimation unit 11 lens group, the

Wavelength-dispersive beam combination element 12 and the front lens group 13 is passed into the object space 14.

Analogous to the example of Figure 2, the first and second illumination light, in particular the light of

Pump wavelength and Stokes wavelength, of which

Beam union element 12 spatially and angularly united.

For example, the beam combining element 12 may be a linear diffraction grating.

The position of the beam combining element 12 can be chosen differently in this design of the optical arrangement since there are two Fourier planes in this arrangement.

The beam combination element 12 can be arranged correspondingly either directly after the collimation unit 8 or after the further collimation unit 11.

FIG. 4 shows a further example of the optical arrangement. In the multi-core fiber 7, the centers of the two fiber cores 1, 2 in the plane shown, for example, 24 ym apart and have a numerical aperture for the pump and Stokes wavelength from 0.12 to. The collimating unit 11 is designed as a GRIN lens and collimates in the optical arrangement the illumination light, which emerges as a fiber scanner

trained multi-core fiber occurs. Subsequently, the illumination light from the wavelength-dispersive

Beam combining element 12, which is for example a linear transmission diffraction grating and a

Wavelength-dependent diffraction angle generated spatially and angularly superimposed. Here are the grid lines of

Transmission diffraction grating orthogonal to spatial

Offset of the fiber cores 1, 2 arranged.

Subsequent chromatic and other aberrations over the field-correcting front lens group 13, which consists of, for example, an achromatic lens and two spherical singlet lenses, focuses the light with a numerical aperture of, for example, about 0.54 into the object space 14 in which it is focused the spectroscopic imaging,

non-linear CARS process comes on a sample. In this case, an NA of at least 0.15 is advantageous in order to ensure in particular the condition of momentum conservation. The generated signal is subsequently returned to the same path

Guided multicore fiber 7 and aufgegesamme 11 through the photoconductive sheath.

It can post an estimate for the paraxial case

following regulation for the grid period of the

Transmission diffraction grating trained

Beam union element 12 can be found:

g = (f * dl) / a. The grating period g is given in ym per line, f is the focal length of the collimation unit 11,

Dl corresponds to the wavelength difference between the pump and Stokes wavelengths, and a corresponds to the distance between the centers of the two fiber cores 1, 2. In the

f = 3, 92 mm, Dl = 245 nm and a = 24 ym, resulting in a grating period of

Beam union element 12 of 40 ym per line.

FIG. 5 shows a further example of the optical arrangement in which the wavelength-dispersive

Beam union element 12 is realized by a two-component prism. The prism consists of a crown and a flint glass and is designed to produce the required wavelength-selective angular offset while maintaining the direction of the optical axis. The

Operation of the other components corresponds to the previous example of Figure 4.

FIG. 6 and FIG. 7 show further examples of the optical arrangement, which are essentially analogous to those of FIGS

Examples of Figures 4 and 5 are, however, under

Using a MEMS mirror scanner 9, which the

Fiber scanner replaced. In the examples of FIGS. 6 and 7, the multicore fiber 7 is fastened to a GRIN lens functioning as a collimation unit 8. By means of a prism, a 90 ° deflected, collimated beam of the

Illuminating light generated. This ray of

Illumination light is scanned by a MEMS mirror scanner 9 and focused into an intermediate image by a lens group 10 that corrects for chromatic aberration. Here begins an analogous structure, as described in the examples of Figures 5 and 6.

Another example of the optical arrangement is shown in FIG. This shows the possibility of an angled measurement using a prism as Wavelength dispersive beam combining element 12. In this example, beam deflection by the prism is 35 degrees. The collimating unit 11 in this example is a lens group consisting of a GRIN lens and a doublet lens, and the front lens group 13 is formed of two singlet lenses.

Another example of the optical arrangement is shown in Figure 9, in which a rectangular beam deflection in

Direction of the object space 14 takes place, as in

Endoscopic applications may be beneficial. As in the previous example, the collimating unit 11 may be a lens group consisting of a GRIN lens and a lens

Doublet lens, and the front lens group 13 is formed of two singlet lenses. The wavelength dispersive beam combining element 12 in this example is a linear reflection diffraction grating disposed at 45 degrees to the optical axis and, for example, one

Grating period of 55.5 ym per line.

In Fig. 10 is an example of the optical arrangement

in which the beam combining element 12 is a grating prism (GRISM) consisting of a grating prism

Combination of a diffraction grating and a prism

consists. This offers the possibility of influencing the spectral course of the beam deflection so that the

Detecting short-wavelength object light from the sample

is deflected laterally too strong and can be efficiently collected by the photoconductive sheath of the multi-core fiber 7, especially when the photoconductive sheath 4 is arranged symmetrically to the fiber cores (as in Figure 1A). Often it is favorable that the optical axis of the optical arrangement is not tilted. This is in particular through the use of a transmission grating as

Wavelength dispersive beam combining element 12, as in the examples of Figures 4 and 6, or a double prism 12, as in the examples of Figures 5 and 7, or by the combination of a grid and a prism as in the example of Figure 10 possible. Under certain circumstances, however, it may also be advantageous for the optical axis to be tilted within the optical arrangement, for example in the case of an endoscopic probe which is laterally oriented

Sample areas, z. B. during an endoscopy, should capture. In this case, it is convenient that

wavelength-dispersive beam combining element 12 as

Reflection diffraction grating, as in the example of Figure 9, to realize, or by a deflection prism, as in the example of Figure 8, to realize.

The invention is not limited by the description with reference to the embodiments. Rather, the includes

Invention every new feature as well as every combination of

Features, which includes in particular any combination of features in the claims, even if this feature or this combination itself is not explicitly in the

Claims or embodiments is given.

Claims

claims

1. Optical arrangement for a spectroscopic

Imaging process comprising:

- A multi-core fiber (7), the at least one first

A fiber core (1) for guiding a first illumination light and a second fiber core (2) for guiding a second

Having illumination light, wherein the multi-core fiber (7) has a fiber scanner for the deflection of the multi-core fiber (7) or the multi-core fiber (7) follows a mirror scanner (9), and

a wavelength-dispersive beam combining element (12) adapted to illuminate the first illumination light and the second illumination light in an object space (14)

spatially superimpose.

2. Optical arrangement according to claim 1,

wherein the spectroscopic imaging method is CARS spectroscopy or SRS spectroscopy.

3. Optical arrangement according to one of the preceding

Claims,

wherein the wavelength-selective beam combining element (12) is arranged between the fiber scanner or the mirror scanner (9) and the object space (14).

4. Optical arrangement according to one of the preceding

Claims,

wherein a collimating lens (11) is disposed between the fiber scanner or the mirror scanner (9) and the wavelength-selective beam combining element (12).

5. Optical arrangement according to one of the preceding

Claims, wherein the multicore fiber (7) has a light-conducting jacket (4) for guiding one out of the object space (14)

Coming object light includes, wherein the light-conducting

Jacket (4) is surrounded by an outer jacket (5) having a lower refractive index than the photoconductive jacket (4).

6. Optical arrangement according to claim 5,

wherein the multicore fiber (7) comprises an inner cladding (3) in which the fiber cores (1, 2) are arranged, the inner cladding (3) being surrounded by the photoconductive cladding (4) and having a lower refractive index than that of FIG

Fiber cores (1, 2) and a lower refractive index than the photoconductive sheath (4).

7. Optical arrangement according to one of the preceding

Claims, wherein the multi-core fiber (7) a

polarization maintaining fiber for the first and second illumination light guided in the fiber cores (1, 2).

8. Optical arrangement according to one of the preceding

Claims, wherein the fiber cores (1, 2) are arranged asymmetrically in the multi-core fiber (7).

9. Optical arrangement according to one of the preceding

Claims, wherein the wavelength dispersive

Beam union element (12)

Transmission diffraction grating, a reflection diffraction grating, a prism or a grid prism comprises.

10. Optical arrangement according to one of the preceding

Claims, wherein the optical arrangement has a diameter of less than 5 mm.

11. An endoscopic probe comprising an optical arrangement according to one of claims 1 to 10.

12. Spectroscopic imaging method, in which

- A first illumination light in a first fiber core (1) of a multi-core fiber (7) and a second illumination light in a second fiber core (2) of the multi-core fiber (7) are guided, wherein the first illumination light and the second illumination light have different wavelengths .

the first illumination light and the second

Illumination light through a wavelength-dispersive

Beam union element (12) in an object space (14) are spatially superimposed, wherein the multi-core fiber (7) is designed as a fiber scanner or the multi-core fiber (7) follows a mirror scanner (9), and wherein the object space (14) through the Movement of the fiber scanner or the mirror scanner (9) is scanned, and

- A from the object space (14) coming object light in a photoconductive jacket (4) of the multi-core fiber (7) is guided in the direction of an evaluation unit.

13. The method of claim 12, wherein the

Wavelength-selective beam combining element (12) between the fiber scanner or the mirror scanner (9) and the

Object space (14) is arranged.

14. The method according to claim 12 or 13,

wherein between the multi-core fiber (7) and the object space (14), a single optical beam path is formed, in which the first and second illumination light in the direction of Object space are guided, and in which the object light in the opposite direction to the multi-core fiber (7) is guided.

15. The method according to any one of claims 12 to 14, wherein the spectroscopic imaging method is CARS spectroscopy or SRS spectroscopy.

16. The method of claim 12, wherein the first illumination light has a pump wavelength and the second illumination light has a Stokes wavelength.