Spectrometer arrangement, method for generating a two-dimensional spectrum using such a

Abstract

Spectrometer arrangement (10) comprising - an entrance slit group (13) for introducing radiation into the spectrometer arrangement (10) and for limiting the optical field of the spectrometer arrangement (10), - a first dispersing element (31) for the spectral decomposition of the radiation in a principal dispersion direction, and - a second dispersing element (21) for spectral decomposition of the radiation in a transverse dispersion direction which forms an angle with the main dispersion direction, so that a two-dimensional spectrum can be generated, wherein the entry gap group (13) comprises a split wheel (14), wherein the splitting wheel (14) is rotatably mounted about a pivot axis (15), wherein the splitting wheel (14) has at least one opening (16), the width (16.min-16.max) of the opening (16) of the split wheel (14) changes depending on the angle, wherein the width of the opening (16) of the splitting wheel (14) runs in the transverse dispersion direction, wherein the entry slit group (13) comprises a slit foil (20), wherein the gap foil (20) includes an opening (22) which is longer than the greatest width (16.max) of the opening (16) of the gap wheel (14), and wherein radiation enters the spectrometer arrangement (10) through the opening (16) of the slit wheel (14) and the opening (22) of the slit foil (20), characterized in that that at least one opening (16) of the splitting wheel (14) is crescent-shaped.

Description

[0001] The invention relates to a spectrometer arrangement with the features of the preamble of the first claim and a method for generating a two-dimensional spectrum using such a spectrometer arrangement. A spectrometer arrangement of this type is disclosed in DE 195 13 871 A1.

[0002] An example of a spectrometer arrangement is an echelle spectrometer with internal ordering. The problem underlying the invention will be explained below using an echelle spectrometer as an example.

[0003] Such a spectrometer arrangement is known, for example, from DE 10 2009 059 280 A1.

[0004] Echelle spectrometers use gratings with a step-like cross-section. Illuminating the short facet of the step-like structure with a suitable blaze angle generates a diffraction pattern that concentrates the diffracted intensity in high orders, e.g., in the fiftieth to one hundredth order. This allows for high spectral resolution in a compact setup. The orders can overlap, depending on the incident wavelengths. Therefore, in echelle spectrometers with internal order separation, the orders are dispersed again perpendicular to the dispersion direction of the echelle grating to separate the different orders. This yields a two-dimensional spectrum that can be acquired using area detectors.

[0005] An echelle spectrometer with internal order separation differs from echelle spectrometers with external order separation in that, in the latter, only radiation from a small spectral range enters the spectrometer. In spectrometers with internal order separation, the spectrum is generated as a two-dimensional structure in the detector plane. This structure consists of spectral sections arranged essentially parallel to one another. The free spectral ranges of the respective diffraction orders combine to form a complete spectrum for a specific wavelength range. The use of an area detector with a large number of detector elements allows for the simultaneous acquisition of a large wavelength range with high spectral resolution.

[0006] As mentioned above, echelle spectrometers with internal order separation in the image plane generate a spectrum in the form of a two-dimensional diffraction order structure. The spacing between two adjacent orders depends on the dispersion properties of the transverse dispersion element. If a prism is used as such, the spatial separation of the orders decreases continuously with increasing wavelength. If different wavelength ranges are sequentially acquired with the spectrometer, the slit height must be adjusted to the respective measurement range in order to maximize the optical conductivity on the one hand and ensure clean order separation on the other.

[0007] To resolve the intensity components of individual wavelengths from a radiation source using a spectrometer, the optical field to be analyzed must be spatially confined. In some cases, the image generated by a pre-optic is small enough that no field limitation is necessary (slitless spectroscopy). In other cases, the radiation from the source is guided to the spectrometer via optical fibers. In this case, the exit surface of the fiber can act as the field boundary.

[0008] Very often, however, the light source is focused onto a field stop, the entrance slit. Slit-shaped apertures are frequently used. In the dispersion direction, the slit opening is very narrow to achieve optimal spectral resolution. In this direction, it is referred to as the slit width. A slit disk is described, for example, in DE 22 01 384 A.

[0009] Perpendicular to the dispersion direction, the so-called slit height is generally chosen to be as large as possible to improve the light throughput and thus the signal-to-noise ratio. To derive a clean spectral intensity distribution from the acquired image, a clean separation of the diffraction orders on the detector is required, which limits the slit height. Furthermore, the distance between two adjacent diffraction orders varies across the wavelength range used. Depending on the transverse dispersion element used, the order spacing increases with increasing wavelength (grating as a transverse disperser) or decreases (prism as a transverse disperser). The height of the entrance slit is normally determined by the distance between the closest detected orders. Consequently, when using area detectors to acquire echelle spectra, a considerable portion of the detector area remains unused.

[0010] Typically, when different aperture sizes (with respect to slit height and / or slit width) are required, different individual slits are swung into the beam path. However, a variable slit is also known from US 4,325,634 A. Similarly, R. Vuilleumier and K. Kraiczek present a variable entrance slit in their article "Variable entrance slit system for precision spectrophotometers," Micro Electro Mechanical Systems, 1995, MEMS '95, Proceedings. IEEE, DOI 10.1109 / MEMSYS.1995.472583. Usually, the slit width can be adjusted by moving two slit jaws, mostly via micrometer screws. Commercially available, for example from Newport (Newport Motor Driven Slit Assembly, M5257), are motorized slits in which the slit width can be continuously adjusted via software. An application of an adjustable slit width in conjunction with an echelle grating reveals, for example, the following: B. the DD 210 753 A1.

[0011] The invention is based on the objective of providing a spectrometer that allows high resolution over a large wavelength range. Furthermore, the optical conductivity should be maximized while simultaneously ensuring clean order separation.

[0012] The problem is solved by a spectrometer arrangement having the features of the first claim.

[0013] Unlike many commercially available variable gaps, the gap height can be changed very quickly, as no geared movements in the micrometer range with movable gap jaws are performed.

[0014] Spectrometer systems with detectors featuring very small pixel sizes particularly benefit from precise slit adjustment. This allows for highly accurate, wavelength-dependent slit height adjustment to maximize light throughput while maintaining clean order separation. The dynamic slit allows for dynamic adaptation to thermal drift and the associated changes in image quality. With pivotable single slits, the intensity center of the spectral line can shift as soon as a new slit is engaged. This is due to limited manufacturing, assembly, and adjustment accuracy. This is especially problematic when analytical applications require a highly accurate wavelength scale.In the case of the proposed slit design, a shift of the line on the detector in the event of a change in slit height is excluded, at least in the main dispersion direction, because the position is predetermined by the fixed slit foil.

[0015] For the purposes of this application, a "splitting wheel" is defined as a disc-shaped object with a substantially circular contour. In one embodiment, the "splitting wheel" is designed as a circular sector (segment of a circle), i.e., a partial area of ​​a circle bounded by a circular arc and two circular radii.

[0016] In one embodiment, the distance from the axis of rotation to the central axis of the crescent-shaped opening is constant over the angle of rotation.

[0017] In one embodiment, the width of the opening of the split wheel increases mathematically continuously with the angle of rotation.

[0018] In one embodiment, the width of the opening of the split wheel changes exponentially with respect to the angle of rotation.

[0019] In one embodiment, the width of the opening changes from 20 µm to 400 µm depending on the angle of rotation.

[0020] In one embodiment, the splitting wheel has several crescent-shaped openings of varying widths. A specific width can occur in multiple openings. Alternatively, a specific width can occur only once. The opening then increases continuously with the angle of rotation.

[0021] In one embodiment, the split wheel is rotated by means of a motor, in particular with a gear reduction.

[0022] In one embodiment, the slit film is rectangular and has an opening of constant width in the main dispersion direction.

[0023] In one embodiment, the width of the opening of the slit film is between 10 µm and 100 µm.

[0024] In one embodiment, the slit foil is movably arranged relative to the slit wheel. This is useful, for example, for adjusting the foil; during operation, the foil is fixed. In spectrometers with area detectors, the images of the spectral lines are aligned as precisely as possible with the pixel grid of the detector. When using a slit wheel with individual slits according to the prior art, either the position of the slit wheel or the alignment of the detector must be fine-tuned. In the proposed solution, the alignment can be achieved via the fixed slit foil by moving it relative to the slit wheel.

[0025] In one embodiment, the slit film has a crescent-shaped opening, the width of which changes depending on the angle, with the width of the opening running in the main dispersion direction.

[0026] In one embodiment, the center of the slit foil (rectangular version) or the central axis of the crescent-shaped opening (crescent-shaped version) of the slit foil lies on the central axis of the crescent-shaped opening of the slit wheel. As mentioned, the slit foil must be longer than the crescent is wide. If the respective centers are located one above the other or along an axis, the light entry in the transverse dispersion direction is limited only by the slit foil.

[0027] In one embodiment, the spectrometer arrangement comprises a collimator, in particular a collimator mirror, especially designed as a parabolic mirror or spherical mirror, which is arranged downstream of the entrance slit group in the direction of the incoming beam.

[0028] In one embodiment, the spectrometer arrangement forms a Littrow spectrometer. In this configuration, the collimator also simultaneously serves as the camera mirror, which projects the image onto the detector.

[0029] In one embodiment, the first dispersive element is designed as an echelle grid.

[0030] In one embodiment, the second dispersive element is designed as a prism.

[0031] In one embodiment, the prism is mirrored on the back.

[0032] In one embodiment, the prism is rotatably mounted. This allows the wavelength range to be adjusted.

[0033] In one embodiment, the second dispersive element is designed as a diffraction grating.

[0034] In one embodiment, the spectrometer arrangement comprises a detector, in particular a CCD array or a CMOS detector, for receiving the two-dimensional spectrum.

[0035] The problem is further solved by a method with the features of the twelfth claim.

[0036] As mentioned, the described concept allows for the rapid and precise adjustment of the slit height to the respective measuring range. In conjunction with a specific class of detectors, dynamic adjustment of the slit height during an exposure (i.e., without intermediate detector readout) is achieved, which will be explained in more detail below.

[0037] As described above, in a conventional echelle spectrometer with a prism as the order sorter element, the distances between two orders become increasingly larger towards the shorter wavelengths. This leaves large portions of the detector unused. If the application involves emission lines with low intensities (meaning intensity per pixel) in the shorter wavelengths and more intense lines in the longer wavelengths, the light transmittance can be improved by changing the slit height during exposure, for example, using the crescent-shaped aperture slit described above. This requires that the detector be able to clear the accumulated charge for individual detector segments during exposure or to dynamically change the detector's measurement range (for example, CMOS detectors with a region of interest (ROI) function).

[0038] In one embodiment, the method further comprises the following steps: rotating the gap wheel to a first position with a large width of the crescent-shaped aperture, so that short-wavelength diffraction orders are distinguishable in the spectrum; waiting until a first saturation value of the detector for the short-wavelength diffraction orders is reached; rotating the gap wheel to a second position with a smaller width of the crescent-shaped aperture compared to the first position; clearing the detector values ​​for long-wavelength diffraction orders; and waiting until a second saturation value of the detector for the long-wavelength diffraction orders is reached.

[0039] In one embodiment, the method further includes the step of rotating an element for the spectral decomposition of the radiation in a transverse dispersion direction to change the wavelength range of the spectrometer arrangement.

[0040] This will be explained in more detail using the following figures. Fig. Figure 1 shows a split wheel. Fig. Figure 2 shows a section of the splitting wheel. Fig. 1. Fig. Figure 3 shows a claimed spectrometer arrangement with a split wheel made of Fig. 1. Fig. 4a / b / c show three different measurement regimes for a spectrometer arrangement made of Fig. 3.

[0041] In the figures, identical features are marked with the same reference symbols.

[0042] The design of the claimed spectrometer arrangement is first described using the following: Fig. Figure 1 illustrates the proposed design. The proposed design consists of a splitting wheel 14. The splitting wheel 14 is mounted in the center so that it can rotate about a pivot axis 15. Rotation about the axis 15 is achieved via a motor, optionally with an intermediate gear reduction. The orientation of the splitting wheel 14 is clearly defined during operation, for example, by a reference position and an angle encoder on the motor or similar device.

[0043] The splitting wheel 14 has a crescent-shaped opening 16. The distance from the center of the crescent M, i.e., the central axis, to the axis of rotation 15 of the splitting wheel is constant, but the width of the crescent changes depending on the angle. During operation, the width of the crescent at the point of light entry into the spectrometer determines the height of the entrance aperture. Accordingly, the crescent width continuously decreases from the largest 16.max to the smallest required slit height 16.min.

[0044] In the present application, the term "crescent width" is used in a right-to-left direction. Similarly, the "gap height" also runs in a right-to-left direction. Likewise, the "length" of the slit film 20 (see below) runs in a right-to-left direction. The "gap width" runs from top to bottom. Likewise, the "width" of the opening 22 of the slit film 20 (see below) runs from top to bottom.

[0045] To also determine the slit width, a second aperture foil 20 with a slit-shaped opening 22 is located directly behind or in front of the slit wheel 14, at the point of light entry into the spectrometer and overlapping with the crescent-shaped opening 16. The longitudinal edge of the opening 22 points essentially in the direction of the axis of rotation 15. The width of the opening 22 corresponds directly to the actual slit width of the spectrometer. The length of the fixed slit 22 is only relevant insofar as it must always be greater than the crescent width to ensure that no light is blocked in the slit height direction.

[0046] By rotating the splitting wheel 14, the opening 16 can now be continuously and precisely adjusted to the desired split height. The resolution of the split height adjustment depends on the radius of the sickle arc (relative to the center of rotation 15), the pitch ratio of the sickle in µm / °, and the smallest possible adjustable angular increment of the motor (or the motor / gearbox combination). The sickle width, depending on the angular position of the splitting wheel, does not have to increase linearly but can be adjusted locally to meet the requirements regarding split height resolution and adjustment speed.

[0047] In one embodiment, the slit width 22 is variable. For this purpose, the fixed slit foil 20 described above is replaced by a second slit wheel with a crescent-shaped opening or by another dynamic device for adjusting the slit width. If a second crescent-shaped opening is used for slit width adjustment, this will, however, become noticeable at high slit widths in the form of slightly curved slit images. On the other hand, such an arrangement could again be used in known spectrometer setups in which curved entrance slits (or exit slits) are used for aberration control or for suppressing the so-called "smile" effect (spectrometer-induced curvature of the slit image, especially in imaging spectrometers).

[0048] In summary, the claimed spectrometer arrangement comprises a slit wheel 14 in combination with a fixed slit film 20. The slit wheel 14 contains a crescent-shaped opening 16 with variable width, which determines the slit height. The slit width, on the other hand, is determined by a fixed slit film 20 directly in front of or behind the slit wheel 14.

[0049] The claimed spectrometer arrangement allows for rapid and precise adjustment of the slit height to the respective measuring range. Furthermore, in conjunction with a specific class of detectors, the spectrometer arrangement enables dynamic adjustment of the slit height during an exposure, i.e., without intermediate readout of the detector 44.

[0050] Specifically, the recording starts with a large slit height, so that the short-wavelength orders containing the useful lines are just barely separated. During this phase of the exposure, the orders in the long-wavelength range overlap considerably – the data from this detector segment is therefore initially unusable. When the pixels in the short-wavelength range reach a certain predetermined saturation level, the slit height is reduced during the recording by rotating the slit wheel. Once this process is complete, the charge in the segment containing the long-wavelength orders is cleared (reset), and the actual recording for this range now begins with cleanly separated orders. No reset occurs in the short-wavelength segment – ​​the recording continues, albeit now with a correspondingly smaller slit height. This will be discussed further below in relation to… Fig. 3 and Fig. 4 explained in more detail.

[0051] Short wavelengths, at which photoelectrons are generated from exposures with different slit heights, exhibit a non-uniform intensity distribution across the slit height in this case. The photoelectrons from the exposure with the longest slit extend across the entire evaluable height of the diffraction order. Additional photoelectrons from the measurement time with smaller slits concentrate in the center M of the slit height. Assuming perfect manufacturing and assembly accuracy and stigmatic imaging, however, this has no influence on the intensity center of the line or on the binning procedure. Furthermore, the slit widens symmetrically towards the crescent center M; see [reference]. Fig. 2.

[0052] Fig. Figure 3 shows a claimed spectrometer arrangement 10. Light from a broadband light source 11 is guided via a pre-optics 12 to an entrance slit group 13 and subsequently 18 into the spectrometer. An example of such a light source 11 is a plasma torch, as used in ICP-OES (inductively coupled plasma optical emission spectrometry). In this case, wavelengths between 165 nm and 900 nm are detected with the system.

[0053] The entrance slit assembly 13 consists of a slit wheel 14, which is rotatably mounted about a pivot axis 15 and is rotated by a stepper motor. The slit wheel 14 contains a crescent-shaped opening 16. The crescent width is 400 µm at its thickest point (reference numeral 16.max) and 20 µm at its thinnest point (reference numeral 16.min). This corresponds to the largest and smallest required slit heights for the described echelle spectrometer. The crescent tapers continuously, but not necessarily linearly, from its thickest to its thinnest point.

[0054] Directly behind or in front of the slit wheel 14 – also in the beam path – is an aperture 20 with a slit opening 22. The longer side of the slit points towards the center of rotation 15 of the slit wheel 14. The orientation of the foil 20 can be easily changed for adjustment purposes, but is fixed during operation. The distance between the slit wheel 14 and the slit foil 20 is as small as possible: The two apertures 14 and 20 together form the entrance slit.

[0055] The radiation 18, passing through the slit group 13, travels to the collimator mirror 17, which directs the collimated beams 19 to a prism 21. The prism 21 is back-mirrored 23 and mounted to rotate about an axis 24. By rotating 24 the prism 21, the wavelength range detected by the detector 44 can be adjusted. The radiation pre-dispersed by the prism 21 (symbolized here by three wavelengths 25, 27, 29) reaches the echelle grating 31, the main dispersion element, which spreads the radiation perpendicular to the prism dispersion before it returns to the prism 21. After passing through the prism 21 twice, the radiation 32, 34, 36 reaches the collimator mirror 17, which in this Littrow setup also functions as a camera mirror. The camera mirror 17 then maps the generated echelle spectrum 46 onto a CCD detector 44. Fig. Figure 3 shows the edge of the free spectral range of an echelle spectrum 46. The area detector 44 is in Fig. 3 is divided into eight fringe segments 48. The detector actually has a resolution of, for example, 1000×1000. The detector 44 is aligned so that the fringes are approximately aligned with diffraction orders. The entire detector 44 is read out simultaneously. However, an individual reset time can be agreed upon for each of the fringes, at which the charge of the respective fringe is "erased." In this way, the effective exposure time for the individual segments can be individually adjusted to the brightness conditions.

[0056] In the present case, the optical elements are aligned such that longer-wavelength radiation 42 of the Fig. 3 or Fig. 4 hits detector 44 on the right, shorter-wavelength radiation 38 on the left.

[0057] The detected wavelength range can be continuously adjusted by rotating prism 21 (rotation 24). In this case, the longest wavelength range covers radiation between 226 nm and 900 nm. The slit height must be 20 µm to separate even the longest wavelength orders. The shortest wavelength measuring range covers light between 165 nm and 193 nm. Due to the larger order spacings, the slit 16 can be increased to 400 µm by rotating slit wheel 14 (rotation 15). For each other measuring range, the exact range at which maximum light transmission is achieved, while simultaneously ensuring clean order separation, can be set.

[0058] In the present example, the following parameters are used for the gap design. The distance of the sickle from the center of rotation M of the splitting wheel 14 is 22 mm. The sickle extends over a quarter of the circumference of the splitting wheel 14 and has a minimum diameter 16.min of 20 µm and a maximum diameter 16.max of 400 µm. The splitting wheel 14 is driven by a stepper motor with an angular resolution of 1.8°. If necessary, the angular resolution can be increased by a factor of, for example, 8, by suitable motor control. Assuming adequate manufacturing, bearing, and assembly accuracy, a gap height resolution of less than 1 µm is achieved with the described setup.

[0059] Dynamically adjusting the slit height during an acquisition is particularly advantageous in a long-wavelength measurement tile. As described above, a minimum slit height of 20 µm is used in the measurement range between 226 nm and 900 nm. However, the shortest wavelength orders are still clearly separated even with a slit height ten times greater. Fig. Figure 4 illustrates how different measurement regimes affect the total measurement time and the total acquired signals. In the example calculation, two lines are measured at the long-wavelength and short-wavelength ends of the range. It is assumed that the short-wavelength line is 5 times weaker (pixel intensity) than the long-wavelength line and that the desired saturation (e.g., 70% detector capacity) is reached after an exposure time of 0.2 s for the latter. The detector readout takes 1.25 seconds in each case.

[0060] In the measurement regime in Fig. In step 4a, only one image is taken with an exposure time of 0.2 s. The slit height is constant at 20 µm. During the total measurement time of 1.45 s, strong signals are obtained in the long-wavelength range, but only very weak overall signals are obtained in the short-wavelength range due to the low intensity and slit height.

[0061] In the case of Fig. In step 4b, an additional image is now taken with a slit height of 200 µm and an exposure time of 1 s. Due to the large slit height, a high signal strength can now be obtained in the shortwave range. However, the total measurement time increases to 3.7 s due to the additional exposure and readout time.

[0062] The method from Fig.Method 4c combines the two approaches described above. An image is captured with a total exposure time of 1 s. The exposure begins with a slit height of 200 µm. Once the intensity in the shortwave range reaches approximately 80% of the desired saturation (after about 0.8 s), the slit height is reduced to 20 µm, and the charge in the longwave range is cleared (reset). For the remaining 0.2 s, measurements are taken at both wavelengths with the smaller slit height. This results in a total measurement time of 2.25 s. Strong signals can be generated at both wavelengths during this time.

[0063] The invention can, in principle, be used in any spectrometer arrangement where the use of an entrance slit with a variable height is desirable. In particular, the invention is suitable for echelle spectrometers with dynamic measuring ranges, where the slit height must be adapted to the respective measuring range in order to maximize the geometric light transmittance.

Claims

[1] Spectrometer arrangement (10) comprising - an entrance slit group (13) for introducing radiation into the spectrometer arrangement (10) and for limiting the optical field of the spectrometer arrangement (10), - a first dispersing element (31) for the spectral decomposition of the radiation in a principal dispersion direction, and - a second dispersing element (21) for spectral decomposition of the radiation in a transverse dispersion direction which forms an angle with the main dispersion direction, so that a two-dimensional spectrum can be generated, wherein the entry gap group (13) comprises a split wheel (14), wherein the splitting wheel (14) is rotatably mounted about a pivot axis (15), wherein the splitting wheel (14) has at least one opening (16), the width (16.min-16.max) of the opening (16) of the split wheel (14) changes depending on the angle, wherein the width of the opening (16) of the splitting wheel (14) runs in the transverse dispersion direction, wherein the entry slit group (13) comprises a slit foil (20), wherein the gap foil (20) includes an opening (22) which is longer than the greatest width (16.max) of the opening (16) of the gap wheel (14), and wherein radiation enters the spectrometer arrangement (10) through the opening (16) of the slit wheel (14) and the opening (22) of the slit foil (20), characterized by , that at least one opening (16) of the splitting wheel (14) is crescent-shaped. [2] Spectrometer arrangement (10) according to claim 1, wherein the distance from the axis of rotation (15) to the central axis (M) of the crescent-shaped opening (16) of the split wheel (14) is constant over the angle of rotation. [3] Spectrometer arrangement (10) according to claim 1 or 2, wherein the width of the opening (16) of the split wheel (14) increases mathematically continuously over the angle of rotation. [4] Spectrometer arrangement (10) according to one of claims 1 to 3, wherein the width of the opening (16) of the split wheel (14) changes exponentially over the angle of rotation. [5] Spectrometer arrangement (10) according to one of claims 1 to 4, wherein the split wheel (14) has several crescent-shaped openings (16) of variable width. [6] Spectrometer arrangement (10) according to one of claims 1 to 5, wherein the slit foil (20) is rectangular and has an opening (22) of constant width in the main dispersion direction. [7] Spectrometer arrangement (10) according to one of claims 1 to 5, wherein the slit film (20) has a crescent-shaped opening (22), wherein the width of the opening (22) of the slit film (20) changes depending on the angle, wherein the width of the opening (22) of the slit film (20) extends in the main dispersion direction, and wherein the center of the slit film (20) or the central axis of the crescent-shaped opening (22) of the slit film (20) lies on the central axis of the crescent-shaped opening (16) of the slit wheel (14). [8] Spectrometer arrangement (10) according to one of claims 1 to 7, wherein the spectrometer arrangement (10) further comprises a collimator (17) which is arranged downstream of the entrance slit group (13) in the direction of the incoming beam. [9] Spectrometer arrangement (10) according to claim 8, wherein the spectrometer arrangement (10) forms a Littrow spectrometer. [10] Spectrometer arrangement (10) according to one of claims 1 to 9, wherein the first dispersive element (31) is configured as an echelle grating. [11] Spectrometer arrangement (10) according to any one of claims 1 to 10, wherein the spectrometer arrangement (10) comprises a detector (44), in particular a CCD array or a CMOS detector, for receiving the two-dimensional spectrum. [12] Method for generating a two-dimensional spectrum using a spectrometer arrangement (10) according to at least one of claims 1 to 11, comprising the steps: - Radiation is introduced into the spectrometer arrangement (10) via an entrance slit group (13), - spectral decomposition of the radiation in one main dispersion direction, - spectral decomposition of the radiation in a transverse dispersion direction, which forms an angle with the main dispersion direction, so that a two-dimensional spectrum can be generated, and - Imaging the two-dimensional spectrum onto a detector (44). [13] The method of claim 12, further comprising the steps of: - Rotating the split wheel (14) into a first position with a large width of the crescent-shaped opening (16), so that short-wavelength diffraction orders are distinguishable in the spectrum, - Starting the exposure process, - Wait until a first saturation value of the detector (44) is reached for the short-wavelength diffraction orders, - Rotating the splitting wheel (14) into a second position with a smaller width of the crescent-shaped opening (16) compared to the first position, - Clearing the values ​​of detector (44) for long-wavelength diffraction orders, - Wait until a second saturation value of the detector (44) for the long-wavelength diffraction orders is reached, and - Termination of the exposure process and readout of the detector (44). [14] Method according to claim 12 or 13, further comprising the step: - Rotating an element for the spectral decomposition of the radiation in a transverse dispersion direction to change the wavelength range of the spectrometer arrangement (10).

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