Dual Spectrometer Arrangement for Detector Area Optimization
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Solution Overview
Problem
Existing spectrometer assemblies face challenges in efficiently utilizing detector area and achieving high dynamic range when detecting large spectral ranges with varying light intensities, often resulting in reduced sensitivity or the need for different exposure times.
Innovation Solution
The use of additional optical components in a separate light path allows for the division of the spectrum into two spectral ranges, enabling individual adaptation of entrance slit width and dispersion elements to match the dynamic range of the detector, thereby optimizing light throughput and reducing detector size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single spectrometer arrangement is used to detect large spectral ranges, then the detector size must be increased, but this increases device complexity and cost
Solution Approach 1:
The spectral range is divided into two separate wavelength ranges, each detected by a dedicated spectrometer arrangement (first and second spectrometers) with their own dispersion elements and imaging optical systems. This segmentation allows each detector to be optimized for a specific wavelength range, reducing the overall detector size while maintaining full spectral coverage capability
Solution Approach 2:
Both spectrometer arrangements share a common detector that can detect both wavelength ranges. The detector serves multiple functions by detecting spectra from two different wavelength ranges, eliminating the need for separate detectors and reducing overall device complexity
2Adaptability or versatility
If the detector dynamic range is increased to handle varying spectral intensities, then the detector size and complexity increase, but if kept simple, sensitivity is reduced
Solution Approach 1:
The spectral range with varying intensities is segmented into two wavelength ranges. The first spectrometer detects the wavelength range with higher intensity (e.g., above 350 nm), while the second spectrometer detects the wavelength range with lower intensity (e.g., below 350 nm). This allows each spectrometer to be optimized for its specific intensity range, improving overall adaptability without requiring a single complex detector
Solution Approach 2:
Each spectrometer arrangement is optimized with local quality principles - the first spectrometer is optimized for higher intensity spectral ranges with appropriate entrance slit widths and dispersion elements, while the second spectrometer is optimized for lower intensity ranges. This localized optimization improves sensitivity for each wavelength range without requiring the entire system to accommodate the full dynamic range
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables simultaneous detection of intense and weak spectral lines with improved light throughput and reduced detector size, minimizing chromatic errors and read-out intervals without moving parts or additional optical losses.
Implementation Method 1
Gratings with a stair-like cross section (Echelle (french)=stairs) are used in such Echelle spectrometers. A diffraction pattern is generated with such stair-like structure with a corresponding Blaze angle, the diffraction pattern concentrating the diffracted Intensity in a high order, for example in fiftieth to one hundredth order.
Implementation Method 2
a dispersion element for separating the orders by means of spectrally dispersing the radiation in a lateral dispersion direction forming an angle with the main dispersion direction of the Echelle grating adapted to generate a two dimensional spectrum with a plurality of separated orders
Implementation Method 3
an imaging optical system for imaging the radiation entering through an entrance slit into the spectrometer assembly in an imaging plane
Data Source
AI summary
The invention relates to a spectrometer arrangement (10) comprising a spectrometer (14) for producing a spectrum of a first wavelength range of radiation from a radiation source on a detector (42). Said arrangement also comprises: an Echelle grating (36) for the spectral decomposition of the radiation penetrating the spectrometer arrangement (10) in a main dispersion direction (46); a dispersing element (34) for separating the degrees by means of spectral decomposition of the radiation in a transversal dispersion direction (48) which forms an angle with the main dispersion direction of the Echelle grating (36), in such a way that a two-dimensional spectrum (50) can be produced with a plurality of separated degrees (52); an imaging optical element (24, 38) for imaging the radiation penetrating through an inlet gap (20) into the spectrometer arrangement (10), in an image plane (40); and a surface detector (42) comprising a two dimensional arrangement of a plurality of detector elements in the image plane (40). The inventive arrangement is characterized in that another spectrometer (12) comprising at least one other dispersing element (64) and another imaging optical element (60,66) is provided in order to produce a spectrum (68) of a second wavelength range of radiation, which is different from the first wavelength range, from a radiation source on the same detector (42). The spectra can be spatially or temporally separated on the detector.