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Multi-Parameter Wavelength Characterization of Array Spectrometers Under Near-Limit Sampling Conditions.
Du Bo1, Liu Liying2,3, Wu Dongli1
1Meteorological Observation Centre of China Meteorological Administration, Beijing, 100081, China.
Applied Spectroscopy
|July 1, 2026
Summary
Accurate wavelength characterization is crucial for spectral measurements. This study reveals sampling conditions significantly impact wavelength definitions and resolution metrics in array spectrometers, necessitating a coupled approach for precise calibration.
Area of Science:
- Spectroscopy and Optical Instrumentation
- Remote Sensing and Earth Observation
Background:
- Precise wavelength characterization is vital for high-accuracy spectral measurements, especially in applications like solar-induced chlorophyll fluorescence (SIF) retrieval.
- Array spectrometers utilize various metrics for wavelength definition (peak, center, centroid) and spectral resolution (FWHM, ERW), which can be sensitive to sampling conditions.
Purpose of the Study:
- To systematically investigate how sampling conditions influence wavelength characterization in array spectrometers.
- To analyze discrepancies among different wavelength definitions and spectral resolution metrics under near-limit sampling.
- To propose a multi-parameter approach for robust wavelength calibration and performance assessment.
Main Methods:
- Employed a crossed Czerny-Turner array spectrometer operating in the 650-800 nm range.
- Utilized the sampling ratio concept to define near-limit sampling conditions (2-5 pixels per spectral peak).
- Experimentally evaluated the impact of sampling variations on peak, center, and centroid wavelength definitions and FWHM/ERW resolution metrics.
Main Results:
- Significant discrepancies were observed among characteristic wavelength definitions due to discrete sampling and spectral peak shape.
- Peak-based estimations were sensitive to local sampling, while centroid-based definitions responded to energy distribution and asymmetry.
- A divergence between ERW and FWHM highlighted their dependence on both geometric width and spectral energy distribution.
Conclusions:
- Wavelength characterization is an interdependent problem involving sampling, peak representation, and resolution metrics, not independent parameters.
- A proposed multi-parameter approach clarifies relationships between sampling ratio, wavelength definitions, and spectral resolution.
- This framework offers a physically interpretable basis for calibrating and evaluating array spectrometers under challenging sampling conditions.
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