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Spectral flattening system for astronomical calibration sources based on a digital micromirror device
Optics Express
|August 14, 2026
Summary
A new digital micromirror device system flattens spectral output from calibration sources, enhancing precision for radial-velocity spectrographs. This spectral flattening improves data accuracy for astronomical observations.
Area of Science:
- Astronomy and Astrophysics
- Optical Engineering
- Spectroscopy
Background:
- High-precision radial-velocity spectrographs require stable calibration sources.
- Intensity fluctuations in current sources (laser frequency combs, Fabry-Perot etalons) limit spectrograph performance.
Purpose of the Study:
- To develop a spectral-flattening system to mitigate intensity fluctuations.
- To improve the calibration rate and stability for radial-velocity spectrographs.
Main Methods:
- A digital micromirror device (DMD)-based spectral-flattening system was designed and implemented.
- A parallel wavelength-calibration method was developed for faster mapping.
- A segmented closed-loop feedback strategy was used for stable output.
Main Results:
- The system flattened a supercontinuum spectrum (540-760 nm, ~14 dB dynamic range) to -6.6 dB relative to maximum throughput.
- Maximum flattening error was 0.21 dB relative to the target attenuation.
- Closed-loop operation maintained error below 1 dB for over 2 hours.
Conclusions:
- The DMD-based system effectively flattens spectral output, addressing limitations of current calibration sources.
- The parallel calibration method and closed-loop feedback enhance calibration rate and stability.
- This technology is suitable for multi-hour calibration sequences in high-precision spectrographs.
