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Broadband astigmatism-free Offner imaging spectrometer with high resolution
Applied Optics
|April 1, 2020
Summary
A novel optical design corrects astigmatism in Offner imaging spectrometers, achieving high spectral resolution (3 nm) and a compact configuration for broadband applications.
Area of Science:
- Optical Engineering
- Spectroscopy
- Imaging Systems
Background:
- Offner spectrometers are widely used but can suffer from astigmatism.
- Achieving high resolution across a broadband spectrum presents significant optical design challenges.
Purpose of the Study:
- To propose and analyze an advanced optical design for an astigmatism-free Offner imaging spectrometer.
- To achieve high spectral resolution and minimize optical aberrations in a broadband spectrum.
Main Methods:
- Thorough analysis of anastigmatic theory.
- Correction of astigmatism using two pairs of lens-mirror combinations.
- Design optimization based on concentric structure principles to equalize meridional and sagittal image distances.
Main Results:
- An example design with f-number 3 operating in the 400-1000 nm range was presented.
- Ray-tracing confirmed spectral sampling of 0.6 nm/pixel.
- RMS spot radii < 5 µm and spectral distortions (keystone, smile) < 0.1% were achieved.
Conclusions:
- A prototype manufactured based on the optimized theory demonstrated high spectral resolution (3 nm).
- The developed optical design offers a compact configuration with astigmatism correction for imaging spectrometers.
