Compact multi-spectral-resolution Wynne-Offner imaging spectrometer with a long slit

Area of Science:

• Optics and Photonics
• Spectroscopy
• Remote Sensing Instrumentation

Background:

• Imaging spectrometers aim for large fields of view (FOV) and high resolution, but this generates large data cubes, complicating acquisition and processing.
• Practical applications benefit from identifying targets within a large FOV using varied spectral resolutions.

Purpose of the Study:

• To propose a compact multi-spectral-resolution Wynne-Offner imaging spectrometer with a long slit.
• To investigate and mitigate astigmatism in the spectrometer design.
• To enable flexible spectral resolution for diverse target identification.

Main Methods:

• Introduction of a specialized diffraction grating with varying groove densities.
• Analysis of astigmatism related to groove density and slit length.
• Utilization of holographic grating aberrations to correct residual astigmatism.

Main Results:

• A compact spectrometer (60mm x 115mm x 103mm) was designed.
• Achieved a long slit (20mm) and a broad waveband (400-760 nm).
• Provided three distinct spectral resolutions: 2 nm, 1 nm, and 0.5 nm.

Conclusions:

• The designed spectrometer offers a unique combination of large FOV and multiple spectral resolutions in a compact form factor.
• This technology is suitable for applications like crop classification and pest detection.
• The method effectively balances astigmatism using holographic aberrations.