Fiber-based light-guide snapshot imaging spectrometer for Earth Science applications
Presenting Author: Tomasz Tkaczyk
Organization: Rice University
Co-Author(s): YE WANG, RAZVAN-IONUT STOIAN, CHRISTOPHER FLYNN, ARTI RANI , DAVID ALEXANDER, JEFFREY LUVALL, SHUNA CHENG, JASON DWIGHT, MICHAL PAWLOWSKI
A fiber-based snapshot imaging spectrometer was developed and implemented in two versions: (1) VIS - 60+ spectral channels in 450nm-750nm range and (2) VIS-SWIR allowing switching between VIS, NIR and SWIR speectral components. A compact, custom-fabricated fiber bundle was used to sample the object image at the input and create gaps between rows at the output for dispersion. To avoid overlapping between the inseparable cores within each multi-core fiber, a subset of cores were selected by two alternative approaches with the aid of a lenslet array and a photomask respectively. To efficiently calibrate the system, a rapid non-scanning spatial calibration method was developed based on Phase-Shifting Interferometry (PSI). The system crosstalk and spectral resolution were characterized. Hyperspectral imaging results of the Rice University campus landscape obtained with the spectrometer are presented to demonstrate the system's spectral imaging capability for distant scenes. The spectrum of different plant species and stages obtained with the spectrometer were in accordance with the reference spectrum measurements. The city traffic was also imaged to demonstrate the system's snapshot hyperspectral imaging capability. Other potential applications of the system include lightning spectroscopy and monitoring of land use, air pollution, and water resources. The fiber-based system design of the system allows the tuning between spatial and spectral sampling to meet specific imaging requirements.