Open AccessLarge-aperture UV (250~400 nm) imaging spectrometer based on a solid Sagnac interferometer
Author(s) -
Wenming Yang,
Ningfang Liao,
Shaoming He,
Haobo Cheng,
Hongsong Li
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.034503
Subject(s) - hyperspectral imaging , optics , spectrometer , imaging spectrometer , spectral imaging , spectral resolution , materials science , imaging spectroscopy , interferometry , image resolution , physics , remote sensing , spectral line , astronomy , geology
Developing an ultraviolet (UV) imaging spectrometer is challenging due to a low level of incident power of photon flux, large chromatic aberration, and relatively low quantum efficiency of imaging sensor in UV waveband. In this paper, a large-aperture UV (250~400 nm) Fourier transform imaging spectrometer is presented for close-range hyperspectral sensing with high spatial resolution and decent spectral resolution. An advanced design based on a modified solid Sagnac interferometer working in UV waveband of 250~400 nm is introduced to improve the interferometric stability. A large-aperture and a reflective-transmissive filtering system are used to increase the spectral purity of the incident UV radiation, and air-spaced achromatic doublets are designed to address the chromatic aberration. The finished spectrometer has a spatial resolution of 23.44 μm on the target plane, a wavelengths resolution of 1.59 nm at 250 nm, and can provide approximately 59 wavelength samples over the waveband of 250~400 nm. The proposed imaging spectrometer acquires a hyperspectral data cube through push-broom scanning in a few minutes. Examples of UV hyperspectral imaging are demonstrated with a sample of resolution test chart, and a cotton sample with vitamin C (VC) and vitamin B6 (VB6) traces. Based on the analysis of spectra, monochromatic images, and k-Means clustering results, it can be concluded that the spectrometer is capable of UV hyperspectral imaging with excellent spectral accuracy, spatial performance, compactness, and robustness. The potential applications of the proposed instrument include materials analysis and traces detection with UV spectral characteristics.