Lenslet Array and Fabry–Pérot-Based Hyperspectral Imaging

Abstract

Snapshot spectroscopic imagers/instruments (SSI) are a class of spectroscopic instruments that are capable of acquiring spectral information of a given field of view in a single frame. Standard spectroscopic instruments like a grating-based spectrograph or a Fabry–Perot-based spectrograph obtain two dimensional data of 2D space or 1D space and 1D wavelength. But SSIs have three dimensional data of 2D space and wavelength embedded in two dimensional detector/image plane. So standard data reduction techniques are not applicable. Lenslet array spectroscope is a novel SSI which images the object on to a hybrid spatio-spectral image plane. A procedure to extract the spatial and spectral information of the field of view from this hyperplane is presented. We demonstrate the snapshot capabilities of this instrument to study dynamic activities of the Sun as inferred from two measurements: (i) Evershed flow in a sunspot in NOAA 12526 at Fe i 6301.5 A and (ii) oscillations in a quiescent prominence at H $\upalpha $ 6562.8 A. This instrument can be used for large or small scale structures, making it efficient for studying a wide range of dynamic activities like helioseismology, Moreton waves, prominence oscillation etc.