BIGRE: a low cross-talk integral field unit tailored for extrasolar planets imaging spectroscopy

TL;DR

This paper introduces BIGRE, a novel dual-lenslet integral field unit design that significantly reduces cross-talk in high contrast imaging spectroscopy for extrasolar planets, improving detector efficiency and reducing costs.

Contribution

The paper presents the BIGRE design, a new dual-lenslet IFU that outperforms classical TIGER designs by lowering cross-talk and optimizing detector pixel usage in high contrast imaging spectrographs.

Findings

BIGRE achieves lower cross-talk than TIGER.

BIGRE allows more efficient detector pixel utilization.

BIGRE reduces overall costs of lenslet-based spectrographs.

Abstract

Integral field spectroscopy (IFS) represents a powerful technique for the detection and characterization of extrasolar planets through high contrast imaging, since it allows to obtain simultaneously a large number of monochromatic images. These can be used to calibrate and then to reduce the impact of speckles, once their chromatic dependence is taken into account. The main concern in designing integral field spectrographs for high contrast imaging is the impact of the diffraction effects and the non-common path aberrations together with an efficient use of the detector pixels. We focus our attention on integral field spectrographs based on lenslet-arrays, discussing the main features of these designs: the conditions of appropriate spatial and spectral sampling of the resulting spectrograph's slit functions and their related cross-talk terms when the system works at the diffraction limit. We present a new scheme for the integral field unit (IFU) based on a dual-lenslet device (BIGRE), that solves some of the problems related to the classical TIGER design when used for such applications. We show that BIGRE provides much lower cross-talk signals than TIGER, allowing a more efficient use of the detector pixels and a considerable saving of the overall cost of a lenslet-based integral field spectrograph.