An integral field unit for the planetary camera and spectrograph (ELT-PCS): comparing lenslet and image slicer-based IFUs

With the ambitious goal of characterizing nearby Earth-like exoplanets, the Planetary Camera and Spectrograph for the Extremely Large Telescope (ELT-PCS) will need to push the boundaries of both high contrast coronagraphic imaging and integral field spectrograph technology. High contrast imaging spectrographs typically employ microlens array-based integral field units (IFU), which provide a large number of spaxels in exchange for short spectra and an inefficient use of detector pixels. In contrast, image slicers provide a high detector use efficiency with a broader spectral bandpass. We report on the progress of a trade study into IFU design choices for ELT-PCS using a modular integral field spectrograph test-bench. At the core of the experiment are two custom-built IFUs: a novel image slicer-based IFU manufactured by Canon Inc. and BIGRE-like microlens array IFU. We provide an overview of the experiment, the individual performances of the two IFUs, and outline future applications of the test-bench for the design of the integral field spectrograph sub-system of ELT-PCS.