RISTRETTO: coronagraph and AO designs enabling High Dispersion Coronagraphy at 2 lambda/D

N. Blind; B. Chazelas; J. Kühn; E. Hocini; C. Lovis; M. Beaulieu; T. Fusco; L. Genolet; O. Guyon; J. Hagelberg; I. Hughes; P. Martinez; J. -F. Sauvage; R. Schnell; M. Sordet; A. Spang

arXiv · 2207.14177

RISTRETTO: coronagraph and AO designs enabling High Dispersion Coronagraphy at 2 lambda/D

N. Blind·B. Chazelas·J. Kühn·E. Hocini·C. Lovis·M. Beaulieu·T. Fusco·L. Genolet·O. Guyon·J. Hagelberg·I. Hughes·P. Martinez·J. -F. Sauvage·R. Schnell·M. Sordet·A. Spang

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Abstract

RISTRETTO is the evolution of the original idea of coupling the VLT instruments SPHERE and ESPRESSO, aiming at High Dispersion Coronagraphy. RISTRETTO is a visitor instrument that should enable the characterization of the atmospheres of nearby exoplanets in reflected light, by using the technique of high-contrast, high-resolution spectroscopy. Its goal is to observe Prox Cen b and other planets placed at about 35mas from their star, i.e. 2lambda/D at lambda=750nm. The instrument is composed of an extreme adaptive optics, a coronagraphic Integral Field Unit, and a diffraction-limited spectrograph (R=140.000, lambda=620-840 nm). We present the status of our studies regarding the coronagraphic IFU and the XAO system. The first in particular is based on a modified version of the PIAA apodizer, allowing nulling on the first diffraction ring. Our proposed design has the potential to reach > 50% coupling and <1E-4 contrast at 2lambda/D in median seeing conditions.

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N. Blind, B. Chazelas, J. Kühn, E. Hocini, C. Lovis, M. Beaulieu, T. Fusco, L. Genolet, O. Guyon, J. Hagelberg, I. Hughes, P. Martinez, J. -F. Sauvage, R. Schnell, M. Sordet, A. Spang. 2022-07-28. RISTRETTO: coronagraph and AO designs enabling High Dispersion Coronagraphy at 2 lambda/D. https://arxiv.org/abs/2207.14177

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