Design, analysis, and testing of a microdot apodizer for the apodized pupil Lyot coronagraph Research note. III. Application to extremely large telescopes - Astrophysics > Instrumentation and Methods for AstrophysicsReportar como inadecuado




Design, analysis, and testing of a microdot apodizer for the apodized pupil Lyot coronagraph Research note. III. Application to extremely large telescopes - Astrophysics > Instrumentation and Methods for Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: The apodized-pupil Lyot coronagraph is one of the most advanced starlightcancellation concepts studied intensively in the past few years. Extremeadaptive optics instruments built for present-day 8m class telescopes willoperate with such coronagraph for imagery and spectroscopy of faint stellarcompanions. Following the development of an early demonstrator in the contextof the VLT-SPHERE project ~2012, we manufactured and tested a second APLCprototype in microdots designed for extremely large telescopes. This study hasbeen conducted in the context of the EPICS instrument project for theEuropean-ELT ~2018, where a proof of concept is required at this stage. Ourprototype was specifically designed for the European-ELT pupil, taking itslarge central obscuration ratio 30% into account. Near-IR laboratory resultsare compared with simulations. We demonstrate good agreement with theory. Apeak attenuation of 295 was achieved, and contrasts of 10^-5 and 10^-6 werereached at 7 and 12 lambda-D, respectively. We show that the APLC is able tomaintain these contrasts with a central obscuration ratio of the telescope inthe range 15% to 30%, and we report that these performances can be achieved ina wide wavelength bandpass BW = 24%. In addition, we report improvement tothe accuracy of the control of the local transmission of the manufacturedmicrodot apodizer to that of the previous prototype. The local profile error isfound to be less than 2%. The maturity and reproducibility of the APLC madewith microdots is demonstrated. The apodized pupil Lyot coronagraph isconfirmed to be a pertinent candidate for high-contrast imaging with ELTs.



Autor: Martinez, P., Dorrer, C., Kasper, M., Boccaletti, A., Dohlen, K

Fuente: https://arxiv.org/







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