Shaped pupil coronagraphy

Abstract

At Princeton we have been studying shaped pupil coronagraphs for high contrast imaging and planet finding. These will find applications in both ground and space imaging. In this article we summarize the design procedure for shaped pupils and review the various families of designs we have found. We describe the manufacturing processes we have used to make free standing shaped pupil masks and review our most recent laboratory results with and without wavefront control. We also discuss the factors limiting high contrast in the laboratory and our plans for mitigating them. RésuméCoronographie à pupille binaires. Notre groupe à Princeton se focalise sur l'étude de coronographes à pupille binaires dans le contexte de l'imagerie à très haut contraste et de la détection d'exo-planètes. Nous étudions en parallèle leur application à des projets spatiaux et à des telescopes conventionnels. Dans cet article, nous introduisons la théorie nécessaire à la conception de tels masques, puis passons en revue différentes familles de diaphragmes capables de produire un contraste de 10 ordres de grandeur.

Focusing through dynamic disordered media using a MEMS spatial light modulator

“…The work presented here describes experimental results on optical transmission through nearly opaque media and focusing using a microelectromechanical system (MEMS) reflective spatial light modulator SLM (Boston Micromachines Corporation kiloSLM®) [10], which can speed optimization rates, enabling robust focusing at intensities up to several hundred times the background level. This SLM has been used previously in a variety of applications requiring control of dynamic aberrations containing high spatial and/or temporal frequencies [11][12][13][14][15][16][17][18][19]. It is comprised of 1020 controllable mirror segments in a 32 × 32 array (with immobile mirror segments at the four corners of the array).…”

Coronagraph-integrated wavefront sensing with a sparse aperture mask

“…This is because the shaped pupil optimization procedure can be tailored to create dark search zones restricted to a finite region of the image plane, in exchange for deeper contrast and small inner working angle. 7,49 This is the case for the ripple SPC, as evident by the vertically extended sidelobe wedges of the nominal star PSF shown in Fig. 1.…”

Shaped pupils with two micromechanical deformable mirrors for exoplanet imaging

“…Figure 1 shows a laboratory image taken with a shaped pupil coronagraph at Princeton University. 1 A mask is used to block the central star, and the openings are the regions of high contrast. Aberrations result in 'speckles' that limit the achievable contrast to no better than one part in 10 4 .…”