Multiple-Star System Adaptive Vortex Coronagraphy Using a Liquid Crystal Light Valve

Abstract

We propose the development of a high-contrast imaging technique enabling the simultaneous and selective nulling of several light sources. This is done by realizing a reconfigurable multiple-vortex phase mask made of a liquid crystal thin film on which local topological features can be addressed electro-optically. The method is illustrated by reporting on a triple-star optical vortex coronagraphy laboratory demonstration, which can be easily extended to higher multiplicity. These results allow considering the direct observation and analysis of worlds with multiple suns and more complex extrasolar planetary systems.

Poincaré sphere representation for spatially varying birefringence

“…Several recent technologies have enabled the production of optical elements with tailored spatially varying birefringence, allowing the generation of beams with complex polarization patterns [1]. These technologies include metasurfaces composed of plasmonic [2,3] or dielectric [4][5][6][7][8] nanostructures, as well as liquid crystal devices such as q-plates [9][10][11], light valves [12,13], and spatial light modulators [14]. Spatially varying birefringence also occurs naturally in standard materials like plastic or glass, due to internal mechanical stress.…”

High-charge and multiple-star vortex coronagraphy from stacked vector vortex phase masks

“…4(b)]. Such maps emphasize one of the advantages of the single stage cascading approach versus the previous one based on laser induced multiple vortex masks [13] regarding an enhanced discovery space without dead zones.…”

“…Recalling that a stellar multiplicity is a rather common event [18], the de velopment of such a direct imaging tool is welcome. To date, a few proposals and attempts have been reported [19 23], but the assets of optical vortex coronagraphy are emerging only very recently in that context [13]. For this reason, the results in this Letter offer a practical roadmap to the realization of future coronagraphic tools with enhanced performances.…”

“…The idea relies on cascading N helical phase masks τ 2 in order to get an effective helical phase mask τ 2N . Then we extend this approach to an off axis design, en abling N star vortex coronagraphy in a simpler way and with better performances than the previous laboratory demonstra tion [13]. In both cases, we report on experimental and numeri cal investigations in the case of a double vortex mask (N 2).…”

“…Following a previous work on the simultaneous eclipsing of multiple star systems by using independent localized second order laser induced vortex phase masks [13], the proposed double off axis vortex mask appears as an interesting upgrade since (1) there is no need to introduce a laser driving system inside the telescope, (2) an optimized solid state second order vortex mask can be used, and (3) the discovery space is no longer endowed with intrinsic dead zones. This is quantitatively investigated from numerical simulations in what follows.…”