Speaker
Description
Conventional coronagraph architectures struggle to reach the theoretical limit of exoplanet detection when the exoplanet is close to the star, particularly when the telescope has a complex aperture or when the star itself is partially resolved. Coronagraphy or nulling using spatial mode-sorting is capable of reaching the theoretical limit, but the optimal solution has so far only been calculated for the idealized scenario of a completely unresolved star, whose signal lies entirely in the fundamental piston mode of the telescope. This work enables the calculation of optimized nulling modes for realistic observational scenarios as a function of the size of the star and planet parameters, with the goal of improving coronagraphic performance at lambda/D working angles given partially resolved stars and complex telescope apertures. We perform calculations using quantum information formalism and combine them with numerical optimization techniques to explore the behavior of optimal mode-sorting measurements. For the pure detection problem, the optimal measurement is derived from the density matrices describing the states with and without the presence of the planet. We show that the mode that maximizes the classical signal-to-noise ratio is also approximately quantum optimal to leading order in the stellar leakage and the planet flux ratio. We present optimal modes for measuring planets with known signals, and we characterize the tradeoffs inherent to coronagraphs for a finite field-of-view. Example coronagraph designs are presented for three cases of scientific interest: 1) following up planets detected by the visible coronagraph of the Habitable Worlds Observatory at more challenging infrared wavelengths, 2) the optimal extension of the fiber nuller architecture for detecting and spectrally characterizing planets using high-resolution spectroscopy, and 3) detecting and localizing planets at close working angles with the Planetary Camera and Spectrograph on the Extremely Large Telescope.
| Talk category | Splinter 1: Large Infrastructure and instrumentation |
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