Related papers: Introduction to stellar coronagraphy
We present the first laboratory experiments using a notch-filter mask, a coronagraphic image mask that can produce infinite dynamic range in an ideal Lyot coronagraph according to scalar diffraction theory. We fabricated the first…
Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…
A set of pupil apodization functions for use with a vortex coronagraph on telescopes with obscured apertures is presented. We show analytically that pupil amplitudes given by real-valued Zernike polynomials offer ideal on-axis starlight…
The vector vortex coronagraph is an instrument designed for direct detection and spectroscopy of exoplanets over a broad spectral range. Our team is working towards demonstrating contrast performance commensurate with imaging temperate,…
External occulters, otherwise known as starshades, have been proposed as a solution to one of the highest priority yet technically vexing problems facing astrophysics - the direct imaging and characterization of terrestrial planets around…
A vortex coronagraph is now available for high contrast observations with the Keck/NIRC2 instrument at L band. Reaching the optimal performance of the coronagraph requires fine control of the wavefront incident on the phase mask. In…
High contrast imaging (HCI) is fundamentally limited by wavefront aberrations, and the ability to perform wavefront sensing from focal plane images is key to reach the full potential of ground and space-based instruments. Vortex focal plane…
The vortex coronagraph is one of the most promising coronagraphs for high contrast imaging because of its simplicity, small inner working angle, high throughput, and clear off-axis discovery space. However, as with most coronagraphs,…
The Habitable Worlds Observatory (HWO) is a flagship mission concept proposing to characterize earth-like exoplanets at high contrast with a coronagraph instrument. The most in-depth, validated contrast error budgets made to date have been…
Accurate segmentation and motion estimation of myocardium have always been important in clinic field, which essentially contribute to the downstream diagnosis. However, existing methods cannot always guarantee the shape integrity for…
Cool giant and supergiant stars are among the largest and most luminous stars in the Universe and, therefore, dominate the integrated light of their host galaxies. These stars were extensively studied during last few decades, however their…
The continual push to directly image exoplanets at lower masses and closer separations orbiting around bright stars remains limited by both quasi-static and residual adaptive optics (AO) aberration. In previous papers we have proposed a…
We conducted a number of multi-band coronagraph experiments using a vacuum chamber and a binary-shaped pupil mask which in principle should work at all wavelengths, in the context of the research and development on a coronagraph to observe…
High-contrast imaging and spectroscopy provide unique constraints for exoplanet formation models as well as for planetary atmosphere models. Instrumentation techniques in this field have greatly improved over the last two decades, with the…
We present the results of the first laboratory experiment of checkerboard shaped pupil binary mask coronagraphs using visible light, in the context of the R&D activities for future mid-infrared space missions such as the 3.5 m SPICA…
The Gemini Planet Imager (GPI) is an instrument designed for the Gemini South telescope to image young Jupiter-mass planets in the infrared. To achieve the high contrast needed for this, it employs an apodized pupil Lyot coronagraph (APLC)…
The design of liquid-crystal diffractive phase plate coronagraphs for ground-based and space-based high-contrast imaging systems is limited by the trade-off between spectral bandwidth and polarization leakage. We demonstrate that by…
We present the first astronomical observations obtained with an Apodizing Phase Plate (APP). The plate is designed to suppress the stellar diffraction pattern by 5 magnitudes from 2-9 lambda/D over a 180 degree region. Stellar images were…
This paper presents initial results from the ESA-funded ``SUPPPPRESS'' project, which aims to develop high-performance liquid-crystal coronagraphs for direct imaging of Earth-like exoplanets in reflected light. The project focuses on…
High-contrast imaging in the next decade aims to image exoplanets at smaller angular separations and deeper contrasts than ever before. A problem that has recently garnered attention for telescopes equipped with high-contrast coronagraphs…