Generalised optical differentiation wavefront sensor: a sensitive high dynamic range wavefront sensor

Instrumentatio

Original use of MUSE's laser tomography adaptive optics to directly image young accreting exoplanets

Stars and planetary system

L-band integral field spectroscopy of the HR 8799 planetary system

Stars and planetary system

Improved companion mass limits for Sirius A with thermal infrared coronagraphy using a vector-apodizing phase plate and time-domain starlight-subtraction techniques

Stars and planetary system

Vector-apodizing phase plate coronagraph: design, current performance, and future development [Invited]

Instrumentatio

The spectrally modulated self-coherent camera (SM-SCC): Increasing throughput for focal-plane wavefront sensing

Context. The detection and characterization of Earth-like exoplanets is one of the major science drivers for the next generation of telescopes. Direct imaging of the planets will play a major role in observations. Current direct imaging instruments are limited by evolving non-common path aberrations (NCPAs). The NCPAs have to be compensated for by using the science focal-plane image. A promising sensor is the self-coherent camera (SCC). An SCC adds a pinhole to the Lyot stop in the coronagraph to introduce a probe electric field. The pinhole has to be separated by at least 1.5 times the pupil size to separate the NCPA speckles from the probe electric field. However, such a distance lets through very little light, which makes it dificult to use an SCC at high speed or on faint targets. Aims. A spectrally modulated self-coherent camera (SM-SCC) is proposed as a solution to the throughput problem. The SM-SCC uses a pinhole with a spectral filter and a dichroic beam splitter, which creates images with and without the probe electric field. This allows the pinhole to be placed closer to the pupil edge and increases the throughput. Combining the SM-SCC with an integral field unit (IFU) can be used to apply more complex modulation patterns to the pinhole and the Lyot stop. A modulation scheme with at least three spectral channels can be used to change the pinhole to an arbitrary aperture with higher throughput. This adds an additional degree of freedom in the design of the SM-SCC. Methods. The performance of the SM-SCC is investigated analytically and through numerical simulations. Results. Numerical simulations show that the SM-SCC increases the pinhole throughput by a factor of 32, which increases the wavefront sensor sensitivity by a factor of 5.7. The reconstruction quality of the sensor is tested by varying the central wavelength of the spectral channels. A smaller separation between the wavelength channels leads to better results. The SM-SCC reaches a contrast of 1109 for bright targets in closed-loop control with the presence of photon noise, phase errors, and amplitude errors. The contrast floor on fainter targets is photon-noise-limited and reaches 1 107. The SM-SCC with an IFU can handle randomly generated reference field apertures. For bright targets, the SM-SCC-IFU reaches a contrast of 3 109 in closed-loop control with photon noise, amplitude errors, and phase errors. Conclusions. The SM-SCC is a promising focal-plane wavefront sensor for systems that use multiband observations, either through integral field spectroscopy or dual-band imaging. © ESO 2022.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

High-resolution integral-field spectroscopy of exoplanets

This thesis describes the implementation and on-sky demonstration of high-resolution integral-field spectroscopy for extreme adaptive optics systems that are used to find and characterize exoplanets. For this work the Leiden EXoplanet Instrument (LEXI) was build, which is a visiting instrument for the William Herschel Telescope on La Palma. LEXI was used a pathfinder for testing new technology. The potential of these technqiues have been demonstrated with the observations of PDS 70 by the MUSE instruments, where we have characterized a proto-planet and found a second proto-planet in the same system. The proposed techniques in this thesis can be implemented on future instruments and telescopes for the characterization of exoplanets.GalaxiesGalaxie

The Single-mode Complex Amplitude Refinement (SCAR) coronagraph. I. Concept, theory, and design

Instrumentatio

Highly multiplexed Bragg gratings for large field of view gas sensing in planetary atmospheres

Instrumentatio