Leiden University Scholarly Publications

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Doelman, D.S. (2021)

It's just a phase: high-contrast imaging with patterned liquid-crystal phase plates to facilitate characterization of exoplanets

Doctoral Thesis
This thesis aims to demonstrate how the achromatic nature and design flexibility of liquid-crystal optics can be used to improve high-contrast imaging instruments to facilitate detailed exoplanet characterization.
Chapter 2 discusses the design, performance, and future development of the liquid-crystal vector-apodizing phase plate (vAPP) coronagraph, five of which have been installed in different instruments on current generation telescopes since 2016. In chapter 3 we use the achromatic nature of the vAPP in combination with the LBT/ALES integral field spectrograph to obtain the first ever thermal infrared spectrum of the inner three HR 8799 planets. In Chapter 4 and 8 we show that by combining multiple grating patterns to reduce the influence of polarization leakage, we can improve the performance of liquid-crystal coronagraphs. In Chapter 5 and 6 we enhance sparse aperture masking, capable of detecting companions beyond the diffraction limit, by using liquid-crystal phase...Show moreThis thesis aims to demonstrate how the achromatic nature and design flexibility of liquid-crystal optics can be used to improve high-contrast imaging instruments to facilitate detailed exoplanet characterization.
Chapter 2 discusses the design, performance, and future development of the liquid-crystal vector-apodizing phase plate (vAPP) coronagraph, five of which have been installed in different instruments on current generation telescopes since 2016. In chapter 3 we use the achromatic nature of the vAPP in combination with the LBT/ALES integral field spectrograph to obtain the first ever thermal infrared spectrum of the inner three HR 8799 planets. In Chapter 4 and 8 we show that by combining multiple grating patterns to reduce the influence of polarization leakage, we can improve the performance of liquid-crystal coronagraphs. In Chapter 5 and 6 we enhance sparse aperture masking, capable of detecting companions beyond the diffraction limit, by using liquid-crystal phase masks to enable low-resolution spectroscopy and improve throughput. In Chapter 7 we demonstrate that a liquid-crystal Zernike wavefront sensor can accurately and efficiently measure phase and amplitude aberrations simultaneously, facilitating extreme contrasts. Together, the concepts presented in this thesis can be used to improve high-contrast imaging instruments of both ground-based and space-based observatories.
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Astronomical instrumentation
High-contrast imaging
Direct imaging
Coronagraphs
Exoplanets
Liquid-crystals
Aperture masking
Wavefront sensing
Geometric phase
All authors
Doelman, D.S.
Supervisor
Keller, C.
Co-supervisor
Snik, F.
Committee
Röttgering, H.J.A.; Snellen, I.A.G.; Pereira, S.; Tuthill, P.; Huby, E.
Qualification
Doctor (dr.)
Awarding Institution
Leiden Observatory, Faculty of Science, Leiden University
Date
2021-06-22
ISBN (print)
9789464192391