David Doelman
A5013084510- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Optical Polarization and Ellipsometry
- Optical Systems and Laser Technology
- Advanced optical system design
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- CCD and CMOS Imaging Sensors
- Astro and Planetary Science
- Photoreceptor and optogenetics research
- Optical Wireless Communication Technologies
- Advanced Semiconductor Detectors and Materials
- Geophysics and Gravity Measurements
- Spectroscopy and Quantum Chemical Studies
- Spectroscopy and Laser Applications
- Planetary Science and Exploration
- Optical Coherence Tomography Applications
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Infrared Target Detection Methodologies
- Photoacoustic and Ultrasonic Imaging
- Gamma-ray bursts and supernovae
- High-pressure geophysics and materials
Leiden University
2017-2024
Space Research Organisation Netherlands
2022-2024
Leiden Observatory
2017-2024
Cornell University
2024
University of California, Santa Cruz
2023
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2023
Université de Versailles Saint-Quentin-en-Yvelines
2023
Sorbonne Université
2023
Université Paris Cité
2023
Observatoire de Paris
2023
HCIPy is a package written in Python for simulating the interplay between wavefront control and coronagraphic systems. By defining an element which merges values/coefficients with its sampling grid/modal basis into single object called Field, this minimizes errors writing code makes it clearer to read. provides monochromatic Wavefront defines Propagator that acts as transformation two wavefronts. In way any physical part of optical system, be piece free space, thin complex apodizer or...
ABSTRACT NASA is engaged in planning for a Habitable Worlds Observatory (HabWorlds ), coronagraphic space mission to detect rocky planets habitable zones and establish their habitability. Surface liquid water central the definition of planetary Photometric polarimetric phase curves starlight reflected by an exoplanet can reveal ocean glint, rainbows, other phenomena caused scattering clouds or atmospheric gas. Direct imaging missions are optimized near quadrature, but HabWorlds ’ coronagraph...
MagAO-X is an entirely new extreme adaptive optics system for the Magellan Clay 6.5 m telescope, funded by NSF MRI program starting in Sep 2016. The key science goal of high-contrast imaging accreting protoplanets at Hα. With 2040 actuators operating up to 3630 Hz, will deliver high Strehls (> 70%), resolution (19 mas), and contrast (< 1 × 10<sup>-4 </sup>) Hα (656 nm). We present overview system, review design, discuss current project status.
ERIS, the Enhanced Resolution Imager and Spectrograph, is an instrument that both extends enhances fundamental diffraction limited imaging spectroscopy capability for VLT. It replaces two instruments were being maintained beyond their operational lifetimes, combines functionality on a single focus, provides new wavefront sensing module natural laser guide stars makes use of Adaptive Optics Facility, considerably improves performance. The observational modes ERIS are integral field at 1-2.5...
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is an extremely modular high- contrast installed on the telescope in Hawaii. SCExAO has a dual purpose. Its position northern hemisphere 8-meter makes it prime for detection and characterization of exoplanets stellar environments over large portion sky. In addition, SCExAO's unique design ideal to test innovative technologies algorithms quickly laboratory setup subsequently deploy them on-sky. benefits from first stage...
The Optimal Optical Coronagraph (OOC) Workshop held at the Lorentz Center in September 2017 Leiden, Netherlands, gathered a diverse group of 25 researchers working on exoplanet instrumentation to stimulate emergence and sharing new ideas. In this second installment series three papers summarizing outcomes OOC workshop, we present an overview common path wavefront sensing/control Coherent Differential Imaging techniques, highlight latest results, expose their relative strengths weaknesses. We...
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 polarization leakage. We demonstrate that combining patterns with a grating (PG) pattern directly followed one or several separate PGs, we can suppress leakage terms additional orders magnitude diffracting them out beam. Using two PGs composed single-layer liquid crystal structure in lab, suppression more than...
Over the last decade, vector-apodizing phase plate (vAPP) coronagraph has been developed from concept to on-sky application in many high-contrast imaging systems on 8-m class telescopes. The vAPP is an geometric-phase patterned that inherently broadband, and its manufacturing enabled only by direct-write technology for liquid-crystal patterns. generates two coronagraphic PSFs cancel starlight opposite sides of point spread function (PSF) have circular polarization states. efficiency, amount...
The Enhanced Resolution Imager and Spectrograph (ERIS) is the new adaptive optics (AO) assisted infrared instrument at Very Large Telescope (VLT). Its refurbished integral field spectrograph (IFS) SPIFFIER leverages a AO module, enabling high-contrast imaging applications giving access to orbital atmospheric characterisation of super-Jovian exoplanets. We tested detection limits ERIS, demonstrate its scientific potential by exploring composition young AF Lep b. Additionally, we improved...
ERIS is an instrument that will both extend and enhance the fundamental diffraction limited imaging spectroscopy capability for VLT. It replace two instruments are now being maintained beyond their operational lifetimes, combine functionality on a single focus, provide new wavefront sensing module makes use of facility Adaptive Optics System, considerably improve performance. The be competitive with respect to JWST in several regimes, has outstanding potential studies Galactic Center,...
SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for more than 5 years, demonstrating a high level of performance. produced outstanding results using variety operating modes, primarily field direct imaging exoplanetary systems, focusing on exoplanets as point sources and circumstellar disks extended objects. The achievements obtained thus far with (~200 refereed publications) different areas (exoplanets, disks, solar system, stellar physics...) have motivated large...
Next-generation large segmented mirror telescopes are expected to perform direct imaging and characterization of Earth-like rocky planets, which requires contrast limits $10^{-7}$ $10^{-8}$ at wavelengths from I J band. One critical aspect affecting the raw on-sky polarization aberrations arising reflection telescope's surfaces instrument optics. We simulate estimate their effect on achievable for three next-generation ground-based telescopes. performed ray-tracing in Zemax computed Jones...
In this article we show that the vector-Apodizing Phase Plate (vAPP) coronagraph can be designed such coronagraphic point spread functions (PSFs) act as a wavefront sensor to measure and correct (quasi-)static aberrations, without dedicated sensing holograms nor modulation by deformable mirror. The absolute retrieval is performed with non-linear algorithm. focal-plane (FPWFS) performance of vAPP algorithm are evaluated numerical simulations, test various photon read noise levels, sensitivity...
The Optimal Optical Coronagraph (OOC) Workshop at the Lorentz Center in September 2017 Leiden, Netherlands gathered a diverse group of 25 researchers working on exoplanet instrumentation to stimulate emergence and sharing new ideas. In this first installment series three papers summarizing outcomes OOC workshop, we present an overview design methods optical performance metrics developed for coronagraph instruments. optimization coronagraphs future telescopes has progressed rapidly over past...
Clouds and other features in exoplanet brown dwarf atmospheres cause variations brightness as they rotate out of view. Ground-based instruments reach the high contrasts small inner working angles needed to monitor these faint companions, but their fields-of-view lack simultaneous photometric references correct for non-astrophysical variations. We present a novel approach making ground-based light curves directly imaged companions using high-cadence differential spectrophotometric monitoring,...
The future Habitable Worlds Observatory aims to characterize the atmospheres of rocky exoplanets around solar-type stars. Vector Vortex Coronagraph (VVC) is a main candidate reach required contrast 10<sup>−10</sup>. However, VVC requires polarization filtering and every observing band different VVC. triple-grating vector vortex coronagraph (tgVVC) mitigate these limitations by combining multiple gratings that minimize leakage over large spectral bandwidth. In this paper, we present...
MagAO-X is a new "extreme" adaptive optics system for the Magellan Clay 6.5 m telescope which began commissioning in December, 2019. based around 2040 actuator deformable mirror, controlled by pyramid wavefront sensor operating at up to 3.6 kHz. When fully optimized, will deliver high Strehls (< 70%), resolution (19 mas), and contrast 1 × 10<sup>−4</sup>) Hα (656 nm). We present brief review of instrument design operations, then report on results first-light run.
The direct-write technology for liquid-crystal patterns allows manufacturing of extreme geometric phase patterned coronagraphs that are inherently broadband, e.g. the vector Apodizing Phase Plate (vAPP). We present on-sky data a double-grating vAPP operating from 2-5 $\mu m$ with 360-degree dark hole and decreased leakage term $\sim 10^{-4}$. report new design used in grating-vAPP SCExAO operates 1-2.5$\mu m$. Furthermore, we wavelength-selective vAPPs work at specific wavelength ranges...
Abstract Understanding the physical processes sculpting appearance of young gas-giant planets is complicated by degeneracies confounding effective temperature, surface gravity, cloudiness, and chemistry. To enable more detailed studies, spectroscopic observations covering a wide range wavelengths are required. Here we present first L-band HR 8799 d e low-resolution wide-bandwidth measurements c. These were facilitated an upgraded LMIRCam/ALES instrument at Large Binocular Telescope, together...
Scattered light imaging has revealed nearly a dozen circumstellar disks around young Herbig Ae/Be stars$-$enabling studies of structures in the upper disk layers as potential signs on-going planet formation. We present first images variable Ae star PDS 201 (V* V351 Ori), and an analysis spectral energy distribution through 3D Monte-Carlo radiative transfer simulations forward modelling. The is detected three datasets with LBTI/LMIRCam at LBT, including direct observations $Ks$ $L'$ filters,...
We present the monochromatic lab verification of newly developed SCAR coronagraph that combines a phase plate (PP) in pupil with microlens-fed single-mode fiber array focal plane. The two designs have been measured, create respectively 360 degree and 180 dark region from 0.8-2.4 λ/D around star. has designed for clear aperture realistic central obscuration spiders. creates measured stellar null $2-3 \times 10^{-4}$ , reaches $1 . Their contrast is maintained within range $\pm$ 0.16...
The Optimal Optical CoronagraphWorkshop at the Lorentz Center in September 2017 Leiden, Netherlands gathered a diverse group of 30 researchers working on exoplanet instrumentation to stimulate emergence and sharing new ideas. This contribution is final part series three papers summarizing outcomes workshop, presents an overview novel optical technologies systems that are implemented or considered for high-contrast imaging instruments both ground-based space telescopes. overall objective high...
The Santa Cruz Extreme AO Lab (SEAL) is a new visible-wavelength testbed designed to advance the state of art in wavefront control for high contrast imaging on large, segmented, ground-based telescopes. SEAL provides multiple options simulating atmospheric turbulence, including custom spatial light modulator. A 37-segment deformable mirror simulates W. M. Keck Observatory segmented primary mirror. adaptive optics system consists woofer/tweeter DM system, and four sensor arms: 1) high-speed...