Various Applications of Methods and Elements of Adaptive Optics

This volume is focused on a wide range of topics, including adaptive optic components and tools, wavefront sensing, different control algorithms, astronomy, and propagation through turbulent and turbid media

The Large UV/Optical/Infrared Surveyor (LUVOIR): Decadal Mission Concept Study Update

In preparation for the 2020 Decadal Survey in Astronomy and Astrophysics, NASA commissioned the study of four large mission concepts: the Large UV/Optical/Infrared Surveyor (LUVOIR), the Habitable Exoplanet Imager (HabEx), the far-infrared surveyor Origins Space Telescope (OST), and the X-ray surveyor Lynx. The LUVOIR Science and Technology Definition Team (STDT) has identified a broad range of science objectives for LUVOIR that include the direct imaging and spectral characterization of habitable exoplanets around sun-like stars, the study of galaxy formation and evolution, the exchange of matter between galaxies, star and planet formation, and the remote sensing of Solar System objects. The LUVOIR Study Office, located at NASA's Goddard Space Flight Center (GSFC), is developing two mission concepts to achieve the science objectives. LUVOIR-A is a 15-meter segmented-aperture observatory that would be launched in an 8.4-m extended fairing on the Space Launch System (SLS) Block 2 configuration. LUVOIR-B is an 8-meter unobscured segmented aperture telescope that fits in a smaller, conventional 5-meter fairing, but still requires the lift capacity of the SLS Block 1B Cargo vehicle. Both concepts include a suite of serviceable instruments: the Extreme Coronagraph for Living Planetary Systems (ECLIPS), an optical/near-infrared coronagraph capable of delivering 10 (sup minus10) contrast at inner working angles as small as 2 lambda divided by D; the LUVOIR UV Multi-object Spectrograph (LUMOS), which will provide low- and medium-resolution UV (100-400 nanometer) multi-object imaging spectroscopy in addition to far-UV imaging; the High Definition Imager (HDI), a high-resolution wide-field-of-view NUV-Optical-NIR imager. LUVOIR-A also has a fourth instrument, Pollux, a high-resolution UV spectro-polarimeter being contributed by Centre National d'Etudes Spatiales (CNES). This paper provides an overview of the LUVIOR science objectives, design drivers, and mission concepts

Dynamic simulation and control of optical systems

This thesis deals with the simulation-based investigation and control of optical systems that are mechanically influenced. Here, the focus is on the dynamic-optical modeling of vibration-sensitive mirror systems, which are utilized, e.g., in large astronomy telescopes or high-precision lithography optics. The large-area primary mirrors of telescopes typically consist of many individual hexagonal mirror segments, which are positioned with precise sensors and actuators. Furthermore, an adaptive optical unit usually compensates for the optical aberrations due to atmospheric disturbances. In practice, these aberrations are detected, and corrected, within a few seconds using deformable mirrors. However, to further improve the performance of these optical systems, dynamical disturbances in the mechanics, i.e., small movements and deformations of the optical surfaces, must also be taken into account. Therefore, multidisciplinary simulation methods are developed and presented. Based on this, the dynamical-optical system behavior is modeled using model-order-reduced, flexible multibody systems. Hence, the dynamical analysis of the mechanical-optical system can be performed at low computation costs. Thanks to the optical analysis in the time domain and using Fourier-optical concepts, one can also simulate exposure processes. To actively compensate for aberrations due to mechanical vibrations, model-based control strategies are also designed. They are not only demonstrated by means of simulation examples, but also illustrated through a laboratory experiment. The latter is realized with a low-cost test setup for student training using Arduino microcontrollers, position and force sensors, as well as high-speed cameras

Robotic processes to accelerate large optic fabrication

The manufacture of metre-scale optics for the next generation of extremely large telescopes (and many other applications) poses a number of unique challenges. For the primary mirror of the European Extremely Large Telescope, each of its 1.45 m segments will need to be completed with nanometre scale accuracy. This demands an unprecedented combination of hybrid fabricating technology to process nearly 1000 segments before the year 2024. One important aspect in improving the current state-of-the-art manufacturing developments is adding an efficient smoothing process that can achieve a faster, and less expensive, manufacturing process-chain. The current process to finish a prototype segment using CNC grinding and CNC polishing takes approximately 1-2 months, and a significant contributing factor in this is the excessive processing times needed to correct the local grinding marks. In this study, therefore, grolishing, an intermediate process between grinding and polishing, is adopted to smooth the part and reduce the overall manufacturing time. This PhD work serves to advance the development of effective robotic grolishing processes (RGP) by the following achievements: (1) to propose the specification and achieve the requirements; (2) to design tools and establish a mechanism for grolishing; (3) to investigate and propose experimental methods to reduce process times while still achieving high performance, reliability and quality surfaces; (4) to establish the RGP and demonstrate that this process can smooth the errors from grinding and provide superior surfaces for polishing to speed up the current process; (5) to develop prototype metrology systems and algorithms to measure grolished surfaces; and, (6) to investigate an innovative proposed method to control mid-spatial frequencies on complex surfaces by using rotating rigid tools. These novel achievements describe the newest fabrication technology, and anticipate the evolution of the process-chain for future high-quality imaging systems for use in astronomy, space-research and laser physics

Efficient light-matter interaction based on 4pi focusing with a monolithic parabolic mirror

Licht-Materie Wechselwirkung ist eine Schlüsseltechnologie für zahlreiche wissenschaftliche Experimente und industriell genutzte Anwendungen. Fortschritte in der Kopplungseffizienz zwischen Licht und Materie könnten neue technische Anwendungen und neuartige Hochpräzisionsexperimente ermöglichen. Im Speziellen könnte die Umkehrbarkeit der spontanen Emission experimentell demonstriert werden. In dieser Arbeit wird deshalb ein optischer Aufbau realisiert, welcher einen 4pi Parabolspiegel nutzt, um hocheffiziente Licht-Materie Wechselwirkung im Freiraum zu erzielen. Ein quantitatives Modell wird erarbeitet, welches die Kopplungseffizienz mithilfe der dominierenden experimentellen Parameter simuliert. Das Modell wird verifiziert, indem die Kopplungseffizienz und die fokale Intensitätsverteilung im optischen Aufbau gemessen werden. Der dabei erzielte Wert der Freiraum-Kopplungseffizienz von 13.7±1.4% ist unter den höchsten bisher realisierten Werten einzuordnen. Basierend auf dem quantitativen Modell werden die technischen Limitationen des Aufbaus identifiziert. Danach werden im zweiten Teil dieser Arbeit die Wellenfrontaberrationen, welche durch die Formabweichungen des Parabolspiegels hervorgerufen werden, genauer untersucht. Sie stellen eine Limitation der experimentell erzielten Wechselwirkungseffizienz dar. Daher werden verschiedene Konzepte zur Wellenfrontkorrektur durch Phasenkonjugation präsentiert und realisiert. Zu den Technologien, die zur Wellenfrontkorrekur eingesetzt werden, gehören: Ein deformierbarer Spiegel mit kontinuierlicher Membran, ein räumlicher Phasenmodulator, ein binäres lithographisch gefertigtes computergeneriertes Hologramm und eine Phasenplatte, welche mittels Magnetorheologischen Polierens hergestellt ist. Alle Konzepte werden auf ihr Potential zur Korrektur der Strehl-Zahl und ihre Relevanz in 4pi Aufbauten untersucht. Um die experimentell-technologische Signifikanz des 4pi Parabolspiegels aufzuzeigen, werden zwei Anwendungen experimentell umgesetzt: Erstens wird die Phasenverschiebung eines schwachen, kohärenten Laserstrahls durch das einzelne Ion gemessen. Zweitens wird die Position des einzelnen Emitters mithilfe des 4pi Parabolspiegels entlang aller drei räumlichen Dimensionen mit einer Auflösung im Bereich weniger Nanometer bestimmt. Die letztgenannte Anwendung besitzt das Potential, die technische Komplexität mancher der heutzutage wichtigsten Techniken der hochauflösenden optischen Mikroskopie wesentlich zu reduzieren.Light-matter interaction is a key technology for many scientific experiments and industrial applications. Efficiency improvements in the free space coupling between light and matter could enable new technological applications or new high-precision experiments. One particular experiment benefiting from this progress will be the experimental demonstration of the time-reversibility of the spontaneous emission process. In this work, a highly efficient light-matter interface is demonstrated that is based on a 4pi parabolic mirror focusing light onto a single, trapped ion. A quantitative model to simulate the coupling efficiency is established that considers the primary experimental parameters. The quantitative model is verified by measuring the free space coupling efficiency and the effective focal intensity distribution in the experiment. The achieved value of the coupling efficiency to one of the ion’s linear dipole transitions amounts to G = 13.7 ± 1.4% and is thus among the highest values ever measured so far. Based on the quantitative model, technical limitations of the interface are determined. In the second part of this work, the most relevant technical limitation for G is subject of further investigations, the wavefront aberrations due to form-figure errors of the parabolic mirror. Different concepts of aberration correction based on phase conjugation are described and are experimentally reviewed. Among the technologies for aberration correction are: A continuous membrane deformable mirror, a phase-only spatial light modulator, a binary lithographic computer generated hologram, and a correction phase plate manufactured with magnetorheological finishing, respectively. The different concepts are evaluated concerning their Strehl ratio correction quality and their relevance for experiments based on 4pi focusing. To demonstrate the potential impact of the 4pi parabolic mirror on technical applications, two applications are experimentally demonstrated: Firstly, the phase-shift imprinted on a weak coherent laser beam by the single ion is measured. Secondly,single particle tracking with an accuracy in the nanometer regime for all spatial directions is realized. The latter utilization of the 4pi parabolic mirror has the potential to significantly impact some of today’s super-resolution light-microscopes

Detecting life outside our solar system with a large high-contrast-imaging mission

In this White Paper, which was submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we recommend the ESA plays a proactive role in developing a global collaborative effort to construct a large high-contrast imaging space telescope, e.g. as currently under study by NASA. Such a mission will be needed to characterize a sizable sample of temperate Earth-like planets in the habitable zones of nearby Sun-like stars and to search for extraterrestrial biological activity. We provide an overview of relevant European expertise, and advocate ESA to start a technology development program towards detecting life outside the Solar System.Publisher PDFPeer reviewe

高速ビジョンを用いたリアルタイムビデオモザイキングと安定化に関する研究

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

Integrated Tip-Tilt Sensing for Single-Mode Fiber Coupling

This thesis presents the development and on-sky tests of the novel Microlens-Ring Tip-Tilt (MLR-TT) sensor. The sensor consists of a micro-lens ring (MLR) that is printed directly on the face of a fiber bundle with a central single-mode fiber (SMF) accepting the light almost unclipped if the beam is aligned. The edge of the beam, however, is refracted by the MLR to couple into six surrounding multi-mode fibers (MMFs). Detecting the flux in these sensor fibers allows reconstruction of the beam position, i.e. the tip and tilt aberrations of the wavefront. The lenses are manufactured in collaboration with Karlsruhe Institute for Technology (KIT) with state-of-the-art two-proton polymerization, a novel technology that allows the fabrication of very precise and freeform lenses. The sensor is integrated with the instrument’s fiber link and features a small physical size of 380 µm. This novel integration of a sensor into existing components reduced opto-mechanical footprint and complexity, as well as reducing non-common path aberrations (NCPAs) to a bare minimum. This thesis describes the various steps that were part of this development, starting with designing, optimizing, and characterizing the sensor itself, setting up a corresponding laboratory environment, and developing a control system for on-sky testing. The system is tested on-sky with iLocater fiber coupling front-end (acquisition camera) at the Large Binocular Telescope (LBT). It was found that principle reconstruction is possible but the observed accuracy is ∼0.19 λ/D both for tip and for tilt. With this accuracy, it was not possible to improve the resulting SMF coupling efficiency. A strong correlation between sensor accuracy and the instantaneous Strehl ratio (SR), i.e. residual adaptive optics (AO) aberrations, is found. Additionally, the corresponding power spectral density (PSD) reveals that most of the reconstruction inaccuracy occurs in low temporal frequencies. This suggests that the dominating limitations of the accuracy of the MLR-TT sensor arise from residual AO aberrations and the false signal they introduce in the sensor. These findings are discussed in detail and the future prospects of further analysis and development are outlined in the context of the most beneficial application environment

Program Annual Technology Report: Cosmic Origins Program Office

What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time. COR also seeks to understand how stars and planets form from clouds in these galaxies to create the heavy elements that are essential to life, starting with the first generation of stars to seed the universe, and continuing through the birth and eventual death of all subsequent generations of stars. The COR Programs purview includes the majority of the field known as astronomy