Dr. Jeffrey B. Jewell Profile

Dr. Jeffrey B. Jewell

at Jet Propulsion Lab

SPIE Involvement:

Author

Publications (27)

Proceedings Article | 12 March 2024 Poster + Paper

Thermal control of long delay lines in a high-resolution astrophotonic spectrograph

Gregory Sercel, Pradip Gatkine, Nemanja Jovanovic, Jeffrey Jewell, Luis Pereira da Costa, James Kent Wallace, Dimitri Mawet

Proceedings Volume 12889, 1288916 (2024) https://doi.org/10.1117/12.3009916

KEYWORDS: Fourier transforms, Optical switching, Control systems, Switches, Waveguides, Spectrographs, Thermal stability, Temperature control, Phase modulation

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Proceedings Article | 5 October 2023 Presentation + Paper

The path to detecting extraterrestrial life with astrophotonics

Nemanja Jovanovic, Yinzi Xin, Michael Fitzgerald, Olivier Guyon, Peter Tuthill, Barnaby Norris, Pradip Gatkine, Greg Sercel, Svarun Soda, Yoo Jung Kim, Jonathan Lin, Sergio Leon-Saval, Rodrigo Amezcua-Correa, Stephanos Yerolatsitis, Julien Lozi, Sébastien Vievard, Chris Betters, Steph Sallum, Daniel Levinstein, Dimitri Mawet, Jeffrey Jewell, J. Kent Wallace, Nick Cvetojevic

Proceedings Volume 12680, 126800G (2023) https://doi.org/10.1117/12.2677951

KEYWORDS: Planets, Photonics, Stars, Exoplanets, Equipment, Astrophotonics, Wavefront sensors, Single mode fibers, Coronagraphy, Spectroscopy

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Proceedings Article | 5 October 2023 Presentation + Paper

Dual purpose lyot coronagraph masks for simultaneous high-contrast imaging and high-resolution wavefront sensing

G. Ruane, J. K. Wallace, A. J. E. Riggs, T. Wenger, M. Bagheri, J. Jewell, N. Raouf, G. Allan, C. Mejia Prada, M. Noyes, A. Walter

Proceedings Volume 12680, 1268018 (2023) https://doi.org/10.1117/12.2676853

KEYWORDS: Wavefront sensors, Coronagraphy, Coating, Reflection, Aluminum, Design and modelling, Phase shifts, Cameras, Wavefronts, Manufacturing

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Proceedings Article | 4 October 2023 Presentation + Paper

Design and fabrication of metasurfaces for wavefront sensing and high-contrast imaging in the visible

T. Wenger, J. Wallace, G. Ruane, J. Jewell, A. J. Riggs, N. Raouf

Proceedings Volume 12646, 1264604 (2023) https://doi.org/10.1117/12.2677961

KEYWORDS: Wavefront sensors, Reflection, Design and modelling, Coronagraphy, Fabrication, Polymethylmethacrylate, Aluminum, Exoplanets, Wavefronts, Titanium dioxide

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SPIE Journal Paper | 8 December 2022 Open Access

Next-generation active telescope for space astronomy

Stefan Martin, Charles Lawrence, David Redding, Bertrand Mennesson, John Rodgers, Kevin Hurd, Rhonda Morgan, Renyu Hu, John Steeves, Jeffrey Jewell, Charles Phillips, Claudia Pineda, Ned Ferraro, Thibault L. Flinois

JATIS, Vol. 8, Issue 04, 044005, (December 2022) https://doi.org/10.1117/12.10.1117/1.JATIS.8.4.044005

KEYWORDS: Telescopes, Space telescopes, Equipment, Mirrors, Astronomical telescopes, Astronomy, Exoplanets, Planets, Coronagraphy, Stars

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We present a design for an active telescope for space astronomy. The telescope is capable of both exoplanet work and general astronomy over wavelengths from ∼100 nm up to 5 μm. The primary mirror is 6 m in diameter, formed by 16 mirror segments that are precisely phased and supported on rigid body actuators and with segment optical surface figures fine-tuned using surface figure actuators. The active primary forms a large deformable mirror (DM) with wavefront error (WFE) correction at the entrance pupil. Thus the largest source of WFE can be removed at the source and is corrected over the entire field of view. This enables diffraction-limited performance at 400 nm and a more efficient optical system over a broader wavelength range than could be achieved by a small DM at a downstream relayed pupil. The telescope is passively cooled to below 100 K at Sun–Earth L2, enabling astronomical-background-limited observations out to 5 μm. Launched on a SpaceX Starship or alternatively National Aeronautics and Space Administration’s Space Launch System, the telescope requires minimal deployments. A 72-m-diameter starshade provides a contrast ratio better than 10 − 10 for exoplanet science. Near the visible region, with a 108% working bandwidth from 300 to 1000 nm, a working distance of 120 Mm provides a 51-mas inner working angle (IWA). This band can be moved to shorter or longer wavelengths by adjusting the starshade range from the telescope. Our first-ever thermal analysis of such a starshade shows that a temperature below 100 K can be achieved over a broad range of observing directions, permitting the possibility of working into the infrared. We model the yield in exoplanets that can be observed. A starshade and associated spectrograph offer significant advantages for exoplanet characterization. They enable a much broader instantaneous spectral bandwidth (here 108%) than current coronagraphs (∼10 % to 20% bandwidth), allow both polarizations to be observed simultaneously, and have higher throughput. The IWA is twice as small as can be achieved with a coronagraph and there is no outer working angle. These differences are particularly pronounced in the UV, where coronagraph performance would be strongly affected by throughput losses, wavefront aberrations, Fresnel polarization effects at surfaces, and thermal instability.

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Proceedings Article | 29 August 2022 Poster + Paper

An all-photonic, dynamic device for flattening the spectrum of a laser frequency comb for precise calibration of radial velocity measurements

Nemanja Jovanovic, Pradip Gatkine, Boqiang Shen, Maodong Gao, Nick Cvetojevic, Katarzyna Ławniczuk, Ronald Broeke, Charles Beichman, Stephanie Leifer, Jeffrey Jewell, Gautam Vasisht, Dimitri Mawet

Proceedings Volume 12188, 121885D (2022) https://doi.org/10.1117/12.2630301

KEYWORDS: Waveguides, Frequency combs, Modulation, Calibration, Spectrographs, Precision calibration, Polarization, Velocity measurements, Light sources, Chemical elements

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Laser frequency combs are fast becoming critical to reaching the highest radial velocity precisions. One shortcoming is the highly variable brightness of the comb lines across the spectrum (up to 4-5 orders of magnitude). This can result in some lines saturating while others are at low signal and lost in the noise. Losing lines to either of these effects reduces the precision and hence effectiveness of the comb. In addition, the brightness of the comb lines can vary with time which could drive comb lines with initially reasonable SNR’s into the two regimes described above. To mitigate these two effects, laser frequency combs use optical flattener’s. Flattener’s are typically bulk optic setups that disperse the comb light with a grating, and then use a spatial light modulator to control the amplitude across the spectrum before recombining the light into another single mode fiber and sending it to the spectrograph. These setups can be large (small bench top), expensive (several hundred thousand dollars) and have limited stability. To address these issues, we have developed an all-photonic spectrum flattener on a chip. The device is constructed from optical waveguides on a SiN chip. The light from the laser frequency comb’s output optical fiber can be directly connected to the chip, where the light is first dispersed using an arrayed waveguide grating. To control the brightness of each channel, the light is passed through a Mach-Zehnder interferometer before being recombined with a second arrayed waveguide grating. Thermo-optic phase modulators are used in each channel before recombination to path length match the channels as needed. Here we present the results from our first generation prototype. The device operates from 1400-1800 nm (covering the H band), with 20, 20 nm wide channels. The device was mounted on a PCB board to enable electrical control of the active elements and tested in the laboratory. It was demonstrated that the Mach- Zehnder’s allowed for nearly 40 dBs of dynamic modulation of the spectrum, which is greater than that offered by most spatial light modulators. With a smooth spectrum light source (superluminescent light source), we reduced the spectral variation to 3 dBs, limited by the properties of the components used. On a laser frequency comb which had strong modulations at high spatial frequencies, we still managed to reduce the modulation to 5 dBs. These devices are of the order of a US quarter and could play a significant role in future PRV and EPRV initiatives.

Proceedings Article | 29 August 2022 Presentation + Paper

A continuously-sampled high-resolution astrophotonic spectrograph using silicon nitride

Pradip Gatkine, Nemanja Jovanovic, Jeffrey Jewell, J. Kent Wallace, Dimitri Mawet

Proceedings Volume 12188, 121882D (2022) https://doi.org/10.1117/12.2630523

KEYWORDS: Waveguides, Spectrographs, Sensors, Silicon, Astrophotonics, Astronomy, Single mode fibers, Polarization, Spectral resolution, Microscopes

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Proceedings Article | 5 March 2022 Presentation + Paper

Simulating the study of exoplanets using photonic spectrographs

Marcos Perez, Pradip Gatkine, Nemanja Jovanovic, Jeffrey Jewell, J. Kent Wallace, Dimitri Mawet

Proceedings Volume 12008, 120080C (2022) https://doi.org/10.1117/12.2610355

KEYWORDS: Spectrographs, Exoplanets, Spectral resolution, Waveguides, Spectroscopy, Integrated photonics, Astrophotonics, Astronomical spectrometers, Astronomical instrumentation, Near infrared

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Proceedings Article | 1 September 2021 Presentation + Paper

Theoretical performance limits for coronagraphs on obstructed and unobstructed apertures: how much can current designs be improved?

Ruslan Belikov, Dan Sirbu, Jeffrey Jewell, Olivier Guyon, Christopher Stark

Proceedings Volume 11823, 118230W (2021) https://doi.org/10.1117/12.2594855

KEYWORDS: Coronagraphy, Stars, Telescopes, Planets, Yield improvement, Physics, Point spread functions, Fourier transforms, Exoplanets

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Proceedings Article | 20 August 2021 Presentation + Paper

An on-chip astrophotonic spectrograph with a resolving power of 12,000

Pradip Gatkine, Nemanja Jovanovic, Jeffrey Jewell, J. Wallace, Dimitri Mawet

Proceedings Volume 11819, 118190I (2021) https://doi.org/10.1117/12.2594635

KEYWORDS: Waveguides, Spectrographs, Spectral resolution, Astrophotonics, Polarization, Optical fibers, Computer aided design, Wave propagation, Silicon, Astronomy

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SPIE Journal Paper | 22 April 2021

Compression algorithms for high-data-volume instruments on planetary missions: a case study for the Cassini mission

Hua Xie, Robert West, Benoît Seignovert, Jeffrey Jewell, William Kurth, Terrance Averkamp

JATIS, Vol. 7, Issue 02, 028002, (April 2021) https://doi.org/10.1117/12.10.1117/1.JATIS.7.2.028002

KEYWORDS: Image compression, Chromium, Chemical species, Saturn, Wavelets, Data compression, Space operations, Distortion, Signal to noise ratio, Plasma

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We investigated data compression algorithms to boost science data return from high-data-volume instruments on planetary missions, particularly outer solar system missions where every bit of data represents an engineering triumph of over severe constraints on mass (limiting antenna size) and power (limiting signal strength). We developed a methodology to (1) investigate algorithms to improve compression and (2) to work with the science teams to evaluate the effects on the science. Our algorithm for compressing the Cassini Radio Plasma Wave Science (RPWS) data achieved a factor of 5 improvement in data compression (relative to what the RPWS team was using), and our algorithm for the Cassini Ultraviolet Imaging Spectrograph (UVIS) Saturn data set achieved a much higher factor (∼70). In both cases, the investigators on the science teams who evaluated our results reported that the science goals were not compromised. Our compression algorithm for Imaging Science Subsystem images achieved on average a factor of ∼1.7 improvement in lossless compression compared to the original algorithm. We also evaluated the compression effectiveness of JPL’s Fast Lossless EXtended (FLEX) hyperspectral/multispectral image compressor on Cassini’s Visible and Infrared Mapping Spectrometer data. FLEX lossless compression provides a factor of 2 improvement over the original compression. We also explore a different range of lossy compression, which can achieve an additional factor 2 to 5 depending on the fidelity required. Our findings have implications for the design of future space missions, particularly with respect to antenna size and overall size, weight, and power budgets, by demonstrating strategies to implement better data compression. In addition to improved algorithms, we show that an iterative process involving real-time science team evaluation and feedback to update the onboard compression algorithm is both essential and feasible. We make the case that a spacecraft facility compressor hosting a toolbox of compression algorithms, available to all of the science instruments and supported by a team of compression experts, convey significant benefits. Beyond the obvious benefits of increased science return and faster playback, better data compression enables design trades between antenna size and number of science instruments on the payload.

Proceedings Article | 23 December 2020 Poster + Paper

Data processing for high-contrast imaging with the James Webb Space Telescope

Marie Ygouf, Graça Rocha, Charles Beichman, Alexandra Greenbaum, Jarron Leisenring, Matthew De Furio, Michael Meyer, Julien Girard, Laurent Pueyo, Marshall Perrin, Taichi Uyama, Joseph Green, Jeffrey Jewell

Proceedings Volume 11443, 114433N (2020) https://doi.org/10.1117/12.2561628

KEYWORDS: James Webb Space Telescope, Data processing, Image processing, Human-computer interaction, Exoplanets, Planets, Point spread functions, Control systems, Coronagraphy, Environmental sensing

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Proceedings Article | 13 December 2020 Presentation + Paper

ATSA: a cold, active telescope for Space Astronomy

Stefan Martin, Charles Lawrence, David Redding, Michael Rodgers, Kevin Hurd, Jeffrey Jewell, Rhonda Morgan, Charles Phillips, Claudia Pineda, Bertrand Mennesson, John Steeves

Proceedings Volume 11443, 114432A (2020) https://doi.org/10.1117/12.2575505

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Proceedings Article | 13 December 2020 Poster

Active telescope for UV-through-midIR space astronomy

Charles Lawrence, David Redding, Kevin Hurd, Jeffrey Jewell, Stefan Martin, Rhonda Morgan, Charles Phillips, Claudia Pineda, Michael Rodgers, John Steeves

Proceedings Volume 11443, 114435Z (2020) https://doi.org/10.1117/12.2563177

KEYWORDS: Space telescopes, Telescopes, Astronomy, Astronomical telescopes, Exoplanets, Imaging spectroscopy, Ultraviolet radiation, Visible radiation, Mid-IR, Optics manufacturing

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SPIE Journal Paper | 9 November 2020

Wavefront sensing and control in space-based coronagraph instruments using Zernike’s phase-contrast method

Garreth Ruane, James Kent Wallace, John Steeves, Camilo Mejia Prada, Byoung-Joon Seo, Eduardo Bendek, Carl Coker, Pin Chen, Brendan Crill, Jeff Jewell, Brian Kern, David Marx, Phillip Poon, David Redding, A. J. Eldorado Riggs, Nicholas Siegler, Robert Zimmer

JATIS, Vol. 6, Issue 04, 045005, (November 2020) https://doi.org/10.1117/12.10.1117/1.JATIS.6.4.045005

KEYWORDS: Coronagraphy, Wavefronts, Stars, Actuators, Wavefront sensors, Space telescopes, Cameras, Equipment, Wavefront errors, Wavefront aberrations

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Proceedings Article | 2 March 2020 Presentation + Paper

Status and future developments of integrated photonic spectrographs for astronomy and Earth and planetary sciences

N. Jovanovic, N. Cvetojevic, M. Daal, B. Mazin, R. Moreira, D. Mawet, G. Vasisht, C. Beichman, K. Wallace, J. Jewell, S. Leifer, R. Dekany, M. Porter

Proceedings Volume 11287, 112870K (2020) https://doi.org/10.1117/12.2546959

KEYWORDS: Spectrographs, Astronomy, Telescopes, Waveguides, Single mode fibers, Spectral resolution, Sensors, Integrated photonics, Planetary science, Photonic devices

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Proceedings Article | 21 August 2018 Paper

Fast linearized coronagraph optimizer (FALCO) IV: coronagraph design survey for obstructed and segmented apertures

G. Ruane, A. Riggs, C. Coker, S. Shaklan, E. Sidick, D. Mawet, J. Jewell, K. Balasubramanian, C. Stark

Proceedings Volume 10698, 106984U (2018) https://doi.org/10.1117/12.2312973

KEYWORDS: Coronagraphy, Telescopes, Apodization, Stars, Diffraction, Mirrors, Optical instrument design, Image segmentation, Point spread functions, Solids

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Proceedings Article | 21 August 2018 Paper

Review of high-contrast imaging systems for current and future ground- and space-based telescopes I: coronagraph design methods and optical performance metrics

G. Ruane, A. Riggs, J. Mazoyer, E. Por, M. N’Diaye, E. Huby, P. Baudoz, R. Galicher, E. Douglas, J. Knight, B. Carlomagno, K. Fogarty, L. Pueyo, N. Zimmerman, O. Absil, M. Beaulieu, E. Cady, A. Carlotti, D. Doelman, O. Guyon, S. Haffert, J. Jewell, N. Jovanovic, C. Keller, M. Kenworthy, J. Kuhn, K. Miller, D. Sirbu, F. Snik, J. Kent Wallace, M. Wilby, M. Ygouf

Proceedings Volume 10698, 106982S (2018) https://doi.org/10.1117/12.2312948

KEYWORDS: Coronagraphy, Space telescopes, Signal to noise ratio, Planets, Point spread functions, Stars, Wavefronts, Telescopes, Optical instrument design, Adaptive optics

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Proceedings Article | 12 July 2018 Paper

Characterization of microdot apodizers for imaging exoplanets with next-generation space telescopes

Manxuan Zhang, Garreth Ruane, Jacques-Robert Delorme, Dimitri Mawet, Nemanja Jovanovic, Jeffrey Jewell, Stuart Shaklan, J. Kent Wallace

Proceedings Volume 10698, 106985X (2018) https://doi.org/10.1117/12.2312831

KEYWORDS: Exoplanets, Coronagraphy, Image segmentation, Space telescopes, Phase measurement, Wavefronts, Telescopes, Planets, Apodization

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A major science goal of future, large-aperture, optical space telescopes is to directly image and spectroscopically analyze reflected light from potentially habitable exoplanets. To accomplish this, the optical system must suppress diffracted light from the star to reveal point sources approximately ten orders of magnitude fainter than the host star at small angular separation. Coronagraphs with microdot apodizers achieve the theoretical performance needed to image Earth-like planets with a range of possible telescope designs, including those with obscured and segmented pupils. A test microdot apodizer with various bulk patterns (step functions, gradients, and sinusoids) and 4 different dot sizes (3 μm, 5 μm, 7 μm, and 10 μm) made of small chrome squares on anti-reflective glass was characterized with microscopy, optical laser interferometry, as well as transmission and reflectance measurements at wavelengths λ=600 nm and λ=800 nm. Microscopy revealed the microdots were fabricated to high precision. Results from laser interferometry showed that the phase shifts observed in reflection vary with the local microdot fill factor. This effect is not explained purely by interference between reflected fields from the chrome and glass portions. Transmission measurements showed that microdot fill factor and transmission were linearly related for dot sizes ≥5 μm. However, anomalously high transmittance was measured when the dot size is <5× the wavelength (i.e. ∼3 μm) and the fill factor is approximately 50%, where the microdot pattern becomes periodic. The transmission excess is not as prominent in the case of larger dot sizes suggesting that it is likely to be caused by the interaction between the incident field and electronic resonances in the surface of the metallic microdots. We used our empirical models of the microdot apodizers to optimize a second generation of reflective apodizer designs, specifically for demonstrating end-to-end instrumentation for planet characterization at Caltech’s High Contrast Spectroscopy Testbed for Segmented Telescopes (HCST), and confirmed that the amplitude and phase of the reflected beam closely matches the ideal wavefront.

Proceedings Article | 10 July 2018 Presentation + Paper

Review of high-contrast imaging systems for current and future ground-based and space-based telescopes: Part II. Common path wavefront sensing/control and coherent differential imaging

Nemanja Jovanovic, Olivier Absil , Pierre Baudoz, Mathilde Beaulieu, Michael Bottom, Eric Cady, Brunella Carlomagno, Alexis Carlotti, David Doelman, Kevin Fogarty, Raphaël Galicher, Olivier Guyon, Sebastiaan Haffert, Elsa Huby, Jeffrey Jewell, Christoph Keller, Matthew Kenworthy, Justin Knight, Jonas Kühn, Kelsey Miller, Johan Mazoyer, Mamadou N'Diaye, Emiel Por, Laurent Pueyo, A. Riggs, Garreth Ruane, Dan Sirbu, Frans Snik, J. Wallace, Michael Wilby, Marie Ygouf

Proceedings Volume 10703, 107031U (2018) https://doi.org/10.1117/12.2314260

KEYWORDS: Exoplanets, Coronagraphy, Wavefronts, Speckle, Wavefront sensors, Point spread functions, Imaging systems, Cameras, Modulation, Coherence imaging, Phase retrieval

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Proceedings Article | 10 July 2018 Presentation + Paper

Review of high-contrast imaging systems for current and future ground-based and space-based telescopes III: technology opportunities and pathways

Frans Snik, Olivier Absil, Pierre Baudoz, Mathilde Beaulieu, Eduardo Bendek, Eric Cady, Brunella Carlomagno, Alexis Carlotti, Nick Cvetojevic, David Doelman, Kevin Fogarty, Raphaël Galicher, Olivier Guyon, Sebastiaan Haffert, Elsa Huby, Jeffrey Jewell, Nemanja Jovanovic, Christoph Keller, Matthew Kenworthy, Justin Knight, Jonas Kuhn, Johan Mazoyer, Kelsey Miller, Mamadou N'Diaye, Barnaby Norris, Emiel Por, Laurent Pueyo, A. J. Eldorado Riggs, Garreth Ruane, Dan Sirbu, J. Kent Wallace, Michael Wilby, Marie Ygouf

Proceedings Volume 10706, 107062L (2018) https://doi.org/10.1117/12.2313957

KEYWORDS: Coronagraphy, Space telescopes, Imaging systems, Exoplanets, Telescopes, Point spread functions, Liquid crystals, Adaptive optics, Wavefront sensors

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SPIE Journal Paper | 28 March 2018 Open Access

Vortex coronagraphs for the Habitable Exoplanet Imaging Mission concept: theoretical performance and telescope requirements

Garreth Ruane, Dimitri Mawet, Bertrand Mennesson, Jeffrey Jewell, Stuart Shaklan

JATIS, Vol. 4, Issue 01, 015004, (March 2018) https://doi.org/10.1117/12.10.1117/1.JATIS.4.1.015004

KEYWORDS: Coronagraphy, Telescopes, Wavefronts, Planets, Exoplanets, Image segmentation, Stars, Mirrors, Space telescopes, Optical instrument design

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Proceedings Article | 13 September 2017 Presentation + Paper

The LUVOIR architecture "A" coronagraph instrument

L. Pueyo, N. Zimmerman, M. Bolcar, T. Groff, C. Stark, G. Ruane, J. Jewell, R. Soummer, K. St. Laurent, J. Wang, D. Redding, J. Mazoyer, K. Fogarty, Roser Juanola-Parramon, S. Domagal-Goldman, A. Roberge, O. Guyon, A. Mandell

Proceedings Volume 10398, 103980F (2017) https://doi.org/10.1117/12.2274654

KEYWORDS: Coronagraphy, Wavefronts, Sensors, Planets, Channel projecting optics, Wavefront sensors, Stars, Imaging systems, Mirrors, Telescopes

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In preparation for the Astro 2020 Decadal Survey NASA has commissioned the study four flagship missions spanning to a wide range of observable wavelengths: the Origins Space Telescope (OST, formerly the Far-Infrared Surveyor), Lynx (formerly the X-ray Surveyor), the Large UV/Optical/Infrared Surveyor (LUVOIR) and the Habitable Exoplanet Imager (HabEx). One of the key scientific objectives of the latter two is the detection and characterization of the earth-like planets around nearby stars using the direct imaging technique (along with a broad range of investigations regarding the architecture of and atmospheric composition exoplanetary systems using this technique). As a consequence dedicated exoplanet instruments are being studied for these mission concepts. This paper discusses the design of the coronagraph instrument for the architecture “A” (15 meters aperture) of LUVOIR. The material presented in this paper is aimed at providing an overview of the LUVOIR coronagraph instrument. It is the result of four months of discussions with various community stakeholders (scientists and technologists) regarding the instrument’s basic parameters followed by meticulous design work by the the GSFC Instrument Design Laboratory team. In the first section we review the main science drivers, presents the overall parameters of the instrument (general architecture and backend instrument) and delve into the details of the currently envisioned coronagraph masks along with a description of the wavefront control architecture. Throughout the manuscript we describe the trades we made during the design process. Because the vocation of this study is to provide a baseline design for the most ambitious earth-like finding instrument that could be possibly launched into the 2030’s, we have designed an complex system privileged that meets the ambitious science goals out team was chartered by the LUVOIR STDT exoplanet Working Group. However in an effort to minimize technological risk we tried to maximize the number of technologies that will be matured by the WFIRST coronagraph instruments.

Proceedings Article | 13 September 2017 Presentation + Paper

Optimization of coronagraph design for segmented aperture telescopes

Jeffrey Jewell, Garreth Ruane, Stuart Shaklan, Dimitri Mawet, Dave Redding

Proceedings Volume 10400, 104000H (2017) https://doi.org/10.1117/12.2274574

KEYWORDS: Coronagraphy, Optimization (mathematics), Telescopes, Expectation maximization algorithms, Optical instrument design, Space telescopes, Deformable mirrors, Planets, Image segmentation, Apodization

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The goal of directly imaging Earth-like planets in the habitable zone of other stars has motivated the design of coronagraphs for use with large segmented aperture space telescopes. In order to achieve an optimal trade-off between planet light throughput and diffracted starlight suppression, we consider coronagraphs comprised of a stage of phase control implemented with deformable mirrors (or other optical elements), pupil plane apodization masks (gray scale or complex valued), and focal plane masks (either amplitude only or complex-valued, including phase only such as the vector vortex coronagraph). The optimization of these optical elements, with the goal of achieving 10 or more orders of magnitude in the suppression of on-axis (starlight) diffracted light, represents a challenging non-convex optimization problem with a nonlinear dependence on control degrees of freedom. We develop a new algorithmic approach to the design optimization problem, which we call the ”Auxiliary Field Optimization” (AFO) algorithm. The central idea of the algorithm is to embed the original optimization problem, for either phase or amplitude (apodization) in various planes of the coronagraph, into a problem containing additional degrees of freedom, specifically fictitious ”auxiliary” electric fields which serve as targets to inform the variation of our phase or amplitude parameters leading to good feasible designs. We present the algorithm, discuss details of its numerical implementation, and prove convergence to local minima of the objective function (here taken to be the intensity of the on-axis source in a ”dark hole” region in the science focal plane). Finally, we present results showing application of the algorithm to both unobscured off-axis and obscured on-axis segmented telescope aperture designs. The application of the AFO algorithm to the coronagraph design problem has produced solutions which are capable of directly imaging planets in the habitable zone, provided end-to-end telescope system stability requirements can be met. Ongoing work includes advances of the AFO algorithm reported here to design in additional robustness to a resolved star, and other phase or amplitude aberrations to be encountered in a real segmented aperture space telescope.

Proceedings Article | 5 September 2017 Presentation + Paper

Laser metrology for ultra-stable space-based coronagraphs

Joel Nissen, Alireza Azizi, Feng Zhao, Shannon Kian Zareh, Shanti Rao, Jeffrey Jewell, Dustin Moore

Proceedings Volume 10398, 103980I (2017) https://doi.org/10.1117/12.2274704

KEYWORDS: Space telescopes, Laser metrology, Active optics, Wavefronts, Telescopes, Optical alignment, Optical sensing, Wavefront sensors

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Proceedings Article | 1 September 2017 Presentation + Paper

Performance and sensitivity of vortex coronagraphs on segmented space telescopes

Garreth Ruane, Dimitri Mawet, Jeffrey Jewell, Stuart Shaklan

Proceedings Volume 10400, 104000J (2017) https://doi.org/10.1117/12.2274508

KEYWORDS: Image segmentation, Space telescopes, Exoplanets, Planets, Telescopes, Apodization, Molecules, Earth's atmosphere, Atmospheric optics, Atmospheric sensing

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Proceedings Article | 22 July 2016 Paper

Apodized vortex coronagraph designs for segmented aperture telescopes

Garreth Ruane, Jeffery Jewell, Dimitri Mawet, Laurent Pueyo, Stuart Shaklan

Proceedings Volume 9912, 99122L (2016) https://doi.org/10.1117/12.2231715

KEYWORDS: Optical instrument design, Planets, Space telescopes, Telescopes, Image segmentation, Optical instrument design, Thirty Meter Telescope, Space telescopes, Telescopes, Image segmentation, Mirrors, Coronagraphy, Speckle, Point spread functions

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Showing 5 of 27 publications

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