Dr. Lianqi Wang Profile

Dr. Lianqi Wang

Senior Adaptive Optics Systems Engineer at Thirty Meter Telescope

SPIE Involvement:

Conference Program Committee | Author

Publications (40)

SPIE Journal Paper | 14 February 2023

Simultaneous sodium profile estimation and LGS SH-WFS pixel processing optimization using LGS sub-aperture images

Lianqi Wang, Corinne Boyer, Brent Ellerbroek, Glen Herriot, Jean-Pierre Veran

JATIS, Vol. 9, Issue 01, 019002, (February 2023) https://doi.org/10.1117/12.10.1117/1.JATIS.9.1.019002

KEYWORDS: Sodium, Wavefront sensors, Simulations, Electronic filtering, Adaptive optics, Tunable filters, Optical transfer functions, Turbulence, Image processing, Telescopes

Read Abstract +

Image displacement pixel processing for laser guide star (LGS) Shack–Hartmann wavefront sensors (WFS) is often based upon a center of gravity with thresholding [thresholded CoG (tCoG)] algorithm. This method yields a nearly linear response to the sub-aperture wavefront gradient, but suffers from zero-point biases due to sodium profile variability and the resulting changes in the shape of the LGS sub-aperture images. This effect interacts with additional biases due to the image truncation caused by the limited field of view of the WFS sub-apertures, as well as from WFS non-common path aberration (NCPA). Natural guide star (NGS) truth wavefront sensors (TWFS) have been proposed to correct for the resulting aberrations in the reconstructed wave-front, and multiple such TWFS would be required to control anisoplanatism effects when there are multiple LGS. We describe a novel algorithm that estimates the sodium profile from time averaged sub-aperture images of one or multiple LGS using a system imaging model. This estimate can then be used to correct for the zero-point bias by adjusting the tCoG reference vector. This eliminates the need for an NGS TWFS to detect sodium profile induced aberrations, and a single TWFS with faint NGS would then be sufficient to monitor any variations in NCPA if needed, which greatly improves the sky coverage. The reconstructed sodium profile can also be used to build constrained matched filters, a noise-optimal alternative to tCoG that requires accurate knowledge of the sub-aperture LGS images and their spatial derivatives (and has yet to be demonstrated on sky). This new sodium profile reconstruction algorithm consequently eliminates the need for dithering LGS spots on sky to determine these derivatives, which greatly simplifies the implementation of matched filtering and also provides better performance. All of the necessary sodium profile estimation, bias computations, and matched filter optimizations can be done with a modern CPU (e.g., Intel Core i7-11700) at around a 0.1-Hz update rate as a background process for the real time controller. Our simulations of this new method are for center launch LGS, but we are confident the profile estimation algorithm will work equally well if not better for side launch LGS, even when there is increased image truncation.

Proceedings Article | 30 August 2022 Presentation + Paper

Simultaneous sodium profile estimation and LGS WFS pixel processing optimization using Shack-Hartmann subaperture images

Lianqi Wang, Corinne Boyer, Brent Ellerbroek, Glen Herriot, Jean-Pierre Veran

Proceedings Volume 12185, 121851I (2022) https://doi.org/10.1117/12.2630596

KEYWORDS: Sodium, Image processing, Digital filtering, Wavefront sensors, Adaptive optics, Wavefronts, Monte Carlo methods, Reconstruction algorithms, Image segmentation, Algorithm development

Read Abstract +

Proceedings Article | 30 August 2022 Poster + Paper

TMT Laser Guide Star Facility preliminary design

M. Trubey, C. Boyer, B. Delabre, B. Irarrazaval, J. Miles, K. Vogiatzis, L. Wang, C. Jiang

Proceedings Volume 12185, 121857H (2022) https://doi.org/10.1117/12.2630542

KEYWORDS: Thirty Meter Telescope, Sodium guide stars, Beam expanders, Laser beam propagation, Mirrors, Telescopes, Adaptive optics, Electronics, Control systems, Beam splitters, Laser systems engineering, Laser safety, Laser guide stars

Read Abstract +

Proceedings Article | 30 August 2022 Poster + Paper

The Infrared Imaging Spectrograph (IRIS) for TMT: achieving high sky coverage through the On-Instrument Wavefront Sensor design

David Andersen, Jenny Atwood, Jennifer Dunn, Jeffrey Crane, Brian Hoff, Ed Chapin, Glen Herriot, Tim Hardy, Lianqi Wang, James Larkin, Shelley Wright, Ryuji Suzuki, Robert Weber, Tim Greffe

Proceedings Volume 12185, 121855R (2022) https://doi.org/10.1117/12.2628668

KEYWORDS: IRIS Consortium, Monte Carlo methods, Wavefront sensors, Thirty Meter Telescope, Telescopes, Point spread functions

Read Abstract +

SPIE Journal Paper | 18 May 2022

Performance of a complementary metal-oxide-semiconductor sensor for laser guide star wavefront sensing

Zibo Ke, Felipe Pedreros Bustos, Jenny Atwood, Anne Costille, Kjetil Dohlen, Kacem El Hadi, Jean-Luc Gach, Glen Herriot, Zoltan Hubert, Pierre Jouve, Patrick Rabou, Jean-Pierre Veŕan, Lianqi Wang, Thierry Fusco, Benoît Neichel

JATIS, Vol. 8, Issue 02, 021511, (May 2022) https://doi.org/10.1117/12.10.1117/1.JATIS.8.2.021511

KEYWORDS: Sensors, CMOS sensors, Wavefront sensors, Relays, Photons, Adaptive optics, Telescopes, Sodium, Optics manufacturing, Tolerancing

Read Abstract +

Proceedings Article | 18 July 2018 Paper

Point spread function reconstruction simulations for laser guide star multi-conjugate adaptive optics on extremely large telescopes

L. Gilles, L. Wang, C. Boyer

Proceedings Volume 10703, 1070349 (2018) https://doi.org/10.1117/12.2315793

KEYWORDS: Point spread functions, Adaptive optics, Optical transfer functions, Actuators, Turbulence, Laser guide stars

Read Abstract +

Proceedings Article | 17 July 2018 Paper

NFIRAOS adaptive optics for the Thirty Meter Telescope

Jeffrey Crane, Glen Herriot, David Andersen, Jenny Atwood, Peter Byrnes, Adam Densmore, Jennifer Dunn, Joeleff Fitzsimmons, Tim Hardy, Brian Hoff, Kate Jackson, Dan Kerley, Olivier Lardière, Malcolm Smith, Jonathan Stocks, Jean-Pierre Véran, Corinne Boyer, Lianqi Wang, Gelys Trancho, Melissa Trubey

Proceedings Volume 10703, 107033V (2018) https://doi.org/10.1117/12.2314341

KEYWORDS: Mirrors, Thirty Meter Telescope, Adaptive optics, Beam splitters, Telescopes, Stars, Calibration, Interfaces, Wavefront sensors, Sensors

Read Abstract +

Proceedings Article | 10 July 2018 Presentation + Paper

Optimizing multi-LGS WFS AO performance in the context of sodium profile evolution and non-common path aberration

Lianqi Wang, Brent Ellerbroek, Glen Herriot, Jean-Pierre Véran, Corinne Boyer

Proceedings Volume 10703, 107032B (2018) https://doi.org/10.1117/12.2312873

KEYWORDS: Electronic filtering, Sodium, Adaptive optics, Wavefront sensors, Turbulence, Wavefronts, Sensors, Thirty Meter Telescope, Calibration, Device simulation

Read Abstract +

Proceedings Article | 10 July 2018 Presentation + Paper

The Real-Time controller (RTC) for the Narrow Field Infrared Adaptive Optics System (NFIRAOS) for TMT final design

Jennifer Dunn, Dan Kerley, Malcolm Smith, Ed Chapin, Glen Herriot, Jean-Pierre Veran, Corinne Boyer, Lianqi Wang, Luc Gilles, Gelys Trancho

Proceedings Volume 10703, 1070317 (2018) https://doi.org/10.1117/12.2314226

KEYWORDS: Real-time computing, Adaptive optics, Control systems, Wavefronts, Wavefront sensors, Telescopes, Prototyping, Stars, Actuators, Laser guide stars

Read Abstract +

Proceedings Article | 10 July 2018 Presentation + Paper

Ground layer adaptive optics for the W. M. Keck Observatory: feasibility study

J. Lu, M. Chun, S. Ammons, K. Bundy, R. Dekany, T. Do, D. Gavel, M. Kassis, O. Lai, C. Martin, C. Max, C. Steidel, L. Wang, K. Westfall, P. Wizinowich

Proceedings Volume 10703, 107030N (2018) https://doi.org/10.1117/12.2314417

KEYWORDS: Telescopes, Image quality, Galactic astronomy, Adaptive optics, Spectrographs, Astronomical imaging, Keck Observatory, Point spread functions, Spectroscopy

Read Abstract +

Proceedings Article | 6 July 2018 Presentation + Paper

The Infrared Imaging Spectrograph (IRIS) for TMT: closed-loop adaptive optics while dithering

Edward Chapin, Jennifer Dunn, David Andersen, Glen Herriot, Dan Kerley, Takashi Nakamoto, Jimmy Johnson, Lianqi Wang, Gelys Trancho, Eric Chisholm, Brent Ellerbroek, Kim Gillies, Yutaka Hayano, James Larkin, Luc Simard, Mark Sirota, Ryuji Suzuki, Robert Weber, Shelley Wright, Kai Zhang

Proceedings Volume 10707, 107071E (2018) https://doi.org/10.1117/12.2312804

KEYWORDS: IRIS Consortium, Telescopes, Adaptive optics, Java, Control systems, Real-time computing, Motion controllers, Error analysis, Observatories, Wavefront sensors

Read Abstract +

Proceedings Article | 8 August 2016 Paper

Thirty Meter Telescope (TMT) Narrow Field Infrared Adaptive Optics System (NFIRAOS) real-time controller preliminary architecture

Dan Kerley, Malcolm Smith, Jennifer Dunn, Glen Herriot, Jean-Pierre Véran, Corinne Boyer, Brent Ellerbroek, Luc Gilles, Lianqi Wang

Proceedings Volume 9913, 99134J (2016) https://doi.org/10.1117/12.2233709

KEYWORDS: Real-time computing, Thirty Meter Telescope, Telescopes, Adaptive optics, Wavefronts, Infrared telescopes, Data storage, Sensors, Stars, Signal processing

Read Abstract +

Proceedings Article | 27 July 2016 Paper

The progress of TMT Laser Guide Star Facility

Min Li, Kai Wei, Jinlong Tang, Changchun Jiang, Muwen Fan, Feng Chen, Daoman Rui, Xiqi Li, Corinne Boyer, Lianqi Wang, Brent Ellerbroek, Hao Xian, Changhui Rao, Yudong Zhang

Proceedings Volume 9909, 99095Q (2016) https://doi.org/10.1117/12.2231987

KEYWORDS: Laser guide stars, Telescopes, Mirrors, Adaptive optics, Laser safety, Laser systems engineering, Prototyping, Laser guide stars, Telescopes, Laser systems engineering, Adaptive optics, Reflectivity, Polarization, Temperature metrology

Read Abstract +

Proceedings Article | 27 July 2016 Paper

Thirty Meter Telescope narrow-field infrared adaptive optics system real-time controller prototyping results

Malcolm Smith, Dan Kerley, Edward Chapin, Jennifer Dunn, Glen Herriot, Jean-Pierre Véran, Corinne Boyer, Brent Ellerbroek, Luc Gilles, Lianqi Wang

Proceedings Volume 9909, 99094N (2016) https://doi.org/10.1117/12.2233711

KEYWORDS: Adaptive optics, Prototyping, Infrared telescopes, Thirty Meter Telescope, Adaptive optics, Infrared telescopes, Prototyping, Real-time computing, Wavefronts, Wavefront sensors, Actuators, Deformable mirrors, Data storage

Read Abstract +

Proceedings Article | 26 July 2016 Paper

Solving the NFIRAOS calibration puzzle

Jean-Pierre Véran, Glen Herriot, David Andersen, Lianqi Wang

Proceedings Volume 9909, 99090L (2016) https://doi.org/10.1117/12.2233669

KEYWORDS: Stars, Calibration, Telescopes, Adaptive optics, Calibration, Adaptive optics, Sensors, IRIS Consortium, Cameras, Diffraction, Near infrared, Mirrors

Read Abstract +

Proceedings Article | 6 August 2014 Paper

The Infrared Imaging Spectrograph (IRIS) for TMT: instrument overview

Anna Moore, James Larkin, Shelley Wright, Brian Bauman, Jennifer Dunn, Brent Ellerbroek, Andrew Phillips, Luc Simard, Ryuji Suzuki, Kai Zhang, Ted Aliado, George Brims, John Canfield, Shaojie Chen, Richard Dekany, Alex Delacroix, Tuan Do, Glen Herriot, Bungo Ikenoue, Chris Johnson, Elliot Meyer, Yoshiyuki Obuchi, John Pazder, Vladimir Reshetov, Reed Riddle, Sakae Saito, Roger Smith, Ji Man Sohn, Fumihiro Uraguchi, Tomonori Usuda, Eric Wang, Lianqi Wang, Jason Weiss, Robert Wooff

Proceedings Volume 9147, 914724 (2014) https://doi.org/10.1117/12.2055216

KEYWORDS: IRIS Consortium, Spectrographs, Imaging systems, Adaptive optics, Telescopes, Diffraction, Stars, Cryogenics, Astronomy, Thirty Meter Telescope

Read Abstract +

Proceedings Article | 28 July 2014 Open Access

The infrared imaging spectrograph (IRIS) for TMT: overview of innovative science programs

Shelley Wright, James Larkin, Anna Moore, Tuan Do, Luc Simard, Maté Adamkovics, Lee Armus, Aaron Barth, Elizabeth Barton, Hope Boyce, Jeffrey Cooke, Patrick Cote, Timothy Davidge, Brent Ellerbroek, Andrea Ghez, Michael Liu, Jessica Lu, Bruce Macintosh, Shude Mao, Christian Marois, Matthias Schoeck, Ryuji Suzuki, Jonathan Tan, Tommaso Treu, Lianqi Wang, Jason Weiss

Proceedings Volume 9147, 91479S (2014) https://doi.org/10.1117/12.2055599

KEYWORDS: IRIS Consortium, Galactic astronomy, Iterated function systems, Stars, Astronomy, Space telescopes, James Webb Space Telescope, Signal to noise ratio, Imaging systems, Spectroscopy

Read Abstract +

DOWNLOAD PAPER