Fienup Research Group

We make images sharper

• Click here to see a recent story of how our group and others from the University of Rochester contributed to making the James Webb Space Telescope a success.
• Click here to see a recent story on Matt Banet’s winning of the US Air Force’s Dr. Samuel Blankenship Directed Energy Scholar Award. Matt had previously won a SMART scholarship.
• Click here to see a recent story on our work on the James Webb Space Telescope.
• Click here to see a recent story on Manuel Guizar’s winning the ICO Prize for 2019.
• Click here to see a recent story on former group member Abbie (Tippie) Watnik’s advice on staying connected.

We perform research in the areas of:

• Unconventional imaging
• Phase retrieval
• Wavefront sensing
• Imaging with sparse-aperture telescopes
• Image reconstruction algorithms

Recently published papers
(available under Publications tab)

By Yaocheng Sparrow Tian:

“Phase retrieval with only a nonnegativity constraint,” Opt. Letters 48, 135-138 (2023).

By Matthias Banet:

“Demonstration of multi-plane sharpness metric maximization on motion-compensated, multi-wavelength 3D digital holographic field data,” Opt. Lett., 49, 418-421 (2024). DOI: 10.1364/OL.499173
“Multiplexed, multi-wavelength 3D digital holographic imaging methods with range unwrapping,” Proc. SPIE 1269304 (2023). doi: 10.1117/12.2676428.
“Speckle decorrelation effects on motion-compensated, multi-wavelength 3D digital holography: theory and simulations,” Opt. Eng 62(7), 073103 (2023), doi: 10.1117/1.OE.62.7.073103.
“3D multi-plane sharpness metric maximization with variable corrective phase screens,” Appl. Opt. 60, G243-G252 (2021).
“Subaperture sampling for digital-holography applications involving atmospheric turbulence,” Appl. Opt. 60, G30-G39 (2021).
“Compensated-beacon adaptive optics using least-squares phase reconstruction,” Opt. Express 28, 36902-36914 (2020).
“Demonstration of single-shot digital holography using a Bayesian framework,” J.Opt.Soc.Am.A 35, 103-107 (2018).

By Joseph Tang: “Integrating Bias and Gain Invariance with the Generalized Anscombe Transform for Wavefront Sensing,” Proc. SPIE 1144348 (2020).

By Scott Will: “High-order coronagraphic wavefront control with algorithmic differentiation: first experimental demonstration,” J. Astron. Telesc. Instrum. Syst. 9(4), 045004 (2023).
“Jacobian-free coronagraphic wavefront control using nonlinear optimization,” J. Astron. Telesc. Instrum. Syst. 7(1), 019002 (2021).
“An algorithm for exact area-weighted antialiasing of discrete circular apertures,” J. Opt. Soc. Am. A 37, 688-696 (2020).
“Field stop diffraction and sampling effects in apodized pupil Lyot coronagraphs,” J. Opt. Soc. Am. A 37, 629-642 (2020).

A famous paper

One of Prof. Fienup’s papers [J.R. Fienup, “Phase Retrieval Algorithms: a Comparison,” Appl. Opt. 21, 2758-2769 (1982)] has received over 6,000 citations (Google Scholar) and is the most highly cited paper (out of over 50,000) in the journal Applied Optics.

Examples of research problems:

NASA’s James Webb Space Telescope

NASA’s James Webb Space Telescope will need phase retrieval to align the 18 segments of the primary mirror. Similar phase retrieval algorithms were used to determine how to fix the Hubble Space Telescope. NASA’s Wide-Field Infrared Survey Telescope (WFIRST), although not segmented, will need precise knowledge of its small wavefront aberrations for exoplanet direct imaging and microlensing, which can be determined with phase retrieval. NASA’s proposed Large UV/Optical/Infrared (LUVOIR) Surveyer telescope will include coronagraph instruments that will be able to image dim planets orbiting bright stars. It will require exquisite wavefront control and highly accurate modeling of the coronagraph optics.

Astronomers and DoD are interested in imaging interferometry

using two or more well-separated, small telescopes to obtain images having the fine resolution of a single, much larger telescope, as illustrated here by NASA’s SPace InfraRed Interferometric Telescope (SPIRIT) concept. We are interested in image and spectral reconstruction despite uncertainties in alignment and motion, incomplete data, and, for ground-based systems, atmospheric turbulence. We are currently applying these techniques to the problem of imaging geosynchronous satellites from the earth, despite atmospheric turbulence, and of wide-field infrared astronomical imaging.