Speakers
Speakers’ bios and abstracts below appear in order of their presentation according to the agenda.
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Workshop Presenters
Five-Minute Rapid Fire Presenters
Lab Tours
Poster Presenters
Workshop Presenters
Brandon Chalifoux, Assistant Professor of Optical Sciences, Assistant Professor of Aerospace and Mechanical Engineering
Title:
Ultrathin mirrors for space applications using ultrafast laser stress figuring
Abstract:
Space-borne optical systems increasingly require large quantities of lightweight mirrors, for which thin meniscus mirrors may be ideal to balance cost, volume, and mass. Ultrafast laser stress figuring is a technique for precisely bending mirrors into a desired shape by focusing ultrafast laser pulses into a substrate. This is part of the solution for enabling accurate thin mirrors, but coating, mounting, and alignment are other challenges that ultrafast laser processing can also help address. This talk will focus on the research directions being pursued in the Lightweight Optics Lab, with emphasis on X-ray telescope optics as an example application where ultrafast laser processing is especially promising.
Bio:
Brandon Chalifoux is an assistant professor of optical sciences and mechanical engineering. He earned his PhD from MIT in 2019, and specializes in optomechanical engineering. He serves as co-chair of the biennial SPIE Optomechanical Engineering conference at Optics and Photonics, and in various roles in the American Society of Precision Engineering.
Jaclyn John, PhD Student, SOC Vice President, OFA Outreach Chair
Title:
High-Altitude LWIR Spectro-Polarimetric Observations of Ice Clouds
Abstract:
Ice clouds remain a dominant source of uncertainty in global climate models due to challenges in constraining microphysical properties such as ice water path (IWP). Neglecting polarization effects in retrievals can introduce errors of up to 30%. Long-wave infrared (LWIR) polarimetry is theoretically more sensitive to small ice crystals and low IWP compared to microwave polarimetry, yet no spaceborne instruments currently provide such measurements. To address this gap, we developed the Infrared Channeled Spectro-Polarimeter (IRCSP), which measures linear Stokes parameters across three LWIR wavebands (8.5, 9.5, and 10.5 um). Following an initial high-altitude balloon demonstration in 2021, we deployed the upgraded instrument from Esrange Space Center (Sweden) in July 2024, obtaining more than 300 minutes of near-space observations at 39 km altitude. Thermal management upgrades stabilized focal-plane array temperatures to within +/-0.1C, enabling 164 minutes of observations with improved radiometric accuracy. Observed brightness temperatures ranged from 220–270 K and were compared against MODIS cloud-top retrievals, confirming predominantly ice-phase clouds in the instrument field of view. Channeled polarimetry encodes polarization via a spectrally modulated carrier frequency determined by the IRCSP’s high-order retarder. Using the Lomb–Scargle periodogram, polarization carrier frequencies consistent with the instrument design were detected in 15%, 42%, and 15% of measurements in the water vapor, ozone, and clear-sky bands, respectively. Polarized signals exhibited a preferential horizontal orientation, consistent with scattering models for nonspherical ice particles. Degree-of-linear-polarization (DoLP) values reached up to 27% with relatively large retrieval uncertainties of 13–18%. Trends between DoLP and brightness temperature indicate a polarization peak at intermediate cloud-top temperatures, similar to patterns observed in the microwave band. These results provide the first measurements of LWIR polarized signatures from ice clouds with thermally stable detectors, highlighting both the promise of LWIR polarimetry for cloud property retrievals and the enhanced instrumental precision needed for future satellite missions.
Bio:
Jaclyn is a 5th year PhD student in the Polarization Lab. She received her B.S in Applied Physics at the University of Arizona in 2021. Her dissertation research focus is in thermal polarimetry for remote sensing applications. She is a NASA FINESST fellow, an Optica Woman Scholar, and an ARCS scholar.
Florian Willomitzer