About

Jared Maxson is an Associate Professor in the Department of Physics at Cornell University. His research focuses on high brightness electron beams, specifically on the physics of beam creation and brightness preservation in linear and circular accelerators. His work encompasses applications such as time-resolved electron diffraction and high brightness synchrotron radiation sources. Maxson's group combines detailed beam simulations with the design, construction, and operation of accelerator hardware, utilizing high-resolution beam diagnostics. His research aims to understand and mitigate brightness-limiting phenomena in accelerators, including the effects of the particle source brightness, collective self-interactions, and nonlinear dynamics. A significant aspect of his work involves growing and characterizing high brightness photoemitting materials using molecular beam epitaxy to develop atomically-ordered photoemissive materials like alkali antimonides. These materials are tested in in-house accelerators, with the goal of deploying high brightness photoemitters in various accelerator applications. Maxson's team has developed an ultrafast electron diffraction device based on these photoemitters, capable of producing high-quality diffraction images with sub-picosecond resolution, enabling the observation of atomic motion in real-time. His research also explores exotic phases in quantum materials that transiently arise on ultrafast timescales, collaborating with condensed matter physics groups. Maxson works closely with the Center for Bright Beams, an NSF science and technology center led by Cornell, to advance accelerator science and technology.

Research topics

• Physics
• Optics
• Materials science
• Optoelectronics
• Atomic physics
• Nuclear physics
• Chemistry
• Condensed matter physics
• Nanotechnology
• Composite material
• Quantum mechanics

Selected publications

• Pulsed laser deposition assisted epitaxial growth of cesium telluride photocathodes for high brightness electron sources

  Scientific Reports · 2025-01-27 · 4 citations

  articleOpen access

  The development of high-brightness electron sources is critical to state-of-the-art electron accelerator applications like X-ray free electron laser (XFEL) and ultra-fast electron microscopy. Cesium telluride is chosen as the electron source material for multiple cutting-edge XFEL facilities worldwide. This manuscript presents the first demonstration of the growth of highly crystalized and epitaxial cesium telluride thin films on 4H-SiC and graphene/4H-SiC substrates with ultrasmooth film surfaces. The ordering of the film was characterized by in situ reflection high energy electron diffraction and multiple X-ray diagnostics. The results of the quantum efficiency performance for epitaxial cesium telluride photocathodes are also reported.

  PublisherOA PDFDOI

• A cesium-iodide surface treatment for enhancement of negative electron affinity photocathode chemical robustness

  Journal of Applied Physics · 2025-06-09 · 2 citations

  articleOpen accessSenior author

  Photocathodes activated to negative electron affinity with a cesium-based activation layer, such as GaAs and GaN, can be used for generating spin-polarized electron beams, but their extreme sensitivity to chemical poisoning limits their operational lifetimes. This work demonstrates that applying and subsequently heating a cesium iodide (CsI) coating can produce a more durable activation layer lacking iodine, but rich in stable cesium suboxides (formal O oxidation state >−2), which significantly extend the dark lifetimes of both GaAs and GaN photocathodes. Through x-ray photoelectron spectroscopy, we examine the stability and formation of these Cs suboxides, which exhibit remarkable resistance to chemical poisoning. Additionally, we investigate the subsequent surface quality using atomic force microscopy. Our findings show that CsI-based surface treatments not only prolong photocathode lifetime but also maintain high spin polarization, positioning this method as a promising approach for enhancing photocathode durability in demanding applications.

  PublisherDOI

• Pulsed-laser lensing for phase modulation in electron microscopy

  Research Square · 2025-07-17

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• Multi-Objective Optimizations of High Gradient C-band Photoinjector for High Bunch Charge Applications

  ArXiv.org · 2025-09-14

  preprintOpen access

  The high gradients potentially achievable in distributed-coupling C-band photoinjectors make them attractive for many high brightness applications. Here we discuss optimization results for a 1.6 cell C-band photoinjector with a 240 MV/m peak field at the cathode that delivers a 250 pC electron bunch charge. We use a Multi-Objective Genetic Algorithm (MOGA), obtaining a Pareto front of emittance vs. bunch length. We also perform MOGA optimizations including an aperture to retain only a bright beam core. We find this reduces the emittance of the final beam by more than factor of 2 in some cases. For example, we find that at a root mean square bunch length of 1.6 ps, the use of an aperture improves the transverse emittance from 120 nm to 58 nm assuming negligible photocathode intrinsic emittance. The sacrificial charge at the periphery of the electron beam removed by the aperture linearizes the final slice phase space inside of the remaining beam core. The results obtained surpass the experimental state-of-the-art for beamlines with similar bunch charge.

  PublisherOA PDFDOI

• Emittance minimization for aberration correction II: Physics-informed Bayesian optimization of an electron microscope

  Ultramicroscopy · 2025-04-06 · 5 citations

  article
  PublisherDOI

• Emittance minimization for aberration correction I: Aberration correction of an electron microscope without knowing the aberration coefficients

  Ultramicroscopy · 2025-04-07 · 5 citations

  article
  PublisherDOI

• Photoinduced twist and untwist of moiré superlattices

  Nature · 2025-11-12 · 2 citations

  article
  PublisherDOI

• Progress in the development of an ultrafast pulsed ponderomotive phase plate for cryo-electron tomography

  Structural Dynamics · 2025-07-01 · 3 citations

  articleOpen access

  Cryo-electron tomography (cryo-ET) is a powerful modality for resolving cellular structures in their native state. While single-particle cryo-electron microscopy excels in determining protein structures purified from recombinant or endogenous sources due to an abundance of particles, weak contrast issues are accentuated in cryo-ET by low copy numbers in crowded cellular milieux. Continuous laser phase plates offer improved contrast in cryo-ET; however, their implementation demands exceptionally high-peak optical intensities. Instead, a novel experimental approach to enhance contrast in cryo-ET is to manipulate the phase of scattered pulsed electrons using ultrafast pulsed photons. Here, we outline the experimental design of a proof-of-concept electron microscope and demonstrate synchronization between electron packets and laser pulses. Furthermore, we show ultrabright photoemission of electrons from an alloy field emission tip using femtosecond ultraviolet pulses. These experiments pave the way toward exploring the utility of the ponderomotive effect using pulsed radiation to increase phase contrast in cryo-ET of subcellular protein complexes in situ, thus advancing the field of cell biology.

  PublisherDOI

• Characterization of electron spin polarization from positive electron affinity GaAs photocathodes

  Journal of Applied Physics · 2025-09-08 · 1 citations

  articleOpen access

  Negative Electron Affinity (NEA) GaAs photocathodes are widely used to generate spin-polarized electron beams, typically achieving Electron Spin Polarizations (ESPs) in the range of 35%–40%. However, when operated in a Positive Electron Affinity (PEA) state, where a potential barrier inhibits low-energy electrons from escaping into vacuum, measured ESPs can exceed 50%. This effect can occur naturally during photocathode operation, as the NEA surface activation layers can degrade easily over time, increasing the electron affinity. In this work, we investigate and characterize the behavior of enhanced ESPs under PEA conditions. We present experimental measurements of ESP using a retarding-field Mott polarimeter on GaAs photocathodes with controlled and varying electron affinities. These results are complemented by theoretical explanations considering the material band structure, the light excitation profile, and spin depolarization mechanisms.

  PublisherDOI

• ESPPU INPUT: C$^3$ within the "Linear Collider Vision"

  ArXiv.org · 2025-03-26

  preprintOpen access

  The Linear Collider Vision calls for a Linear Collider Facility with a physics reach from a Higgs Factory to the TeV-scale with $e^+e^{-}$ collisions. One of the technologies under consideration for the accelerator is a cold-copper distributed-coupling linac capable of achieving high gradient. This technology is being pursued by the C$^3$ collaboration to understand its applicability to future colliders and broader scientific applications. In this input we share the baseline parameters for a C$^3$ Higgs-factory and the energy reach of up to 3 TeV in the 33 km tunnel foreseen under the Linear Collider Vision. Recent results, near-term plans and future R\&D needs are highlighted.

  PublisherOA PDFDOI

Frequent coauthors

• Ivan Bazarov

  Cornell University

  72 shared

• L. Cultrera

  Brookhaven National Laboratory

  44 shared

• P. Musumeci

  University of California, Los Angeles

  41 shared

• Adam Bartnik

  Cornell University

  36 shared

• Alice Galdi

  34 shared

• Siddharth Karkare

  Arizona State University

  33 shared

• Jai Kwan Bae

  Cornell University

  27 shared

• Matthew Andorf

  Cornell University

  23 shared

Labs

• Maxson LabPI

Awards & honors

• Center for Bright Beams (NSF science and technology center)