About

Ivan Bazarov is a Professor in the Department of Physics at Cornell University. He holds an M.S. degree from Moscow Institute of Physics and Technology and Far Eastern State University, obtained in 1998, and a Ph.D. from Far Eastern State University, earned in 2000. His research focuses on accelerator physics, specifically on photoemission sources and beam dynamics in accelerators. His group concentrates on producing high brightness electron beams and their applications, such as ultrafast imaging of molecules and providing beams for particle and nuclear physics. They also work on advancing photocathodes for accelerators and high-energy detectors, modeling the physics of photoemission, intense beam dynamics, and optimization methods for accelerators at both design and operational stages. Bazarov has received notable awards, including the DOE Early Career Award in 2010 and the IEEE Particle Accelerator Science and Technology Award in 2015. His professional experience includes roles as a Research Associate at Cornell Laboratory for Accelerator-based Sciences and Education, Assistant Professor, Associate Professor, and currently, Professor of Physics.

Research topics

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

Selected publications

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

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

  articleOpen access

  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

• Photoinduced twist and untwist of moiré superlattices

  Nature · 2025-11-12 · 2 citations

  article
  PublisherDOI

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

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

  articleOpen accessSenior author

  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

• A comparison-relationship-surrogate evolutionary algorithm for multi-objective optimization

  Swarm and Evolutionary Computation · 2025-04-24 · 5 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Experimental Reconstruction of Source 4D Phase Space Without Prior Knowledge of Transfer Matrix

  ArXiv.org · 2025-10-06

  preprintOpen access

  We experimentally demonstrate a method for reconstructing the transverse 4D phase space of an electron beam at the time of emission from downstream diagnostics of the 4D phase space. This method does not rely on detailed knowledge of the beamline transport, besides assuming that linearity and symplecticity are satisfied. We apply this method to measure the transverse position and momentum phase space of electrons emitted from a spatially-structured alkali-antimonide cathode. This method can uncover local correlations between emission location and momentum spread. We formulate this method analytically and investigate resolution limits.

  PublisherOA PDFDOI

• Development of a Methodology for Ensuring Optimal Parameters of Flexible Automated Lines of Mechanical Assembly Production

  Journal of Machinery Manufacture and Reliability · 2024-12-01 · 1 citations

  articleSenior author

  The problems of ensuring high technical and economic performance of flexible automated lines of mechanical assembly production through the development of a methodology for determining the optimal parameters of the automated storage and retrieval system are considered. The functioning of a flexible automated line is simulated in order to verify the adequacy of the methodology developed. As a result of this research, an algorithm of the methodology for providing the optimal parameters of the automated storage and retrieval system is developed, the use of which makes it possible to increase the accuracy and reduce the labor intensity of the development of the design and technological solutions at the initial stage of design of automated lines of mechanical assembly productions.

  PublisherDOI

• Measurement of Spin-Polarized Photoemission from Wurtzite and Zinc-Blende Gallium Nitride Photocathodes

  arXiv (Cornell University) · 2024-05-07

  preprintOpen access

  Spin-polarized photoemission from wurtzite and zinc-blende gallium nitride (GaN) photocathodes has been observed and measured for the first time. The p-doped GaN photocathodes were epitaxially grown and activated to negative electron affinity (NEA) with a cesium monolayer deposited on their surfaces. A field-retarding Mott polarimeter was used to measure the spin-polarization of electrons photoemitted from the top of the valence band. A spectral scan with a tunable optical parametric amplifier (OPA) constructed to provide low-bandwidth light revealed peak spin polarizations of 17% and 29% in the wurtzite and zinc-blende photocathodes, respectively. Zinc-blende GaN results are analyzed with a spin-polarization model accounting for experimental parameters used in the measurements, while possible mechanisms influencing the obtained spin polarization values of wurtzite GaN are discussed.

  PublisherOA PDFDOI

• Measurement of spin-polarized photoemission from wurtzite and zinc blende gallium nitride photocathodes

  Applied Physics Letters · 2024-07-15 · 6 citations

  article

  Spin-polarized photoemission from wurtzite and zinc blende gallium nitride (GaN) photocathodes has been observed and measured. The p-doped GaN photocathodes were epitaxially grown and activated to negative electron affinity with a cesium monolayer deposited on their surfaces. A field-retarding Mott polarimeter was used to measure the spin polarization of electrons photoemitted from the top of the valence band. A spectral scan with a tunable optical parametric amplifier constructed to provide low-bandwidth light revealed peak spin polarizations of 17% and 29% in the wurtzite and zinc blende photocathodes, respectively. Zinc blende GaN results are analyzed with a spin polarization model accounting for experimental parameters used in the measurements, while possible mechanisms influencing the obtained spin polarization values of wurtzite GaN are discussed.

  PublisherDOI

• Demonstrating improved lifetime in superlattice photocathodes with robust activating coatings for high current, highly spin-polarized beam production

  2024-01-01

  reportOpen access

  This document summarizes the findings resulting from the award No DE-SC0021039.

  PublisherDOI

• HERACLES: A high-voltage DC test beamline for high average current photocathodes

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2023-04-05

  articleOpen accessSenior author
  PublisherOA PDFDOI

Recent grants

• REU Site: Accelerator Physics and Synchrotron Radiation Science

  NSF · $411k · 2018–2023

Frequent coauthors

• Jared Maxson

  Cornell University

  72 shared

• Bruce Dunham

  CapeSym (United States)

  68 shared

• L. Cultrera

  Brookhaven National Laboratory

  67 shared

• Siddharth Karkare

  Arizona State University

  61 shared

• Adam Bartnik

  Cornell University

  56 shared

• Jai Kwan Bae

  Cornell University

  48 shared

• C. K. Sinclair

  Thomas Jefferson National Accelerator Facility

  38 shared

• Alice Galdi

  33 shared

Labs

• Ivan Bazarov's Research GroupPI

  High Brightness Source Group

Awards & honors

• 2010 DOE Early Career Award
• 2015 IEEE Particle Accelerator Science and Technology Award