Department of Chemistry at Columbia University, New York
WELCOME TO DEL-LABS
Directing Electrons with Light
LATEST NEWS
05/2026
Ding and Saeed's discovery of giant optical spin orbit interactions in the ferroelectric NbOI2 is posted on arXiv! Check out beautiful movies directly tracking light splitting into circularly polarized currents through the optical spin Hall effect in waveguides, featuring awesome theory from the Mandal group.
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05/2026
Andrea and Fuyang's discovery of chiral polaritons and the hyperbolic spin Hall effect in the natural highly anisotropic metal MoOCl2 is posted on arXiv! Featuring a brand new far-field approach to probe hyperbolic polaritons beyond the light cone.
05/2026
Very honored to be selected as a C&EN Talented 12!
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04/2026
Yongseok takes off, soon starting a faculty position and his own research group at POSTECH - many congratulations Yongseok!
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01/2026
Welcome to two new postdocs in the group: Agata Azzolin from Hamburg University/DESY, and Ziyi Wang from UC Berkeley!
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01/2026
Congratulations to Jack for successfully defending his thesis on quasiparticle interactions in semiconductors!
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12/2025
Congratulations to Inki for successfully defending his thesis on molecular polaritons!
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11/2025
We are honored to receive the Coblentz Award in Spectroscopy, and the UW-Chemistry/PhaseTech award in ultrafast spectroscopy!
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10/2025
Yongseok's heroic work on ultrafast imaging of polariton transport across a large range of materials and temperatures is out in Chem! This work develops a comprehensive understanding of how material properties affect polariton transport, providing quantitative guidelines for simultaneously optimizing coherence and nonlinear interactions in polaritonic systems.
Read all news here.
RESEARCH
The efficient transport and interconversion of energy between photons, electrons, ions and heat underpins life on earth. In modern technologies ranging from solar panels to computers, batteries and health sensors, energy moves slowly, randomly and often inefficiently towards target conversion sites. We aim to direct energy flow in emerging materials in ways that are targeted and efficient, moving beyond random motion to unleash new paradigms for extracting more energy from solar panels, storing more energy in batteries, speeding up information transport and processing, and exploiting correlated electronic systems for new applications.
We use light as a powerful stimulus to initiate, image and control electronic behavior in emerging materials on extreme spatiotemporal scales. Questions we explore include:
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How do we image individual electrons moving and interacting with their surroundings in material lattices?
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How do we control the direction and speed at which energy packets move towards functional targets?
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How do we unlock exotic emergent phenomena and exploit them in modern devices?
The ongoing explosion of discoveries in quantum, meta- and nanomaterials provides the perfect platform for us to answer these questions now.
Super-resolution imaging
of electronic transport and material energy landscapes
Optical control of nuclear-electronic coupling and energy flow on material mesoscales
Optical manipulation of strongly correlated electronic behavior with confined light
In the process of answering these questions, we invent new tools capable of non-invasively imaging events happening over femtoseconds to hours at the single-nanometer scale. These tools are also relevant for imaging phenomena in a broad range of disciplines, including self-assembly of biological or material building blocks, protein dynamics, and non-dissipative electronic transport in superconductors.
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In addition to gaining a deep fundamental understanding of light-matter interactions, students and postdocs in the group acquire experience in nonlinear optics, super-resolution microscopy, ultrafast visible, IR and terahertz spectroscopy, nanofabrication including lithography and van der Waals heterostructure devices, and materials design and characterization. We collaborate broadly with both theoretical and experimental research groups at Columbia and beyond.
THE TEAM
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Postdoctoral scholar, 2016-2019
University of California, Berkeley
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Doctoral Prize Fellow, 2015
​PhD Physical Chemistry, 2010-2014
University of Sheffield​
BS Chemistry & Physics, 2016-2020
University of California, Los Angeles
BS Chemistry, 2016-2020
University of Texas at Austin
BS Chemistry, 2014-2018
MEd Curriculum and Instruction, 2018-2019
University of Maryland, College Park
PhD Chemistry, 2015-2021
Yonsei University (South Korea)
BS Chemistry, 2018-2022
Bard College
BS Chemistry 2019 - 2023
Princeton University
BS Chemistry 2019-2023
University of Chicago
BS Chemical Engineering, 2018-2022
University of California, Berkeley
Chem Engineering & Materials Science
BS 2016-2019, MS 2019-2021
Ewha Womans University (South Korea)
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PhD Applied Physics, 2019-2024
Rice University
PhD Materials Science & Engineering, 2019-2024
Georgia Institute of Technology
BS Chemistry, 2020-2024
University of California, San Diego
BS Chemistry, 2020-2024
Brigham Young University
Agata Azzolin
Postdoc
aa5946@columbia.edu
PhD Physics, 2021-2025
Deutsches Elektronen-Synchrotron (DESY),
Universität Hamburg, Germany
Ziyi Wang
Postdoc
zw3203@columbia.edu
PhD Physical Chemistry, 2019-2025
University of California, Berkeley
Read more about the team here.
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We continue to look for motivated students and postdocs interested in spectroscopy, microscopy and materials science to join the group. Postdoc candidates have a strong background in physical chemistry or physics and experience with one or a combination of the following: ultrafast spectroscopy, super-resolution microscopy, quantum materials, nonlinear optics. Contact Milan for more information.
SELECTED PUBLICATIONS
Yongseok Hong, Ding Xu, Milan Delor (2025). Exciton Delocalization Suppresses Polariton Scattering. Chem, 10.1016/j.chempr.2025.102759
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Si Tong Bao, Yongseok Hong, Haoyu Jiang, Luke Lackovic, Shayan Louie, Ding Xu, Fay Ng, Nicholas Olsen, Xiaoyang Zhu, Michael L. Steigerwald, Milan Delor, Colin Nuckolls, Qifeng Jiang (2025). Chirality Unbound in Graphene Nanoribbons. Angewandte Chemie, e202508426.
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Ding Xu, Zhi Hao Peng, Chiara Trovatello, Shan-Wen Cheng, Xinyi Xu, Aaron Sternbach, Dmitri N. Basov, P. James Schuck, Milan Delor (2024). Spatiotemporal imaging of nonlinear optics in van der Waals waveguides. Nature Nanotechnology, 20, 374.
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Lee I, Melton S, Xu D, Delor M (2024). Controlling Molecular Photoisomerization in Photonic Cavities through Polariton Funneling. Journal of the American Chemical Society, 146, 9544-9553.
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Baxter J, Koay C, Xu D, Cheng SW, Tulyagankhodjaev J, Shih P, Roy X, Delor M (2023). Coexistence of Incoherent and Ultrafast Coherent Exciton Transport in a Two-Dimensional Superatomic Semiconductor. The Journal of Physical Chemistry Letters, vol. 14, pp. 10249-10256.
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Tulyagankhodjaev J, Shih P, Yu J, Russell J, Chica D, Reynoso M, Su Haowen, Stenor A, Roy X, Berkelbach T, Delor M (2023). Room Temperature Wavelike Exciton Transport in a van der Waals Superatomic Semiconductor. Science, vol. 382, pp. 438-442.
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Cheng SW, Xu D, Su H, Baxter J, Holtzman L, Watanabe K, Taniguchi T, Hone J, Barmak K, Delor M (2023). Optical Imaging of Ultrafast Phonon-Polariton Propagation through an Excitonic Sensor. Nano Letters, vol. 23, pp. 9936-9942.
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Xu D, Mandal A, Baxter J, Cheng SW, Lee I, Su H, Liu S, Reichman D, Delor M (2023). Ultrafast imaging of polariton propagation and interactions. Nature Communications, vol. 14, 3881.
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Su H, Xu D, Cheng SW, Li B, Liu S, Watanabe K, Taniguchi T, Hone J, Delor M (2022). Dark-exciton driven energy funneling into dielectric inhomogeneities in two-dimensional semiconductors. Nano Letters, vol. 22, pp. 2843-2850.
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CONTACT
Columbia University
Department of Chemistry
3000 Broadway, 117 Havemeyer Hall
New York, NY 10027
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Office: 506 Havemeyer
Lab: 117 Havemeyer
