Current Group Members
Postdoctoral Researchers

Dr. Feifan Wang
Ph.D. from Peking University
I try to complete the solar-chemical energy conversion puzzle from the aspects of photophysics and surface/interface chemistry. During my PhD program, I studied the solid-state semiconductor nanomaterials for photocatalysis and photoelectrochemical cells, with focusing on material synthesis and performance characterization, more about the chemistry and molecular engineering. Here, I am establishing some fundamental understanding of photophysics in the novel optoelectronic materials through synthesizing andprobing the carrier screening in these model systems. After work, I like to jog, read, and learn cooking food.

Dr. Yusong Bai
Ph.D. from Duke University
During my Ph.D., my research emphasis was on interrogating and managing photo-induced electronically excited-state dynamics of various supermolecular to nanoscale structures, including ethyne-bridged highly-conjugated (porphinato)metal(II) architectures, semiconducting single-walled carbon nanotubes, etc. Currently, I investigate charge transfer dynamics at donor/acceptor interfaces.

Dr. Mark Ziffer
Ph.D. from University of Washington
My research focuses on using EUV time resolved two photon photoemission spectroscopy to study electronic structure and charge carrier dynamics in 2D semiconductor monolayers and heterostructures based on superatomic solids and transition metal dichalcogenides. I received my PhD from the University of Washington working with David Ginger, where I used electric field modulation spectroscopy and luminescence spectroscopy techniques to study exciton electronic structure and charge recombination in hybrid organic-inorganic perovskite and organic semiconductors. In my spare time I like exploring new places and trying new foods, which luckily NYC has no shortage of.

Dr. Yanan Dai
Ph.D. from University of Pittsburgh
My PhD research was focused on imaging of femtosecond dynamics of space-time structured surface evanescent waves using interferometric time-resolved coherent multi-photon photoemission microscopy, and studying their physical properties such as spin angular momentum, field chirality and topological spin textures. Now I am trying to explore the rich electronic and excitonic properties of bilayer heterostructures composed of transition metal dichalcogenides, using time-resolved and angle-resolved photoemission spectroscopy with a femtosecond laser-based excitation source.

Dr. Qiuyang Li
Ph.D. from Emory University
I received my Ph.D. in Physical Chemistry focusing on the charge separation/recombination and exciton transport/dissociation in semiconductor nanocrystals for solar-to-hydrogen conversion and lasing applications. In the XYZ group, my research is mainly on ultrafast laser spectroscopic studies on exciton, electron, and phonon dynamics in new and emerging semiconductors. In my spare time, I enjoy movies, foods, badminton, and swimming.

Dr. Yongping Fu
Ph.D. from the University of Wisconsin-Madison
My research interests are focused on the chemistry, physics, and optoelectronic applications of nanoscale and solid-state materials. I received a Ph.D. in chemistry from the University of Wisconsin-Madison (2018) and my B.S. degree in chemistry from Peking University (2012). During my Ph.D. study with Prof. Song Jin, I worked on the rational synthesis and optoelectronic applications of halide perovskite nanostructures (e.g. 1D nanowires and 2D quantum wells), phase stabilization of metastable perovskites, and discovery of new perovskite materials. After graduation, I held a postdoc with Prof. Elad Harel at Northwestern University, where I studied carrier dynamics in 2D perovskites and nanostructures using transient absorption microscopy. In the XYZ group, I am studying exciton-polaritons in semiconductor microcavities using various spectroscopic techniques. I also enjoy swimming, cooking, traveling and gardening.

Dr. Lucas Huber
Ph.D. from ETH Zurich
I am interested in the formation of polarons in para-and ferroelectric semiconductors and how carrier transport properties may benefit from the specific environment found in these systems. My Ph.D. work focused on the development of time-resolved nonlinear spectroscopy techniques such as second-harmonic generation and 2D THz spectroscopy. In the XYZ group, I am now applying optical Kerr effect, transient absorption as well as THz spectroscopy to investigate electron-phonon coupling. And if there is time left, I enjoy the outdoors and like to climb.

Dr. Jue Wang
B.S. in Chemistry from Peking University
I use time-resolved optical spectroscopy and microscopy to study interlayer excitons in two-dimensional van der Waals heterostructures. Before this dimension reduction, I worked on hot carriers and polaron physics in lead halide perovskites. When getting my B.S. at Peking University, I researched single-molecule biophysics of DNA repair and met Rachael with whom I spend my spare time and travel around the world.

Dr. Youn Jue (Eunice) Bae
Ph.D. from Northwestern University
During my Ph.D. my research focused on investigating the down-conversion process in organic chromophores, also know as singlet fission. I used optical- and magnetic- spectroscopy to study how excitons and spins evolve over time and space in various acene and rylene derivatives in the Wasielewski group at Northwestern Unviersity. Here in the XYZ group, I am planning to study spin waves in 2D magnetic materials and many-body interactions in 2D TMDCs. Outside of the lab, I like traveling, eating goood foods, climbing and snowboarding.

Dr. Taketo Handa
Ph.D. from Kyoto University
I am interested in charge-carrier dynamics in optoelectronic materials and try to explore new optical functionalities of materials. I received my Ph.D. from Kyoto University, where I studied unusual thermal and phonon properties and photovoltaic conversion processes in metal halide perovskites and solar cells. After graduation, I worked at Kyoto University for one year and focused on nonlinear optical responses of halide perovskites. In XYZ group, I will work on the ultrafast spectroscopy of energetic carrier dynamics in emerging materials. In my free time, I like walking around the NYC.
Graduate Students

Michael Scott Spencer
B.S. in Chemistry & Physics from West Virginia University
I work on polariton lasing and the application of novel spectroscopic techniques. In my free time, I enjoy the outdoors, especially hiking.
Email: mss2257@columbia.edu

Felisa Conrad-Burton
B.S. in Chemistry from George Mason University
I use time-resolved optical techniques to explore and understand the fundamental processes of new singlet fission materials. I also enjoy taking full advantage of the variety of food and Broadway shows available in NYC, as well as fattening up my fellow group members with copious amounts of homemade pie.
Email: fsc2118@columbia.edu

Yufeng Liu
B.S. in Chemistry from Fudan University
I worked on infrared photodissociation spectroscopy of cluster ions during my undergraduate. Here, bidding farewell to the gas phase and entering the regime of solid state, I resume my connection with optical experiments and clusters by exploring the electron-phonon coupling in superatomic materials. You can constantly find my practicing the piano in the lounge after work
Email: yl3983@columbia.edu

Shirell Klein
B.S. in Chemistry with minor in Studio Art from California State University, Los Angeles
In my undergrad I focused on synthesis of hybrid metal-organic framework polymer gels. Switching to the realm of optical spectroscopy, I’m planning to spend my graduate degree obsessing over magnetic materials and spin perturbations. Fluff fantasy novels are my favorite pastime. I’m also having lots of fun discovering seasons in new york.
Email: sek2221@columbia.edu

Nicholas Olsen
B.S. in Chemistry with minor in Physics from University of Utah
I crawled out of the Utah desert with a degree in chemistry and a minor in physics from the University of Utah, where I studied the crystallization of simple chiral molecules using molecular dynamics. However, I’m excited to make my return to experiment. Playing with lasers makes light work. Catch me wandering aimlessly around different neighborhoods exploring as much of the city’s culture as I can.
Email: no2331@columbia.edu

Morgan Thinel
B.S. in Honours Chemistry – Measurement from McGill University
I am from Montréal, Canada, where I obtained my B.Sc. at McGill University. At McGill, I studied a negative refractive index plasmonic metamaterial under professor Amy Blum, and acceptor-donor-acceptor molecular semiconductors under professor Dima Perepichka. I travelled south of the border to be co-sponsored in the Zhu and Pasupathy groups in order to combine optical spectroscopies with scanning tunneling microscopy to study a variety of interesting materials. Particularly, I am interested in imaging the structure and dynamics of spin and electronic states in magnetic semiconductors. When I have free time, I practice judo, go on long bike rides and indulge in video games or a science-fiction movie to relax.
Email: mt3458@columbia.edu

Yiliu Li
B.S. in Chemistry from Zhejiang University
During my undergrad at Zhejiang University, I focused on optimizing the measurement of absolute fluorescence quantum yield. In 2019, I attended the “Summer School for Silicon Nanotechnology” at UC San Diego and worked on fabricating porous silicon photonic crystal sensor. Then I find optical spectroscopy really excites me. I am planning to investigate light-matter interaction with various spectroscopic techniques. My leisure activities include hiking, painting and cooking.
Email: yl4495@columbia.edu
Past Group Members
Graduate Students
Wenjing Wu (M.A., 2020) – Graduate Student, Penn State University (Huang Group)
Andrew Schlaus (Ph.D., 2020) – Technology Specialist, Wolf, Greenfield & Sacks, P.C.
Kihong Lee (Ph.D., 2019) – Postdoc, Cornell University (Shan and Mak Groups)
Prakriti Joshi (Ph.D., 2019) – Postdoc, University of Chicago (King Group)
Xinjue Zhong (Ph.D., 2018) – Postdoc, Princeton University (Kahn Group)
Tyler Evans (Ph.D., 2018) – Sigray Inc
Timothy Atallah (Ph.D., 2017) – Postdoc, UCLA (Caram Group)
Kristopher Williams (Ph.D., 2017) – Postdoc, MIT (Tisdale Group)
Nicholas Monahan (Ph.D., 2015) – Research Scientist, ETH Zurich
Cory Nelson (Ph.D., 2015) – Intel Corporation
Xiaoxi Wu (Ph.D., 2015) – Senior Data Scientist, Pillar Biosciences
Kin-Wai Wesker Lei (Ph.D., 2014) – Novati Technologies Inc.
Adam Garland (Ph.D., 2014) – Water Lens, LLC
Joshua Morris (Ph.D., 2013) – Associate Professor, Georgia Gwinnett College
John Tritsch (Ph.D., 2013) – Intel Corporation
Kenrick Williams (Ph.D., 2012) – Lecturer, Green River College
Williams Tisdale (Ph.D., 2010) – Associate Professor, MIT
Travis Mills (Ph.D., 2009) – Associate Professor, St. Paul’s College
Loren Kaake (Ph.D. 2009) – Associate Professor, Simon Frasier University
Matthew Goertz (Ph.D., 2009) – Donaldson Company
Yang Deng (Ph.D., 2008) – L’Oreal
Chad Lindstrom (Ph.D., 2006) – Air Force Research Lab
Gregory Dutton (Ph.D., 2006) – National Institute of Justice (DOJ)
Taewoon Cha (Ph.D., 2005) – Apple, Inc.
Joo H. Kang (Ph.D., 2005) – Dow Chemical Company
Yong Seok Jun (Ph.D., 2004) – Associate Professor, Konkuk University, Korea
Ryan C. Major (Ph.D., 2003) – Hysitron, Inc.
Hanfu Wang (Ph.D., 2001) – Associate Professor, National Center for Nanoscience and Technology of China
Postdocs
Fang Liu (2016-2020) – Assistant Professor, Stanford University
Sebastian Maehrlein (2017-2020) – P.I. at Max Planck Institute
Doyk Hwang (2019-2020) – Postdoc, University of Washington (Schlenker Group)
Florian Geyer (2017-2018) – BASF
Kiyoshi Miyata (2015-2018) – Assistant Professor, Kyushu University (Onda Group)
Daniel Niesner (2014-2017) – Postdoc, University of Erlangen-Nuremberg (Fauster Group)
M. Tuan Trinh (2013-2016) – Assistant Professor, University of South Florida
Haiming Zhu (2014-2016) – Professor, Zhejiang University
Manuel Marks (2013-2015) – Bausch (Germany)
Heungman Park (2011-2013) – Assistant Professor, Texas A&M University-Commerce
Lei Shen (2009-2013) – Professor, Wuhan University of Technology
Wai-lun Chan (2009-2012) – Associate Professor, University of Kansas
A. Jailaubekov (2009-2012) – Staff Scientist, Cymer Corporation
Manuel Ligges (2010-2011) – Univ. Essen, Germany
Luis Miaja-Avila (2010-2012) – NIST, Colorado
Abe Wolcott (2010-2012) – Assistant Professor, San Jose State University
Matthias Muntwiler (2005-2009) – Group Leader, Paul Scherer Institute, Switzerland
Qinxing Yang (2007-2009) – Associate Professor, Harbin Institute of Technology, China
Vassil Boiadjiev (2000-2002) – Lecturer, Temple University
Research Scientists
Lin Zhou (2018-2019) – Associate Professor, Nanjing University