Ultrafast Laser Spectroscopy and Nanomicroscopy

초고속 레이저 분광학 및 나노현미경학 연구실

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The recent emergence of 4D electron microscopy, which uniquely combines the ultrafast time resolution of femtochemistry and ultrafine spatial resolution of TEM, has opened a new era for direct visualization of atomic and molecular motions of matter. Yet, because of limited function, observations have been made to periodic (crystalline) atomic and molecular architectures and non-periodic (amorphous) objects of hundreds nanometers or bigger. In the ULSaN lab, we develop an advanced ultrafast electron microscope with invulnerable capabilities that can circumvent present limitations and promote the new methodology to a powerful platform to directly image molecular and collective motions, dissect fundamental phenomena, and deliver new concepts for specific control and global function of matter.

초고속 전자현미경은 (4D microscopy) 기존의 TEM 장비에 수 피코초 단위의 매우 높은 시간 분해능을 도입하여, 원자 또는 분자 수준에서 매우 짧은 시간에 일어나는 반응을 직접적으로 관측할 수 있다는 혁명적인 변화를 가져온 장비입니다. 물질이 동역학 반응을 일으키는 과정은 현미경을 통하여 매우 짧은 시간 분해능을 가진 일련의 사진(image)으로 기록되며, 각 사진의 변화 양상은 물질의 구조적 변화와 그 원리에 관한 정보를 제공합니다. ULSaN lab에서는 이러한 초고속 전자현미경을 새로이 구축하여 물질이 나노 수준에서 보이는 다양한 동역학 현상과 기저 원리를 해명하는 실험적 기틀을 마련하고자 합니다.


초고속 레이저 분광학 및 나노현미경학 연구실

관심분야

Femtochemistry/biology, 4D electron microscopy, Structural dynamics

희망분야

Femtochemistry/biology, 4D electron microscopy, Structural dynamics

Research Keywords and Topics

1. Development of a new UEM

The new UEM (n-UEM) in the ULSaN lab will be built with combining the two extreme capabilities of ultrafast stroboscopic imaging for reversible phenomena in UEM-2 and single-shot imaging for irreversible materials dynamics in DTEM with unprecedented spatiotemporal resolutions.

2. Femtochemistry

To investigate elementary chemical and biophysical dynamics. To do so, we will set up a robust fluorescence upconversion spectrometer and a time-correlated single photon counter, for which the femtosecond laser system coupled to the n-UEM is shared as a common light source.

3. Femtobiology

To develop methodologies that monitor the energetics of hydrogen-bondings among biological water molecules and track their in situ properties during the conformational changes of biological structures.

Research Publications
MORE

1. Science, "4D Electron Tomography", Oh-Hoon Kwon and Ahmed H. Zewail, 2010, 328, 1668-1673.

2. Science, “Dynamics of Chemical Bonding Mapped by Energy-Resolved 4D Electron Microscopy”, Fabrizio Carbone, Oh-Hoon Kwon, and Ahmed H. Zewail, 2009, 325, 181-184.

3. Matter, "Ultrafast Electron Microscopy Visualizes Acoustic Vibrations of Plasmonic Nanorods at the Interfaces", Ye-Jin Kim, Hayoon Jung, Sang Woo Han, and Oh-Hoon Kwon, 2019, 1, 481-495.

Patents

1. “Method and System for 4D Tomography and Ultrafast Scanning Electron Microscopy”, Ahmed H. Zewail, Oh-Hoon Kwon, Omar F. Mohammed, and Ding-Shyue Yang, Sep 16, 2010: US 2011/0284744 A1.​​​​​​​​​

2. “Method and System for 4D Tomography and Ultrafast Scanning Electron Microscopy”, Ahmed H. Zewail, Oh-Hoon Kwon, Omar F. Mohammed, and Ding-Shyue Yang, Nov 24, 2011: WO 2011/146084.