Light is electromagnetic wave that propagates with the speed of light in vacuum. There are countless applications in science and engineering in which light pulses are used. In many applications, it is essential to know the temporal shape of the light wave to precisely understand the light matter interaction. The advances in femtosecond laser technology and compression technique allow us to generate few cycle laser pulses. Since the few cycle laser pulses have only a few oscillations in the pulse envelope, it is very important to know the shape of the oscillation including the absolute phase. In this presentation, the history of the light measurement will be briefly introduced. Then, the conventional pulse measurement techniques will be reviewed. Finally, the petahertz optical oscilloscope will be presented, which measure an arbitrary optical waveform with sub-cycle resolution. The petahertz optical oscilloscope uses a perturbative approach in which a weak signal field is super-posed with the fundamental laser field used for high harmonic generation. The signal field gently alters the electron trajectories in the process of high harmonic generation and thus the phase of the generated harmonic radiation. The phase shift of the harmonic radiation is proportional to the field strength of the signal pulse. Therefore, the light wave can be completely determined if one measures the phase shift of the harmonic radiation.
Research Interests :
- Attosecond pulse generation and characterization
- High harmonic generation and strong field physics
- Ultrafast pump-probe experiments in atoms, molecules and solids
- Photoelectron/ion spectroscopy
- High harmonic spectroscopy
- Strong field plasmonics
Professional Activities :
- 2014-present Group Leader, Attosecond Science Group, Center for Relativistic Laser Science,Institute for Basic Science (IBS)
- 2014-present Assistant Professor, Dept. of Physics and Photonics, Gwangju Institute of Science and Technology
- 2010-2014 Research Associate, Joint Attosecond Science Laboratory, University of Ottawa and National Research Council, Ottawa, ON, Canada (Research Advisor: Prof. Paul Corkum).
- 2008-2011 Senior Researcher, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, Korea.
- 2007-2008 Postdoctoral Fellow, Coherent X-ray Research Center, Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, Korea (Research Advisor: Prof. Chang Hee Nam)
- 2003-2007 Ph.D.,Coherent X-ray Research Center, Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, Korea (Research Advisor: Prof. Chang Hee Nam)
- 2001-2002 M.Sc., Coherent X-ray Research Center, Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, Korea (Research Advisor: Prof. Chang Hee Nam)