Center for Relativistic Laser Science

          IBS Center for Molecular Spectroscopy and Dynamics

■        SPEAKER

Dr. Jong Min Lim (IBS Center for Molecular Spectroscopy and Dynamics, Korea University)

■        TITLE

Sub-10 fs Time-resolved Vibronic Optical Microscopy

■        ABSTRACT

We introduce femtosecond wide-field transient absorption microscopy combining sub-10 fs pump and probe pulses covering the complete visible (500−650 nm) and near-infrared (650−950 nm) spectrum with diffraction-limited optical resolution. We demonstrate the capabilities of our system by reporting the spatially- and spectrally-resolved transient electronic response of MAPbI3−xClx perovskite films and reveal significant quenching of the transient bleach signal at grain boundaries. The unprecedented temporal resolution enables us to directly observe the formation of band- gap renormalization, completed in 25 fs after photoexcitation. In addition, we acquire hyperspectral Raman maps of TIPS pentacene films with sub-400 nm spatial and sub-15 cm−1 spectral resolution covering the 100−2000 cm−1 window. Our approach opens up the possibility of studying ultrafast dynamics on nanometer length and femtosecond time scales in a variety of two-dimensional and nanoscopic systems.

■        DATE AND VENUE

March 21, 2017 (Tuesday, 5:00-6:00 p.m.)

Seminar Room 116, KU R&D Center

■        Language

Korean