Invited Speakers

Yasuo Nabekawa (RIKEN, Japan)

Probing attosecond dynamics of molecules by an intense a-few-pulse attosecond pulse train

Title: Probing attosecond dynamics of molecules by an intense a-few-pulse attosecond pulse train
Yasuo Nabekawa

Tomoya Okino

Katsumi Midorikawa
Author: Yasuo Nabekawa, Tomoya Okino, Katsumi Midorikawa
Affiliation: Attosecond Science Research Team, RIKEN center for Advanced Photonics (RAP), RIKEN, Wako-shi, Saitama, Japan.
Email: nabekawa[at]riken.jp
URL: http://www.riken.jp/lab-www/mid-lab/staff.html
Probing attosecond dynamics of molecules by an intense a-few-pulse attosecond pulse train
(a) Top: Delay-KER spectrogram of H$^{+}$ fragments measured
using a velocity mapping imaging (VMI) spectrometer.
(b) Bottom: Magnitude square of the Fourier transform
of the delay-KER spectrogram in Fig. (a).
The advent of the coherent high-harmonic pulse in extreme ultraviolet (XUV) wavelength region generated from an intense femtosecond near infrared pulse, has made it possible to observe ultrafast dynamics of matters with a time scale less than 1 femtosecond, which is conventionally called ‘attosecond’ time scale.  The world main stream of this kind of study is based on the pump-probe measurement, in which an XUV attosecond pump/probe pulse is should be always accompanied by an intense near infrared probe/pump laser pulse because the intensity of the XUV attosecond pulse is usually so low to be utilized for the attosecond-pump and attosecond-probe measurement. In contrast, we have aimed at generating an intense attosecond pulse so as to realize the such measurement, and now developed the XUV harmonic beam line with a pulse energy more than 1 micro joule, which is sufficient for interacting with matters in both pump and probe pulses, even though the temporal profile exhibits a train of attosecond pulses in a-few-fs train envelope. In this presentation, we introduce the studies on the attosecond electronic dynamics and 10-fs nuclear dynamics in diatomic molecules, which could not be observed without using our XUV harmonic beam line.
Biographical Sketch: Yasuo Nabekawa: Senior researcher, RIKEN
He was born in1966. He received the B.S. and M.S. degrees in theoretical physics from Waseda University, Tokyo, Japan, in 1990 and 1992, respectively, and a Doctor of Engineering degree from the Graduate School of Engineering, the University of Tokyo in 2000. He worked for the Institute for Solid State Physics, University of Tokyo, until 2001, when he joined RIKEN as a researcher. He is presently a senior researcher at RIKEN.. He has worked on many fields including attosecond science and metrology, generation of intense attosecond pulse trains, high- field phenomena, and development and application of terawatt ultrafast laser systems. He is a senior member of Optical Society of America and also a member of Japan Society of Applied Physics and Laser Society of Japan.

Tomoya Okino: Researcher, Attosecond science research team at RIKEN Center for Advanced Photonics,
He received his Ph.D from the University of Tokyo in 2009. He has served as Assistant Professor at the Department of Chemistry, School of Science, the University of Tokyo from 2006 to 2012. He has been involved in the investigation of ultrafast hydrogen migration process in intense laser fields and the development of new attosecond nonlinear spectroscopic method for attosecond molecular dynamics. His current research interest is visualizing and controlling chemical reaction with attosecond temporal and sub-Angstrom spatial resolution.

Katsumi Midorikawa: Chief scientist and director of laser technology laboratory, RIKEN
He received the B. S., M. S., and Ph.D. degrees in electrical engineering from Keio University, in 1978, 1980, and 1983, respectively. In 1983, he joined laser science research group, RIKEN. Since 1997, he has been a chief scientist and director of laser technology laboratory, RIKEN. Currently, his research interests focus on ultrashort high-intensity laser-matter interaction for application to generation of coherent x-ray, including high harmonics, x-ray lasers and attosecond pulses. Dr. Midorikawa is a senior member of IEEE, a fellow of the Optical Society of America, and a member of the Japan Society of Applied Physics, the Laser Society of Japan, the physical Society of Japan, and the Institute of Electrical Engineers of Japan.