レーザー高次高調波による分子ダイナミクスの超高速光電子分光

抄録

Laser high-order harmonics in the extreme ultraviolet (EUV) and soft X-ray region serve as a unique tool to study ultrafast molecular dynamics associated with valence or inner-shell electron excitations. The harmonics are often obtained as a train of pulses, which result in a spectrum with a comb consisting of the odd harmonic orders. However, it is often the case that isolated pulses rather than pulse trains are preferred in the conventional pump-probe spectroscopy, to avoid signal overlaps associated with different harmonic orders. Here we review our approach for the single-order harmonics generation in EUV by using dielectric multilayer mirrors and metal foils, and the application to photoelectron spectroscopy on wavepacket dynamics of simple molecules such as Br2, I2 and N2.