Katsuya Oguri

TL;DR: In this paper, the authors demonstrate optical driving at a petahertz frequency in the wide-bandgap semiconductor gallium nitride, which corresponds to instantaneous light-induced switching from insulator to conductor.

TL;DR: In this article, the authors constructed matrix elements of electron-light interactions for armchair and zigzag graphene nanoribbons using a tight-binding model, and showed that an incident light with a specific polarization and energy induces an indirect transition, which results in a characteristic peak in absorption spectra.

TL;DR: In this paper, optical measurements on highly doped single-layer epitaxial graphene reveal that the photoexcitation of charge carriers leads to an enhancement of the THz transmission, and the results are explained in terms of the change in the carrier scattering rate due to the optical pump fluence and the THZ electric field.

TL;DR: NIR lightwave-field-induced multiple dipole oscillations in Cr:Al2O3 in the time domain reaching PHz scale is measured by using an isolated attosecond pulse and this method shows potential for higher speed signal processing.

TL;DR: In this article, the nanohole-array size dependence of the characteristics of soft x-ray pulse generation from femtosecond-laser-produced plasma was investigated in detail.