Optical dual-pulse pumping actively creates quantum-mechanical superposition of the electronic and phononic states in a bulk solid. We here made transient reflectivity measurements in an n-GaAs using a pair of relative-phase-locked femtosecond pulses and found characteristic interference fringes. This is a result of quantum-path interference peculiar to the dual-pulse excitation as indicated by theoretical calculation. Our observation reveals that the pathway of coherent phonon generation in the n-GaAs is impulsive stimulated Raman scattering at the displaced potential due to the surface-charge field, even though the photon energy lies in the opaque region.
@article{arxiv.1905.08362,
title = {Ultrafast Quantum-path Interferometry Revealing the Generation Process of Coherent Phonons},
author = {Kazutaka G. Nakamura and Kensuke Yokota and Yuki Okuda and Rintaro Kase and Takashi Kitashima and Yu Mishima and Yutaka Shikano and Yosuke Kayanuma},
journal= {arXiv preprint arXiv:1905.08362},
year = {2019}
}