2026-07-20 ミシガン大学
When two pulses of different colored lasers (the two waves at the top of the image) light meet in a new device created at the University of Michigan, researchers create a beam of electrons (small golden particles) that flows in a controllable direction. By changing the laser colors, the electron beam can sweep through different directions like the beam of a lighthouse. Image credit: Yiming Gong
＜関連情報＞
- https://news.umich.edu/electron-lighthouse-illuminates-new-physics/
- https://journals.aps.org/prl/abstract/10.1103/3v91-5pzf
量子干渉制御によって生成される方向性光電流 Directional Photocurrent Generated by Quantum Interference Control
Yiming Gong, Kai Wang, and Steven T. Cundiff
Physical Review Letters Published :16 July, 2026
DOI: https://doi.org/10.1103/3v91-5pzf
Abstract
Although the absorption of light in a bulk homogeneous semiconductor produces photocarriers with nonzero momenta, it generally does not produce a current in the absence of an applied electric field because equal amounts of carriers with opposite momenta are injected. The interference of absorption processes, for example, between one-photon and two-photon absorption can produce a current because constructive interference for carriers with one momentum can correspond to destructive interference for carriers with the opposite momentum. We show that for the interference between two-photon and three-photon absorption, the current has a narrower angular spread, i.e., a “beam” of electrons in a specified direction is produced in the semiconductor.
