All-optical generation and detection of sub-picosecond ac spin current pulses in GaAs

TL;DR

This paper demonstrates the all-optical generation and detection of sub-picosecond ac spin current pulses in GaAs at room temperature and 90K, using quantum interference and ultrafast laser pulses, with real-time nanoscale detection.

Contribution

It introduces a novel method for generating and detecting ultrafast spin currents in GaAs using quantum interference with phase-locked laser pulses.

Findings

Successful generation of sub-picosecond ac spin current pulses in GaAs.

Real-time optical detection of electron motion at nanoscale.

Effective control of spin currents at room temperature and cryogenic conditions.

Abstract

Sub-picosecond ac spin current pulses are generated optically in GaAs bulk and quantum wells at room temperature and 90K through quantum interference between one-photon and two-photon absorptions driven by two phase-locked ultrafast laser pulses that are both circularly polarized. The dynamics of the current pulses are detected optically by monitoring in real time and real space nanoscale motion of electrons with high-resolution pump-probe techniques.