# Radiofrequency driving of coherent electron spin dynamics in $n$-GaAs detected by Faraday rotation

## TL;DR

This paper introduces a novel pump-probe technique using radiofrequency magnetic fields and Faraday rotation to study coherent electron spin dynamics in n-GaAs, enabling measurement of the spin coherence time T2.

## Contribution

The paper presents a new rf-based pump-probe method for semiconductor spin dynamics, allowing direct measurement of the homogeneous spin coherence time T2.

## Key findings

- Demonstrated rf-driven coherent spin precession in n-GaAs
- Resonant addressing of electron spins near Larmor frequency
- Enabled measurement of spin coherence time T2

## Abstract

We suggest a new pump-probe method for studying semiconductor spin dynamics based on pumping of carrier spins by a pulse of oscillating radiofrequency (rf) magnetic field and probing by measuring the Faraday rotation of a short laser pulse. We demonstrate this technique on $n$-GaAs and observe the onset and decay of coherent spin precession during and after the course of rf pulse excitation. We show that the rf field resonantly addresses the electron spins with Larmor frequencies close to that of the rf field. This opens the opportunity to determine the homogeneous spin coherence time $T_2$, that is inaccessible directly in standard all-optical pump-probe experiments.