Control of carrier transport in GaAs by longitudinal-optical phonon-carrier scattering using a pair of laser pump pulses

TL;DR

This paper demonstrates optical control of carrier transport in GaAs by using a pair of femtosecond laser pulses to manipulate LO phonon-plasmon coupled modes, revealing how pulse timing affects scattering and mode dynamics.

Contribution

It introduces a method to control LO phonon-plasmon coupled modes in GaAs via femtosecond pulse timing, highlighting the influence on carrier scattering and mode relaxation.

Findings

Relaxation time depends on pump-pulse separation time.

Maximum relaxation occurs when separation matches specific phonon and plasmon periods.

Carrier-LO phonon scattering can be modulated by pulse timing.

Abstract

We demonstrate optical control of the LO phonon-plasmon coupled (LOPC) modes in GaAs by using a femtosecond pump-pulse pair. The relaxation time of the plasmon-like LOPC mode significantly depends on the separation time (\Delta t) of the pump-pulse pair. Especially it is maximized when \Delta t becomes simultaneously comparable to the half period of the longitudinal optical (LO) phonon oscillation and resonant to the 3/4 period of the plasmon-like LOPC oscillation. We attribute these observations to the modification of carrier-LO phonon scattering and ballistic motion of the plasmon-like LOPC mode.