Picosecond acoustic dynamics in stimulated Brillouin scattering

TL;DR

This paper investigates the limits of stimulated Brillouin scattering for storing optical pulses in acoustic phonons, revealing the breakdown of classical models and proposing an extended framework for ultra-short pulse dynamics.

Contribution

It identifies the limitations of the classical coupled mode formalism in describing picosecond-scale photon-phonon interactions and introduces a generalized model for such ultrafast processes.

Findings

Classical coupled mode theory breaks down for ultrashort pulses.

Proposed an extended model to accurately describe picosecond acoustic dynamics.

Potential measurable effects in Brillouin experiments with ultra-short pulses.

Abstract

Recent experiments demonstrating storage of optical pulses in acoustic phonons based on stimulated Brillouin scattering raise a number of questions about the spectral and temporal capacities of such protocols and the limitations of the theoretical frameworks routinely used to describe them. In this work, we consider the dynamics of photon-phonon scattering induced by optical pulses with temporal widths comparable to the period of acoustic oscillations. We revisit the widely adopted classical formalism of coupled modes and demonstrate its breakdown. We propose a simple extension to generalise the formulation and find potentially measurable consequences in the dynamics of Brillouin experiments involving ultra-short pulses.