Subpicosecond stimulated Raman scattering in high-pressure hydrogen

Abstract

We studied the effect of self-phase modulation and self-focusing on transient stimulated Raman scattering in high-pressure hydrogen by using high-energy, subpicosecond laser pulses. Adding argon to the hydrogen emphasizes the effect of self-phase modulation on stimulated Raman scattering by increasing the former effect without affecting the latter. The behavior of the observed stimulated Raman scattering falls into three regimes depending on input energy: normal stimulated Raman scattering at low energies, suppression by self-phase modulation at medium energies, and a recovery at high energies because strong self-focusing limits self-phase modulation.