Impulsive stimulated Raman excitation of coherent phonons in antimony

Summary form only given. The excitation of coherent phonons in semimetals with femtosecond laser pulses has recently been investigated by several groups and accounted for by an excitation mechanism called displacive excitation of coherent phonons (DECP). DECP is considered to be different from conventional Raman processes in that it only launches fully symmetric A-phonons and that these oscillations have a cosine behavior rather than the sine behavior that is expected for impulsive stimulated Raman scattering (ISRS). In this work we re-investigated the excitation of phonons in antimony using both time-resolved and cw-Raman techniques.