We explore the feasibility of reducing the lifetime of longitudinal optical phonons in InP by injecting coherent longitudinal acoustic modes of frequency given by the difference between those of the longitudinal and transverse optical phonons. Calculations show that a ten-fold reduction in the lifetime can be attained using a 40 mW acoustic source. The increase in the phonon decay should reduce the scattering rate of hot electrons in fast devices. © 2002 American Institute of Physics. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/70344/2/APPLAB-80-16-2901-1.pdf