The influence of initial phonon states on the generation of coherent optical phonons

The generation of coherent phonons is theoretically studied using a thermal equilibrium phonon distribution as the initial condition. The time evolution of the coherent phonon amplitude and phonon population is calculated for 4.5-THz phonons with initial phonon distributions at 10 and 300 K. It is determined that the coherent-phonon amplitudes of state-selected phonons are dependent on the initial phonon distribution. The coherent-phonon amplitudes, when considering all phonon states instead of selecting certain phonon levels, are almost the same for both initial distributions. The variance of the coherent-phonon amplitudes is found to oscillate with twice the phonon frequency, and its oscillation amplitude depends on the initial phonon distribution.

Automated summary

The generation of coherent phonons is investigated using a thermal equilibrium phonon distribution as the initial condition. The study calculates the time evolution of the coherent phonon amplitude and phonon population for 4.5-THz phonons with initial distributions at 10 and 300 K. Results show that the coherent-phonon amplitudes of state-selected phonons depend on the initial phonon distribution, while considering all phonon states leads to nearly identical coherent-phonon amplitudes for both initial distributions. The variance of the coherent-phonon amplitudes oscillates with twice the phonon frequency and its oscillation amplitude depends on the initial phonon distribution.