Control of coherent optical phonon excitations in GaN using femtosecond pulse shaping

We report on the control of coherent optical phonon oscillations in GaN using the femtosecond pulse shaping technique. The enhancement or the discrimination of the E-2 phonon mode is demonstrated depending on whether or not the spectral separation of the shaped pulse matches the frequency of the phonon. The numerical calculations simulate quite well the lattice motions which are driven by shaped pulses.