  Coherent control is an optical technique to manipulate quantum states of
matter. The coherent control of 40-THz optical phonons in diamond was
demonstrated by using a pair of sub-10-fs optical pulses. The optical phonons
were detected via transient transmittance using a pump and probe protocol. The
optical and phonon interferences were observed in the transient transmittance
change and its behavior was well reproduced by quantum mechanical calculations
with a simple model which consists of two electronic levels and shifted
harmonic oscillators.
