Interference of optical phonons in diamond studied using femtosecond pulses of polarized near-infrared light.

The phononic interference of optical phonons in diamond is studied via transient transmittance change measurements using the double pump–probe protocol with polarized pump pulses. With orthogonal-polarized pulses, the phonon amplitude is enhanced/suppressed if the second pump pulse is irradiated by a half-integer/integer multiple of the phonon period. This is contrary to the usual phononic interference (enhancement at integer multiples of the phonon period) observed when using parallel-polarized pulses. These observed results are well explained using a quantum-mechanical model in calculations involving the Raman tensor of the diamond lattice structure. The amplitude of the optical phonons generated via the off-diagonal term of Raman tensor is proportional to the product of the x - and y − components of the optical electric field. The phase of the phonon oscillations is dependent on the angle between the crystal orientation and the polarization of the pump pulse. • Optical phonons in diamond were coherently controlled using polarized optical pulses. • Phononic interferences under orthogonal and parallel polarized pulses were reversed. • Detected phononic interferences were well explained with the quantum model. [ABSTRACT FROM AUTHOR]