Time Resolved Four-Wave Mixing in Nanocomposites

Abstract

We elaborate methods of femtosecond time resolved spectroscopy of nanocomposites. Features of photon echo (PE) and time resolved four-wave mixing (TRFWM) signals in nanocomposites consisted of semiconductor quantum dots (QD) incorporated into nonlinear dielectric matrix are studied. In particular, impacts of value and angular distribution of permanent dipole moments (PDM) as well as their spatial dispersion on two pulse responses are under investigation. As is known, large values of permanent dipole moments are inherent to many semiconductor QDs, including ZnO QDs. Moreover, the presence of giant dipole moment in cellulose nanocrystals what reaches 4400+400 Debye has been demonstrated [1]. To the best of our knowledge, the PDM impact on the signals of time resolved four-wave mixing as a whole, and, in particular, photon echo has been yet unrevealed.