Despite the tremendous developments in LC based technology and though sub-picosecond liquid crystal (LC) dynamics has been observed, its understanding is still of a fragmentary nature. The physics of ultrafast LCs dynamics, involving possible coupling between electron and molecular degrees of freedom, in fact is largely unexplored.
Changes of LC refractive index at the femtosecond time scale has been reported by inducing an ultrafast electronic Kerr response. Moreover, such an electronic excitation relaxed via coherent molecular vibrations modulating the LCs birefringence at a frequency of few THz.
The research proposed here will mainly focus on the understanding of such low-frequency phenomena across LCs phase transition from isotropic (liquid) to liquid crystal and finally solid phase. In particular, this investigation will allow to define the degree of localization in collective molecular dynamics excited with phase-stable THz pulses, answering questions such as:
- What is the nature of the collective molecular dynamics in LCs vs. single-molecular dynamics?
- Can resonant collective dynamics transiently impact on LCs electronic (charge and energy transfer) and/or structural properties (phase transition)?
- Does chirality have any impact on these processes?