Terahertz ionic Kerr effect: Two-phonon contribution to the nonlinear optical response in insulators
Materials Science
2024-07-01 v3
Abstract
The THz Kerr effect measures the birefringence induced in an otherwise isotropic material by a strong THz pulse driving the Raman-active excitations of the systems. Here we provide experimental evidence of a sizable Kerr response in insulating SrTiO3 due to infrared-active lattice vibrations. Such a signal, named ionic Kerr effect, is associated with the simultaneous excitation of multiple phonons. Thanks to a theoretical modeling of the time, polarization and temperature dependence of the birefringence we can disentangle the ionic Kerr effect from the off-resonant electronic excitations, providing an alternative tunable mechanism to modulate the refractive index on ultrashort time-scales via infra-red active phonons.
Keywords
Cite
@article{arxiv.2210.14053,
title = {Terahertz ionic Kerr effect: Two-phonon contribution to the nonlinear optical response in insulators},
author = {Martina Basini and Mattia Udina and Matteo Pancaldi and Vivek Unikandanunni and Stefano Bonetti and Lara Benfatto},
journal= {arXiv preprint arXiv:2210.14053},
year = {2024}
}