Second-harmonic generation studies in the SmCP phase of bent-shaped mesogens

摘要

We have studied several compounds of non-chiral mesogens composed of symmetrically and non-symmetrically bent-shaped molecular core with thermally stable ester linkages and laterally substituted by methoxy group. Recently, mesomorphic properties have been described and the SmCP (B_2) phase has been identified in a wide temperature range below the isotropic phase. Additionally, symmetrical bent-shaped mesogens exhibit the B_7 phase on cooling from the B_2 phase. Herein we concentrated on nonlinear optical properties in the observed mesophases. Second harmonic generation (SHG) supports the idea that the ground state of the B_2 phase in studied bent-shaped mesogens has antiferroelectric character and demonstrates the switching from antiferroelectric to ferroelectric state under applied electric field.